The document discusses adsorption as a treatment method for removing pollutants like dyes and heavy metals from industrial effluents. It covers topics like the chemistry of adsorption, adsorption isotherms, factors affecting adsorption like pH and temperature. It also discusses the use of agricultural waste materials as low-cost adsorbents for wastewater treatment and their characterization. Activating the agricultural wastes through chemical or physical treatment can enhance their adsorption capacity. Analytical techniques are used to study the surface properties of adsorbents and how they influence adsorption.
Adsorption, types of adsorption, physisorption, chemisorption, mechanism of adsorption, Difference between adsorption and absorption, Factors affecting adsorption, applications of adsorption-
Gas masks
Adsorption indicators
Chromatographic separation
Removal of coloring matter
Heterogeneous catalysis
Controlling humidity
Curing diseases
Froth flotation process
Production of high vacuum
Purification,
adsorption equilibrium, adsorption isotherms, Langmuir isotherm- assumptions, Langmuir equation, limitations of Langmuir isotherm, equation, Freundlich isotherm- Assumptions of Freundlich Isotherm,Limitations of Freundlich Isotherm,Differences between Freundlich and Langmuir adsorption isotherms, BET isotherm-Drawbacks of BET adsorption theory, Types of BET adsorption isotherms, Differences between Langmuir and BET adsorption isotherm, Applications of BET isotherm, Why is Langmuir surface area always higher than BET surface area?
Temkin isotherm, D-R isotherms, Drawbacks of D-R Isotherm, Drawbacks of Temkin Isotherm, Uses of D-R isotherms, applications of adsorption isotherms -Spontaneity,
Exothermicity,
Percentage removal of adsorbate,
Langmuir parameters- maximum adsorbent uptake and affinity between adsorbent and adsorbate,Freundlich parameters- adsorption capacity of adsobents.
BET isotherms- specific surface area, pore size distribution curves
D-R parameters- adsorption mechanism
Temkin parameters- adsorbent-adsobate interactions
Adsorption, types of adsorption, physisorption, chemisorption, mechanism of adsorption, Difference between adsorption and absorption, Factors affecting adsorption, applications of adsorption-
Gas masks
Adsorption indicators
Chromatographic separation
Removal of coloring matter
Heterogeneous catalysis
Controlling humidity
Curing diseases
Froth flotation process
Production of high vacuum
Purification,
adsorption equilibrium, adsorption isotherms, Langmuir isotherm- assumptions, Langmuir equation, limitations of Langmuir isotherm, equation, Freundlich isotherm- Assumptions of Freundlich Isotherm,Limitations of Freundlich Isotherm,Differences between Freundlich and Langmuir adsorption isotherms, BET isotherm-Drawbacks of BET adsorption theory, Types of BET adsorption isotherms, Differences between Langmuir and BET adsorption isotherm, Applications of BET isotherm, Why is Langmuir surface area always higher than BET surface area?
Temkin isotherm, D-R isotherms, Drawbacks of D-R Isotherm, Drawbacks of Temkin Isotherm, Uses of D-R isotherms, applications of adsorption isotherms -Spontaneity,
Exothermicity,
Percentage removal of adsorbate,
Langmuir parameters- maximum adsorbent uptake and affinity between adsorbent and adsorbate,Freundlich parameters- adsorption capacity of adsobents.
BET isotherms- specific surface area, pore size distribution curves
D-R parameters- adsorption mechanism
Temkin parameters- adsorbent-adsobate interactions
adsorption of methylene blue onto xanthogenated modified chitosan microbeadsSiti Nadzifah Ghazali
Methylene Blue (MB) is thiazine dyes that widely use to color product in many industry such as textile, printing, leather, cosmetic and paper. Xanthogenated-Modified Chitosan Microbeads (XMCM) is use to observe the new alternative adsorbent in removing MB from water body through adsorption process. The interactions between MB and functional group in XMCM were confirmed by Fourier Transform Infrared (FT-IR) spectra. Several parameters that influence adsorption ability such as the effect of adsorbent dosage of XMCM and the effect of initial pH of MB aqueous solution were studied. This study were done at optimum condition which is at pH 4 of initial pH of MB solution, 0.01 g of initial XMCM dosage, 6 hours stirring time and temperature of (30 ± 2 ℃). The adsorption data fit well Langmuir model more than Freundlich model. Based on Langmuir model, the maximum monolayer adsorption capacity of MB was 21.62 mg g-1 which indicated that XMCM can be a new alternative adsorbent for removing MB.
Aimed to investigate the potential of untreated jute stick charcoal as an alternative adsorbent for the treatment of dye containing wastewater. Removal of methylene blue dye from aqueous solution using jute stick charcoal has been investigated. Liquid phase adsorption experiments were conducted. Batch adsorption studies are carried out by observing the effect of experimental parameters, namely, pH, adsorbent dose, contact time and initial methylene blue concentration. The maximum removal of MB dye was 90.57% at pH 9, contact time 120 min, adsorbent dose 3 g/L and 20 mg/L initial dye concentration. Kinetic studies showed that the biosorption of MB followed Pseudo second-order kinetics. The adsorption isotherms are described by the Langmuir and Freundlich isotherms. It was found that the Freundlich equation fit better than the Langmuir equation. The maximum adsorption capacity obtained from Langmuir isotherm equation at was 29.33 mg/g. To conclude, jute stick charcoal holds promise for methylene blue removal from aqueous solution and can be used for other dyes removal and applicable in dyeing industries in Bangladesh where centralized effluent treatment plant is absent.
Activated carbon is a form of carbon processed to be riddled with small, low-volume pores that increase the surface area available for adsorption or chemical reactions.
Wastewater got much of our intention these days because wastewater is polluting our lakes, pounds and even sea have a lot of
contaminated amount of waste. This water is hazardous for the acute life, dangerous for living things. Wastewater polluted the natural
reservoirs. Over the past, the knowledge of the mechanisms of electrochemical wastewater treatment has progressively evolved. A
comprehensive understanding of the types of methods and mechanisms of treatment of wastewater is a prerequisite to the understanding of
their relativities and elucidation of intermediate products generated during the oxidation process and degradation pathways. The type,
nature, and quantity of reactive species generated in electrochemical treatment processes are controlled by many factors, including the type
of the treatment technique, electrode/electro catalyst materials, water/wastewater composition, water pH conditions, and operating
parameters are to be considered. Multiple methods such as separation, conversion and combined methods are used for treatment. However,
basic principle works on the electrochemical mechanism. This article gives the basic idea of electrochemical methods working principles,
techniques being considered. It will also help us understand the byproducts recovery of different metal ions and how they converted into
useful form. Best methods based on the efficiency and economic value. Feasibility of long term and short term methods for the treatment of
wastewater.
Dye removal by adsorption on waste biomass - sugarcane bagasseMadhura Chincholi
The dye solution of Methylene blue was adsorbed onto bioadsorbent- sugarcane bagasse. Parameters studied were pH, contact time, adsorbent dosage, initial dye conc.
Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or ...hrishikesh261005
Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. This process differs from absorption, in which a fluid (the absorbate) is dissolved by or permeates a liquid or solid (the absorbent). While adsorption does often precede absorption, which involves the transfer of the absorbate into the volume of the absorbent material, alternatively, adsorption is distinctly a surface phenomenon, wherein the adsorbate does not penetrate through the material surface and into the bulk of the adsorbent. The term sorption encompasses both adsorption and absorption, and desorption is the reverse of sorption.
adsorption of methylene blue onto xanthogenated modified chitosan microbeadsSiti Nadzifah Ghazali
Methylene Blue (MB) is thiazine dyes that widely use to color product in many industry such as textile, printing, leather, cosmetic and paper. Xanthogenated-Modified Chitosan Microbeads (XMCM) is use to observe the new alternative adsorbent in removing MB from water body through adsorption process. The interactions between MB and functional group in XMCM were confirmed by Fourier Transform Infrared (FT-IR) spectra. Several parameters that influence adsorption ability such as the effect of adsorbent dosage of XMCM and the effect of initial pH of MB aqueous solution were studied. This study were done at optimum condition which is at pH 4 of initial pH of MB solution, 0.01 g of initial XMCM dosage, 6 hours stirring time and temperature of (30 ± 2 ℃). The adsorption data fit well Langmuir model more than Freundlich model. Based on Langmuir model, the maximum monolayer adsorption capacity of MB was 21.62 mg g-1 which indicated that XMCM can be a new alternative adsorbent for removing MB.
Aimed to investigate the potential of untreated jute stick charcoal as an alternative adsorbent for the treatment of dye containing wastewater. Removal of methylene blue dye from aqueous solution using jute stick charcoal has been investigated. Liquid phase adsorption experiments were conducted. Batch adsorption studies are carried out by observing the effect of experimental parameters, namely, pH, adsorbent dose, contact time and initial methylene blue concentration. The maximum removal of MB dye was 90.57% at pH 9, contact time 120 min, adsorbent dose 3 g/L and 20 mg/L initial dye concentration. Kinetic studies showed that the biosorption of MB followed Pseudo second-order kinetics. The adsorption isotherms are described by the Langmuir and Freundlich isotherms. It was found that the Freundlich equation fit better than the Langmuir equation. The maximum adsorption capacity obtained from Langmuir isotherm equation at was 29.33 mg/g. To conclude, jute stick charcoal holds promise for methylene blue removal from aqueous solution and can be used for other dyes removal and applicable in dyeing industries in Bangladesh where centralized effluent treatment plant is absent.
Activated carbon is a form of carbon processed to be riddled with small, low-volume pores that increase the surface area available for adsorption or chemical reactions.
Wastewater got much of our intention these days because wastewater is polluting our lakes, pounds and even sea have a lot of
contaminated amount of waste. This water is hazardous for the acute life, dangerous for living things. Wastewater polluted the natural
reservoirs. Over the past, the knowledge of the mechanisms of electrochemical wastewater treatment has progressively evolved. A
comprehensive understanding of the types of methods and mechanisms of treatment of wastewater is a prerequisite to the understanding of
their relativities and elucidation of intermediate products generated during the oxidation process and degradation pathways. The type,
nature, and quantity of reactive species generated in electrochemical treatment processes are controlled by many factors, including the type
of the treatment technique, electrode/electro catalyst materials, water/wastewater composition, water pH conditions, and operating
parameters are to be considered. Multiple methods such as separation, conversion and combined methods are used for treatment. However,
basic principle works on the electrochemical mechanism. This article gives the basic idea of electrochemical methods working principles,
techniques being considered. It will also help us understand the byproducts recovery of different metal ions and how they converted into
useful form. Best methods based on the efficiency and economic value. Feasibility of long term and short term methods for the treatment of
wastewater.
Dye removal by adsorption on waste biomass - sugarcane bagasseMadhura Chincholi
The dye solution of Methylene blue was adsorbed onto bioadsorbent- sugarcane bagasse. Parameters studied were pH, contact time, adsorbent dosage, initial dye conc.
Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or ...hrishikesh261005
Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. This process differs from absorption, in which a fluid (the absorbate) is dissolved by or permeates a liquid or solid (the absorbent). While adsorption does often precede absorption, which involves the transfer of the absorbate into the volume of the absorbent material, alternatively, adsorption is distinctly a surface phenomenon, wherein the adsorbate does not penetrate through the material surface and into the bulk of the adsorbent. The term sorption encompasses both adsorption and absorption, and desorption is the reverse of sorption.
Removal of Heavy Metals from Aqueous Solutions by Modified Activated Carbon f...inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Type of adsorption- Pharmaeutical Physical ChemistrySanchit Dhankhar
Adsorption
Adsorption versus absorption, Desorption
Types of adsorption: Physisorption and Chemisorption
Factors affecting adsorption
Adsorption isotherms: Freundlich and Langmuir
Gibbs adsorption isotherm
Bet equation and its use in surface area determination
Applications
ADSORPTION
Adsorption is the process in which matter is extracted from one phase and concentrated at the surface of a second phase. (Interface accumulation). This is a surface phenomenon as opposed to absorption where matter changes solution phase, e.g. gas transfer. This is demonstrated in the following schematic.
A Method For Evaluating the Sorption Capacity of The SorbentsIJMERJOURNAL
ABSTRACT: A new method for evaluating the sorption capacity of the sorbents is offered. The proposed model is based on the adsorption data of the sorbent depending on the sorption duration in static mode. The new model allows to quickly and easily evaluate the duration of sorbent saturation. The formula of this relationship is determined by means of plotting of sorbent saturation curve on the base of experimental data, and using of Exel Trendline program. After the appropriate calculations and plotting q from time the sorption capacity of the sorbent is estimated. The model, as a primary parameter, includes time. The experimental data were obtained on the base of peat-containing sorbent for sorption of copper and cobalt. Sorption processes were evaluated by ICP-MS.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Immunizing Image Classifiers Against Localized Adversary Attacks
Adsorption
1. ADSORPTION
Submitted to:
Professor Atif Mustafa
Environmental Engineering Department
N.E.D. UET KARACHI
Prepared By:
Abu Umeer (EN-22/2018-19)
u.ahmed8@yahoo.com
Subject:
Physico-Chemical Processes
EN-22/2018-19 1
3. Textile industries consume (up to 150 l of water to dye 1 kg of
cotton)(Jadhav et al. 2010).
Rated as high dye polluters.
Environmental pollution, is a global concern.
Dye is a colored, aromatic organic compound.
Inert and difficult to biodegrade when
discharged into waste streams.
Heavy metal contamination into the aqueous media
and in industrial effluents is a major ecological problem
due to their toxic nature.
BACKGROUND
EN-22/2018-19 3
5. EN-22/2018-19 5
Flexibility and
simplicity of
design,
Low operating
cost,
insensitivity to
toxic pollutants
ease of
operation.
Adsorption also
does not
produce harmful
substances
Adsorption has been found to be superior to other techniques in terms of
• Introduction
6. Adsorption processes: Applications
- SO2 from vent gases
- H2O from air, methane, N2
- Removal of solvent, odours
from air
- NOx from N2
- Organics from water solution
- Water from organic solution
- Decolourization
Purifications: Separations:
- Removal of organics from - N2/O2
vent gases
- Acetone from ventstream
- C2H4 fromvent
- Normal paraffins/ Iso praffins
- CO, CH4, CO2, N2, Ar from
hydrogen
- Normal paraffins from Iso paraffins
- Normal paraffins from olefins
gasphaseliquidphase
EN-22/2018-19 6
7. • adsorbate does diffuse into the structure
of the adsorbent (in this case indeed the process is
called absorption).
• Adsorption is the process when a molecule, or ion, called
adsorbate present in a gaseous or liquid bulk sticks on the
surface of a solid, rarely a liquid, called adsorbent.
• The reverse process, that is, the drop of a
molecule from a solid surface, is called desorption
It is a surface process, that is, only the surface of the adsorbent
is involved,
EN-22/2018-19 7
8. adsorbate: material being adsorbed
adsorbent: material doing the adsorbing.
(examples are activated carbon or ion
exchange resin).
Example:
If we have to remove soluble material from the solution phase, but the
material is neither volatile nor biodegradable, we often employ adsorption
processes.
9. THE CHEMISTRY OF ADSORPTION
When the adsorbate adheres
to the surface because of
physical forces.
If the adsorbate molecules
hit the surface with low
energy, it is dissipated as
heat by vibration of the
lattice of solid; hence, they
are trapped on the surface.
If the molecules hit the
surface with too much
energy, this cannot be
dissipated by the adsorbent,
and they bounce away.
When the adsorbate is chemically bound (usually
covalent) to the adsorbent’s surface.
It can be activated process, it requires that the
adsorbate has a minimum of E in order to be sorbed.
This depends on the presence of an energetic barrier
between the physiosorbed and chemisorbed state
(Figure A):
If B>E , then the adsorbate will chemically bond to
the adsorbent only if it has more energy than the
barrier, otherwise it will be desorbed.
If B<E, all the molecules physiosorbed can quickly
form a chemical bond with the adsorbent surface and
chemisorption will occur rapidly.
Irreversible. Monolayer, ΔΗ ≥ 40 ≤ 400 kJ mol1, @ 20 ⁰C ≈ 1 h, /100 ⁰C ≈ 1 s.Reversible, Multilayer, ΔΗ≤.20kj/mol, @20 ⁰C≈108
𝑠 / -170⁰c=S
EN-22/2018-19 9
10. Δ H c
Δ
H c
d
Δ H p Δ H p
E a,c
d
Figure (A) Diagram of energy of adsorption depending on distance (d) of adsorbate molecule from surface.
• Solid line is for physisorption, involving low enthalpy (Hp),
• Dashed for chemisorption, where the energy required is higher (Hc).
• On the left is the case of activated chemisorption: Ea,c is the activation
energy for chemisorption.
EN-22/2018-19 10
12. • adsorption is described through a relationship independent from time between the amount of adsorbate attached to the
adsorbent and the amount in the environment (expressed as a pressure if it is a gas, a concentration if it dissolved in a solution).
• In case of dissolved adsorbate,
•
where q (mg 𝑔−1
) is the mass adsorbed per mass unit of adsorbent.
• C (mg/l) the concentration of adsorbate in the environment.
• Such relationships are called isotherms, which means that their validity is limited to the case of constant temperature.
There are several kinds of isotherms.
The most used are the isotherm of
• Langmuir
• isotherm of Freundlich.
EN-22/2018-19 12
13. Described by the following equation:
where qm (mg/ g) is the maximum amount of adsorbate in the adsorbent.
b (l/mg) is the equilibrium constant related to the enthalpy of the process.
Four hypotheses are behind this formulation.
1. Adsorbate attach only on particular sites, that is, they establish a link with the adsorbate (by of van der Waals forces or
chemical bonds).
2. Adsorption occurs only in a monolayer, that is, once a site is occupied by a molecule, it cannot bind to another one: this leads
to the saturation shape of the isotherm.
3. Last two assumptions can be summarized stating that Adsorption occurs homogeneously (even if discreetly) on the surface.
The Langmuir isotherm
EN-22/2018-19 13
14. Freundlich isotherm
Described by the following equation:
Where,
• a (mg/g) is the mass adsorbed with a unitary concentration.
• n is an empirical constant usually greater than 1.
• Freundlich model is not empirical but it is
theoretically based.
Assumptions:
1) Adsorption is Multilayer.
2) Energy required for adsorption is not constant, it
varies and it is exponentially distributed.
Another isotherm that fits well the data of adsorption of gases on solids is the BET isotherm (Brunauer, Emmet, Teller).
The main assumption :
The first layer of adsorbate can adsorb on its another layer,
EN-22/2018-19 14
15. Langmuir-Freundlich-BET
C , z
Figure (B):
They describe the amount of adsorbate expressed in term of mass fraction q (or fraction of sites
occupied for BET) depending on its concentration C (or on pressure of gaseous adsorbate relative to
Langmuir
BET
Freundlich
• Langmuir isotherm is shown in Figure B. The shape of
the curve clearly depends on parameters; however,
usually the saturation is reached quite fast
• The Freundlich curve (Figure B): the
slope decreases when concentration of
adsorbate increases.
BET isotherm implies an endless
adsorption, even if in this case the slope of
the curve increases with the pressure of
adsorbate (Figure B).
EN-22/2018-19 15
16. • Effect of Various Physicochemical Process Parameters on Heavy Metal and Dye Adsorption:
The efficiency of liquid phase adsorption process in solids is dependent on:
adsorbent properties (surface area, pore structure, chemistry of the surface, particle size, etc.)
adsorbate properties (molecular weight, molecular structure, molecular size, polarity, etc.).
Solution PH
Temperature
Contact time
Initial solution
concentration
Presence of other
ions
Many physicochemical factors such as
Investigation of these parameters can give information on the
Adsorption mechanism that is of fundamental importance in
selecting (Adsorbent) and preparation conditions to be used for the
efficient adsorption of a specific Adsorbate (heavy metal or dye).
EN-22/2018-19 16
17. Process parameters
Effects on adsorption of pollutants (heavy metals and ionic dyes)
Solution pH ↑ It enhances adsorptive removal of cationic metals or basic dyes but reduces that of anionic metals or
acidic dyes.
Initial adsorbate
concentration ↑
It increases the quantity of adsorbed pollutant per unit weight of adsorbent but decreases its removal
efficiency.
Temperature ↑ It usually enhances adsorptive removal of water pollutant by increasing surface activity and kinetic
energy of the adsorbate but may damage physical structure of adsorbent.
Adsorbent dosage ↑ It decreases the quantity of adsorbed pollutant per unit weight of adsorbent but increases its removal
efficiency.
Addition of salt ↑ It reduces adsorptive removal of adsorptive pollutant by competing with the adsorbate for binding sites
of adsorbent.
Adsorbent size ↓ It is favorable for batch process due to higher surface area of the adsorbent, but not for column process
due to its low mechanical strength and clogging of the column.
Agitation speed ↑ It enhances adsorptive removal rate of adsorptive pollutant by minimizing its mass transfer resistance
but may damage physical structure of adsorbent.
Table: Influences of physicochemical process parameters on adsorption capacity of water pollutants,
such as metals and dyes modified from (Park et al. 2010)
EN-22/2018-19 17
18. Adsorbents Adsorbates (heavy metals and
dyes)
Initial concentration
range (mg L−1)
Percentage (%)
removal range
References
Tomato waste (acid treated) Cu(II) 25–125 Decrease Yargıç et al.
(2015)
Cucumber peel (chemically
modified)
Remazol black 5 5–150 94.82–21.84 Sayğılı and
Güzel
(2017)
Tomato seeds Acid red 14 50–150 89–85 Najafi et al.
(2015)
Sugarcane bagasse Basic blue 9 250–500 94–55.5 Zhang et al.
(2013)
Table (a) The effect of initial concentration of heavy metals and dyes using several agricultural
solid waste adsorbents
Adsorbents Adsorbates (heavy
metals and dyes)
pH range Percentage (%)
removal range
References
Tomato leaf powder Ni2+ 2–5.5 Increase Gutha et al. (2015)
Rice husk Zn2+ 4–8 Increase Galletti et al. (2015)
Coffee waste Toluidine blue 2.0–10.5 50–95 Lafi et al. (2014)
Cucumber peels Methylene blue 2–10 13.44–77.70 Akkaya and Güzel
(2014)
Potato peel waste Acid blue 1 2–11 Decrease Hoseinzadeh et al.
(2014)
Table (b) The effect of solution pH on the adsorption of heavy metals and dyes by different
agricultural solid waste adsorbents.
`
Adsorbents Adsorbates (heavy
metals and dyes)
Temperature
range
(°K)
Type of References
Process
Tomato leaf Ni2+ 303–323 Endothermic Gutha et al. (2015)
Tomato waste
derived biochar
Co2+ 293–313 Endothermic Önal et al. (2014)
Rice husk (nitric acid
treated)
Malachite green 303–333 Endothermic Ramaraju et al. (2013)
Sugarcane bagasse Rhodamine B 303–323 Endothermic Zhang et al. (2013)
Adsorbents Adsorbates
(heavy metals
and dyes)
Adsorbent
dosage
Percentage
(%) removal
range
References
Bagasse pith (sulfurized
activated carbon)
Zn2+ 0.5–8 g L−1
Increase Krishnan et al. (2016)
Sugarcane bagasse
(sulfuric acid treated)
Cu2+ 0.5–2 g 100
mL−1
Increase Rana et al. (2014)
Cucumber peel (modified) Direct blue 71 0.1–1.0 g 41.92–97.60 Sayğılı and Güzel (2017)
Tea waste Acid orange 7 2–20 g L−1
90–99 Khosla et al. (2013)
Table (c) Influence of solution temperature on heavy metal and dye adsorption using various
agricultural solid waste adsorbents
Table (d) The effect of adsorbent dosage on the percentage of heavy metal and dye removal
using several agricultural wastes as adsorbents
EN-22/2018-19 18
19. • Analytical techniques & instruments are used to characterize the physicochemical surface properties of adsorbent which further decide the
effectiveness of material as adsorbent and its suitability in adsorption field.
Role of Agricultural Solid Waste Adsorbent Characteristics on Adsorption
1. Morphology and Surface Properties of Agricultural Solid Waste Adsorbents During Adsorption:
i. Scanning Electron Microscopy (SEM): Used to examine the surface micromorphological texture of adsorbent
materials.
ii. X-ray Diffraction Spectrum Study : Investigate crystalline nature of adsorbent materials.
iii. Powder X-ray diffraction (XRD) : Measure crystalline content of adsorbent materials, crystalline phases present, spacing between
lattice planes, the preferential ordering and epitaxial growth of crystallites within the material.
iv. Point of zero Charge: The pH at which the surface charge = 0. To understand the mechanism of adsorption process under
varying pH. SEM: image of
CHARCOAL
XRD patterns of Wheat Straw adsorbents. (pHpzc): (a) raw (b) NaOH treated eucalyptus sheathiana bark.
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20. v. BET Analysis : Brunauer–Emmett–Teller (BET) equation to calculate specific surface area known as BET surface area.
vi. Particle Size: adsorbent particle size affects the surface area for adsorption. It is indicator of content uniformity, dissolution,
quality and performance of absorption rates
2. Elemental and Functional Group Analysis of Agricultural Solid Waste Adsorbents.
It is done using a CHNS/O elemental analyzer. (carbon, hydrogen, nitrogen, sulfur, and oxygen) in an adsorbent to understand the influence of
chemical properties participating in adsorption phenomenon.
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21. 3. Activation of Agricultural Solid Waste Adsorbents
Physical ChemicalBiological
i.e.: Acid and Caustic, Methanol, Formaldehyde,
etc.
boiling / heating autoclaving mechanical disruption.
Washing raw
adsorbent
with
detergents
Treatment
with organic
and inorganic
compounds
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22. Adsorbents Modifying agents Adsorbates References
Olive stone Phosphoric acid (H3PO4) Cu2+, Ni2+, and Pb2+ Bohli et al. (2015)
Leaf biomass Nitric acid (HNO3) Pb2+ Madala et al. (2015)
Sugarcane bagasse Sulfuric acid (H2SO4) Cu2+ Rana et al. (2014)
Rice husk Nitric acid (HNO3) Malachite green Ramaraju et al. (2013)
Activated agricultural solid waste adsorbents and their modifying agents used for the removal of heavy metals and dyes
Modification Treatment Advantages Disadvantages
Chemical
characteristics
Basic Enhances uptake of organics Insome cases, decrease the uptakeof
metal ions
Acidic Increases acidic functional groups on activated carbon
surface enhances chelation ability with metal species
May decrease BET surface area and pore
volume
Impregnation of foreign
materials
Enhances in-built catalytic oxidation capability May decrease BET surface area and pore
volume
Physical characteristics Heat Increases BET surface area and pore volume Decreases oxygen surface functional
groups
Biological characteristics adsorption Prolongs activated carbon bed life by rapid oxidation of
organics by bacteria before the material can occupy
adsorption sites
Thick biofilm encapsulating activated
carbon may impede diffusion of
adsorbate species
Technical advantages and disadvantages of existing modification techniques adapted from Gautam et al. (2014)
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24. 4. Adsorption with Activated Carbon Adsorbents Derived from Agricultural Biomass
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Activated carbons from biomass
Carbonization
(to enrich the carbon content and to create an initial poro
Chemical
Activation
(to enhance the pore structure of the selected adsorben
Physical
activation
Activatio
n
process
• lower temperature
• Greater carbon yield
Activation
25. EN-22/2018-19 25
Chemical and physicochemical methods Physical methods Biological methods
Explosion:
Steam, ammonia, CO2, SO2, and acids
Alkali:
CaO, ZnCl2, NaOH, NH3, and (NH4)2SO3
Acid:
H2SO4, HCl, HNO3 and H3PO4 acids
Oxidizing agents:
H2O2
O3
-Wet oxidation
Solvent extraction of lignin: -
Ethanol–water extraction
Benzene–water extraction
Butanol–water extraction
Milling:
Ball milling
Two-roll milling - Hammer
milling
Irradiation:
Ultrasound irradiation
Gamma-ray irradiation
Electron-beam irradiation -
Microwave irradiation
Others:
Hydrothermal
High pressure steaming
Extrusion
Pyrolysis
Fungi and actinomycetes:
Lignin peroxidase, manganese peroxidase,
laccase
White-rot and brown-rot fungi
The classification of pre-treatment methods for the production of activated adsorbents modified from source (Gautam et al. 2014)
26. EN-22/2018-19 26
AC from agricultural waste materials
Heavy metals and dyes
Maximum adsorption capacity
− (qm (mg g 1))
References
Almond shell Reactive red 2 1639.9 Thitame and Shukla (2016)
Egg shell wastes Acid blue 25 109.80 Tovar-Gómez et al. (2015)
Coconut shell Malachite green 214.63 Bello and Ahmad (2012)
Rice husk Basic green 4 511 Guo et al. (2003)
Pine cone Congo red 435 Dawood et al. (2014)
Bamboo dust Methylene blue 143.2 Kannan and Sundaram (2001)
Groundnut shell and pine Methylene blue 164.9 Kannan and Sundaram (2001)
Adsorption capacities qm (mg g 1) for activated carbon (AC) materials prepared from agricultural solid wastes
27. EN-22/2018-19 27
Eggshell Pb2+ 90.90 Putra et al. (2014)
Mango seeds Methylene blue 25.36 Senthil Kumar et al. (2014)
Rice husk Crystal violet 44.87 Chakraborty et al. (2011)
Adsorbents Adsorbates (heavy metals and dyes) Maximum adsorption capacity References
−1 (qm (mg g ))
Langmuir maximum adsorption capacities qm (mg g−1) of raw agricultural solid wastes used as adsorbents
28. EN-22/2018-19 28
Modified adsorbents Heavy metals and dyes
−
Maximum adsorption capacity (qm (mg g 1)) References
Sugarcane bagasse Cu2+ 30.9 Rana et al. (2014)
Rice husk Malachite green 26.6 Ramaraju et al. (2013)
Bagasse Methylene blue 69.93 (60 °C) Low et al. (2013)
Rice straw Malachite green 256.41 Gong et al. (2007)
Adsorption capacities (qm (mg g)) for modified agricultural waste adsorbent materials
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Cost Comparison
Pollutant to be
removed (dye/metal)
Adsorbent −
qmax (mg
g 1)
Relative cost of
− adsorbent (US$ kg 1)
References
Cu2+ Acid-modified sugarcane bagasse 5.35 4.76 Gupta et al. (2018)
Commercial activated carbon 5.62 56.06
Zn2+ Peanut husk charcoal 0.3681 0.4 Salam et al. (2011)
Fly ash 0.1806 0.2
Natural zeolite 1.3189 0.34
Commercial activated carbon – 0.57
Cr6+ Activated tamarind seeds 29.7 0.57 Gupta and Babu (2008)
Activated neem seeds 62.9 1.25
Sawdust 21.5 0.068
Commercial activated carbon 71.7 7.68
Hg2+ and Ni2+ Chitosan 815 and 164 16 Babel and Kurniawan (2003)
Commercial activated carbon – 20–22
Pb2+ and Zn2+ Lignin (extracted from black liquor) 1865 and 95 0.06 Srivastava et al. (1994)
Commercial activated carbon – 0.1
Methylene blue Fuller’s earth (FE) FE < CAC 0.04 Atun et al. 2003)
Commercial activated carbon (CAC) 20
Methylene blue Activated carbon prepared from rice husk (RHC)
Activated carbon prepared from straw (SC)
37.57
42.60
RHC and SC nearly
5 times cheaper than
CAC
Kannan and Sundaram (2001)
Cost comparison of low-cost adsorbents with commercially activated carbons as reported in literature
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Association of adsorbate-adsorbent particles for a good adsorption is mostly influenced by their
individual physical and chemical characteristics together with some process settings such as
solution pH, initial adsorbate concentration, adsorbent mass, solution temperature, and ionic
load of the system.
Adsorption processes are still at the stage of laboratory scale batch studies. Thus, much more
work in this area is necessary to demonstrate its possibilities on an industrial scale by
conducting pilot plant studies and designing packed bed column for continuous flow systems.
More research are needed for the sustainable valorization of post-sorption materials as
alternative other green chemical products such as fertilizers, catalyst, feed additives, etc.
Conclusion
33. EN-22/2018-19 33
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