• Journal of Soil and Groundwater Environment
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• v.18 no.4
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• pp.8-18
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• 2013

Biocarrier beads with dead biomass, Bacillus drentensis, immobilized in polymer polysulfone were synthesized to remove heavy metals from wastewater. To identify the sorption mechanisms and theoretical nature of underlying processes, a series of batch experiments were carried out and a mathematical model was developed to quantify the biosorption of Pb(II) by the biocarrier beads. A series of mass balance equations for representing mass transfer of metal sorbents in biocarrier beads and surrounding solution were established. Major model parameters such as external mass transfer coefficient and maximum sorption capacity, etc. were determined from pseudo-first-order kinetic models and Langmuir isotherm model based on kinetic and equilibrium experimental measurements. The model simulation displays reasonable representations of experimental data and implied that the proposed model can be applied to quantitative analysis on biosorption mechanisms by porous granular beads. The simulation results also confirms that the biosorption of heavy metal by the biocarrier beads largely depended on surface adsorption.

• Membrane and Water Treatment
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• v.8 no.1
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• pp.73-88
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• 2017

Adsorption kinetics of aqueous ferric ion ($Fe^{3+}$) onto bio-natural rice grains (BRG) have been studied in a batch system. The influence of contact time (0-180 minutes), the dosage of BRG adsorbent (10, 20, 40, and $60gL^{-1}$), and ambient temperature (27, 37, 47, and $57^{\circ}C$) for the adsorption system have been reported. The equilibrium time achieved after 20 minutes of adsorption contact time. The maximum removal of ferric ion is 99% by using $60gL^{-1}$ of BRG, $T=37^{\circ}C$, and $50mgL^{-1}$ ferric ion solution. Adsorption kinetic and diffusion models, such as pseudo-first order, pseudo-second order, and Weber-Morris intra-particle diffusion model, have been used to describe the adsorption rate and mechanism of the ferric ion onto BRG surface. The sorption data results are fitted by Lagergren pseudo-second order model ($R^2=1.0$). The kinetic parameters, rate constant, and sorption capacities have been calculated. The new information in this study suggests that BRG could adsorb ferric ion from water physiosorption during the first 5 minutes. Afterward, the electrostatic interaction between ferric ion and BGR-surface could take place as a very weak chemisorptions process. Thus, there is no significant change could be noticed in the FTIR spectra after adsorption. I recommend producing BGR as a bio-natural filtering material for removing the ferric ion from water.

• Nuclear Engineering and Technology
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• v.23 no.4
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• pp.410-419
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• 1991

Four domestic bentonite samples collected from the south-eastern area of Korea were identified as Ca-bentonite by analysing XRD-patterns and chemical compositions. By comparing the surface area, CEC and the swelling rate of these samples, Dong-Hae A was selected as a suitable sample for the investigation of distribution coefficients. Sorption equilibrium of Cs, Co and Am was reached in around 10 days, but that of Sr was found to be much earlier. From the measured distribution coefficients, the domestic bentonite was found to have high sorption capacity. In the effect of varying concentration on the distribution coefficient, the values of radionuclides peaked at about 10$^{-7}$ mo1/$\ell$ of concentration.

• Membrane and Water Treatment
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• v.15 no.2
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• pp.89-98
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• 2024

The ability of Zizyphus lotus stem powder (ZLSP) to remove Pb (II) and Cd (II) ions from an aqueous solution was evaluated. The present phenomenon of biosorption was revealed to depend on pH, biosorbent dosage, temperature, initial ionic concentration, time of contact and biosorbent's particle size. The sorption process was exothermic (∆H°<0), and showing a strong Pb(II)/Cd(II)-ZLSP affinity (∆S°>0). Gibbs free energy data (∆G°<0, and decreases as temperature increase) reveals that the process studied is characterized by its feasibility and spontaneous nature. The best fits of the equilibrium data were obtained by the Temkin model and the Langmuir model. The maximum Pb(II)/Cd(II)-ZLSP biosorption capacities were 33.02 mg/g for Pb (II) and 20.73 mg/g for Cd (II). The pseudo-second order model was the most appropriate for fitting the kinetic data. The characterization of the biochemical groups essentially involved in the sorption phenomenon was made possible by FTIR spectral analysis. The capacity of ZLSP as an effective and ecofriendly biosorbent is confirmed through this study.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.969-973
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• 1999

In this work, we studied the degree of hydrolysis of ion exchanger in $NH_4OH$ solution and sorption characteristics of $NH_3$ by potentiometric titration curves with using carboxylic acid ion exchanger Fiban K-4. We knew that the theoretical pH values agreed with the experimental pH values on the $NH_4OH$ concentrations in various concentrations of supporting electrolyte $(NH_4)_2SO_4$. The sorption values of $NH_3$ using the ion exchanger can be calculated from equivalent sorption curves for various pH. Also, the degree of hydrolysis increased with decreasing concentration of supporting electrolyte and pH. In order to obtain the mono ion form below 0.01 M as the decreasing concentration of supporting electrolyte, the pH values should be increased. From these results, therefore, the concentrations of supporting electrolyte and pH values were determined.

• Food Science and Preservation
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• v.17 no.4
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• pp.513-518
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• 2010

This study was carried out to estimate the moisture sorption characteristics and prediction model of anchovy powders with different particle size as above 80 mesh, 80-60 mesh and 40-60 mesh. The equilibrium moisture content had higher values at lower storage temperatures, and higher water activity. The monolayer moisture content calculated using the GAB equation showed a higher level of significance than that of BET equation. The estimated monolayer moisture content was 0.024-0.052 g $H_2O/g$ dry solid. The absorption enthalpy was calculated with different particle size and various water activities. It showed that the absorption energy was decreased with increasing water activity but no difference was found on particle size increasement. The fitness of the isotherm curve was shown to be in the order of Khun, Halsey, Caurie and Oswin model. The prediction model equations for the moisture content were established by ln(time), water activity, and temperature, respectively. The model equation will be helpful for future work on drying and storage of anchovy powder.

• Korean Journal of Food Science and Technology
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• v.18 no.2
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• pp.77-81
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• 1986

The water sorption isotherms of individual insoluble components of corn starch, isolated soybean protein (ISP) and casein and their binary mixtures of corn starch-lSP and corn starch-casein were measured and analyzed. BET monolayer values and Smith plot parameters from the results of sorption isotherms were calculated by mass balance concept . The comparisons between experimental and predicted values resulted in an error of 2.29% for equilibrium moisture content and an error of 2.95% in monolayer value for the mixture 50% corn starch-50% ISP. On the other hand , for the mixture 50% corn starch-50% casein the errors were 2.66% and-5.34%, respectively.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.1
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• pp.3-10
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• 2016

Effects of acid ($HNO_3$ and HCl) modification on the adsorption properties of Pb(II) and Cu(II) onto bamboo-based activated carbon (BAC) were investigated through a series of batch experiments. The carbon content increased and oxygen content decreased with acid treatment. $HNO_3$ induced carboxylic acids and hydroxyl functional groups while HCl added no functional group onto BAC. The pseudo-second order model better described the kinetics of Pb(II) and Cu(II) adsorption onto experimented adsorbents, indicating that the rate-limiting step of the heavy metal sorption is chemical sorption involving valency forces through sharing or exchange of electrons between the adsorbate and the adsorbent. The equilibrium sorption data followed both Langmuir and Freundlich isotherm models. The adsorption capacities of BAC were affected by the surface functional groups added by acid modification. The adsorption capacities were enhanced up to 36.0% and 27.3% for Pb(II) and Cu(II), respectively by the $HNO_3$ modification, however, negligibly affected by HCl.

• Environmental Engineering Research
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• v.21 no.2
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• pp.152-163
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• 2016

Present study investigates the potential of cassava peel and rubber tree bark for the removal of Cr (VI) from aqueous solution. Removal efficiency of more than 99% was obtained during the kinetic adsorption experiments with dosage of 3.5 g/L for cassava peel and 8 g/L for rubber tree bark. By comparing popular isotherm models and kinetic models for evaluating the kinetics of mass transfer, it was observed that Redlich-Peterson model and Langmuir model fitted well ($R^2$ > 0.99) resulting in maximum adsorption capacity as 79.37 mg/g and 43.86 mg/g for cassava peel and rubber tree bark respectively. Validation of pseudo-second order model and Elovich model indicated the possibility of chemisorption being the rate limiting step. The multi-linearity in the diffusion model was further addressed using multi-sites models (two-site series interface (TSSI) and two-site parallel interface (TSPI) models). Considering the influence of interface properties on the kinetic nature of sorption, TSSI model resulted in low mass transfer rate (5% for cassava peel and 10% for rubber tree bark) compared to TSPI model. The study highlights the employability of two-site sorption model for simultaneous representation of different stages of kinetic sorption for finding the rate-limiting process, compared to the separate equilibrium and kinetic modeling attempts.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.195-202
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• 2007

Milled Korean pine (Pinus densiflora) wood was used to evaluate its adsorption capacity of Cu(II) ions from aqueous solution by running a series of batch experiments. Prior to the tests, the milled woods were pretreated with 1N NaOH, 1N $HNO_3$, and distilled water, respectively, to examine the effect of pretreatment. Within the tested pH range between 3 and 6, copper adsorption efficiency of NaOH-treated wood(96~99%) was superior to the $HNO_3$-treated wood(19~31%) and distilled water-treated wood(18~35%). The efficiency of copper removal by wood enhanced with increasing solution pH and reached a maximum copper ion uptake at pH 5~6. Adsorption behavior of copper onto both raw and $HNO_3$-treated woods was mainly attributed to interaction with carboxylic acid group. For NaOH-treated wood, carboxylate ion produced by hydrolysis or saponification was a major functional group responsible for Cu sorption. NaOH treatment of wood changed the ester and carboxylic acid groups into carboxylate group, whereas $HNO_3$ treatment did not affect the production of functional groups which could bind copper. A pseudo second-order kinetic model fitted well for the sorption of copper ion onto NaOH-treated wood. A batch isotherm test using NaOH-treated wood showed that equilibrium sorption data were better represented by the Langmuir model than the Freundlich model.