• Journal of Microbiology and Biotechnology
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• 제14권2호
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• pp.250-255
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• 2004

The aim of this work was to investigate the adsorption isotherm and kinetic model for the biosorption of lead $(Pb^{2+})$ by Rhodotorula aurantiaca and to examine the environmental factors for this metal removal. Within five minutes of contact, $Pb^{2+}$ sorption reached nearly 86% of the total $Pb^{2+}$ sorption. The optimum initial pH value for removal of $Pb^{2+}$ was 5.0. The percentage sorption increased steeply with the biomass concentration up to 2 g/l and thereafter remained more or less constant. The Langmuir sorption model provided a good fit throughout the concentration range. The conformity of these data to the Langmuir model indicated that biosorption of $Pb^{2+}$ by R. aurantiaca could be characterized as a monolayer, single-site type phenomenon with no interaction between ions adsorbed in neighboring sites. The maximum $Pb^{2+}$ sorption capacity $(q_{max})$ and Langmuir constant (b) were 46.08 mg/g of biomass and 0.04 l/mg, respectively. The pseudo second-order equation was well fitted to the experimental data. The correlation coefficients for the linear plots of t/q against t for the second-order equation were 0.999 for all the initial concentrations of biosorbent for contact times of 180 min. The theoretical $q_{eq}$ value was very close to the experimental $q_{eq}$ value.

• 한국의류학회지
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• 제14권1호
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• pp.13-19
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• 1990

The water-vapor sorption isotherms of viscose rayon and of modified viscose rayon were studied to elucidate the change of sorptivity by the DMDHEU resin finish. To determine the sorption isotherms, moisture regains of the samples were measured at various humidities. The sorption isotherms were determined by the BET and GAB multilayer adsorption theories. The adsorption isotherm of the starting rayon was Brunauer Type II while with increasing resin content those of the DMDHEU-treated rayon became progressively more like Type IV. The DMDHEU-treated samples appeared to be hydrophilic due to the hydrophilicity of DMDHEU although moisture regains at higher humidities markedly decreased because of an impediment in swelling by crosslinkings. The $W_{m}$ value and surface area of crosslinked samples increased with increasing resin content. VR-R-6 which was the most heavily crosslinked viscose rayon had the highest $W_{m}$ and surface area values among all the samples. Relative sorption hysteresis was decreased as humidity increased for all samples. The untreated viscose rayon appeared to have a higher value than the DMDHEU-treated rayon.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.407-416
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• 2018

This study presents a novel complete solution starting with a synthesis of silica modified with potassium-nickel hexacyanoferrate and ethanolamine (SiEA-KNiFe) sorbent through radiocesium sorption in different process configurations and moving on to the vitrification of the spent sorbent, using the sol-gel method. The experimental data for deionized water solution, as well as seawater solution, correlates strongly with the Langmuir isotherm model. Moreover, the study also presents a method for spent sorbent solidification in the glass matrix. The cesium leaching test confirmed that spent sorbent can be stably bound in the glass matrix after radionuclide removal.

• 한국축산식품학회:학술대회논문집
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• 한국축산식품학회 2003년도 제31차 춘계 학술대회
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• pp.185-185
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• 2003

• 한국축산식품학회:학술대회논문집
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• 한국축산식품학회 2003년도 제31차 춘계 학술대회
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• pp.184-184
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• 2003

• Carbon letters
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• 제22권
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• pp.14-24
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• 2017

Carboxylated multi-wall carbon nanotubes (MWCNTs-COOH) have been used as efficient adsorbents for the removal of picric acid from aqueous solutions under stirring and ultrasound conditions. Batch experiments were conducted to study the influence of the different parameters such as pH, amount of adsorbents, contact time and concentration of picric acid on the adsorption process. The kinetic data were fitted with pseudo-first order, pseudo-second-order, Elovich and intra-particle diffusion models. The kinetic studies were well described by the pseudo-second-order kinetic model for both methods. In addition, the adsorption isotherms of picric acid from aqueous solutions on the MWCNTs were investigated using six two-parameter models (Langmuir, Freundlich, Tempkin, Halsey, Harkins-Jura, Fowler-Guggenheim), four three-parameter models (Redlich-Peterson, Khan, Radke-Prausnitz, and Toth), two four-parameter equations (Fritz-Schlunder and Baudu) and one five-parameter equation (Fritz-Schlunder). Three error analysis methods, correlation coefficient, chi-square test and average relative errors, were applied to determine the best fit isotherm. The error analysis showed that the models with more than two parameters better described the picric acid sorption data compared to the two-parameter models. In particular, the Baudu equation provided the best model for the picric acid sorption data for both methods.

• Carbon letters
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• 제14권1호
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• pp.27-33
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• 2013

An increase in population initiating rapid industrialization was found to consequently increase the effluents and domestic wastewater into the aquatic ecosystem. In this research the potentialities of Sambucus nigra L. (SNL) plant in the remediation of water, contaminated with methylene blue (MB), a basic dye were investigated. SNL was chemically impregnated with $KHCO_3$. Operating variables studied were pH, amount of adsorbent and contact time. In general, pH did not have any significant effect on colour removal and the highest adsorption capacity was obtained in 0.035 g MB/g-activated carbon. The Langmuir, Freundlich, Temkin and Dubinin-Radushkevich adsorption models were applied to describe the equilibrium isotherms. The adsorption isotherm data were fitted to the Temkin isotherm. The mass transfer property of the sorption process was studied using Lagergren pseudo-first-order and chemisorption pseudo-second-order kinetic models. The sorption process obeyed the pseudo-second-order kinetic model. The surface area, pores volume and diameter were assessed by the Brunauer-Emmett-Teller and Barrett-Joyner-Halenda methods. The results were compared to those from activated carbon (Merck) and an actual sample. The results indicate that SNL can be employed as a natural and eco-friendly adsorbent material for the removal of dye MB from aqueous solutions.

• Environmental Engineering Research
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• 제14권3호
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• pp.153-157
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• 2009

Arsenic at abandoned mine sites has adversely affected human health in Korea. In this study, the feasibility of using cationic surfactant-modified activated carbon (MAC) to remove As(V) was evaluated in terms of adsorption kinetics, adsorption isotherms, and column experiments. The adsorption of As(V) onto MAC was satisfactorily simulated by the pseudo-second-order kinetics model and Langmuir isotherm model. In column experiments, the breakthrough point of AC was 28 bed volumes (BV), while that of MAC increased to 300 BV. The modification of AC using cationic surfactant increased the sorption rate and sorption capacity with regard to As(V). As a result, MAC is a promising adsorbent for treating As(V) in aqueous streams.

• 한국축산식품학회지
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• 제18권4호
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• pp.285-291
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• 1998

Adsorption isotherms of water vapour for infant formula milk powders manufactured by P. M. and N company in Korea were measured at temperatures between 20, 30 and 40$^{\circ}C$ using COST-90 modified method. Results showed that the isotherms were sigmoidal in shape. The adsorption isotherms of milk powder were depending on the temperature and products. The BET-model were applied and analyzed to compare the experimental value. It was found that the BET-model is fitted with measuring data. Sample P showed the lowest monolayer value and sample N showed the highest. Isosteric heat obtained upon application of BET-model was calculated in this field of temperature using the Clausius-Clapeyron equation. It is suggested that the usage of the BET-model to estimate the heat of water sorption in infant formula milk powder should be in agreement with the results from COST-90 project.

• Advances in environmental research
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• 제1권3호
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• pp.223-236
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• 2012

Biosorption of methylene blue (MB) from aqueous solution was studied with respect to the point of zero charge of coconut husk, dye concentration, particle size, pH, temperature, as well as adsorbent and NaCl concentration using coconut husk biomass. Amongst Langmuir and Freundlich adsorption isotherms studied, Langmuir adsorption isotherm showed better agreement. Pseudo second order kinetics model was found to be more suitable for data presentation as compared to pseudo first order kinetics model. Also, involvement of diffusion process was studied using intraparticle diffusion, external mass transfer and Boyd kinetic model. Involvement of intraparticle diffusion model was found to be more relevant (prominent) as compared to external mass transfer (in) for methylene blue biosorption by the coconut husk. Moreover, thermodynamic properties of MB biosorption by coconut husk were studied. Desorption of methylene blue from biomass was studied with different desorbing agents, and the highest desorption achieved was as low as 7.18% with acetone, which indicate stable immobilization. Under the experimental conditions MB sorption was not significantly affected by pH, temperature and adsorbent concentration but low sorption was observed at higher NaCl concentrations.