IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This work studied the effect of applying pulse current
(ton=off=1s) on the electrodeposition of silver nanoparticles on
carbon sphere surface as a substrate. The electrolyte is made of 0.1
M KNO3, 0.1 M KCN and 0.01M AgNO3. The pH value has been
adjusted in the alkaline region of 9.1 with the help of K(NO3)
addition. Experiments were carried out at room temperature for
periods up to 12 minutes. The cell is fitted with a mechanical stirrer
to keep the electrolyte in a dynamic state. Product(s) was
characterized with the help of SEM and EDX and field emission.
Results obtained show that silver nanoparticles has successfully
electrodeposited under pulse current conditions with a particle size
of 100–400 nm after 2 minutes. Deposition takes place on certain
accessible sites of the carbon surface of the substrate forming a
monolayer of scattered silver nanoparticles. Formation of macro
particles with larger diameter and multilayer in thickness takes
place with continuous deposition of silver nanoparticles on the
formerly deposited silver. Pulse current helps management of the
monolayer deposition as compared to the steady DC application
with respect to particle diameter and number of layers.
A study of micro structural, magnetic and electrical properties of La-Co-Sm n...IJECEIAES
A Lanthanum (La 3+ ) doped Samarium-Cobalt nanoferrites (La_x,Co_0.2,Sm_0.2,Fe_(2-x) O_4, where x=0.0,0.5,1.0) have been synthesized by sol-gel method in citrate media. Obtained spinal ferrites micro structure properties have been investigated by XRD, FTIR, SEM-EDX, and TEM-SAED techniques. All the samples are nano in size with significant hysteresis. Micro structural analysis by XRD confirms the obtained samples showing the single phase cubic spinal structures with an average crystal size found from 12 nm to 25 nm, while the average particles sizes identified from TEM analysis are ranging from 21.5nm-26.8 nm (~23.4nm) and from 20.5 nm to 28(~26.4nm) nm for x=0.5,1.0. The lattice parameter found to be a= 8.402, 8.423, 8.467Å for the respective values of x= 0.0, 0.05, and 1.0. Electrical properties show increase in dc resistivity with increase in La ion concentration. Finally, it was concluded that the doping of Lanthanum ion (La 3+ ) in the ferrites structure is found to influencing the structural and electrical properties without scarifying the ferromagnetic character.
Direct Synthesis Carbon/Metal Oxide Composites for Electrochemical Capacitors...drboon
This paper deals with the study of the carbon/metal oxide composites synthesis for electrochemical capacitor electrode material. Transition metal salts, such as FeCl3 and TiCl3 act as activator in the synthesis of activated carbon from gelam wood sawdust (Melaleuca cajuputi Powell) which also have the functions as substrates for the composites. The surface functionalities of activated carbons were modified using oxidative treatments. The changes on crystallography and surface functionalities were analyzed based on XRD and FTIR data. The electrical conductivities and electrochemical properties were determined using kelvin and cyclic voltammetry methods, respectively. FTIR analyses showed that the activation and oxidation treatments affected their surface functionalities. The XRD analyses showed that oxidative treatments also affected carbons crystallite. The electrical conductivities and electrochemical properties were influenced by their crystallite and surface functionalities. The shape of the cyclic voltammograms varied according to the changes on the surface functionalities and on the metals loading. TEM analyses indicated the existence of nanoparticles metal oxides in the carbon samples.
This work studied the effect of applying pulse current
(ton=off=1s) on the electrodeposition of silver nanoparticles on
carbon sphere surface as a substrate. The electrolyte is made of 0.1
M KNO3, 0.1 M KCN and 0.01M AgNO3. The pH value has been
adjusted in the alkaline region of 9.1 with the help of K(NO3)
addition. Experiments were carried out at room temperature for
periods up to 12 minutes. The cell is fitted with a mechanical stirrer
to keep the electrolyte in a dynamic state. Product(s) was
characterized with the help of SEM and EDX and field emission.
Results obtained show that silver nanoparticles has successfully
electrodeposited under pulse current conditions with a particle size
of 100–400 nm after 2 minutes. Deposition takes place on certain
accessible sites of the carbon surface of the substrate forming a
monolayer of scattered silver nanoparticles. Formation of macro
particles with larger diameter and multilayer in thickness takes
place with continuous deposition of silver nanoparticles on the
formerly deposited silver. Pulse current helps management of the
monolayer deposition as compared to the steady DC application
with respect to particle diameter and number of layers.
A study of micro structural, magnetic and electrical properties of La-Co-Sm n...IJECEIAES
A Lanthanum (La 3+ ) doped Samarium-Cobalt nanoferrites (La_x,Co_0.2,Sm_0.2,Fe_(2-x) O_4, where x=0.0,0.5,1.0) have been synthesized by sol-gel method in citrate media. Obtained spinal ferrites micro structure properties have been investigated by XRD, FTIR, SEM-EDX, and TEM-SAED techniques. All the samples are nano in size with significant hysteresis. Micro structural analysis by XRD confirms the obtained samples showing the single phase cubic spinal structures with an average crystal size found from 12 nm to 25 nm, while the average particles sizes identified from TEM analysis are ranging from 21.5nm-26.8 nm (~23.4nm) and from 20.5 nm to 28(~26.4nm) nm for x=0.5,1.0. The lattice parameter found to be a= 8.402, 8.423, 8.467Å for the respective values of x= 0.0, 0.05, and 1.0. Electrical properties show increase in dc resistivity with increase in La ion concentration. Finally, it was concluded that the doping of Lanthanum ion (La 3+ ) in the ferrites structure is found to influencing the structural and electrical properties without scarifying the ferromagnetic character.
Direct Synthesis Carbon/Metal Oxide Composites for Electrochemical Capacitors...drboon
This paper deals with the study of the carbon/metal oxide composites synthesis for electrochemical capacitor electrode material. Transition metal salts, such as FeCl3 and TiCl3 act as activator in the synthesis of activated carbon from gelam wood sawdust (Melaleuca cajuputi Powell) which also have the functions as substrates for the composites. The surface functionalities of activated carbons were modified using oxidative treatments. The changes on crystallography and surface functionalities were analyzed based on XRD and FTIR data. The electrical conductivities and electrochemical properties were determined using kelvin and cyclic voltammetry methods, respectively. FTIR analyses showed that the activation and oxidation treatments affected their surface functionalities. The XRD analyses showed that oxidative treatments also affected carbons crystallite. The electrical conductivities and electrochemical properties were influenced by their crystallite and surface functionalities. The shape of the cyclic voltammograms varied according to the changes on the surface functionalities and on the metals loading. TEM analyses indicated the existence of nanoparticles metal oxides in the carbon samples.
Consistently High Voc Values in p-i-n Type Perovskite Solar Cells Using Ni3+-...Pawan Kumar
Leading edge p-i-n type halide perovskite solar cells (PSCs) severely underperform n-i-p PSCs. p-i-n type PSCs that use PEDOT:PSS hole transport layers (HTLs) struggle to generate open-circuit photovoltage values higher than 1 V. NiO HTLs have shown greater promise in achieving high Voc values albeit inconsistently. In this report, a NiO nanomesh with Ni3+ defect grown by the hydrothermal method was used to obtain PSCs with Voc values that consistently exceeded 1.10 V (champion Voc = 1.14 V). A champion device photoconversion efficiency of 17.75% was observed. Density functional theory modeling was used to understand the interfacial properties of the NiO/perovskite interface. The PCE of PSCs constructed using the Ni3+-doped NiO nanomesh HTL was ∼34% higher than that of conventional compact NiO-based perovskite solar cells. A suite of characterization techniques such as transmission electron microscopy, field emission scanning electron microscopy, intensity-modulated photocurrent spectroscopy, intensity-modulated photovoltage spectroscopy, time-resolved photoluminescence, steady-state photoluminescence, and Kelvin probe force microscopy provided evidence of better film quality, enhanced charge transfer, and suppressed charge recombination in PSCs based on hydrothermally grown NiO nanostructures.
Development of Ni-doped Yttria stabilized Zirconia composite for SOFC applica...IOSRJAP
Ni-doped Yttria stabilized Zirconia (NiO/YSZ) has been synthesized using low cost combustion process from an aqueous solution containing ZrO(NO3)2.6H2O, Y(NO3)3.6H2O, Ni(NO3)2.6H2O and urea. Pellets were sintered at 13500C for 5 hours and its sintered density is estimated to be of 95%. Sintered pellets were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) & X-ray photoelectron spectroscopy (XPS) techniques. From the XRD analysis, as grown powder of NiO/YSZ showed nano-crystalline behavior with homogeneous mixture of YSZ and NiO phases. However sintered powder showed µ-size dense grain growth. Temperature and frequency dependent dielectric properties are corroborated with the conduction mechanism. Both dielectric constant (K) and loss (tan δ) are increased sharply at high temperature region, which is expected to be the onset of dipolar relaxation phenomena due to the presence of oxygen vacancies. A mixed conductivity involving ionic conduction in the high temperature range and electronic conduction in the low temperature range was observed. The decrease in K and tan δ with increase in frequency at a given temperature suggests the dynamic interaction of oxygen vacancies & oxide ion pairs.
Synthesis and characterization of pure zinc oxide nanoparticles and nickel do...eSAT Journals
Abstract In this paper, Zinc oxide nanoparticles are synthesized by simple wet chemical precipitation method. Zinc nitrate and sodium hydroxide are used as the starting materials.Zinc oxide nanoparticles are formed at a very low temperature of the order of 800C. Nickel doped zinc oxide nanoparticles are synthesized in two steps. In first step precipitate is obtained by reduction of mixture of zinc nitrate, ferric nitrate and starch by sodium hydroxide solution while in second step the given precipitate is thermally decomposed at high temperature of the order of 4000C. The crystallinity of the synthesized nanoparticles is then confirmed by X ray diffraction spectroscopy (XRD).The elemental composition of the powder is detected by Energy Dispersive X ray spectroscopy (EDAX). The morphology of the powder is investigated by Scanning Electron Microscopy (SEM). Magnetic characterization of nickel doped zinc oxide nanoparticles is done by Squid Magnetometer. Low temperature magnetization behavior revealed ferromagnetic behavior of sample. Key Words: Zinc oxide nanoparticles, Nickel doped ZnO, Antibacterial activity, Squid magnetometer, SEM
Photoelectrochemical characterization of titania photoanodes fabricated using...Arkansas State University
Design and fabrication of new electrodes for photo-electrolysis using a material that is photo-active, stable, corrosion resistant, and cost effective.
Polymeric carbon nitride-based photocatalysts for photoreforming of biomass d...Pawan Kumar
Photoreforming of biomass to value-added chemicals and fuels is a chemical approach to extract photosynthetically-trapped energy in complex biomolecules which otherwise disintegrate naturally in the environment. Designing precise photocatalytic materials that can selectively break the sturdy, nature-designed biomass with multiplex chemical composition/bonding and inaccessible sites is central to deploying this technology. Polymeric carbon nitride (CN) comprised of a 2D network of condensed heptazine/triazine (C6N7/C3N3) core has shown great promise for photoreforming of biomass derivatives due to intriguing physicochemical and optical properties. This review comprehensively summarizes the state-of-the-art applications of CN-based photocatalysts for the conversion of lignocellulosic biomass derivatives. Various chemical and structural modifications in CN structure such as doping, surface functionalization, hybridization entailing to higher selectivity and conversion have been discussed aiming at providing valuable guidance for future CN-based materials design.
Electrochemical study of anatase TiO2 in aqueous sodium-ion electrolytesRatnakaram Venkata Nadh
In this paper, a basic electro-analytical study on the behavior of anatase TiO2 in aqueous NaOH has been presented using cyclic voltammetry technique (CV). The study has explored the possibility of using TiO2 as anode material for ARSBs in presence of 5 M NaOH aqueous electrolyte. CV profiles show that anatase TiO2 exhibits reversible sodium ion insertion/de-insertion reactions. CV studies of TiO2 anode in aqueous sodium electrolytes at different scan rate shows that the Na+ ion insertion reaction at the electrode is diffusion controlled with a resistive behavior. Proton insertion from aqueous sodium electrolytes into TiO2 cannot be ruled out. To confirm the ion inserted and de-inserted, CV studies are done at different concentration of NaOH and it is found that at lower concentrations of NaOH, proton insertion process competes with Na+ ion insertion process and as the concentration increases, the Na+ ion insertion process becomes the predominant electrode reaction making it suitable anode materials for aqueous sodium batteries in 5 M NaOH.
Mixed-Valence Single-Atom Catalyst Derived from Functionalized GraphenePawan Kumar
Single-atom catalysts (SACs) aim at bridging the gap between homogeneous and heterogeneous catalysis. The challenge is the development of materials with ligands enabling coordination of metal atoms in different valence states, and preventing leaching or nanoparticle formation. Graphene functionalized with nitrile groups (cyanographene) is herein employed for the robust coordination of Cu(II) ions, which are partially reduced to Cu(I) due to graphene-induced charge transfer. Inspired by nature's selection of Cu(I) in enzymes for oxygen activation, this 2D mixed-valence SAC performs flawlessly in two O2-mediated reactions: the oxidative coupling of amines and the oxidation of benzylic CH bonds toward high-value pharmaceutical synthons. High conversions (up to 98%), selectivities (up to 99%), and recyclability are attained with very low metal loadings in the reaction. The synergistic effect of Cu(II) and Cu(I) is the essential part in the reaction mechanism. The developed strategy opens the door to a broad portfolio of other SACs via their coordination to various functional groups of graphene, as demonstrated by successful entrapment of FeIII/FeII single atoms to carboxy-graphene.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Consistently High Voc Values in p-i-n Type Perovskite Solar Cells Using Ni3+-...Pawan Kumar
Leading edge p-i-n type halide perovskite solar cells (PSCs) severely underperform n-i-p PSCs. p-i-n type PSCs that use PEDOT:PSS hole transport layers (HTLs) struggle to generate open-circuit photovoltage values higher than 1 V. NiO HTLs have shown greater promise in achieving high Voc values albeit inconsistently. In this report, a NiO nanomesh with Ni3+ defect grown by the hydrothermal method was used to obtain PSCs with Voc values that consistently exceeded 1.10 V (champion Voc = 1.14 V). A champion device photoconversion efficiency of 17.75% was observed. Density functional theory modeling was used to understand the interfacial properties of the NiO/perovskite interface. The PCE of PSCs constructed using the Ni3+-doped NiO nanomesh HTL was ∼34% higher than that of conventional compact NiO-based perovskite solar cells. A suite of characterization techniques such as transmission electron microscopy, field emission scanning electron microscopy, intensity-modulated photocurrent spectroscopy, intensity-modulated photovoltage spectroscopy, time-resolved photoluminescence, steady-state photoluminescence, and Kelvin probe force microscopy provided evidence of better film quality, enhanced charge transfer, and suppressed charge recombination in PSCs based on hydrothermally grown NiO nanostructures.
Development of Ni-doped Yttria stabilized Zirconia composite for SOFC applica...IOSRJAP
Ni-doped Yttria stabilized Zirconia (NiO/YSZ) has been synthesized using low cost combustion process from an aqueous solution containing ZrO(NO3)2.6H2O, Y(NO3)3.6H2O, Ni(NO3)2.6H2O and urea. Pellets were sintered at 13500C for 5 hours and its sintered density is estimated to be of 95%. Sintered pellets were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) & X-ray photoelectron spectroscopy (XPS) techniques. From the XRD analysis, as grown powder of NiO/YSZ showed nano-crystalline behavior with homogeneous mixture of YSZ and NiO phases. However sintered powder showed µ-size dense grain growth. Temperature and frequency dependent dielectric properties are corroborated with the conduction mechanism. Both dielectric constant (K) and loss (tan δ) are increased sharply at high temperature region, which is expected to be the onset of dipolar relaxation phenomena due to the presence of oxygen vacancies. A mixed conductivity involving ionic conduction in the high temperature range and electronic conduction in the low temperature range was observed. The decrease in K and tan δ with increase in frequency at a given temperature suggests the dynamic interaction of oxygen vacancies & oxide ion pairs.
Synthesis and characterization of pure zinc oxide nanoparticles and nickel do...eSAT Journals
Abstract In this paper, Zinc oxide nanoparticles are synthesized by simple wet chemical precipitation method. Zinc nitrate and sodium hydroxide are used as the starting materials.Zinc oxide nanoparticles are formed at a very low temperature of the order of 800C. Nickel doped zinc oxide nanoparticles are synthesized in two steps. In first step precipitate is obtained by reduction of mixture of zinc nitrate, ferric nitrate and starch by sodium hydroxide solution while in second step the given precipitate is thermally decomposed at high temperature of the order of 4000C. The crystallinity of the synthesized nanoparticles is then confirmed by X ray diffraction spectroscopy (XRD).The elemental composition of the powder is detected by Energy Dispersive X ray spectroscopy (EDAX). The morphology of the powder is investigated by Scanning Electron Microscopy (SEM). Magnetic characterization of nickel doped zinc oxide nanoparticles is done by Squid Magnetometer. Low temperature magnetization behavior revealed ferromagnetic behavior of sample. Key Words: Zinc oxide nanoparticles, Nickel doped ZnO, Antibacterial activity, Squid magnetometer, SEM
Photoelectrochemical characterization of titania photoanodes fabricated using...Arkansas State University
Design and fabrication of new electrodes for photo-electrolysis using a material that is photo-active, stable, corrosion resistant, and cost effective.
Polymeric carbon nitride-based photocatalysts for photoreforming of biomass d...Pawan Kumar
Photoreforming of biomass to value-added chemicals and fuels is a chemical approach to extract photosynthetically-trapped energy in complex biomolecules which otherwise disintegrate naturally in the environment. Designing precise photocatalytic materials that can selectively break the sturdy, nature-designed biomass with multiplex chemical composition/bonding and inaccessible sites is central to deploying this technology. Polymeric carbon nitride (CN) comprised of a 2D network of condensed heptazine/triazine (C6N7/C3N3) core has shown great promise for photoreforming of biomass derivatives due to intriguing physicochemical and optical properties. This review comprehensively summarizes the state-of-the-art applications of CN-based photocatalysts for the conversion of lignocellulosic biomass derivatives. Various chemical and structural modifications in CN structure such as doping, surface functionalization, hybridization entailing to higher selectivity and conversion have been discussed aiming at providing valuable guidance for future CN-based materials design.
Electrochemical study of anatase TiO2 in aqueous sodium-ion electrolytesRatnakaram Venkata Nadh
In this paper, a basic electro-analytical study on the behavior of anatase TiO2 in aqueous NaOH has been presented using cyclic voltammetry technique (CV). The study has explored the possibility of using TiO2 as anode material for ARSBs in presence of 5 M NaOH aqueous electrolyte. CV profiles show that anatase TiO2 exhibits reversible sodium ion insertion/de-insertion reactions. CV studies of TiO2 anode in aqueous sodium electrolytes at different scan rate shows that the Na+ ion insertion reaction at the electrode is diffusion controlled with a resistive behavior. Proton insertion from aqueous sodium electrolytes into TiO2 cannot be ruled out. To confirm the ion inserted and de-inserted, CV studies are done at different concentration of NaOH and it is found that at lower concentrations of NaOH, proton insertion process competes with Na+ ion insertion process and as the concentration increases, the Na+ ion insertion process becomes the predominant electrode reaction making it suitable anode materials for aqueous sodium batteries in 5 M NaOH.
Mixed-Valence Single-Atom Catalyst Derived from Functionalized GraphenePawan Kumar
Single-atom catalysts (SACs) aim at bridging the gap between homogeneous and heterogeneous catalysis. The challenge is the development of materials with ligands enabling coordination of metal atoms in different valence states, and preventing leaching or nanoparticle formation. Graphene functionalized with nitrile groups (cyanographene) is herein employed for the robust coordination of Cu(II) ions, which are partially reduced to Cu(I) due to graphene-induced charge transfer. Inspired by nature's selection of Cu(I) in enzymes for oxygen activation, this 2D mixed-valence SAC performs flawlessly in two O2-mediated reactions: the oxidative coupling of amines and the oxidation of benzylic CH bonds toward high-value pharmaceutical synthons. High conversions (up to 98%), selectivities (up to 99%), and recyclability are attained with very low metal loadings in the reaction. The synergistic effect of Cu(II) and Cu(I) is the essential part in the reaction mechanism. The developed strategy opens the door to a broad portfolio of other SACs via their coordination to various functional groups of graphene, as demonstrated by successful entrapment of FeIII/FeII single atoms to carboxy-graphene.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
Atividade desenvolvida em sala pelos alunos do Curso de MBA em Marketing da PUC/SP - turma 7 - Weekend para a disciplina de CRM do Prof. Dr. Luiz claudio Zenone.
INVESTIGATION ON ACID LEACHING OF E-WASTE SCRAPS OBTAINED FROM MODEM BOXESIAEME Publication
Electronic waste is one of the hazardous waste concerns which pose threat to the both developed and developing countries in terms of environmental pollution. Generation of electronic waste is increasing year by year globally and it is important to treat the e-waste properly. Electronic waste contains materials such as Al, Ag, Cu including hazardous materials such as lead in various electronic waste products. In this work integrated circuit chips, header pins and edge connectors from modem e-waste are selected for the investigation due to the availability of precious metals in them. Experiments were conducted on these selected components by acid leaching followed by elemental analysis by ICP-OES. The components for the acid leaching were removed from PCBs of computer modem boxes by de-soldering method. The acid leaching experiment on header pin was conducted using 200ml of HNO3 solution. The leaching experiment on IC chip was carried out using aqua regia solution containing 25ml of HNO3 and 120 ml of HCl. The precipitation was done using sodium metabisulfite (Na₂S₂O₅). The elements in output residue obtained from acid leaching were identified using ICP-OES. Concentration of silver was found to be highest with the value of 64.40 mg/l among all the other elements present. Similarly, in header pins residue the concentration of silver was found to be 14.18 mg/l and copper 7.68 mg/l. The silver present in the IC chip ash was found to be 13.99 mg/l and the concentration of copper was 7.77 mg/l.
Thermal Oxidation of Copper for Favorable Formation of Cupric Oxide (CuO) Sem...IOSR Journals
Thermal oxidation of copper has been restudied to control the formation of photovoltaic active cupric oxide (CuO) phase against the cuprous oxide (Cu2O) phase. It has been established that the thermal oxidation of copper is governed by the outward lattice diffusion and grain boundary diffusion of copper ions at the interface. The lattice diffusion favors the formation of Cu2O phase whereas grain boundary diffusion favors the formation of CuO phase. In the present work, a fine copper powder is taken as starting material for thermal oxidation to increase the grain boundary diffusion and to study its on phase formation. Further, to suppress the grain boundary diffusion the starting material is chemically passivated with diethylenetriamine and olelamine to chameically passivated the surface defects. Thermal oxidation of these pre-treated materials is carried out in open air at temperature 500 oC and 700 oC to study the phase formation. The resulting materials are characterized by x-ray diffraction and scanning electron microscopy. These studies clearly confirm that grain boundary diffusion or defect mediated diffusion due to small particle size and more surface atoms of copper favor the formation of CuO at low temperature in case of pure copper, whereas the chemical passivation and high temperature heating favours the formation of Cu2O phase and hence the resulting material is biphasic. Hence, the present study is useful information in controlling the phase formation of copper oxide to obtain more photoactive material that is CuO.
RECOVERY OF METALS FROM ELECTRONIC WASTE (e-scrap).suzi smith
E-Waste i.e. electronic waste is discarded electronic equipments. In other words it refers to the electronic products nearing the end of their useful life period. It includes a broad range of electronic devices from computer to hand – held cellular phones, stereos, consumer electronics, ovens, refrigerator, monitors, etc.
Waste of all sort put together is a major cause of Global Warming and electronic waste (e-waste) is one of the biggest contributor. E-Waste contains several different substances and chemicals, many of which are toxic & are not biodegradable and are likely to create adverse impact on environment and health, if not handled properly. In addition to that it contains metal values which can be recovered.
Manufacturers, government agencies and users are now looking for environmentally responsible management of this E-waste. Besides proper disposal, economical recovery of precious and exhaustible materials is also a matter of interest.
TiO2-HfN Radial Nano-Heterojunction: A Hot Carrier Photoanode for Sunlight-Dr...Pawan Kumar
The lack of active, stable, earth-abundant, and visible-light absorbing materials to replace
plasmonic noble metals is a critical obstacle for researchers in developing highly efficient and costeffective photocatalytic systems. Herein, a core–shell nanotube catalyst was fabricated consisting of
atomic layer deposited HfN shell and anodic TiO2 support layer with full-visible regime photoactivity
for photoelectrochemical water splitting. The HfN active layer has two unique characteristics: (1) a
large bandgap between optical and acoustic phonon modes (2) and no electronic bandgap, which
allows a large population of long life-time hot carriers, which are used to enhance the photoelectrochemical performance. The photocurrent density (≈2.5 mA·cm−2 at 1 V vs. Ag/AgCl) obtained in
this study under AM 1.5G 1 Sun illumination is unprecedented, as it is superior to most existing
plasmonic noble metal-decorated catalysts and surprisingly indicates a photocurrent response that
extends to 730 nm. The result demonstrates the far-reaching application potential of replacing active
HER/HOR noble metals such as Au, Ag, Pt, Pd, etc. with low-cost plasmonic ceramics.
Carbon-cuprous oxide composite nanoparticles
were chemically deposited on surface of thin glass tubes of spent
energy saving lamps for solar heat collection. Carbon was
obtained from fly ash of heavy oil incomplete combustion in
electric power stations. Impurities in the carbon were removed by
leaching with mineral acids. The mineral free-carbon was then
wet ground to have a submicron size. After filtration, it was
reacted with concentrated sulfuric/fuming nitric acid mixture on
cold for 3-4 days. Potassium chlorate was then added drop wise on
hot conditions to a carbon slurry followed by filtration.
Nanocarbon sample was mixed with 5% by weight PVA to help
adhesion to the glass surface. Carbon so deposited was doped with
copper nitrate solution. After dryness, the carbon/copper nitrate
film was dipped in hydrazine hydrate to form cuprous oxide -
carbon composite, It was then roasted at 380-400 °C A heat
collector testing assembly was constructed of 5 glass coils
connected in series with a total surface area of 1250 cm2
. Heat
collection was estimated by water flowing in the glass coils that
are coated with the carbon/copper film,. Parameters affecting the
solar collection efficiency such as time of exposure and mass flow
rate of the water were studied. Results revealed that the prepared
glass coil has proven successful energy collector for solar heat.
Hydrothermal Assisted Microwave Pyrolysis of Water Hyacinth for Electrochemic...drboon
We develop ‘green’ approach to prepare conductive carbon material from water hyacinth (Eichhornia crassipes) powder for use in electrochemical capacitor device. The features on morphology, crystallography and surface functionality were analyzed based on SEM, XRD and FTIR instrumentation, respectively. The electrical conductivities were measured using four-point probe. Electrochemical properties were studied using cyclic voltammetry. SEM analyses indicated the existence of nanoparticles in the carbon samples. XRD analysis showed that carbon sample had sharp peaks indicating crystallite carbon and sylvite. FTIR analysis showed that the carbon have common surface functionalities which also can be found in other conductive carbon samples. The electrical conductivities test showed that the carbon had 0.001–1.5 S cm-1 of conductivity. The shape of the cyclic voltammograms were typical for carbon electrode that use in electrochemical capacitor.
Equilibrium and Kinetics Adsorption of Cadmium and Lead Ions from Aqueous Sol...theijes
Sourcing cheap adsorbents for the treatment of waste water is imperative for local environments. The adsorption of cadmium (Cd) and lead (Pb) from aqueous solution onto bamboo activated carbon prepared by chemical activation with ZnCl2 was investigated. The unwashed chemical activated bamboo carbon (UCABC) achieved up to 87.81% and 96.45% removal of Cd and Pb at pH-5 and 11, respectively. Removal equilibrium was attained within 1hr and 2.5hrs for Cd and Pb, respectively. The Cd and Pb adsorption increased with adsorbent dosage decrease while removal rate (%) increased with Cd and Pb concentration. Adsorption isotherm of Cd and Pb onto UCABC was determined and correlated with four isotherm models (Langmuir, Freundlich, Temkin and Hills). The equilibrium data fitted into Freundlich Cd (R2 = 0.9873, SSE = 0.045), Pb (R2 =0.9903, SSE = 0.051); Temkin Cd (R2 =0.9730, SSE = 0.052), Pb (R2 = 0.9079, SSE = 0.056); Hills Cd (R2 = 0.9961, SSE = 0.048), Pb (R2.= 0.9183, SSE = 0.053) and Langmuir Cd (R2 = 0.9653, SSE = 0.302), Pb (R2 = 0.9899, SSE = 0.136) isotherms. The Freundlich fitting showed isotherm adsorption capacity constants Kf = 7.843 and 5.098 (mg/g) for Cd and Pb, respectively. Furthermore, their adsorption kinetics correlated with the Pseudo-first order, Pseudo-second order and Intra-particle diffusion models and could be best described by the Pseudo-second order equation, suggesting chemisorptions as the limiting process. This study demonstrated that the UCABC can remove Cd2+ and Pb+ ions from aqueous solution to avert expensive commercial adsorbents
Synthesis of flower-like magnetite nanoassembly: Application in the efficient...Pawan Kumar
A facile approach for the synthesis of magnetite microspheres with flower-like morphology is reported
that proceeds via the reduction of iron(III) oxide under a hydrogen atmosphere. The ensuing magnetic
catalyst is well characterized by XRD, FE-SEM, TEM, N2 adsorption-desorption isotherm, and
Mössbauer spectroscopy and explored for a simple yet efficient transfer hydrogenation reduction of a
variety of nitroarenes to respective anilines in good to excellent yields (up to 98%) employing hydrazine
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Orchestrator execution result
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Key Trends Shaping the Future of Infrastructure.pdf
Bx32469473
1. S.Pradeep Kumar, S.Govindaradjane, T.Sundararajan / International Journal of Engineering
Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 2, March -April 2013, pp.469-473
Recovery Of Copper From Printed Circiut Boards Through
Electrolytic Process –A Case Study
S.Pradeep Kumar1, S.Govindaradjane2, T.Sundararajan3
1
Assistant Professor, Department of Civil Engineering,
CK College of Engineering and Technology, Cuddalore-607003
2,3
Associate Professor and Professor, Department of Civil Engineering,
Pondicherry Engineering College, Puducherry-605014
ABSTRACT
Printed Circuit Boards (PCBs) collected
from local sources were used for recovering impact on human health and environment,
copper by electrolytic process, using a laboratory especially, in countries like: China, India, Pakistan,
reactor setup of working volume 15 liters and Ghana and Nigeria (Huo et.al, 2007; Kuper and
nitric acid for dissolution. Copper plate was used Hojsik, 2008 and Manhart, 2010).
as the cathode and graphite rod as the anode for PCB as a key component of WEEE, can be
the deposition process. Five durations were considered as a significant raw material due to its
adopted both for the dissolution and deposition complex composition, mainly consisting of metals
processes. Based on the above investigations it (40%), organics and ceramics (each 30%). Among
found that 5 hours for 132 gm copper has the various metals that are typically present in PCBs,
dissolved and the maximum copper deposited was copper is available in large quantity (27%), which
14.861 gm in 120 minutes, which is equal to 12% has considerable material value. Hence, efforts were
of maximum recovery of copper from the PCBs. directed to recover metals from PCBs, through best
The maximum power consumption is found to be available technologies, which helps not only manage
0.0214 kWh for 14.861 gm of copper recovered. hazardous substances scientifically, but also, to
The maximum copper (Cu) recovered in 120 reduce dependencies on primary metal resources.
minutes of the deposition process can be Two major techniques, namely,
considered as the optimum for the 5 L of Pyrometallurgical and Hydrometallurgical, were
dissolved solution. There is scope to refine the widely recognized for recovery of metal from e-
process and scale it up, if proper funding and waste (Cui and Zhang, 2008; Quinet et.al, 2005) and
facilities are made available. in the last decade the attention has moved to
hydrometallurgical process. Several investigators
Keywords – E-waste management, electrolytic cell have reported the feasibility of copper recovery by
process, operating conditions, recovery of copper, electrodeposition techniques (Oishi et.al, 2007;
recycling. Masavetas et.al, 2009). However, it has also been
reported that attention has been paid very rarely to
the relationship between the applied electrolytic
I. INTRODUCTION conditions and the recovered copper (Masavetas
Rapid technological progress made in
et.al, 2009). Hence, in this study recovery of copper
electronics, especially in the last decade, has led to
from PCBs, using the electrolytic process has been
very frequent replacement of electronic equipment.
investigated and an attempt has also been made to
Thus, used electrical and electronic equipment ended
study the performance of the copper recovery
up as waste materials. Waste Electrical and
process, based on the operational parameters such
Electronic Equipment (WEEE), popularly known as
as: electrolysis duration, energy consumption etc.
e-waste, is reported to be generated in the range of
20 to 50 million tones (MT), in the world (Heart,
2009). Printed Circuit Boards (PCBs) represent 3% II. MATERIALS AND METHODS
of mass of global WEEE generated (Dalrymple et.al, a) Printed Circuited Boards
2007). E-waste in general contains hazardous Based on the available literature, it was
substances, such as, toxic metals (Cadmium, found that there are no separate collection systems in
mercury etc.) and persistent organic pollutants (e.g.: India, and hence there is no authentic data available
halogenated flame retardants). Due to significant on the quantity generated and disposed-off every
risks to human health and environment posed E- year, and the resulting environmental risk. However,
waste, legislations have been enacted all over the a field survey conducted by the authors (Pradeep
world, for their collection, recycling and safe Kumar et al., 2013) on the IT industries located in
disposal. In spite of the existence of specific Puducherry (India), revealed that the general
legislation, recycling activities are mostly carried out awareness on the potential hazardous nature of e-
in poor working conditions, leading to adverse waste is rather poor, and that no attempt has been
469 | P a g e
2. S.Pradeep Kumar, S.Govindaradjane, T.Sundararajan / International Journal of Engineering
Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 2, March -April 2013, pp.469-473
made to recover metals, in spite of the fact that the anode and stainless steel mesh of diameter 100 mm
total e-waste generation is 11.06 TPA (at present). as the cathode for dissolution process. Copper plate
Hence, waste PCBs were collected from various of 40 mm width, 150 mm length and 10 mm thick
local sources and used as source material for the was used in the recovery process as cathode and the
present study. The waste PCBs were used in “as is same dimensional graphite rod was used as a anode
where is” basis, i.e. used in “as collected form”, in the recovery process. A direct current (DC) power
without giving any pretreatment. supply and a multimeter was used to measure the
current and voltage during the electrolytic process.
b) Electrolytic reactor setup The experimental setup adopted is shown in Fig. 1,
A glass reactor of working volume of 15L which is based on the one reported by Zeljko
was used for electrolytic process. The setup Kamberovic et.al, (2011).
consisted of a graphite rod of 25 mm diameter as the
Fig.1. Experimental setup of the electrolytic process
concentrated nitric acid (HNO3) was added first and
c) Methodology after that 300 gm sodium nitrate (NaNO3) was
The experimental methodology has been carried out added. (Nitric acid was added as it can dissolve
in three stages. The selection and preparation of metals like lead, tin and copper, but it does not
source material (PCBs) as a first stage, followed by dissolve gold). Nitric acid is steadily consumed
dissolution of metal present in PCBs into the during the dissolution and hence it has to be added
prepared solution as a second stage and finally periodically. Sodium nitrate was added in the bath as
recovery of the dissolved metals from the solution it helps to maintain the electrical conductivity of the
by electrolytic process, at the third stage. Capacitors, bath and hence the release of nitrate ions. Sulphuric
ICs, joints, mountings, etc. were removed from the acid could not be used as it does not dissolve copper,
PCBs and sorted manually. The PCBs were then cut but, it reacts with lead forming lead sulphate, which
into pieces as small as possible, and the cut pieces is water insoluble. The probable chemical reactions
were weighed. The weighed PCBs were then placed involved in the dissolution process are given in Eqn.
in the reactor. It was ensured that the cut pieces are (1).
in maximum contact with the graphite anode to
enhance the dissolution of the metal in the PCBs by HNO3 H+ + NO3-
+
improving the conductivity. The anode set was NaNO3 Na + NO3-
+
connected to the positive terminal of the rectifier and Na + H2O NaOH + H2 … (1)
stainless steel mesh was connected to the negative H2O H+ + OH-
terminal of the rectifier (current 1 A and voltage 0- H2O + 2OH- ½ O2 + H+
12V). Maximum possible current was set to carry Dissolution of metals present in PCBs takes place
out the experiment and the voltage was maintained according to the following reactions: [Eqn. 2(a) to 2
such that to achieve maximum current and hence (c)]
rate of dissolution. In the process, 5 liters of distilled For Copper:
water was taken in a container, then 500 ml Cu + NO3- Cu (NO3)2 + 2e- …2(a)
470 | P a g e
3. S.Pradeep Kumar, S.Govindaradjane, T.Sundararajan / International Journal of Engineering
Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 2, March -April 2013, pp.469-473
For Lead: III. RESULTS AND DISCUSSION
Pb + NO3- Pb(NO3)2 + 2e- …2(b) a) Effect of electrolysis duration on dissolution
For Tin: and deposition process
Sn + 2NO3- Sn(NO3)2 + 2e- In the five sets of experiments that were conducted
-
Sn + 4NO3 Sn(NO3)4 + 4e- …2(c) for the dissolution and deposition processes the
Sn(NO3)4 + H2O Sn(OH)4 + HNO3 duration for the dissolution process was 5, 4, 3, 2, 1
Sn(OH)4 (Ignite) SnO2 (Fusion with alkali) Na2SnO3 hours and the initial amount of PCBs taken for the
dissolution process was 500 gm for every set of
The remains in the reactor were taken out, dried, experiment. Weight of the dried sample of PCBs
weighed, and the weight loss in the scrap was was noted after 5 hours of dissolution process and it
calculated, which is equal to the amount of metals was found that 132 gm was dissolved in nitric acid
that have gone into solution. The current, voltage bath. The results obtained during the dissolution and
and time were measured so as to calculate the energy deposition processes were presented in Figs 2 to 4.
consumed for the dissolution of metals. Based on the analysis of the results obtained, critical
The copper plate was polished by emery paper, inferences are drawn as detailed below:
cleaned with acetone and after drying the plate, its (i) Weight of PCBs dissolved goes on gently
initial weight was noted. This copper plate was increasing, with the rate of increase being
connected to negative terminal (cathode) and higher during initial stages, and stabilises at
graphite rod was connected to positive terminal latter stages, within the range of duration
(anode) of the rectifier. Both electrodes were dipped considered.
in solution and an external supply was given. The (ii) However, the weight of copper deposited in
copper ions in the solution move to the cathode for the cathode plate almost increases linearly
deposition. The probable reactions at anode and with time, barring the initial stage.
cathode are given in Eqn. 3(a) to 3(c) (iii) On the other hand, power consumption
Reaction at Anode: during the dissolution and recovery
H2O + 2OH- ½ O2 + H+ … (3a) processes with time, almost exhibit the
+
2H H2 … (3b) same trend.
Reaction at Cathode: Initial weight of the copper plate was noted for the
Cu2+ + 2e- Cu (deposited on cathode) … (3c) deposition process and after the electro deposition of
copper the deposited weight of copper in the cathode
A study was also conducted to analyze the governing electrode was assessed by taking the weight. The
parameters like: electrolysis duration both during for duration for the deposition process was set as: 120,
the dissolution and deposition processes. The study 90, 60, 30, 15 minutes. It was found that 14.861 gm
was also extended to understand effect of pH, energy of copper deposited during 120 minutes is the
consumption during both the dissolution and highest, among all the durations considered. It is
deposition processes, the relation between found that the maximum copper (Cu) recovered was
electrolysis duration with energy consumption for 12% and achieved after 120 minutes, in 5 L of
recovering the maximum percentage of copper. dissolved solution.
140
Wt. of PCBs (gm) dissolved
120
100
in solution
80
60
40
20
0
0 100 200 300 400
Time (min.)
Fig.2. Time (min.) Vs Weight of PCBs dissolved in
solution (gm)
471 | P a g e
4. S.Pradeep Kumar, S.Govindaradjane, T.Sundararajan / International Journal of Engineering
Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 2, March -April 2013, pp.469-473
the reaction that is undergoing in the reactor. At the
16
end of the electrolytic process, pH was reduced to
Wt. of Cu deposited in cathode
14 near „neutral‟, by adding Na2 Co3 and NaOH (i.e.
12 12 gm / 100 ml and 7.2 gm /100 ml of acidic
10 solution), before it is disposed off, in an eco-
plate(gm)
8 friendly manner.
6 c) Energy consumption
4 Specific electrical energy consumption is
2 defined as the amount of electrical energy
0 consumed per unit mass of E-waste loaded and it
was calculated in terms of kilo watt hour (kWh)
0 50 100 150 one gram of copper recovered (kWh g-1 Cu). The
Time (min.) maximum power or energy consumption was found
to be 0.0214 kWh for 14.861gm of copper
recovered (Figs. 6&7). It can be seen that as the
Fig.3 Time (min.) Vs Weight of Copper deposited in cathode plate
power consumption increases drastically, as the
(gm)
weight of PBS dissolved in solution increases.
0.06 However, the weight of copper deposited increases
gently with increase in power.
0.05
140
Power (kWh)
0.04
Wt. of PCBs (gm) dissolved in 120
0.03
100
0.02
solution
80
0.01
0 60
0 100 200 300 400 40
Time (min.) 20
0
Fig.4 Time (min.) Vs Power consumption for
dissolution process (kWh) 0 0.02 0.04 0.06
0.025 Power (kWh)
0.02 Fig.6 Power (kWh) Vs Weight of PCBs dissolved
in solution (gm)
Power (kWh)
0.015
16
Wt. Cu deposited in cathode plate
0.01 14
12
0.005 10
8
0
(gm)
6
0 50 100 150
4
Time (min.) 2
0
Fig.5 Time (min.) Vs Power consumption for
recovery process (kWh) 0 0.005 0.01 0.015 0.02 0.025
b) Effect of pH
Power (kWh)
The pH of the solution i.e. in dissolution
process and deposition process was 1.0 (i.e. very
highly acidic), due to the usage of nitric acid for Fig. 7 Power (kWh) Vs Weight of Copper
dissolution of metals. No addition of any buffer deposited in cathode plate (gm)
solution was made for the study of pH variation in
the experimental investigations, as it would affect
472 | P a g e
5. S.Pradeep Kumar, S.Govindaradjane, T.Sundararajan / International Journal of Engineering
Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 2, March -April 2013, pp.469-473
IV. CONCLUSION of Industerial Ecology, 15(1): 13-30,
i. For the recovery of copper from E-waste 2010.
(PCBs), the maximum duration for the 8) Masavetas I, Moutsatsou, Nikolaou,
dissolution process was found to be 5 Spanou S, Zoikis-Karathanasis A,
hours for the dissolution of 132 gm of Pavlatou E A, Spyrellis N, Production of
PCBs compounds and the maximum copper powder from PCBs by
duration of electrolysis for deposition of electrodeposition, Global NEST Journal,
copper was 120 minutes for 14.861 gm. 11(2): 241-247, 2009.
ii. The maximum power consumption was 9) Oishi T, Koyama K, Alan S, Tanaka M
0.0214 kWh for 14.861 gm of copper and Lee H, Recovery of high purity
recovered. copper cathode from PCBs using
iii. Maximum copper (Cu) recovered is 12% ammoniacal sulfate or chloride solution,
and it was achieved in 120 minutes using Hydrometallurgy, 89: 82-88, 2007.
5 L of dissolved solution. 10) Pradeep Kumar S, Govindaradjane S,
iv. The performance of the process seems to Sundararajan T, Management strategies
depend on the choice of the electrolyte, for various E-waste generators in
the initial state of PCBs, duration and Puducherrt region – A case study.
power consumed duration the dissolution International Journal of Emerging
and deposition stages. Technology and Advanced Engineering,
v. There is scope for improvement in the 3(1): 546-551, January 2013.
process and scaling it up, with the support 11) Quinet P, Proost J, Van Lierde A,
for research from funding agencies, as Recovery of precious metals from
laboratory investigation has its own electronic scrap by hydrometallurgical
limitations. processing routes, Miner. Metall. Process,
22(1): 17-22, 2205.
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1) Cui. J, Zhang L, Metallurgical recovery of
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