This document summarizes a study investigating ultra-deep adsorptive desulfurization of diesel fuel over supported TiO2−CeO2 adsorbents. Key findings include:
1) Light irradiation of diesel fuel prior to adsorption treatment resulted in a 30-fold increase in desulfurization capacity compared to untreated fuel, achieving sulfur removal to below 1 ppmw.
2) Sulfur K-edge XANES analysis identified sulfones as the primary sulfur species on spent adsorbents, suggesting light irradiation chemically transforms original sulfur compounds.
3) Adsorption selectivity tests showed higher removal of indole and sulfones compared to thiophenes and poly
Effect of alumina support on the performance ofNan Wu
This document describes a study that investigated the effect of different alumina supports on the performance of Pt-Sn-K/γ-Al2O3 catalysts in isobutane dehydrogenation. Alumina supports were synthesized by hydrochloric acid reflux and ammonia precipitation methods. Pt-Sn-K/γ-Al2O3 catalysts were prepared using these different alumina supports. Testing found that the catalyst supported on alumina from ammonia precipitation had smaller Pt particle sizes, weaker acidity, higher activity, and better selectivity and stability for isobutene production compared to the catalyst supported on alumina from hydrochloric acid reflux.
Biomass to olefins cracking of renewable naphthapxguru
This document discusses cracking renewable naphtha produced from biomass to produce light olefins like ethylene and propylene. The biomass is first converted to a renewable naphtha fraction using a two-step process involving hydrodeoxygenation and hydrocracking. Comprehensive characterization of the renewable naphtha showed it consists mainly of paraffins suitable for steam cracking. Steam cracking this naphtha in a pilot plant yielded high amounts of ethylene (31 wt%) and propylene (17.5 wt%) while producing small amounts of byproducts. Experimental coking studies also showed this naphtha feed has attractive coking properties. Simulations predict higher run lengths compared to fossil n
The document summarizes research on a Homogeneous Combustion Catalyst called FPC. Key findings include:
1) Laboratory tests on diesel engines confirmed that FPC provides significant fuel savings and reductions in emissions such as carbon monoxide and particulate matter.
2) The research improved understanding of FPC's mechanisms for improving combustion and reducing soot formation in diesel engines.
3) FPC was also found to improve the combustion and emissions of biodiesel in diesel engines.
Hydrodeoxygenation-supported metal catalyst-lignin-aromatic monomers- A.K.Dee...Deepa A K
Pd, Pt, and Ru catalysts supported on various supports were evaluated for hydrodeoxygenation of lignin-derived phenolic compounds. Pd/SiO2-Al2O3 showed the highest activity for guaiacol HDO, achieving 99% conversion to cyclohexane within 6 hours. Pt and Ru catalysts gave similar results. The acidic SiO2-Al2O3 support promoted cleavage of the C-O bond, while neutral carbon and basic hydrotalcite supports favored ring hydrogenation over full deoxygenation. Combining metals with strongly acidic supports maximized HDO. The catalysts could be recycled with no loss of activity. HDO of phenolic mixtures mimicking lignin
Effect of Solvent Swelling on the reactivity of demineralized Turkish LigniteIJERA Editor
In this research, effect of demineralization and solvent swelling on pyrolysis kinetics was investigated. The experiments were carried out to investigate theeffects of solvent swelling with different solvents, such as THF, Pyridine and DMSO after demineralization with HCl, HNO3 and HF successively. To calculate the activation energies of lignite sample during pyrolysis, TGA analyses were performed with raw and swollen samples at 5, 10 and 20° C/min heating rates. Coast-Redfernmodel was used for the determination of kinetic parameters. According to the results, the macromolecular structure of lignite was affected from these hydrogen bonding solvents. So, the activation energies of swollen samples found to be less than the raw lignite sample for all heating rates. The reactivity of lignite samples can be ordered as follows; DMSO swollen sample > Pyridine swollen sample> THF swollen sample. Activation energy of DMSO swollen lignite sample is 10.62 kJ/mole whereas activation energies of pyridine swollen and THF swollen sample are 17.83, 25.76 kJ/mol, respectively at a heating rate of 10° C/min. The results indicated that, solvent swelling has catalytic effect on pyrolysis kinetics.
Propylene Production by Propane Dehydrogenation (PDH)Amir Razmi
In this article a description about different processes which are commercialized to produce propylene via Propane dehydrogenation were presented.
To receive more reports about cost estimation analysis and other reports (about the propylene and PDH ) contact the author.
The document discusses natural gas composition, processing, and transportation. It defines key hydrocarbon and non-hydrocarbon components in natural gas. The processing steps remove impurities like water, H2S, and CO2. Processed gas is then transported through pipelines and fractionated into products like NGL, LPG, and condensate. Major processing includes dehydration, refrigeration, and distillation. Transportation involves high pressure pipelines and LNG facilities.
Carbon dioxide reforming of methane to synthesis gas over ni la2 o3 catalystsLuciano Costa
1. The study examines carbon dioxide reforming of methane to synthesis gas over Ni/La203 catalysts.
2. In contrast to other nickel-based catalysts that continuously deactivate over time, the Ni/La203 catalyst's rate initially increases for 2-5 hours then remains stable, displaying very good longevity.
3. X-ray diffraction studies reveal a large CO2 pool accumulates on the catalyst surface from the CH4/CO2 mixture, stored as La202CO3. Results from temperature-programmed desorption show the Ni-H bond is weakened and CO disproportionation is disfavored on Ni/La203 compared to Ni/A1203.
Effect of alumina support on the performance ofNan Wu
This document describes a study that investigated the effect of different alumina supports on the performance of Pt-Sn-K/γ-Al2O3 catalysts in isobutane dehydrogenation. Alumina supports were synthesized by hydrochloric acid reflux and ammonia precipitation methods. Pt-Sn-K/γ-Al2O3 catalysts were prepared using these different alumina supports. Testing found that the catalyst supported on alumina from ammonia precipitation had smaller Pt particle sizes, weaker acidity, higher activity, and better selectivity and stability for isobutene production compared to the catalyst supported on alumina from hydrochloric acid reflux.
Biomass to olefins cracking of renewable naphthapxguru
This document discusses cracking renewable naphtha produced from biomass to produce light olefins like ethylene and propylene. The biomass is first converted to a renewable naphtha fraction using a two-step process involving hydrodeoxygenation and hydrocracking. Comprehensive characterization of the renewable naphtha showed it consists mainly of paraffins suitable for steam cracking. Steam cracking this naphtha in a pilot plant yielded high amounts of ethylene (31 wt%) and propylene (17.5 wt%) while producing small amounts of byproducts. Experimental coking studies also showed this naphtha feed has attractive coking properties. Simulations predict higher run lengths compared to fossil n
The document summarizes research on a Homogeneous Combustion Catalyst called FPC. Key findings include:
1) Laboratory tests on diesel engines confirmed that FPC provides significant fuel savings and reductions in emissions such as carbon monoxide and particulate matter.
2) The research improved understanding of FPC's mechanisms for improving combustion and reducing soot formation in diesel engines.
3) FPC was also found to improve the combustion and emissions of biodiesel in diesel engines.
Hydrodeoxygenation-supported metal catalyst-lignin-aromatic monomers- A.K.Dee...Deepa A K
Pd, Pt, and Ru catalysts supported on various supports were evaluated for hydrodeoxygenation of lignin-derived phenolic compounds. Pd/SiO2-Al2O3 showed the highest activity for guaiacol HDO, achieving 99% conversion to cyclohexane within 6 hours. Pt and Ru catalysts gave similar results. The acidic SiO2-Al2O3 support promoted cleavage of the C-O bond, while neutral carbon and basic hydrotalcite supports favored ring hydrogenation over full deoxygenation. Combining metals with strongly acidic supports maximized HDO. The catalysts could be recycled with no loss of activity. HDO of phenolic mixtures mimicking lignin
Effect of Solvent Swelling on the reactivity of demineralized Turkish LigniteIJERA Editor
In this research, effect of demineralization and solvent swelling on pyrolysis kinetics was investigated. The experiments were carried out to investigate theeffects of solvent swelling with different solvents, such as THF, Pyridine and DMSO after demineralization with HCl, HNO3 and HF successively. To calculate the activation energies of lignite sample during pyrolysis, TGA analyses were performed with raw and swollen samples at 5, 10 and 20° C/min heating rates. Coast-Redfernmodel was used for the determination of kinetic parameters. According to the results, the macromolecular structure of lignite was affected from these hydrogen bonding solvents. So, the activation energies of swollen samples found to be less than the raw lignite sample for all heating rates. The reactivity of lignite samples can be ordered as follows; DMSO swollen sample > Pyridine swollen sample> THF swollen sample. Activation energy of DMSO swollen lignite sample is 10.62 kJ/mole whereas activation energies of pyridine swollen and THF swollen sample are 17.83, 25.76 kJ/mol, respectively at a heating rate of 10° C/min. The results indicated that, solvent swelling has catalytic effect on pyrolysis kinetics.
Propylene Production by Propane Dehydrogenation (PDH)Amir Razmi
In this article a description about different processes which are commercialized to produce propylene via Propane dehydrogenation were presented.
To receive more reports about cost estimation analysis and other reports (about the propylene and PDH ) contact the author.
The document discusses natural gas composition, processing, and transportation. It defines key hydrocarbon and non-hydrocarbon components in natural gas. The processing steps remove impurities like water, H2S, and CO2. Processed gas is then transported through pipelines and fractionated into products like NGL, LPG, and condensate. Major processing includes dehydration, refrigeration, and distillation. Transportation involves high pressure pipelines and LNG facilities.
Carbon dioxide reforming of methane to synthesis gas over ni la2 o3 catalystsLuciano Costa
1. The study examines carbon dioxide reforming of methane to synthesis gas over Ni/La203 catalysts.
2. In contrast to other nickel-based catalysts that continuously deactivate over time, the Ni/La203 catalyst's rate initially increases for 2-5 hours then remains stable, displaying very good longevity.
3. X-ray diffraction studies reveal a large CO2 pool accumulates on the catalyst surface from the CH4/CO2 mixture, stored as La202CO3. Results from temperature-programmed desorption show the Ni-H bond is weakened and CO disproportionation is disfavored on Ni/La203 compared to Ni/A1203.
The document describes the carbon nanotube-gold nanohybrid (AuCNT) catalyzed N-formylation of various primary and secondary amines using aqueous formaldehyde. Key findings include:
1) AuCNT catalyzes the room temperature N-formylation of various primary and secondary amines with aqueous formaldehyde, affording formamides in excellent yields.
2) The reaction proceeds with low catalyst loading (0.34 mol%), excellent chemoselectivity, and recyclability of the AuCNT catalyst.
3) Control experiments confirm the AuCNT nanohybrid is the active catalytic species, and the reaction proceeds through a hemiaminal intermediate that is oxidized to the
Are you working on exempt VOC formulations for your coating or industrial finished goods? Learn here how the application of Dimethyl Carbonate (DMC) could give a competitive edge to your formulation. DMC received VOC Exempt status from Environment Canada last July.
This document summarizes research evaluating Pt/GMC and Pt/rGO electrocatalysts for electro-oxidation of methanol. Graphitic mesoporous carbon (GMC) and reduced graphene oxide (rGO) were synthesized and used to support platinum nanoparticles. The materials were characterized using various techniques and their electrocatalytic performance for methanol oxidation was measured via cyclic voltammetry. The results showed that Pt/GMC exhibited the highest mass activity and best resistance to carbon monoxide poisoning compared to Pt/rGO and a commercial Pt/C catalyst. Therefore, Pt/GMC demonstrated the best electrocatalytic performance for methanol electrooxidation.
Synthesis of Oxygenated Fuel Additives via Acetylation of Bio-Glycerol over H...DanesBlake
Abstract
Growing global biodiesel production demands valorization of bio-glycerol derived from biodiesel, which is crucial to make biorefinery process economical. Hence, a series of H2SO4 modified sulfonated Montmorillonite K10 catalysts were synthesized, characterized, and evaluated for acetylation of bio- glycerol with acetic acid to produce mono acetin (MAG), di acetin (DAG), tri acetin (TAG), and di-glycerol tri-acetate (DGTA), which are the oxygenated fuel additives and facilitate the economic viability of biodiesel production so the biorefinery. The synthesized catalysts were characterized by a compressive suite of characterization techniques such as powder X-ray diffraction (XRD), low temperature N2 physisorption, temperature-programmed ammonia desorption (TPAD), and Fourier transform infrared (FTIR). The glycerol conversion and product distribution results were found to correlate with the acidity and textural properties of the catalyst. 20% (w/w) SO4/K10 was revealed to be a promising catalyst for glycerol acetylation with 99% glycerol conversion and with respective yield towards MAG, DAG, TGA and DGTA of 23%, 59%, 15%, and 2%. Moreover, 20% (w/w) SO4/K10 catalyst
was found to maintain the stable catalytic activity for three reaction cycles. However, the partial catalyst deactivation was observed after third reaction cycle, partly due to deposition of coke and loss of active sites during the reaction. https://crimsonpublishers.com/pps/fulltext/PPS.000501.php
Synthesis of Oxygenated Fuel Additives via Acetylation of Bio-Glycerol over H...crimsonpublisherspps
1) The document discusses the acetylation of glycerol, a byproduct of biodiesel production, using sulfonated montmorillonite K10 catalysts.
2) A series of H2SO4-modified sulfonated montmorillonite K10 catalysts were synthesized and characterized. They were then evaluated for catalyzing the acetylation of glycerol with acetic acid to produce oxygenated fuel additives.
3) The 20% (w/w) SO4/K10 catalyst achieved 99% glycerol conversion and respective yields of 23% for MAG, 59% for DAG, 15% for TAG, and 2% for DGTA. This catalyst also maintained
This document summarizes a method for synthesizing water-soluble graphene through a three step process: 1) prereduction of graphene oxide using sodium borohydrate to remove most oxygen functionality, 2) controlled sulfonation using aryl diazonium salt to introduce sulfonic acid groups for solubility while minimally impacting graphene properties, and 3) postreduction using hydrazine to remove remaining oxygen functionality. Characterization with 13C NMR and FTIR indicates restoration of the graphene sp2 carbon network. The introduced sulfonic acid groups allow individually dispersed graphene sheets in water, maintaining stability through electrostatic repulsion.
Aluminum doped sba 15 silica as acid catalyst for the methanolysis of sunflow...Solange Quintella
The document summarizes research on using aluminum-doped SBA-15 silica materials as solid acid catalysts for the methanolysis (biodiesel production) of sunflower oil. Different Si/Al molar ratios were tested after post-synthesis alumination of SBA-15 silica. The catalyst with a Si/Al ratio of 20 achieved 96% biodiesel yield using only 10% catalyst at 200°C over 4 hours and showed good stability and recyclability. The catalysts were able to simultaneously catalyze transesterification of triglycerides and esterification of free fatty acids, even with 9% free fatty acids present.
Performance and Emission characteristics of a Single Cylinder Four Stroke Die...IJSRD
The current trends in CI engine are to use Water-diesel emulsion as alternative fuel. It can be employed directly to the existing CI Engine system with no additional modifications. This system helps in reduction of NOx as well as PM, which in turn improve the combustion efficiency of the engine. However there are still investigations have to be done. The current work mainly concentrated on diesel engine run on water-diesel emulsions and its effect on engine performance and emissions were studied. The various loads were applied on a constant speed diesel engine run on water-diesel emulsions of varying ratios of 0.2:1, 0.3:1. 0.4:1 and 0.5:1. Emission and performance characteristics were measured and were compared with base diesel operation. The emissions like NOx and smoke density were found to decrease greatly and brake thermal efficiency was found to increase at high loads. Smoke level was 4.2 BSU and 3 BSU for base diesel and water diesel emulsion of 0.4. The ignition delay was found to increase with water diesel emulsions. This also increased the maximum rate of pressure rise and peak pressure. The engine was found to run rough with water-diesel emulsions. The optimal water-diesel ratio was found to be 0.4:1 by weight. HC and CO emissions were found to increase with water diesel emulsions.
1. The document describes an experiment on reducing NOx emissions from a diesel engine fueled with Pongamia pinata methyl ester using urea injection and a marine ferromanganese nodule as a selective catalytic reduction (SCR) catalyst.
2. Tests were conducted at various urea solution concentrations (0%, 10%, 20%, 30%) and flow rates with the SCR catalyst installed. The highest NOx reduction of 64% was achieved with 30% urea solution at a flow rate of 0.60 liters/hour.
3. Marine ferromanganese nodules were selected as the SCR catalyst due to their high porosity, surface area, structural stability, and ability
Natural gas primarily consists of methane and is colorless, odorless, and clean-burning. It is found underground in sedimentary basins trapped by layers of porous and impermeable rock. Exploration uses seismic surveys to map underground formations, followed by exploratory wells to collect samples. Once deposits are located, production wells extract the gas, which is processed to remove impurities before being transported via pipelines to storage facilities and local distribution networks for delivery to customers.
This presentation summarizes the hydrotreating process. Hydrotreating reduces sulfur, nitrogen and aromatics in petroleum feeds using hydrogen. It has various applications including desulfurizing naphtha, kerosene, gas oil and fuel oils. The process involves reacting feeds over catalysts in fixed beds to hydrogenate contaminants like sulfur, nitrogen and olefins. Typical hydrotreating removes these through reactions like desulfurization and denitrogenation. The presentation describes specific hydrotreating processes for distillate desulfurization and kerosene smoke point improvement.
Ever wondered what are the chemical properties of a number of VOC Exempt Solvents – Dimethyl Carbonate, Acetone, PCBTF, TBAc, vs. other common solvents such as MEK, MIBK, IP Acetate and n-Butyl Acetate (not VOC Exempt solvents)? The case of Dimethyl Carbonate (DMC).
This environmental poster from 2010 provides data on energy use, emissions, discharges, and waste for Norwegian Continental Shelf operations in Norway and Denmark. It includes information on products produced, utilities used, emissions to air and water, spills, and waste generation. Charts show trends from 2006-2010 for CO2 and NOx emissions, oil in oily water discharges, and oil spills.
Conference for Catalysis Webinar 2021: "The Key Role of Catalysts and Adsorb...Dr. Meritxell Vila
Energy transition is a challenge for refineries and petrochemical plants. In this sense, the role of catalysts and adsorbents will be crucial in three areas:
New schemes of refineries: crude oil to chemicals (COTC)
Production of biofuels
Production of green hydrogen
This presentation was done at Catalysis Webinar 2021, the 24th March.
The document describes an emulsified heavy crude oil equipment called ECH-A that can save energy and reduce carbon emissions. ECH-A emulsifies heavy crude oil with up to 40% water to generate micro-explosions during combustion for more complete burning. Test results show that compared to heavy crude oil alone, ECH-A emulsified oil can achieve a higher oil-efficient rate of 16.19% and reduce maximum flame temperatures.
A Unique Syngas Cleanup Scheme - China Syngas to Acetic Acid James Bixby
The document describes a unique syngas cleanup scheme developed by Merichem for a Chinese client's coal-to-acetic acid plant. The scheme uses a combination of multi-stage catalytic hydrolysis and liquid redox processing to remove sulfur compounds and hydrogen cyanide from the syngas to levels below 0.1 ppm, without using zinc oxide. This is achieved through two stages of hydrolysis separated by an intermediate hydrogen sulfide removal step using a liquid redox LOCAT process, which can achieve over 99.9% H2S removal. Wastewater from the process is treated in a sour water stripper to remove hydrogen sulfide and ammonia before discharge. Initial indications are that the scheme will
The document summarizes an experimental investigation of operating a diesel engine in dual fuel mode using LPG and processed waste engine oil. Key findings from the study include:
- Performance characteristics of the engine using processed waste engine oil were comparable to diesel, while NO emissions decreased and CO/UHC increased.
- In dual fuel mode, efficiency slightly decreased while CO/UHC increased and NO/smoke decreased compared to single fuel diesel mode.
- Further work is needed to develop better waste oil processing methods and evaluate dual fuel operation with other gases like natural gas.
This document summarizes a study on the catalytic dehydration of methanol to dimethyl ether over γ-alumina. The researchers investigated the effects of temperature and feed composition on the conversion of methanol and deactivation of the catalyst. They found that methanol conversion strongly depended on the reactor operating temperature, increasing with higher temperatures. Using pure methanol as a feed resulted in slow catalyst deactivation, while adding water to the feed increased deactivation significantly. A temperature-dependent model was developed to predict methanol conversion and reasonably correlated with experimental data.
This document provides an overview of a course on petroleum gas processing. The course covers gas properties calculations, natural gas liquids extraction, liquid petroleum gas fractioning, and liquid natural gas production. It focuses on major unit process operations and some design aspects. The document reviews basic terminology and concepts, including elements, atoms, molecules, compounds, mixtures, and the periodic table. It also discusses the origin of gas and oil from organic materials buried underground, geological conditions for formation, and migration of crude oil.
This document describes a fixed bed vapor phase adsorptive desulfurization process for removing sulfur from naphtha (a type of fuel) using zeolite adsorbents. Metal ion exchanged zeolite Y adsorbents were found to selectively remove refractory organosulfur compounds from refinery naphtha. Under optimized conditions, around 54 mL of naphtha per gram of adsorbent could be treated, achieving a breakthrough sulfur concentration of 30 mg/L in the effluent with no loss of octane number. The adsorbents were fully regenerable by controlled oxidation at high temperature using diluted air, requiring no temperature swing between adsorption and regeneration cycles.
The document describes the carbon nanotube-gold nanohybrid (AuCNT) catalyzed N-formylation of various primary and secondary amines using aqueous formaldehyde. Key findings include:
1) AuCNT catalyzes the room temperature N-formylation of various primary and secondary amines with aqueous formaldehyde, affording formamides in excellent yields.
2) The reaction proceeds with low catalyst loading (0.34 mol%), excellent chemoselectivity, and recyclability of the AuCNT catalyst.
3) Control experiments confirm the AuCNT nanohybrid is the active catalytic species, and the reaction proceeds through a hemiaminal intermediate that is oxidized to the
Are you working on exempt VOC formulations for your coating or industrial finished goods? Learn here how the application of Dimethyl Carbonate (DMC) could give a competitive edge to your formulation. DMC received VOC Exempt status from Environment Canada last July.
This document summarizes research evaluating Pt/GMC and Pt/rGO electrocatalysts for electro-oxidation of methanol. Graphitic mesoporous carbon (GMC) and reduced graphene oxide (rGO) were synthesized and used to support platinum nanoparticles. The materials were characterized using various techniques and their electrocatalytic performance for methanol oxidation was measured via cyclic voltammetry. The results showed that Pt/GMC exhibited the highest mass activity and best resistance to carbon monoxide poisoning compared to Pt/rGO and a commercial Pt/C catalyst. Therefore, Pt/GMC demonstrated the best electrocatalytic performance for methanol electrooxidation.
Synthesis of Oxygenated Fuel Additives via Acetylation of Bio-Glycerol over H...DanesBlake
Abstract
Growing global biodiesel production demands valorization of bio-glycerol derived from biodiesel, which is crucial to make biorefinery process economical. Hence, a series of H2SO4 modified sulfonated Montmorillonite K10 catalysts were synthesized, characterized, and evaluated for acetylation of bio- glycerol with acetic acid to produce mono acetin (MAG), di acetin (DAG), tri acetin (TAG), and di-glycerol tri-acetate (DGTA), which are the oxygenated fuel additives and facilitate the economic viability of biodiesel production so the biorefinery. The synthesized catalysts were characterized by a compressive suite of characterization techniques such as powder X-ray diffraction (XRD), low temperature N2 physisorption, temperature-programmed ammonia desorption (TPAD), and Fourier transform infrared (FTIR). The glycerol conversion and product distribution results were found to correlate with the acidity and textural properties of the catalyst. 20% (w/w) SO4/K10 was revealed to be a promising catalyst for glycerol acetylation with 99% glycerol conversion and with respective yield towards MAG, DAG, TGA and DGTA of 23%, 59%, 15%, and 2%. Moreover, 20% (w/w) SO4/K10 catalyst
was found to maintain the stable catalytic activity for three reaction cycles. However, the partial catalyst deactivation was observed after third reaction cycle, partly due to deposition of coke and loss of active sites during the reaction. https://crimsonpublishers.com/pps/fulltext/PPS.000501.php
Synthesis of Oxygenated Fuel Additives via Acetylation of Bio-Glycerol over H...crimsonpublisherspps
1) The document discusses the acetylation of glycerol, a byproduct of biodiesel production, using sulfonated montmorillonite K10 catalysts.
2) A series of H2SO4-modified sulfonated montmorillonite K10 catalysts were synthesized and characterized. They were then evaluated for catalyzing the acetylation of glycerol with acetic acid to produce oxygenated fuel additives.
3) The 20% (w/w) SO4/K10 catalyst achieved 99% glycerol conversion and respective yields of 23% for MAG, 59% for DAG, 15% for TAG, and 2% for DGTA. This catalyst also maintained
This document summarizes a method for synthesizing water-soluble graphene through a three step process: 1) prereduction of graphene oxide using sodium borohydrate to remove most oxygen functionality, 2) controlled sulfonation using aryl diazonium salt to introduce sulfonic acid groups for solubility while minimally impacting graphene properties, and 3) postreduction using hydrazine to remove remaining oxygen functionality. Characterization with 13C NMR and FTIR indicates restoration of the graphene sp2 carbon network. The introduced sulfonic acid groups allow individually dispersed graphene sheets in water, maintaining stability through electrostatic repulsion.
Aluminum doped sba 15 silica as acid catalyst for the methanolysis of sunflow...Solange Quintella
The document summarizes research on using aluminum-doped SBA-15 silica materials as solid acid catalysts for the methanolysis (biodiesel production) of sunflower oil. Different Si/Al molar ratios were tested after post-synthesis alumination of SBA-15 silica. The catalyst with a Si/Al ratio of 20 achieved 96% biodiesel yield using only 10% catalyst at 200°C over 4 hours and showed good stability and recyclability. The catalysts were able to simultaneously catalyze transesterification of triglycerides and esterification of free fatty acids, even with 9% free fatty acids present.
Performance and Emission characteristics of a Single Cylinder Four Stroke Die...IJSRD
The current trends in CI engine are to use Water-diesel emulsion as alternative fuel. It can be employed directly to the existing CI Engine system with no additional modifications. This system helps in reduction of NOx as well as PM, which in turn improve the combustion efficiency of the engine. However there are still investigations have to be done. The current work mainly concentrated on diesel engine run on water-diesel emulsions and its effect on engine performance and emissions were studied. The various loads were applied on a constant speed diesel engine run on water-diesel emulsions of varying ratios of 0.2:1, 0.3:1. 0.4:1 and 0.5:1. Emission and performance characteristics were measured and were compared with base diesel operation. The emissions like NOx and smoke density were found to decrease greatly and brake thermal efficiency was found to increase at high loads. Smoke level was 4.2 BSU and 3 BSU for base diesel and water diesel emulsion of 0.4. The ignition delay was found to increase with water diesel emulsions. This also increased the maximum rate of pressure rise and peak pressure. The engine was found to run rough with water-diesel emulsions. The optimal water-diesel ratio was found to be 0.4:1 by weight. HC and CO emissions were found to increase with water diesel emulsions.
1. The document describes an experiment on reducing NOx emissions from a diesel engine fueled with Pongamia pinata methyl ester using urea injection and a marine ferromanganese nodule as a selective catalytic reduction (SCR) catalyst.
2. Tests were conducted at various urea solution concentrations (0%, 10%, 20%, 30%) and flow rates with the SCR catalyst installed. The highest NOx reduction of 64% was achieved with 30% urea solution at a flow rate of 0.60 liters/hour.
3. Marine ferromanganese nodules were selected as the SCR catalyst due to their high porosity, surface area, structural stability, and ability
Natural gas primarily consists of methane and is colorless, odorless, and clean-burning. It is found underground in sedimentary basins trapped by layers of porous and impermeable rock. Exploration uses seismic surveys to map underground formations, followed by exploratory wells to collect samples. Once deposits are located, production wells extract the gas, which is processed to remove impurities before being transported via pipelines to storage facilities and local distribution networks for delivery to customers.
This presentation summarizes the hydrotreating process. Hydrotreating reduces sulfur, nitrogen and aromatics in petroleum feeds using hydrogen. It has various applications including desulfurizing naphtha, kerosene, gas oil and fuel oils. The process involves reacting feeds over catalysts in fixed beds to hydrogenate contaminants like sulfur, nitrogen and olefins. Typical hydrotreating removes these through reactions like desulfurization and denitrogenation. The presentation describes specific hydrotreating processes for distillate desulfurization and kerosene smoke point improvement.
Ever wondered what are the chemical properties of a number of VOC Exempt Solvents – Dimethyl Carbonate, Acetone, PCBTF, TBAc, vs. other common solvents such as MEK, MIBK, IP Acetate and n-Butyl Acetate (not VOC Exempt solvents)? The case of Dimethyl Carbonate (DMC).
This environmental poster from 2010 provides data on energy use, emissions, discharges, and waste for Norwegian Continental Shelf operations in Norway and Denmark. It includes information on products produced, utilities used, emissions to air and water, spills, and waste generation. Charts show trends from 2006-2010 for CO2 and NOx emissions, oil in oily water discharges, and oil spills.
Conference for Catalysis Webinar 2021: "The Key Role of Catalysts and Adsorb...Dr. Meritxell Vila
Energy transition is a challenge for refineries and petrochemical plants. In this sense, the role of catalysts and adsorbents will be crucial in three areas:
New schemes of refineries: crude oil to chemicals (COTC)
Production of biofuels
Production of green hydrogen
This presentation was done at Catalysis Webinar 2021, the 24th March.
The document describes an emulsified heavy crude oil equipment called ECH-A that can save energy and reduce carbon emissions. ECH-A emulsifies heavy crude oil with up to 40% water to generate micro-explosions during combustion for more complete burning. Test results show that compared to heavy crude oil alone, ECH-A emulsified oil can achieve a higher oil-efficient rate of 16.19% and reduce maximum flame temperatures.
A Unique Syngas Cleanup Scheme - China Syngas to Acetic Acid James Bixby
The document describes a unique syngas cleanup scheme developed by Merichem for a Chinese client's coal-to-acetic acid plant. The scheme uses a combination of multi-stage catalytic hydrolysis and liquid redox processing to remove sulfur compounds and hydrogen cyanide from the syngas to levels below 0.1 ppm, without using zinc oxide. This is achieved through two stages of hydrolysis separated by an intermediate hydrogen sulfide removal step using a liquid redox LOCAT process, which can achieve over 99.9% H2S removal. Wastewater from the process is treated in a sour water stripper to remove hydrogen sulfide and ammonia before discharge. Initial indications are that the scheme will
The document summarizes an experimental investigation of operating a diesel engine in dual fuel mode using LPG and processed waste engine oil. Key findings from the study include:
- Performance characteristics of the engine using processed waste engine oil were comparable to diesel, while NO emissions decreased and CO/UHC increased.
- In dual fuel mode, efficiency slightly decreased while CO/UHC increased and NO/smoke decreased compared to single fuel diesel mode.
- Further work is needed to develop better waste oil processing methods and evaluate dual fuel operation with other gases like natural gas.
This document summarizes a study on the catalytic dehydration of methanol to dimethyl ether over γ-alumina. The researchers investigated the effects of temperature and feed composition on the conversion of methanol and deactivation of the catalyst. They found that methanol conversion strongly depended on the reactor operating temperature, increasing with higher temperatures. Using pure methanol as a feed resulted in slow catalyst deactivation, while adding water to the feed increased deactivation significantly. A temperature-dependent model was developed to predict methanol conversion and reasonably correlated with experimental data.
This document provides an overview of a course on petroleum gas processing. The course covers gas properties calculations, natural gas liquids extraction, liquid petroleum gas fractioning, and liquid natural gas production. It focuses on major unit process operations and some design aspects. The document reviews basic terminology and concepts, including elements, atoms, molecules, compounds, mixtures, and the periodic table. It also discusses the origin of gas and oil from organic materials buried underground, geological conditions for formation, and migration of crude oil.
This document describes a fixed bed vapor phase adsorptive desulfurization process for removing sulfur from naphtha (a type of fuel) using zeolite adsorbents. Metal ion exchanged zeolite Y adsorbents were found to selectively remove refractory organosulfur compounds from refinery naphtha. Under optimized conditions, around 54 mL of naphtha per gram of adsorbent could be treated, achieving a breakthrough sulfur concentration of 30 mg/L in the effluent with no loss of octane number. The adsorbents were fully regenerable by controlled oxidation at high temperature using diluted air, requiring no temperature swing between adsorption and regeneration cycles.
Study of the Sulfur Trioxide Generation Mechanism and Control Method Using We...inventionjournals
In coal fired power plant, especially using sulfur content fossil fuels, much attention in recently paid to sulfur trioxide and sulfuric acid mist emission, because conventional desulfurization system should not be removed, which is installed to meet air quality standard for sulfur dioxide. Sulfur trioxide is highly reactive with water vapor and generally convert to sulfuric acid mist in atmosphere. Sulfuric acid is very fine under-submicron sized particulate matter or droplets. Recently sulfur trioxide cause air pollution and public health, discussion comes out, especially in the United States and Japan, that regulations and guideline should be enlarge the sulfur dioxide to sulfur trioxide and sulfuric acid. Moreover most countries reinforce sulfur oxides emission regulations or guidelines from coal-fired power plant. In this study, focusing that how to control the sulfur trioxide and sulfuric acid mist. Sulfuric acid mist found depending on the flue gas temperature. Generation and conversion rate of sulfur trioxide were measured according to temperature. The absorbent was selected to remove sulfur trioxide and sulfuric acid using wet type desulfurization system which the most proven technology at this moment.
Graphene oxide immobilized copper phthalocyanine tetrasulphonamide: the first...Pawan Kumar
The first successful synthesis of DMC directly from methanol and carbon dioxide using a heterogenized
homogeneous graphene oxide immobilized copper phthalocyanine tetrasulphonamide catalyst in the
presence of N,N0-dicyclohexylcarbodiimide (DCC) as a dehydrating agent is described. The presence of a
dehydrating agent was found to be vital and in its absence the yield of DMC was found to be decreased
significantly. Under the optimized reaction conditions, the maximum yield of DMC reaches up to 13.3%.
Although the homogeneous copper phthalocyanine tetrasulphonamide catalyst provided a little higher
yield of DMC (14.2%), the facile recovery and recycling ability of the heterogeneous catalyst make the
developed method more attractive from environmental and economical viewpoints.
This document describes a study that used ultrasound-assisted oxidative desulfurization (UAOD) and mixing-assisted oxidative desulfurization (MAOD) to remove sulfur from synthetic oil. Different polyoxometalate catalysts were tested in the oxidation of benzothiophene and dibenzothiophene using hydrogen peroxide as the oxidant. Results showed that sodium phosphotungstate was the most effective catalyst. Both UAOD and MAOD achieved high oxidation rates that correlated well with pseudo-first order kinetics and the Arrhenius equation. MAOD performed comparably to UAOD with lower energy requirements, indicating potential for scale-up.
Kinetics and feasibility studies of thiol oxidation using magnetically separa...Pawan Kumar
This work describes kinetic studies of the catalytic oxidation of thiols (RSHs) found in kerosene to disulphides using a magnetically separable iron oxide coated Mg-Al layered double hydroxide supported tetra-sulphonated cobalt phthalocyanine (CoPcS/LDH@Fe3O4) catalyst in an alkali-free environment. Using 1-octanethiol as a representative RSH, we investigated the effects of different experimental parameters on RSH oxidation kinetics, including catalyst concentration, temperature (30–60 °C), and initial thiol concentration ([RSH]0, 100–300 ppm). The catalyst concentration was varied so that the [RSH]0/[Co]tot molar ratio ranged from 45 to 180. Based on the results, we propose a mechanistic rate expression to explain the observed oxidation of RSH in the presence of the CoPcS/LDH@Fe3O4 catalyst. The proposed rate law resembles double substrate Michaelis-Menten kinetics, however, for commonly …
Kinetics and feasibility studies of thiol oxidation using magnetically separa...Pawan Kumar
This research article studies the kinetics of catalytic oxidation of thiols to disulfides using a novel magnetically separable catalyst. The catalyst contains cobalt phthalocyanine grafted onto an iron oxide-coated layered double hydroxide supported on magnetic iron oxide nanoparticles. Experiments were conducted to investigate the effects of various parameters on thiol oxidation kinetics, including catalyst concentration, temperature, and initial thiol concentration. Kinetic data was analyzed to propose a rate law that could be used to design industrial reactors for an alkali-free sweetening process.
Visible light driven photocatalytic oxidation of thiols to disulfides using i...Pawan Kumar
The present paper describes the synthesis of graphene oxide immobilized iron phthalocyanine (FePc) for
the photocatalytic oxidation of thiols to disulfides under alkaline free conditions. Iron phthalocyanine
tetrasulfonamide was immobilized on carboxylated graphene oxide supports via covalent attachment.
The loading of FePc on GO nanosheets was confirmed by FTIR, Raman, ICP-AES, UV-Vis and elemental
analyses. The synthesized catalyst was found to be highly efficient for the photo-oxidation of thiols to
disulfides in aqueous medium using molecular oxygen as oxidant under visible light irradiation. The
identification of photo-oxidation products and their quantitative determination was done using GC-MS.
After completion of the reaction, the catalyst was easily recovered by filtration and reused for several
runs without loss in activity and no leaching was observed during the reaction
Kinetics and feasibility studies of thiol oxidation using magnetically separa...Pawan Kumar
This work describes kinetic studies of the catalytic oxidation of thiols (RSHs) found in kerosene to disulphides
using a magnetically separable iron oxide coated Mg-Al layered double hydroxide supported tetra-sulphonated
cobalt phthalocyanine (CoPcS/LDH@Fe3O4) catalyst in an alkali-free environment. Using 1-octanethiol as a representative
RSH, we investigated the effects of different experimental parameters on RSH oxidation kinetics, including
catalyst concentration, temperature (30–60 °C), and initial thiol concentration ([RSH]0, 100–300 ppm).
The catalyst concentration was varied so that the [RSH]0/[Co]tot molar ratio ranged from 45 to 180. Based on
the results, we propose a mechanistic rate expression to explain the observed oxidation of RSH in the presence
of the CoPcS/LDH@Fe3O4 catalyst. The proposed rate law resembles double substrate Michaelis-Menten kinetics,
however, for commonly encountered industrial conditions, we were able to simplify it to a linear form. This rate
law for RSH oxidation can be used to design industrial reactors for an alkali-free sweetening process.
Advancements in diesel desulphurization pdfSaifullah Azam
The document discusses various techniques for desulfurizing diesel fuel, including hydrodesulfurization (HDS), oxidative desulfurization (ODS), and adsorptive desulfurization. HDS is the primary industry standard method and can remove 80-98% of sulfur using catalysts like nickel, molybdenum, and cobalt at high temperatures and pressures. ODS uses oxidizing agents like hydrogen peroxide to convert sulfur compounds into extractable sulfones at milder conditions than HDS. The document concludes that adsorptive desulfurization may be the most economical and environmentally friendly method after further optimization to achieve full desulfurization.
Development of Mesoporous Materials and Noble Metal Based Hydrodesulfurizatio...Lebong Andalaluna
The document discusses the development of mesoporous materials and noble metal-based hydrodesulfurization catalysts. It was found that Pt supported on acidic mesoporous materials like SiAlMCM-41 showed high catalytic activity for thiophene hydrodesulfurization that was higher than commercial CoMo/Al2O3 catalysts. Pt supported on moderately acidic SiAlMCM-41 (Si/Al=15) exhibited particularly high activity. The acidic properties of the MCM-41 support and the spillover hydrogen on Pt particles in Pt/MCM-41 catalysts were found to play an important role in thiophene hydrodesulfurization.
Combustion synthesis was used to prepare cobalt catalysts supported on alumina and silica-doped alumina for Fischer-Tropsch synthesis. Compared to catalysts made by conventional impregnation, the combustion-synthesized catalysts had smaller cobalt crystallite sizes of 17-18 nm, higher cobalt reduction levels over 92%, and higher metal dispersion of 16.1%. In Fischer-Tropsch testing, the combustion-synthesized catalysts produced 40-70% more C6+ hydrocarbons and formed longer hydrocarbon chain waxes compared to middle distillates, indicating higher chain growth probability. Silica-doped alumina as a support gave 12-13% higher C6+ yields than al
This document describes the development of a lean NOx trap (LNT) catalyst that does not require precious metals. It proposes using ultrasmall nanoparticles of iron, vanadium, and cerium oxides as the active catalytic components, supported on a porous barium oxide substrate. During lean exhaust conditions, NOx would be oxidized and stored as nitrates in the barium oxide. Under brief rich conditions, the stored NOx would be reduced to N2 via reactions with hydrocarbons facilitated by the redox activity of the iron, vanadium, and cerium oxides. Laboratory testing of prototypes made with this design could evaluate the catalyst's performance versus EPA emissions standards at reducing temperatures compared to conventional precious metal-based
This document discusses refinery processes for upgrading heavy oils into clean transportation fuels. As petroleum supplies become heavier and more sour, refineries need improved processes like hydrodesulfurization (HDS) to remove sulfur. The document outlines several HDS approaches, including conventional HDS using sulfided CoMo/Al2O3 and NiMo/Al2O3 catalysts. It also discusses new generation HDS catalysts needed to meet stringent low-sulfur fuel standards. Modifying catalyst supports and developing advanced structured catalysts may improve HDS efficiency to allow deep desulfurization of refinery streams.
This document summarizes a study investigating the kinetics of the liquid-liquid-solid phase transfer catalyzed synthesis of dibenzyl disulfide (DBDS) using hydrogen sulfide (H2S) absorbed in monoethanolamine (MEA) and benzyl chloride (BC) as reactants. Amberlite IR-400 resin is used as a heterogeneous phase transfer catalyst. The effects of various parameters such as stirring speed, sulfur loading, and catalyst concentration on the conversion of BC were examined. Optimal conditions for 100% selectivity of DBDS product were determined. A reaction mechanism and kinetic model are proposed to explain the reaction.
The document describes the gasification process for producing synthesis gas (syngas) from coal. Gasification involves partially combusting coal under controlled conditions to produce a gaseous mixture of carbon monoxide, hydrogen, carbon dioxide, and other gases. This syngas can then be further processed to produce alternative fuels like methanol, dimethyl ether (DME), and liquid hydrocarbons. The document provides details on the fabrication and design of a gasifier, the chemical reactions involved, and the composition and applications of syngas. It concludes that syngas production from Pakistan's indigenous coal resources could provide an economical and environmentally-friendly alternative fuel.
This document summarizes a study that investigated the effect of granulation on the activity and stability of a Co-Al2O3 aerogel catalyst for methane-carbon dioxide reforming in a fluidized-bed reactor. The aerogel catalyst was granulated using ethanol as a binding agent to improve its fluidization properties. Testing found that granulation significantly improved the catalytic performance of the aerogel catalyst, giving it better stability and higher methane conversion compared to the non-granulated catalyst. The improved performance was attributed to the better fluidization quality achieved through granulation.
Lecture 4 (H2SO4), it is manufacturing and descriptionnewarqadir51
This document discusses the production of sulfuric acid through the contact process. It begins by describing the properties of sulfuric acid and how it is sold. It then discusses how earlier plants were simpler but modern plants recover energy through cogeneration. The contact process is described, including the exothermic reaction of SO2 to SO3, how temperature and equilibrium affect conversion, and the multi-pass converter design. Catalyst materials and converter design are also covered. Finally, it briefly discusses how SO3 is absorbed into sulfuric acid in the absorption tower to form oleum.
Lecture 4 (H2SO4), it is manufacturing and descriptionnewarqadir51
This document discusses the production of sulfuric acid through the contact process. It begins by describing the properties of sulfuric acid and how it is sold. It then discusses how earlier plants were simpler but modern plants recover energy through cogeneration. The contact process is described, including the exothermic reaction of SO2 to SO3, how temperature and equilibrium affect conversion, and the multi-pass converter design. Catalyst materials and converter design are also covered. Finally, it briefly discusses how SO3 is absorbed into sulfuric acid in the absorption tower to form oleum.
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELgerogepatton
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
International Conference on NLP, Artificial Intelligence, Machine Learning an...gerogepatton
International Conference on NLP, Artificial Intelligence, Machine Learning and Applications (NLAIM 2024) offers a premier global platform for exchanging insights and findings in the theory, methodology, and applications of NLP, Artificial Intelligence, Machine Learning, and their applications. The conference seeks substantial contributions across all key domains of NLP, Artificial Intelligence, Machine Learning, and their practical applications, aiming to foster both theoretical advancements and real-world implementations. With a focus on facilitating collaboration between researchers and practitioners from academia and industry, the conference serves as a nexus for sharing the latest developments in the field.
ACEP Magazine edition 4th launched on 05.06.2024Rahul
This document provides information about the third edition of the magazine "Sthapatya" published by the Association of Civil Engineers (Practicing) Aurangabad. It includes messages from current and past presidents of ACEP, memories and photos from past ACEP events, information on life time achievement awards given by ACEP, and a technical article on concrete maintenance, repairs and strengthening. The document highlights activities of ACEP and provides a technical educational article for members.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
2. new selective desulfurization approaches for ultraclean fuel with
sulfur content less than 1 ppmw from current commercial diesel
fuel.
In our recent communication,21
we proposed a new
approach for ultra-deep desulfurization of diesel fuel with a
superior desulfurization capacity, in which the original fuel was
treated by light irradiation before it was desulfurized by
adsorption over the TiO2−CeO2/MCM-48 adsorbent under
ambient conditions. Yet the mechanism of ultra-deep
desulfurization remains unclear. Remaining questions include:
What is the sulfur chemistry involved in ADS and how it affects
desulfurization capacity? What is the effect of support for
TiO2−CeO2? How is the regenerability of the adsorbent? What
is a feasible process configuration? As a follow-up, a detailed
study of ultra-deep adsorptive desulfurization from light-
irradiated diesel fuel over supported TiO2−CeO2 adsorbents
was carried out in this work. Sulfur K-edge X-ray absorption
near-edge structure (XANES) spectroscopy was used to
identify sulfur species on the spent supported TiO2−CeO2
adsorbent. Adsorption selectivity of different compounds in a
model fuel, including sulfone, nitrogen- and sulfur- containing
heteroatom compounds, and aromatics over the supported
TiO2−CeO2 adsorbent was studied. Dipole magnitude of
various sulfur compounds was calculated. Various supports with
different PZC values and surface areas were used to prepare
supported TiO2−CeO2 adsorbents and compared on the basis
of desulfurization performance evaluated in a fixed-bed flow
sorption system under ambient conditions using a commercial
diesel fuel with a sulfur content of 14.5 ppmw. Regenerability of
TiO2−CeO2/MCM-48 adsorbent was also examined. A
conceptual process for ultra-deep desulfurization of diesel fuel
was proposed.
2. EXPERIMENTAL SECTION
2.1. Materials. Support. Al2O3 and TiO2 were purchased
from Aldrich Chemical Co. Silica material of EH-5 was
provided by Cabot Co. AC-WPH was provided by Calgon,
Co. Mesoporous silica supports, including SBA-15, MCM-41,
and MCM-48, were synthesized in our laboratory by a
hydrothermal method.22
Supported TiO2−CeO2 Adsorbents. The supported TiO2−
CeO2 adsorbents were prepared by incipient wetness
impregnation assisted with ultrasound7
using cerium ammo-
nium nitrate (NH4)2Ce(NO3)6 (Aldrich, 99.99%), titanium
oxysulfate TiOSO4·xH2SO4·xH2O (Aldrich, Ti: 20 wt %) as
metal precursors. The molar ratio of Ti:Ce was 9:123
and the
optimized loading amount of TiO2−CeO2 was 13.3 wt % as
indicated in Supporting Information Figure S1. The sample of
bulk TiO2−CeO2 mixed oxides with a molar ratio of Ti:Ce of
9:1 prepared by urea coprecipitation was used as a reference.
The preparation procedure of TiO2−CeO2 mixed oxides was
described elsewhere.23
2.2. Fuels. Diesel Fuel. The low-sulfur diesel fuel with 14.5
ppmw sulfur was supplied by BP America. The composition
was reported elsewhere.7
Light Irradiation of Diesel Fuel. Diesel fuel was loaded and
constantly stirred in a two-necked flat-bottom flask, and
irradiated with a Hamamatsu 150 W xenon lamp. A constant
air flow at 10 mL/min was bubbled into the fuel
simultaneously. Peroxides with a concentration of 12 mmol/
kg,21
as monitored with a Milwaukee MI490 peroxide
photometer, was generated in the diesel fuel by light irradiation
that mimics sunlight with light intensity of 65.1 mW/cm2
for
9.6 h at 25 °C (controlled by a water bath), which is denoted as
light-irradiated diesel fuel in this study. It should be noted that
peroxides generation in the fuel is strongly dependent on the
irradiation time and light intensity applied but insensitive to the
photon energy (or wavelength) as reported in our recent
letter.21
Also the rate of peroxides generation can be improved
by increasing temperature, as shown in Figure 1. Neither a
catalyst nor an adsorbent was added during the light irradiation
of fuel.
Model Fuel. To study the adsorption selectivity of different
compounds over TiO2−CeO2/MCM-48 adsorbent, a model
fuel (MDF) containing the same molar concentration (3.12
μmol/g) of benzothiophene (BT), dibenzothiophene (DBT),
4-methyldibenzothiophene (4-MDBT), 4,6-dimethyldibenzo-
thiophene (4,6-DMDBT), dibenzothiophenesulfone (DBTO2),
indole, naphthalene (Nap), fluorene (Flu), 2-methylnaphtha-
lene (MNap), and phenanthrene (Phe) in a mixed solvent was
prepared. The composition of the model fuel is listed in Table
1. The model fuel also contained 8.0 wt % of tert-butyl benzene
to mimic the monoaromatics in real diesel and 2 wt % of furan
as fuel additives. All the chemicals were purchased from Sigma-
Aldrich and were used as received.
2.3. Adsorption Tests. The ADS was performed at 25 °C
in a fixed-bed flow adsorption system with a stainless steel
column (4.6 mm I.D. × 75 mm length, bed volume of 1.25
mL). A given amount (i.e., 0.25 g for TiO2−CeO2/MCM-48)
of the adsorbent was packed into the column and treated under
air flow at 120 °C for 2 h. The fuel was then fed by a HPLC
pump at a flow rate of 0.2 mL/min (i.e., a LHSV of 9.6 h−1
).
The effluent fuel was periodically collected at an interval of 15−
20 min for analysis. The total sulfur concentration of the
treated fuel samples was analyzed using ANTEK 9000 series
sulfur analyzer. The sulfur compounds in the initial and treated
fuels were analyzed using a Hewlett-Packard gas chromato-
graph equipped with a sulfur-selective, pulsed flame photo-
metric detector (GC-PFPD). A detailed analysis method was
reported in a previous study.24
For the adsorption selectivity
study, concentrations of different compounds in treated MDF
samples were analyzed by a gas chromatograph (Varian CP
3800) equipped with a flame ionization detector (FID). A
detailed analysis method has been reported previously.25
2.4. Characterization. Sulfur K-edge XANES. Sulfur K-
edge (2472.0 eV) X-ray absorption near edge structure
(XANES) spectroscopic measurements of spent adsorbents
were performed at Beamline 9-BM/XOR of the Advanced
Photon Source (APS) at Argonne National Laboratory. The
storage ring was operated with an electron beam of 7 GeV and
an electron current of 100 mA in a top-up mode. The
Figure 1. Amount of peroxides (mmol-peroxides/kg) generated in
diesel fuel under light irradiation that mimics sunlight at an air flow
rate of 10 mL/min at 25, 50, and 100 °C_dark.
Industrial & Engineering Chemistry Research Article
dx.doi.org/10.1021/ie402724q | Ind. Eng. Chem. Res. 2013, 52, 15746−1575515747
3. monochromator was double-crystal Si(111), and the XANES
spectra were collected in fluorescence mode with a Si DRIFT 4-
element detector (Vortex). Air absorption was controlled by
the use of helium purging in the incident light path and the
sample chamber, which were separated by a 5 μm thick
polycarbonate window. The monochromator crystals had an
energy resolution of approximately 0.3 eV at 2.5 KeV.
Harmonics were rejected by use of a Rh-coated flat mirror in
the experimental station. The beam was focused to a spot size
of approximately 1 mm in the horizontal and vertical directions
by the use of a Rh-coated toroidal mirror.26
To avoid further
oxidation, the spent adsorbent was sealed in the adsorption
column after ADS experiment and transferred to and sealed in a
sample cell with a propylene window, which allows for XANES
measurements of liquid or volatile samples. Energy calibration
was accomplished by setting the edge energy of elemental sulfur
to 2472.0 eV. Reference compounds, 4,6-DMDBT and DBTO2
were diluted in sulfur-free fuel, resulting in a concentration of
1−2 wt %. Up to 5 scans were collected and averaged to
improve the signal-to-noise ratio. XANES data were processed
using Athena.27
N2 Adsorption Test. Textural properties of adsorbents were
measured by nitrogen adsorption/desorption at −196 °C using
an ASAP2020 analyzer (Micromeritics). The surface area and
pore volume were calculated using BET method28,29
and the
amount of nitrogen adsorbed at P/P0 = 0.95, respectively. The
pore size distribution was determined according to density
functional theory (DFT) method.30
Prior to each measure-
ment, all samples were outgassed at 150 °C for 12 h.
Zeta Potential Measurement. The zeta potential distribu-
tions were obtained using a Brookhaven ZetaPALS zeta
potential analyzer, and the point of zero charge (PZC) of
various supports was calculated on the basis of the distribution
curves.
2.5. Molecular Calculation. The dipole magnitude of
different sulfur compounds examined in this study was
calculated by a semiempirical quantum chemistry method,
PM3 in Hyperchem 7.0. The PM3 method determines both the
optimum geometry and electronic properties of molecules by
solving the Schrödinger equation using the PM3 semiempirical
Hamiltonians developed by Stewart.31,32
3. RESULTS AND DISCUSSION
3.1. Promoting Effect of Light Irradiation of Diesel
Fuel on ADS. In order to examine the effect of light irradiation
of diesel fuel on ultra-deep adsorptive desulfurization (ADS),
ADS tests over the MCM-48-supported TiO2−CeO2 adsorbent
from the regular and light-irradiated diesel fuel were compared.
Figure 2 shows the breakthrough capacity of total sulfur
compounds over the MCM-48-supported TiO2−CeO2 adsorb-
ent from the two diesel fuels under ambient conditions. Over
30 times greater ADS capacity (1.143 mg-S/g-sorb or 95 mL-
F/g-sorb) of light-irradiated diesel fuel was achieved as
compared to that of the original diesel fuel (0.036 mg-S/g-
sorb or 3 mL-F/g-sorb) at a breakthrough point of 1 ppmw-S.
The same trend is noticed at a breakthrough point of 4 ppmw-
S, as ADS capacity reaches 1.432 mg-S/g-sorb (or 119 mL-F/g-
sorb) from the light-irradiated diesel fuel, whereas it is 0.170
mg-S/g-sorb (or 14 mL-F/g-sorb) for the original fuel. The
sharp contrast clearly indicates a strong promotion effect of the
light irradiation of diesel fuel on ADS over the MCM-48-
supported TiO2−CeO2 adsorbent.
To clarify the possible change in sulfur chemistry due to the
light irradiation of diesel fuel, sulfur compounds on the spent
MCM-48-supported TiO2−CeO2 adsorbent after ADS were
examined by XANES at the sulfur K-edge, which is a powerful
tool to provide detailed information of the adsorbed sulfur
species on the spent adsorbent/catalyst.26
Figure 3 shows sulfur
K-edge XANES spectra of the spent TiO2−CeO2/MCM-48
adsorbent and two reference compounds, 4,6-DMDBT and
DBTO2. Interestingly, no initial refractory sulfur compounds,
such as 4,6-DMDBT were present on the spent MCM-48-
supported TiO2−CeO2 adsorbent. Instead, the major sulfur
species were sulfone species having almost the same white line
position as the reference compound, DBTO2. The result
provides direct evidence that the initial refractory sulfur
compounds in diesel are chemically transformed to sulfone
species during ADS and adsorbed over the MCM-48-supported
TiO2−CeO2 adsorbent, which further supports our earlier
hypothesis on chemical transformation of sulfur compounds
Table 1. Composition of the Model Diesel Fuel
concentration
chemicals wt.% ppmw S or N
molar concentration
(μmol/g)
sulfur compounds
BT (99%) 0.042 100.0 3.12
DBT (98%) 0.058 100.0 3.12
4-MDBT (96%) 0.063 100.0 3.12
4,6-DMDBT (97%) 0.067 100.0 3.12
DBTO2 (97%) 0.068 100.0 3.12
nitrogen compounds
indole (≥99%) 0.038 43.8 3.12
aromatics
Nap (99%) 0.040 3.12
Flu (98%) 0.053 3.12
MNap (97%) 0.045 3.12
Phe (98%) 0.057 3.12
tert-butylbenzene
(99%)
8.0
paraffins
n-decane (≥99%) 44.7
n-hexadecane
(≥99%)
44.7
n-tetradecane (98%) 0.063 (internal
standard)
3.12
additives
furan (98%) 2.0
total 100.0
Figure 2. Desulfurization capacity of TiO2−CeO2/MCM-48 adsorb-
ent for the original and light-irradiated diesel fuel at breakthrough
(B.T.) points of 1 ppmw-S and 4 ppmw-S at 25 °C and LHSV of 9.6
h−1
.
Industrial & Engineering Chemistry Research Article
dx.doi.org/10.1021/ie402724q | Ind. Eng. Chem. Res. 2013, 52, 15746−1575515748
4. during ADS using the indirect evidence of detected sulfone
species with GC-PFPD in acetone solvent washing of the spent
MCM-48-supported TiO2−CeO2 adsorbent.21
It should be
noted that sulfones were formed in the adsorption step rather
than the irradiation step, as no sulfones were detected in the
light-irradiated fuel from the GC-PFPD analyses.21
The
irradiation step is accompanied by air bubbling through the
fuel. Therefore, besides peroxide generation, some side
oxidation reactions may take place, which can be indicated by
the fuel color change to more yellowish or brownish.33
In our
system, the fuel color change before and after irradiation was
almost invisible, and only a trace amount of peroxides (12
mmol/kg) was generated under the current irradiation
conditions, as can also be seen in Figure 1. Thus, the change
in the fuel properties induced by light irradiation under air-
bubbling should be negligible. The in situ generated peroxides
during light irradiation of diesel fuel were suggested as the
oxygen source for the later chemical transformation of sulfur
compounds during ADS over the MCM-48-supported TiO2−
CeO2 adsorbent. Therefore, besides being an adsorbent, the
MCM-48-supported TiO2−CeO2 seems to act as a catalyst for
the oxidation of the sulfur compounds to sulfone species during
ADS under ambient conditions. It should also be mentioned
here that using supported metal oxides-based catalysts for
catalytic oxidative desulfurization (ODS) under mild reaction
conditions has been reported in the literature. Chica et al.
studied the Ti-MCM-41 catalyst using tert-butyl hydroperoxide
as oxidant for ODS of diesel fuel at 80 °C.33
Sundararaman et
al. studied silica supported MoO3 using in situ catalytically
generated hydroperoxides for ODS of diesel and jet fuels at 85
°C.34
Here, our result indicates that under ambient conditions,
MCM-48-supported TiO2−CeO2 adsorbent may serve as a
catalyst for oxidation of the sulfur compounds in diesel fuel.
In the literature, there are reported adsorbents for ADS from
model fuels and high sulfur fuels achieving high ADS capacity.
It was reported that Cu+
and Ag+
exchanged zeolite Y can
adsorb sulfur compounds from a commercial 430 ppmw-S
diesel by π complexation under ambient conditions with a
capacity of 12.1 mg-S/g-sorb (or 34 mL-diesel fuel/g-sorb).9
Microporous coordination polymers (MCPs) were reported to
be effective adsorbents for ADS from a 300 ppmw-S diesel fuel,
and UMCM-150 MCP showed a high capacity of 17.4 mg-S/g-
sorb (or 70 mL-diesel fuel/g-sorb).12
Different from high sulfur
diesel fuels, ADS from current low-sulfur diesel (<15 ppmw-S)
in this work is much more difficult due to the refractory nature
of the remaining sterically hindered thiophenic sulfur
compounds and more significant competitive adsorption
between sulfur compounds and other fuel components. Carbon
materials showing high ADS capacity for model fuels were also
tested for ADS of the real low-sulfur diesel fuel in our
laboratory, and low capacities of less than 0.120 mg-S/g-sorb
(or 10 mL-F/g-sorb) were obtained. Sentorun-Shalaby et al.
developed Ni/MCM-48 adsorbent for ADS of current low
sulfur diesel through direct Ni−S chemical interaction, and
achieved a desulfurization capacity of 1.812 mg-S/g-sorb or 160
mL-F/g-sorb,7
where H2 was used in the ADS process at an
operating temperature of 200 °C. In this study, MCM-48-
supported TiO2−CeO2 adsorbent achieved a superior ADS
capacity of 1.143 mg-S/g-sorb or 95 mL-F/g-sorb from the real
diesel fuel to produce ultraclean fuel with <1 ppmw-S under
ambient conditions without H2, which is a less energy-intensive
desulfurization approach.
The adsorption capacity of an adsorbent would be influenced
by the total number of the accessible adsorption sites and
adsorption affinity of each adsorption site on the adsorbent.8
In
addition, the competitive adsorption of the fuel molecules
should always be considered. For the adsorption of the
refractory sulfur species in low-sulfur diesel fuel over the
TiO2−CeO2/MCM-48 sorbent, a very low desulfurization
capacity of 3 mL-F/g-sorb was obtained, as shown in Figure 2.
This can be mainly attributed to the weak adsorption affinity
between the adsorbent and the original sulfur compounds (e.g.,
4, 6-DMDBT in the fresh low-sulfur diesel fuel) due to the
steric hindrance effect19,35
in diesel fuel. In addition, strong
competitive adsorption due to the other fuel components, that
is, a significant amount (5−10 wt % or higher) of polyaromatic
hydrocarbons (PAHs),20
could inhibit ultra-deep desulfuriza-
tion. With the chemical transformation of initial sulfur species
to sulfones during ADS from light-irradiated diesel fuel, MCM-
48-supported TiO2−CeO2 adsorbent showed a significantly
higher breakthrough capacity of 1.143 mg-S/g-sorb compared
to 0.036 mg-S/g-sorb from the fresh fuel, suggesting a much
stronger adsorption of transformed sulfones over the MCM-48-
supported TiO2−CeO2 adsorbent compared to that of the
unoxidized, refractory sulfur compounds in the diesel fuel.
To shed light on the adsorption mechanism, adsorption
selectivity of different compounds in fuel over the MCM-48-
supported TiO2−CeO2 adsorbent was studied. Figure 4 shows
the breakthrough curves of different compounds, including
aromatics, refractory sulfur compounds, sulfone, and nitrogen
compound in the model fuel (MDF) over the TiO2−CeO2/
MCM-48 adsorbent. The first breakthrough species are
aromatic compounds, including Nap, Flu, MNap, and Phe,
Figure 3. Sulfur K-edge XANES spectra of the spent TiO2−CeO2/
MCM-48 adsorbent and two reference compounds, 4,6-DMDBT and
DBTO2.
Figure 4. Adsorption selectivity for different compounds in a model
diesel fuel (MDF) over the MCM-48-supported TiO2−CeO2
adsorbent at 25 °C and 9.6 h−1
of LHSV.
Industrial & Engineering Chemistry Research Article
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5. which give adsorption capacities of <6 mL-F/g-sorb. The
second type of breakthrough species are refractory sulfur
species, including DMDBT, BT, MDBT, and DBT, which give
desulfurization capacities of <12 mL-F/g-sorb. In a sharp
contrast, the third kind of breakthrough species are DBTO2 and
indole, which give similar capacities of around 76 mL-F/g-sorb,
significantly higher than the aromatic compounds and
refractory sulfur compounds. The much higher breakthrough
capacities of sulfone (DBTO2) and indole suggest a much
stronger adsorption affinity between the TiO2−CeO2/MCM-
48 adsorbent and sulfone/indole compared to that of the other
compounds. An interesting phenomenon in Figure 4 is that
after passing through the saturation point (C/C0 = 1), the
outlet concentrations of some compounds, especially the
aromatic compounds and refractory sulfur compounds, rise
over its initial concentration in the model fuel by even more
than 25% (C/C0 > 1.25). After passing the maximum value, the
outlet concentration gradually decreases to the initial one,
whereas the concentrations of the subsequent breakthrough
compounds increase to C/C0 = 1. This phenomenon reflects
the competitive adsorption among the compounds over the
adsorbent, which resulted in at least partial replacement of the
initially adsorbed compounds with lower adsorptive affinity by
the compounds with higher adsorptive affinity.25
A significant
replacement of DMDBT after saturation was observed in
Figure 4, indicating the adsorption of subsequent compounds
(e.g., BT, MDBT, and DBT) was stronger, which further
indicates that the steric hindrance effect of 4- and 6-methyl
groups on the adsorption of DMDBT over the TiO2−CeO2/
MCM-48 adsorbent can be significant. In addition, BT showed
a weaker adsorption compared to DBT with one more aromatic
ring, which is likely due to its lower dipole moment than DBT
as shown in Table 2. To sum up, on the basis of the order of
partial replacements, the adsorptive affinity follows the order of
indole ∼ DBT sulfone > refractory sulfur compounds >
aromatic compounds.
To make a quantitative discussion of the adsorptive
selectivity, a relative selectivity factor is defined in this study as
α =− Q /Qi n i n (1)
where Qi is the adsorptive capacity of compound i
corresponding to the breakthrough point and Qn is the
adsorptive capacity of the reference compound, naphthalene
(Nap), corresponding to its breakthrough point. It should be
mentioned that in using the kinetic breakthrough capacities
instead of the equilibrium capacity in eq 1, the defined
selectivity factor is not for the equilibrium selectivity.25
The adsorption selectivity for the ten compounds over the
TiO2−CeO2/MCM-48 adsorbent decreases in the order of
indole > DBTO2 ≫ DBT > MDBT > BT > DMDBT > Phe >
MNap ∼ Flu > Nap with the relative selectivity factor (αi−n) of
27.6, 26.9, 3.7, 2.7, 2.4, 2.0, 1.5, 1.3, 1.3, and 1, respectively, as
listed in Table 2. Both the breakthrough and saturation
capacities of the ten compounds listed in Table 2 follow the
order of indole > DBTO2 ≫ DBT > MDBT > BT > DMDBT
> Phe > MNap ∼ Flu > Nap, which is consistent with the order
of adsorption selectivity. The selectivity of refractory sulfur
compounds follows the order of DBT > MDBT > DMDBT,
suggesting that the presence of −CH3 groups neighboring
sulfur atom in nonoxidized sulfur compounds sterically hinder
ADS over the TiO2−CeO2/MCM-48 adsorbent. The result
also indicates that the adsorption of nonoxidized sulfur
compounds over the TiO2−CeO2/MCM-48 sorbent is likely
through the sulfur atom, similar as the case of supported nickel
adsorbent7
but different from the case of activated carbon.13,14
In contrast, the adsorption of DBT sulfone can go through the
oxygen atom instead of sulfur atom, because of the higher
electronegativity of oxygen than sulfur and much greater dipole
moment of sulfones than nonoxidized sulfur compounds,
resulting in a significantly higher adsorption selectivity and
capacity, as indicated in Table 2. In this case, chemical
transformation of initial refractory sulfur compounds in diesel
fuel to sulfones over the TiO2−CeO2/MCM-48 adsorbent is
likely to strengthen ADS by shifting the adsorbate from the
sterically hindered sulfur atom on alkylated refractory sulfur
molecules (e.g., 4,6-DMDBT) to a more attractive oxygen atom
on the corresponding sulfone molecules. In other words, the
adsorption between sulfone and adsorbent may go through a
highly electronegative oxygen atom rather than a less
electronegative sulfur atom in sulfone, resulting in higher
ADS selectivity and capacity.
Without light irradiation to generate peroxides, the refractory
sulfur compound 4,6-DMDBT is not oxidized and, thus, is less
strongly adsorbed on the surface of TiO2−CeO2/MCM-48
than DBT or BT, whereas the oxidized DBT compounds (e.g.,
DBTO2) is much more strongly adsorbed on TiO2−CeO2/
MCM-48, showing that the oxidation of refractory sulfur
compounds to sulfones, with the help of light irradiation, is
necessary and highly beneficial for achieving high adsorption
capacity for ultra-deep adsorptive desulfurization. Moreover, in
terms of sulfone formation, 4,6-DMDBT may show higher
reactivity than DBT because of the higher electron density of
the sulfur atom.36,37
Therefore, with the combination of light
irradiation and adsorptive desulfurization, the present system is
particularly promising for ultra-deep desulfurization of low-
sulfur diesel fuel.
Additionally, a strong adsorption capacity of indole was
observed over the TiO2−CeO2/MCM-48 adsorbent as shown
in Figure 4, which is similar to DBTO2. However, indole shows
a lower dipole moment than DBTO2 as listed in Table 2,
suggesting the interaction mode for the adsorption of indole
may be different from DBTO2 over the TiO2−CeO2/MCM-48
adsorbent. As indole shows a bifunctional structure38
(i.e.,
electron acceptor from the hydrogen bonded to N and electron
donor from conjugated π system), it behaves both as a weak
acid due to the presence of the H−N bond and as a weak base
due to the basicity of the N atom.39
With available silanol group
sites and TiO2−CeO2 oxide sites on the surface of the TiO2−
Table 2. Adsorption Selectivity Factor Relative to Naphthalene (αi−n), Adsorption Breakthrough and Saturation Capacities
(QB.T. and QSat., μmol/g), and Dipole Moment for Each Compound in MDF over the TiO2−CeO2/MCM-48 Adsorbent
Nap Flu MNap Phe DMDBT BT MDBT DBT DBTO2 indole
αi−n 1 1.3 1.3 1.5 2.0 2.4 2.7 3.7 26.9 27.6
QB.T. 7 9 9 11 14 16 19 26 188 193
QSat. 10 12 12 20 20 23 25 39 225 233
dipole (D) 0.764 1.090 1.087 1.363 5.453 2.004
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6. CeO2/MCM-48 adsorbent, both hydrogen bonding interaction
as well as acid−base interaction might play important roles in
the adsorption of indole. The strong adsorption of indole over
the TiO2−CeO2/MCM-48 adsorbent also suggests that the
presence of nitrogen compounds in the fuel might suppress
ADS over the TiO2−CeO2/MCM-48 adsorbent through
competitive adsorption. An integration of two or more
adsorbent beds may further improve the ultra-deep desulfuriza-
tion process.
3.2. Effect of Support of TiO2−CeO2 Oxides on ADS.
By comparison of the desulfurization performance of MCM-48-
supported TiO2−CeO2 and bulk TiO2−CeO2 in this study, the
desulfurization capacity of the former is over 30 times higher
than the latter, even though only 13.3 wt % of TiO2−CeO2
oxides were loaded on MCM-48. This suggests a strong effect
of the support on ADS performance of the TiO2−CeO2 oxide-
based adsorbents. In order to clarify support effect, various
types of supports, including fumed silica (EH-5), activated
carbon (AC-WPH), anatase TiO2, and gamma-Al2O3, were
examined. Table 3 lists some physical properties and
desulfurization capacities of bulk and supported TiO2−CeO2
adsorbents. Both the gravimetric and volumetric desulfurization
capacities of various supported TiO2−CeO2 oxides follow the
order of EH-5 > AC > TiO2 > Al2O3. The calculated
desulfurization capacity on the basis of BET surface area is
also listed in Table 3, which follows the order of EH-5 > TiO2 >
AC > Al2O3. Supporting Information Figure S2 shows
desulfurization capacity versus SBET of various supported
TiO2−CeO2. No correlation is found between desulfurization
capacity and SBET, suggesting desulfurization capacity is not
mainly determined by BET surface area of supported TiO2−
CeO2 adsorbents. More active sites (TiO2−CeO2) may be
exposed on silica support (EH-5) followed by those on TiO2,
AC, and Al2O3, which could be attributed to the electronic or
chemical properties of the supported materials.
The PZC value of the support affects the adsorption of
metal-containing ions in metal precursors via electrostatic
interaction, which could further influence the dispersion of
formed metal oxides,40
and thus alter its adsorption perform-
ance. Figure 5 shows desulfurization capacity of various
supported TiO2−CeO2 adsorbents versus the PZC value of
the support. It can be seen that desulfurization capacity of
supported TiO2−CeO2 adsorbents increases with decreasing
PZC value of the support. It should be mentioned that the pH
of the precursor solutions of mixed Ti−Ce salts to prepare
supported TiO2−CeO2 adsorbent was as low as 0.185.
Therefore, the surfaces of the studied supports (PZC > 2)
were all positively charged during impregnation. It is likely that
silica support had a stronger electrostatic adsorption to Ti−Ce
precursors, yielding better dispersion of the supported oxides,41
resulting in a higher desulfurization capacity. High dispersion of
TiO2−CeO2 on silica supports are also reflected by the absence
of TiO2−CeO2 peak on EH-5 and MCM-48 supports, unlike
the unsupported TiCeO in XRD patterns (Supporting
Information Figure S3), as the XRD technique has limitation
on the identification of smaller particles. The result suggests
that the PZC value of the support plays a more important role
than surface area. An exceptional case was AC, which had a
higher PZC value than TiO2 but a slightly higher desulfuriza-
tion capacity than TiO2. This may be attributed to the
significantly higher surface area of AC (930 m2
/g) than that of
TiO2 (90 m2
/g). Another possibility is that TiO2−CeO2 may
have more suitable interaction with silica support than other
supports, which makes the TiO2−CeO2 sites more active for
sulfur oxidation and/or sulfones adsorption. To clarify the
effect of support, further investigations are needed and in
progress in our laboratory by using the DFT method.
As suggested from the above results, silica is the most
effective support to load TiO2−CeO2 oxides for desulfurization
among the supports investigated. Mesoporous silica materials,
such as SBA-15, have PZC values similar to EH-5 (between 2
and 4)42,43
but differ in the surface area. In order to examine
the effect of surface area of silica supported TiO2−CeO2
adsorbents, various silica supports with different surface area,
including EH-5, SBA-15, MCM-41, and MCM-48, were
investigated for desulfurization. Mesoporous silica supports
were chosen to ensure the pore size is large enough so that
diffusion of the bulky sulfur compounds in the diesel fuel (i.e.,
4,6-DMDBT (0.6 nm44
)) would not be limited. Table 4 lists
BET surface area of the supports and supported TiO2−CeO2
adsorbents and the desulfurization capacity of various silica-
supported TiO2−CeO2 adsorbents. The adsorption capacity
per unit volume of adsorbent follows the order of MCM-48 >
MCM-41 > EH-5 > SBA-15. The higher volume-based capacity
of TiO2−CeO2/EH-5 than TiO2−CeO2/SBA-15 is due to the
higher packing density of the EH-5 supported TiO2−CeO2.
The correlation between BET surface area and desulfuriza-
tion capacity of various silica-supported TiO2−CeO2 adsorb-
ents is shown in Figure 6. It is worth noting that desulfurization
capacity increases monotonically with increasing surface area of
the silica supports. This is probably due to a better dispersion
of metal oxides with higher surface area of silica support,
resulting in a greater amount of accessible TiO2−CeO2 active
Table 3. BET Surface Area of Various Supports and Supported TiO2−CeO2 Adsorbents, and Desulfurization Capacity of the
Supported TiO2−CeO2 Adsorbents
support SBET‑support (m2
/g) SBET‑supportedTiO2−CeO2
(m2
/g) PZC value Q (mg-S/g-sorb) Q (μg-S/m2
-sorb) pack. density (mg/cm3
) Q (mg-S/mL-sorb)
Al2O3 155 104 8.9 0 0 0.80 0
TiO2 170 90 5.5 0.010 0.10 0.80 0.008
AC 1087 930 7.4 0.048 0.05 0.20 0.010
EH-5 315 196 2.4 0.354 1.80 0.40 0.142
Figure 5. Desulfurization capacity of supported TiO2−CeO2
adsorbents versus PZC value of the supports, SiO2 (EH-5), TiO2,
AC, and Al2O3.
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7. sites or exposed surface area of the TiO2−CeO2 particles45
for
sulfur oxidation and/or sulfone adsorption and thus a higher
desulfurization capacity. The MCM-48-supported TiO2−CeO2
adsorbent shows the highest desulfurization capacity, which
may be attributed to a better dispersion of TiO2−CeO2 oxides
over MCM-48 support.7
The control experiment shows that the
desulfurization capacity of MCM-48 support itself is only 0.012
mg-S/g-sorb as shown in Figure 6, indicating that MCM-48
support alone does not contribute to the significant increase in
the desulfurization capacity.
It should be mentioned that the TiO2−CeO2/MCM-48
adsorbent plays at least two main roles in ADS; one is to
provide active sites for sulfur oxidation, which can be
determined by the supported TiO2−CeO2 oxides, and the
other is to provide adsorption sites for oxidized sulfones, which
can be influenced by not only the supported TiO2−CeO2
oxides but also the silica support itself. The adsorption of
oxidized sulfones is likely through two types of interactions, (a)
acid−base interaction between acidic sites on TiO2−CeO2
oxides and basic sulfones (electronegative oxygen in sulfones
acts as electron donor and thus it can behave as a weak Lewis
base46
) and (b) hydrogen bonding interaction between
sulfones and silanol groups47
on the surface of the silica
support (the average concentration of silanol groups on silica
materials is 5 −OH/nm−2
).48
The contribution of the two
modes to the sulfone adsorption will be further studied in the
future work.
3.3. Adsorbent Regeneration. For practical applications,
a potential adsorbent should not only possess a high adsorption
capacity and selectivity to sulfur species but also have excellent
regenerability and stability.49
The regeneration of spent TiO2−
CeO2/MCM-48 adsorbent was performed via oxidative treat-
ment at 340 °C under an air flow rate of 50 cm3
/min for 2 h.
The adsorption performance of the regenerated adsorbents was
examined and compared with that of the fresh ones. The
breakthrough curves of total sulfur compounds and the
desulfurization capacity over the regenerated TiO2−CeO2/
MCM-48 adsorbents in the first three cycles are shown in
Figure 7. The breakthrough curves for the regenerated TiO2−
CeO2/MCM-48 adsorbent coincide well with that for the fresh
one, with the breakthrough desulfurization capacities of 1.143,
1.083, and 1.095 mg-S/g-sorb, or 95, 90, and 91 mL-F/g-sorb,
respectively, for the first three regeneration cycles. The
standard deviations were 1.6%, 2.2%, and 1.1%, respectively.
The results show that the adsorption capacity can be recovered
by air oxidation. In other words, oxidative air treatment can be
an effective regeneration method for the TiO2−CeO2/MCM-
48 adsorbent.
Figure 8 shows sulfur K-edge XANES spectra of the spent
and regenerated TiO2−CeO2/MCM-48 adsorbent and three
reference compounds, 4,6-DMDBT, DBTO2, and NiSO4. The
peak positions of sulfur compounds vary with the different
oxidation states of sulfur in XANES spectra. It can be seen that
no sulfur species were detected on the regenerated TiO2−
CeO2/MCM-48 adsorbent, indicating that the adsorbed sulfone
species can be oxidatively decomposed during air treatment.
Additionally, the fact that the spent TiO2−CeO2/MCM-48
Table 4. BET Surface Area of Supports and Supported TiO2−CeO2 Adsorbents and Desulfurization Capacity of Various Silica
Supported TiO2−CeO2 Adsorbents
support for TiO2−CeO2 EH-5 SBA-15 MCM-41 MCM-48 unsupported
SBET‑support (m2
/g) 315 950 1229 1281
SBET‑supported TiO2−CeO2
(m2
/g) 196 750 850 1089 249
Q (mg-S/g-sorb) 0.354 0.636 0.778 1.143 0.035
Pack. Density(mg/cm3
) 0.40 0.20 0.20 0.20 0.46
Q (mg-S/mL-sorb) 0.142 0.127 0.156 0.229 0.016
Figure 6. Desulfurization capacity of various silica supported TiO2−
CeO2 oxides, bulk TiO2−CeO2, and MCM-48 support versus their
surface areas.
Figure 7. Breakthrough curves of total sulfur compounds over the
TiO2−CeO2/MCM-48 adsorbent in the first three regeneration cycles
via oxidative treatment using air at 340 °C. (Inset: Desulfurization
capacity versus regeneration cycles.)
Figure 8. Sulfur K-edge XANES spectra of the spent and regenerated
TiO2−CeO2/MCM-48 adsorbent and three reference compounds,
4,6-DMDBT, DBTO2, and NiSO4.
Industrial & Engineering Chemistry Research Article
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8. adsorbent was effectively regenerated at 340 °C also implies a
good thermal stability of the adsorbent. The negligible loss in
the adsorption capacity of the regenerated TiO2−CeO2/MCM-
48 adsorbent suggests that the TiO2−CeO2/MCM-48
adsorbent can be a promising air-regenerable adsorbent for
ultra-deep desulfurization of diesel fuel.
3.4. Proposed Two-Stage Process for Ultra-deep
Desulfurization. On the basis of the above study, a novel
two-stage process for selective and ultra-deep desulfurization of
diesel fuel is proposed for the production of ultraclean fuel, as
shown in Figure 9. In the first stage, peroxides are generated in
fuel through sunlight or visible light irradiation. In the second
stage, light-irradiated fuel is fed into an adsorption bed packed
with dual-functional adsorbent/catalyst material (e.g., TiO2−
CeO2/MCM-48) which serves as the oxidation catalyst for
refractory sulfur compounds to sulfone species by the peroxides
generated in the first step, as well as the adsorbent for
simultaneous sulfone adsorption. After the adsorption bed
reaches its working capacity, it can be switched to the
regeneration side using oxidative air treatment. With the
proposed new process, ultra-deep adsorptive desulfurization of
diesel fuels can be achieved effectively under ambient
conditions without using costly hydrogen. Moreover, this
process may incorporate a good utilization of natural sunlight,
which may lead to a more sustainable and clean process.
4. CONCLUSION
A systematic study was carried out on ultra-deep adsorptive
desulfurization from light-irradiated diesel fuel over supported
TiO2−CeO2 adsorbents. Sulfur K-edge XANES identified
sulfones as were the major sulfur species on the spent TiO2−
CeO2/MCM-48 adsorbent. Adsorption selectivity of different
compounds from a model fuel follows the order of DBTO2 ≫
DBT > MDBT > BT > DMDBT > Phe > MNap ∼ Flu > Nap,
indicating a higher adsorption selectivity of sulfones over the
original sulfur compounds and aromatics in fuel. We conclude
that the original sulfur species are chemically transformed to
sulfones that are more selectively adsorbed during ADS of light-
irradiated diesel fuel over the supported TiO2−CeO2
adsorbent, resulting in over 30-fold higher desulfurization
capacity (95 mL-F/g-sorb or 1.143 mg-S/g-sorb) as compared
to ADS of the original diesel fuel. Additionally, the adsorption
of sulfones over supported TiO2−CeO2 adsorbent is likely
through the highly electronegative oxygen atom rather than
sulfur atom.
Desulfurization capacity of light-irradiated fuel over
supported TiO2−CeO2 adsorbents is found to increase with
decreasing PZC value of the supports.
Among the different supports examined in this work, silica
material with the lowest PZC value (2−4) is the most effective
support to load TiO2−CeO2 oxides for desulfurization, possibly
through a strong electrostatic adsorption of Ti−Ce precursors
over the silica support.
For different silica supported TiO2−CeO2 oxides, the
desulfurization capacity increases monotonically with the
increasing of surface area in the order of MCM-48 > MCM-
41 > SBA-15 > EH-5, which may be attributed to a higher
dispersion of TiO2−CeO2 oxides on the higher surface area
support.
The TiO2−CeO2/MCM-48 adsorbent can be regenerated by
oxidative air treatment; no sulfur of any types (sulfones, or
sulfates, or DMDBT) was detected on the regenerated TiO2−
CeO2/MCM-48 adsorbent by sulfur K-edge XANES spectros-
copy.
On the basis of the present study, a new two-stage process
for ultra-deep adsorptive desulfurization of diesel fuel is
proposed that may provide an attractive path to achieve
ultraclean fuel more effectively and efficiently under ambient
conditions without using costly hydrogen.
■ ASSOCIATED CONTENT
*S Supporting Information
Effect of TiO2−CeO2 loading on the desulfurization capacity
over the TiO2−CeO2/MCM-48 adsorbent with TiO2−CeO2
loading of 10.0, 13.3, 15.0, and 20.0 wt % from light-irradiated
diesel at a breakthrough point of 1 ppmw-S at 25 °C and LHSV
of 9.6 h−1
(Figure S1), effect of BET surface area of adsorbents,
desulfurization capacity (mg-S/m2
-sorb) versus BET surface
area (m2
/g) of various supported TiO2−CeO2 adsorbents
(Figure S2), and XRD patterns of various supported TiO2−
CeO2 adsorbents (Figure S3). This information is available free
of charge via the Internet at http://pubs.acs.org.
■ AUTHOR INFORMATION
Corresponding Author
*C. Song. Phone: (814) 863-4466. Fax: (814) 865-3573. E-
mail: csong@psu.edu.
Notes
The authors declare no competing financial interest.
■ ACKNOWLEDGMENTS
This work was supported in part by the U.S. Department of
Energy, National Energy Technology Laboratory, the U.S.
Office of Naval Research, and the U.S. National Science
Foundation−U.S. Environmental Protection Agency Joint TSE
program. J. Xiao gratefully acknowledges the support by the
National Natural Science Foundation of China (21306054), the
Guangdong Natural Science Foundation (S2013040014747),
and the Fundamental Research Funds for the Central
Universities (2013ZM0047). Sulfur K-edge XANES work at
the CMC Beamline is supported in part by the Office of Basic
Energy Sciences of the U.S. Department of Energy and by the
National Science Foundation Division of Materials Research.
Use of the Advanced Photon Source, an Office of Science User
Facility operated for the U.S. Department of Energy (DOE)
Office of Science by Argonne National Laboratory, was
supported by the U.S. DOE under Contract No. DE-AC02-
Figure 9. Proposed selective desulfurization process for ultra-deep desulfurization of diesel fuel.
Industrial & Engineering Chemistry Research Article
dx.doi.org/10.1021/ie402724q | Ind. Eng. Chem. Res. 2013, 52, 15746−1575515753
9. 06CH11357. We would like to thank Prof. Jim Adair at Penn
State for the help on Zeta potential measurements.
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