scholarly journals Effect of Treatment on the Adsorption Capacity of Activated Carbon

2002 ◽  
Vol 20 (9) ◽  
pp. 917-925 ◽  
Author(s):  
Sirous Nouri
Keyword(s):  
Adsorption Capacity ◽  
Activated Carbons ◽  
Ph Value ◽  
Carbon Surface ◽  
Point Of Zero Charge ◽  
Molecular Forms ◽  
Model Parameters ◽  
Ionic Form ◽  
Solution Ph ◽  
Adsorption Affinity

The adsorption of p-cresol by three activated carbons, one untreated S.E.I. and the other two treated S.E.I., was carried out under controlled conditions. Such treatment led to a change in the point of zero charge (PZC) and the adsorption capacity (Qmax) of the carbon concerned. The adsorption capacity and affinity (K1) of each carbon was determined using the Langmuir homogeneous and binary models to compare the effects of different treatments on these and relative parameters. The variation of the model parameters with the solution pH was also studied. The fitted parameters obtained from both models showed the pH value had the most significant effect on the adsorption capacity (Qmax) and the adsorption affinity (K1) of a given carbon, with both quantities showing a decrease with increasing pH. It was found that the uptake of the molecular forms of the aromatic solute was dependent on the PZC of the carbons. Treatment with H2 increased the PZC whilst treatment with H2SO4 led to a decrease in this factor. At higher pH (when the solute was in an ionic form), it was found that electrostatic forces played a significant role on the extent of adsorption. Under these conditions, the adsorption of the solute depended on the concentration of its anionic form. It was shown that the effect of pH must be considered from the viewpoint of its combined effect on the carbon surface and on the solute molecules.

scholarly journals Effect of Different Treatment on the Adsorption of p-Cresol by Activated Carbon

2017 ◽  
Vol 5 (1) ◽  
pp. 55 ◽  
Author(s):  
Sirous Nouri
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Activated Carbons ◽  
Molecular Form ◽  
Carbon Surface ◽  
Ionic Form ◽  
Freundlich Model ◽  
London Dispersion ◽  
Carbon Change ◽  
London Dispersion Forces

<p>Adsorption of p-Cresol by three activated carbons (one untreated and two treated) was carried out at 301 K and at controlled pH conditions. By treating the activated carbon the PZC and adsorption capacity (Q<sub>max</sub>) of carbon change. The adsorption capacity of each carbon, by using the homogenous Langmuir-Freundlich model, was found to comparing the effect of different treatment. At pH lower than pK<sub>a</sub> of p-cresol (molecular form), it was observed that the electron density of aromatic ring and also those of the carbon surface, are the main forces involved in the adsorption process, by affecting the extent of London dispersion forces. Treating by H<sub>2</sub> increase the PZC and treating by H<sub>2</sub>SO<sub>4</sub> decrease this factor. At higher pH (in ionic form), it was found that the electrostatic forces played a significant role on the extent of adsorption. In this condition the adsorption of the solute dependent on the concentration of anionic form of the solute. The effect of pH must be considered from its combined effects on the carbon surface and on the solute molecules. It was found that the uptake of the molecular form of the aromatic solute was dependent on the PZC of the carbon.</p>

scholarly journals Efficient adsorption of benzoic acid from aqueous solution by nitrogen-containing activated carbon

2018 ◽  
Vol 2017 (3) ◽  
pp. 686-694 ◽  
Author(s):  
Hangdao Qin ◽  
Rong Xiao ◽  
Renhui Zhang ◽  
Jing Chen
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Benzoic Acid ◽  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Ph Value ◽  
Point Of Zero Charge ◽  
Dispersion Force ◽  
Solution Ph ◽  
Efficient Treatment

Abstract Adsorption is an efficient treatment process to remove benzoic acid from aqueous solution. In this study, nitrogen-containing surface groups were introduced onto activated carbon (AC) surface by modification with ammonium hydroxide, ammonium carbonate, melamine or urea. The nitrogen-containing AC samples were characterized using N2 adsorption-desorption, Boehm titration, determination of the pH of the point of zero charge (pHpzc) and X-ray photoelectron spectroscopy. The adsorption of benzoic acid from aqueous solution by nitrogen-containing AC has been studied. The Langmuir model fitted the experimental data of equilibrium isotherms better than the Freundlich model. At initial solution pH 2.1, the adsorption capacity was closely related with the amount of pyridinic and pyrrolic N on the AC surface, which indicated these two nitrogen-containing groups played an important part in the adsorption process. The enhancement of adsorption capacity was due to the strengthened π–π dispersion force between benzoic acid and the AC basal plane. Since the surface charge of AC as well as the existence form of benzoic acid varied with solution pH value, the adsorption capacity was found to be highest at pH 3.8 and dropped sharply at higher or lower pH values.

scholarly journals Dysprosium Removal from Water Using Active Carbons Obtained from Spent Coffee Ground

2019 ◽  
Author(s):  
Lorena Alcaraz ◽  
María Esther Escudero ◽  
Francisco J. Alguacil ◽  
Irene Llorente ◽  
Ana Urbieta ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Activated Carbons ◽  
Chemical Study ◽  
Bet Surface Area ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Microporous Material ◽  
Physico Chemical ◽  
Spent Coffee Ground ◽  
Coffee Ground

This paper describes the physico-chemical study of the adsorption of dysprosium (Dy3+) in aqueous solution onto two types of activated carbons synthesized from spent coffee ground. KOH activated carbon is a microporous material with a specific BET surface area of 2330 m2&middot;g-1 and pores with a diameter of 3.2 nm. Carbon activated with water vapor and N2 is a solid mesoporous, with pores of 5.7 nm in diameter and a specific surface of 982 m2&middot;g-1. A significant dependence of the adsorption capacity on the solution pH was found, while it does not depend significantly neither on the dysprosium concentration nor on the temperature. A maximum adsorption capacity of 31.26 mg&middot;g-1 and 33.52 mg&middot;g-1 for the chemically and physically activated carbons, respectively, were found. In both cases, the results obtained from adsorption isotherms and kinetic study were better fit to a Langmuir model and a pseudo-second-order kinetics. In addition, thermodynamic results indicate that dysprosium adsorption onto both activated carbons is an exothermic, spontaneous and favorable process.

The Effectiveness Adsorption of Au(III) and Cu(II) Ion by Mangosteen Rind (Garcinia mangostana L.) Using Point of Zero Charge Calculation

2020 ◽  
Vol 840 ◽  
pp. 10-15
Author(s):  
Dian Hana Saraswati ◽  
Mellia Harumi ◽  
Triyono Triyono ◽  
Sri Sudiono
Keyword(s):  
Adsorption Capacity ◽  
Ph Value ◽  
Point Of Zero Charge ◽  
Garcinia Mangostana ◽  
Isotherm Equation ◽  
Solid Adsorbent ◽  
Zero Charge ◽  
Before And After ◽  
Langmuir Isotherm Equation ◽  
Gold Metal

Adsorption of Au(III) and Cu(II) by mangosteen rind adsorbent had been carried out. Mangosteen rind has several functional groups including –OH phenolics, ‒C=C‒ aromatics, and ethers. Dried mangosteen rind which was obtained from maceration was used to determine Point of Zero Charge (PZC). The most effective pH adsorption was determined by mixing adsorbent with Au(III) or Cu(II) solutions with various pH. The adsorption capacity was affected by the interaction between adsorbent and adsorbate. The solid adsorbent before and after interaction was characterized by FTIR, XRD, and microphotography. The PZC pH value of adsorbent was 3.7 while the optimum pH for Au(III) and Cu(II) were at pH 2 and pH 5, respectively. The adsorption capacity (qmax) value was 333.33 mg/g by following the Langmuir isotherm equation. The crystalline structure of adsorbent was analyzed using XRD and gave 4 peaks characteristics of gold metal on 2ϴ = 38º, 44º, 64º, and 77º after adsorption which indicated the reduction of Au(III) ions into Au(0).

scholarly journals Selenate Adsorption from Water Using the Hydrous Iron Oxide-Impregnated Hybrid Polymer

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1630
Author(s):  
Vesna Marjanovic ◽  
Aleksandra Peric-Grujic ◽  
Mirjana Ristic ◽  
Aleksandar Marinkovic ◽  
Radmila Markovic ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Adsorption Capacity ◽  
Ph Value ◽  
Xrd Analysis ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Adsorbent Regeneration ◽  
Desorption Efficiency ◽  
Hydrous Iron Oxide ◽  
The Cross

Hybrid adsorbent, based on the cross-linked copolymer impregnated with hydrous iron oxide, was applied for the first time for Se(VI) adsorption from water. The influence of the initial solution pH, selenate concentration and contact time to adsorption capacity was investigated. Adsorbent regeneration was explored using a full factorial experimental design in order to optimize the volume, initial pH value and concentration of the applied NaCl solution as a reagent. Equilibrium state was described using the Langmuir model, while kinetics fitted the pseudo-first order. The maximum adsorption capacity was found to be 28.8 mg/g. Desorption efficiency increased up to 70%, and became statistically significant with the reagent concentration and pH increase, while the applied solution volume was found to be insignificant in the investigated range. Based on the results obtained, pH influence to the adsorption capacity, desorption efficiency, Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analysis of loaded adsorbent, it was concluded that the outer- and inner-sphere complexation are mechanisms responsible for Se(VI) separation from water. In addition to the experiments with synthetic solutions, the adsorbent performances in drinking water samples were explored, showing the purification efficiency up to 25%, depending on the initial Se(VI) concentration and water pH. Determined sorption capacity of the cross-linked copolymer impregnated with hydrous iron oxide and its ability for regeneration, candidate this material for further research, as a promising anionic species sorbent.

scholarly journals Dysprosium Removal from Water Using Active Carbons Obtained from Spent Coffee Ground

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1372 ◽  
Author(s):  
Lorena Alcaraz ◽  
María Esther Escudero ◽  
Francisco José Alguacil ◽  
Irene Llorente ◽  
Ana Urbieta ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Potassium Hydroxide ◽  
Activated Carbons ◽  
Bet Surface Area ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Microporous Material ◽  
Spent Coffee Ground ◽  
Coffee Ground ◽  
Pseudo Second Order

This paper describes the physicochemical study of the adsorption of dysprosium (Dy3+) in aqueous solution onto two types of activated carbons synthesized from spent coffee ground. Potassium hydroxide (KOH)-activated carbon is a microporous material with a specific Brunauer–Emmett–Teller (BET) surface area of 2330 m2·g−1 and pores with a diameter of 3.2 nm. Carbon activated with water vapor and N2 is a solid mesoporous, with pores of 5.7 nm in diameter and a specific surface of 982 m2·g−1. A significant dependence of the adsorption capacity on the solution pH was found, but it does not significantly depend on the dysprosium concentration nor on the temperature. A maximum adsorption capacity of 31.26 mg·g−1 and 33.52 mg·g−1 for the chemically and physically activated carbons, respectively, were found. In both cases, the results obtained from adsorption isotherms and kinetic study were better a fit to the Langmuir model and pseudo-second-order kinetics. In addition, thermodynamic results indicate that dysprosium adsorption onto both activated carbons is an exothermic, spontaneous, and favorable process.

Quinone/hydroquinone redox couple as a source of enormous capacitance of activated carbon electrodes

2013 ◽  
Vol 1505 ◽  
Author(s):  
Krzysztof Fic ◽  
Mikolaj Meller ◽  
Grzegorz Lota ◽  
Elzbieta Frackowiak
Keyword(s):  
Activated Carbon ◽  
Redox Reactions ◽  
Electrode Materials ◽  
Activated Carbons ◽  
Hydroxyl Group ◽  
Carbon Surface ◽  
Carbon Electrodes ◽  
Main Subject ◽  
Solution Ph ◽  
Reversible Redox

ABSTRACTThe main subject of this paper is to examine and to evaluate the capacitive behaviour of activated carbon electrodes electrochemically decorated by quinone-type functional groups. For this purpose, different electrolytes, i.e. hydroquinone, catechol and resorcinol at the concentration of 0.38 mol L-1, dissolved in 1 mol L-1 H2SO4, 1 mol L-1 Li2SO4 and 6 mol L-1 KOH were used. These electrolytes could generate electroactive groups (able to undergo reversible redox reactions) on the surface of electrode material. Apart from typical adsorption of the mentioned dihydroxybenzenes, so called grafting could occur and might cause generation of quinone|hydroquinone functionals on carbon surface. As an effect of functional reversible redox reaction, additional capacitance value, called pseudocapacitance, could be achieved. Hence, besides typical charge originating from charging/discharging of the electrical double layer on the electrode/electrolyte interface, additional capacitance comes also from faradaic reactions. Activated carbons are the most promising electrode materials for this purpose; apart from great physicochemical properties, they are characterized by well-developed specific surface area over 2000 m2 g-1 which results in high capacitance values.In the manuscript the influence of the hydroxyl group location as well as electrolyte solution pH on the electrochemical performance of the electrode is discussed.

SURFACE MODIFICATIONS OF ACTIVATED CARBON AND ITS IMPACT ON APPLICATION

2019 ◽  
Vol 26 (01) ◽  
pp. 1830006 ◽  
Author(s):  
MATHEUS PEGO ◽  
JANAÍNA CARVALHO ◽  
DAVID GUEDES
Keyword(s):  
Surface Modification ◽  
Activated Carbon ◽  
Surface Chemistry ◽  
Surface Structure ◽  
Adsorption Capacity ◽  
Activated Carbons ◽  
Surface Modifications ◽  
Hazardous Substances ◽  
Carbon Surface ◽  
Corona Treatment

The main and new surface modification methods of activated carbon (AC) and their influence on application (adsorption capacity) were reviewed. Adsorption capacity is an important issue, contributing to hazardous substances environment management. According to literature, it is true that surface chemistry strongly affects adsorption capacity. Surface chemistry can be modified by several methods that lead to different activated carbon properties. Furthermore, adsorbate properties, and their relationships with surface structure, can impact adsorption properties. Surface modifications can be conducted by adding some atoms to the surface structure, making the surface more acidic or basic. Introduction of oxygen and ammonia atoms (chemical modification) are the main processes to make the surface more acidic and basic, respectively, although may bring chemical wastes to environment. Surface modification is done by chemical and physical modifications that lead activated carbons to present different properties. The main and new methods of chemical and physical modifications are compared and presented in this paper. Some new physical methods, like corona treatment, plasma discharge and microwave radiation, can be applied to cause surface modifications. Corona treatment can be a practical and new way to cause surface modification on an activated carbon surface.

Adsorption of cadmium(II) from aqueous solution onto activated carbon

1997 ◽  
Vol 35 (7) ◽  
pp. 205-211 ◽  
Author(s):  
R. Leyva-Ramos ◽  
J. R. Rangel-Mendez ◽  
J. Mendoza-Barron ◽  
L. Fuentes-Rubio ◽  
R. M. Guerrero-Coronado
Keyword(s):  
Activated Carbon ◽  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Freundlich Isotherm ◽  
Carbon Surface ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Ph Values ◽  
Average Percent Deviation ◽  
Initial Ph

The adsorption isotherm of cadmium on activated carbon was measured in a batch adsorber. Effects of temperature and solution pH on the adsorption isotherm were investigated by determining the adsorption isotherm at temperatures of 10, 25, and 40°C and at initial pH values from 2 to 8. Langmuir isotherm better fitted the experimental data since the average percent deviation was lower than with the Freundlich isotherm It was noticed that the amount of Cd2+ adsorbed was reduced about 3 times by increasing the temperature from 10 to 40°C. It was found that Cd2+ was not adsorbed on activated carbon at pH of 2 or lower and that Cd2+ was precipitated out as Cd(OH)2 at pH values above 9. Maximum adsorption capacity was observed at pH of 8 and the adsorption capacity was decreased about 12 times by reducing the initial pH from 8 to 3. According to the cadmium speciation diagram the predominant species below pH of 8 is Cd2+. Thus, cadmium was adsorbed on the activated carbon surface as Cd2+. It was concluded that the adsorption capacity is a strong function of pH and temperature.

Metal Adsorbent Prepared from Coir Pith as Agricultural Waste: Adsorption of Zn(II) and Pb(II) from Aqueous Solution

2013 ◽  
Vol 545 ◽  
pp. 101-108 ◽  
Author(s):  
Kitirote Wantala ◽  
Nusavadee Pojananukij ◽  
Pongsert Sriprom ◽  
Tinnakorn Kumsaen ◽  
Arthit Neramittagapong ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Adsorption Capacity ◽  
Calcination Temperature ◽  
Ph Value ◽  
Agricultural Waste ◽  
Initial Solution ◽  
Order Kinetic ◽  
Solution Ph ◽  
Freundlich Isotherms ◽  
Coir Pith

Adsorption of Zn(II) and Pb(II) from aqueous solution were studied by using modified coir pith as an adsorbent. The extended adsorption conditions were investigated as a function of calcination temperature, contact time, adsorbent size, initial pH of solution and initial Zn(II) and Pb(II) concentrations. The adsorption capacity increased rapidly in first 5 minute and reached equilibrium in 120 minutes for Zn(II) and 10 minutes for Pb(II). In case of Zn(II); the results showed that the calcination temperature of modified coir pith above 600oC gave the higher adsorption capacity. The sizes of modified coir pith have no effect on the adsorption capacity. The adsorption capacity increased with increasing initial solution pH value. In case of Pb(II); the calcination temperature of modified coir pith showed no effect on the adsorption capacity. The sizes of modified coir pith showed a little effect on the adsorption capacity. The adsorption capacity increased with increasing of initial solution pH value up to pH of 3 and then stable. The results also corresponded with the Langmuir and Freundlich isotherms and pseudo second order kinetic adsorption models. The modified coir pith gave a higher Zn(II) and Pb(II) adsorption capacity of 29.33 mg Zn(II)/g adsorbent and 36.50 mg Pb(II)/g adsorbent, respectively.

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