• Carbon letters
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• v.6 no.2
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• pp.89-95
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• 2005

Crushed peach stone shells were impregnated with $H_3PO_4$ of increasing concentrations (30-70%) followed by heat treatment at 773 K for 3 h. Produced carbons (ACs) were characterized by $N_2$ adsorption at 77 K using the BET-equation and the ${\alpha}$-method. High surface area microporous ACs were obtained, with enhanced internal pore volume, as function of % $H_3PO_4$. Adsorption isotherms from aqueous solution were determined for methylene blue (MB) and p-nitrophenol (PNP), as representatives for dye and phenolics pollutant molecules. Application of the Langmuir model proved the high limiting capacity towards both solute molecules, MB was uptaken in increasing amounts as function of $H_3PO_4$ concentration and generated porosity. High removal of PNP was almost the same irrespective of porosity characteristics. Competitive adsorption of $H_2O$ molecules on the hydrophilic carbon surface seems to partially reduce the available area to the PNP molecules. Application of the pseudo-second order law described well the fast adsorption (${\leq}$ 120 min) at two initial dye concentrations.

• Journal of Pharmaceutical Investigation
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• v.25 no.4
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• pp.331-338
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• 1995

In order to screen appropriate preservatives for the suspension containing sucralfate, neusilin and hydrotalcite, the patterns and mechanism of the adsorption and desorption of several preservatives on these antacids were studied. The employed preservatives were parabens(methyl, propyl, butyl), chlorhexidine diacetate and sorbic acid. While none of parabens were adsorbed on three antacids, chlorhexidine diacetate was strongly adsorbed on all the antacids employed, especially on hydrotalcite. Sorbic acid was not adsorbed on neusilin and hydrotalcite, however, 65% of sorbic acid was adsorbed on sucralfate. The adsorption of chlorhexidine diacetate on neusilin and hydrotalcite was partly physical and partly chemical, while its adsorption on sucralfate was almost chemical. Sorbic acid was completely deserted from sucralfate. In all cases, the adsorption isotherms were fitted well to both Freundlich equation and Langmuir equation. Based on these results, parabens and sorbic acid were the preservatives of choice for the suspension containing sucralfate, neusilin and hydrotalcite.

• Advances in environmental research
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• v.3 no.3
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• pp.217-230
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• 2014

The large quantity of green cull bananas has the potential of being used industrially and, thereby, to improve banana economics and eliminate the large environmental problem presented by banana waste. Wastewaters from textile, cosmetics, printing, dying, food colouring, and paper-making industries are polluted by dyes. The adsorption of basic dye by waste banana pith was investigated by varying dye concentrations, adsorbent dose, particle size and agitation rate. The adsorption capacity was found to be maximum value of removal by using 0.1 g of sorbent with particle size 1mm at mixing speed 200 rpm for initial concentration 25 mg/l to reach value of approximate 89%. The Langmuir, Temkin and Freundlich adsorption models were used for mathematical description of the adsorption equilibrium and it was found that experimental data fitted very well to these models except Langmuir model. Adsorption of dye was applied on (pseudo-first and pseudo-second-order kinetics), and the experimental data was more fitted to pseudo second order. The results of this study showed that banana pith could be employed as effective and low-cost materials for the removal of dyes from aqueous solutions.

• Membrane and Water Treatment
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• v.13 no.5
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• pp.227-233
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• 2022

The objective of the study, to develop adsorbent based purifier for removal of radiological and nuclear contaminants from contaminated water. In this regard, 3-aminopropyl silica functionalized with ethylenediamine tetraacetic acid (APS-EDTA) adsorbent prepared and characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). Prepared APS-EDTA used for adsorptive studies of Cs(I), Co(II), Sr(II), Ni(II) and Cd(II) from contaminated water. The effect on adsorption of various parameters viz. contact time, initial concentration of metal ions and pH were also analyzed. The batch method has been employed using metal ions in solution from 1000-10000 ㎍/L, contact time 5-60 min., pH 4-10 and material quantities 50-200 mg at room temperature. The obtained adsorption data were used for drawing Freundlich and Langmuir isotherms model and both models were found suitable for explaining the metal ions adsorption on APS-EDTA. The adsorption data were followed pseudo second order reaction kinetics. The maximum adsorption capacity obtained 1.3037-1.4974 mg/g for above said metal ions. The results show that APS-EDTA have great potential to remove Cd(II), Co(II), Cs(I), Ni(II) and Sr(II) from aqueous solutions through chemisorption and physio-sorption.

• Advances in nano research
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• v.11 no.6
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• pp.667-678
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• 2021

Multiwalled carbon nanotubes (MWCNTs) were first oxidized (O-CNTs) to introduce carboxylic group and then further functionalized (F-CNTs) with m-phenylenediamine, which was confirmed by FTIR and SEM. It was used as an effective adsorbent for the adsorptive removal of diclofenac drug from water. Under optimum conditions of pH 6, stirring speed 600 rpm, the maximum adsorption capacity obtained was 532 mg g^-1 which is superior to the values reported in literature. The adsorption was quite rapid as 25 mg L^-1 drug solution was adsorbed in only 3 minutes of contact time with 10 mg of adsorbent dose. The adsorption kinetics and isotherms were studied using various models to evaluate the adsorption process. The results showed that the data best fit in kinetics pseudo-second order and Langmuir isotherm model. Furthermore, the oxidized and functionalized MWCNTs were applied on gram-negative Escherichia coli and gram-positive Staphylococcus aureus using agar disc diffusion assay to validate their anti-microbial activity. Results were unique as both oxidized and functionalized MWCNTs were equally active against both E. coli and S. aureus. The newly synthesized F-CNTs have great potential in water treatment, with their dual action of removing drug and pathogens from water, makes it potential applicant to save environment.

• Clean Technology
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• v.20 no.3
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• pp.290-297
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• 2014

Batch adsorption studies were carried out for equilibrium, kinetics and thermodynamic parameters for adsorption of coomassi brilliant blue G (CBBG) using activated carbon with varying the operating variables like initial concentration, contact time and temperature. Equilibrium adsorption data were fitted into Langmuir, Freundlich and Dubinin-Radushkevich isotherms. From estimated separation factor of Langmuir and Freundlich, this process could be employed as effective treatment for removal of CBBG. Also from Dubinin-Radushkevich isotherm model, adsorption energy (E) indicated adsorption process is physical adsorption. From kinetic experiments, the adsorption reaction was found to confirm to the pseudo second order model with good correlation. Intraparticle diffusion was rate controlling step. Thermodynamic parameters like change of free energy, enthalpy, and entropy were also calculated to predict the nature of adsorption. The change of enthalpy (406.12 kJ/mol) indicated endothermic nature of the adsorption process. The change of entropy (1.66 kJ/mol K) showed increasing disorder in process. The change of free energy found that the spontaneity of process increased with increasing adsorption temperature.

• Carbon letters
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• v.6 no.4
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• pp.248-254
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• 2005

Silver impregnated activated carbon fibers were post-modified using hydrochloric acid. Adsorption behaviors, SEM morphologies, and functional groups for the silver impregnated ACFs were compared with those of post-modified ACFs. Adsorption isotherms were used to characterize $S_{BET}$, the pore structure and volume of silver-activated carbon fibers (ACFs) before and after acid post-treatment. In order to the reveal the causes of the differences surface states after the samples were washed with hydrochloric acid, outer surface and pore structure were investigated by SEM. And the type and quality of various functional groups were studied from FT-IR spectra and Boehm titration method. Finally, the quantitative properties in silver contents were also examined by EDX spectra.

• Journal of the Korean Society of Clothing and Textiles
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• v.18 no.5
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• pp.622-627
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• 1994

The purpose of this study is to investigate the adsorption rate, adsorption quantities and the UV-Cut effects of cotton fabrics treated with several UV absorbents. The result of this study were as follows: cotton fabric treated with 2,2'-dihydroxy-4- methoxy-benzophenone shows more efficient than ones treated with 4-aminobenzoic acid and 2·hydroxy-1, 4-naphthoquinone in UV absorption. This may be due to the absorption of UV light by formation of intra moleculaar hydrogen bond. The formation of hydrogen bonds between hydrogen atoms of two hydroxy groups and one oxygen atom of carboxyl group in 2, 2'-dihydroxy-4-methoxy-benzophenone would be easier than that of the other absorbents. The adsorption isotherms of 4-aminobenzoic acid and 2-hydroxy-1, 4-naphthoquinone were similar to Freundlich type, while that of 2, 2'-Dihydroxy-4-methoxy-benzophenone was Henry type. Cotton fabrics treated with Antifade MC-100 and W Cut I-2 were just alike in UV absorption, but Antifade 8001 was inferior to the others.

• Journal of environmental and Sanitary engineering
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• v.14 no.2
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• pp.40-45
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• 1999

This study deals with an investigation on low cost adsorbents locally available n dyeing wastewater treatment of color removal. Peat, bentonite, slag and fly ash were utilized for this study. Considering that low cost adsorbents contained in $SiO_2$, $Fe_2O_3$ and $Al_2O_3$ compositions, and coagulants were mainly used aluminate and ferrate in color removal. Color of dyeing wastewater was high removed in peat, berntonite and slag except for fly ash with passed time. It could be known that color removal of peat and slag were increased to pH 4, but was hardly changed with advancing to alkaline. Color intended to be high removed with increasing of agitation speed but to be almost slow after 150rpm. As a result on the experiment of Freundlich adsorption isotherms, adsorption intensity(l/n) appeared to be peat>fly ash>slag>bentonite and adsorption capacity(k) came out peat>bentonite>slag>fly ash. Therefore, if low cost adsorbents substituted for existing adsorbents, peat, bentonite and slag could look forward to an expected economical effect.

• Journal of Sericultural and Entomological Science
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• v.42 no.2
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• pp.78-82
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• 2000

In this study, a comparative removal of chlorine from aqueous solutions of mulberry leaf powder(MLP) and activated carbon(AC) was investigated. The chlorine removal capacities of MLP and AC were shown as a function of contact time, pH and initial chlorine concentration. Optimum contact time and removal pH value of MLP were determined as 2 hr and pH 10, respectively. Chlorine removal increased with increasing initial chlorine concentration up to 1.3g/L. Both Langmuir and Freundlich adsorption models were suitable for describing the short-term removal of chlorine by MLP and AC. According to Freundlich adsorption isotherms, the maximum removal capacity of MLP(0.264 mg Cl$_2$/mg) was nearly two times greater than that of AC(0.56 mg Cl$_2$/mg). These results suggested that MLP might potentially be used as an alternative to traditional water treatment materials for removal of residual chlorine in drinking water or process wastewater.