• Journal of Korean Society of Water and Wastewater
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• v.33 no.3
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• pp.205-213
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• 2019

Batch adsorption tests were performed to evaluate the applicability of adsorption kinetic model by using hydrogel chitosan bead crosslinked with glutaraldehyde (HCB-G) for Cu(II) as cation and/or phosphate as anion. Pseudo first and second order model were applied to determine the sorption kinetic property and intraparticle and Boyd equation were used to predict the diffusion of Cu(II) and phosphate at pore and boundary-layer, respectively. According to the value of theoretical and experimental uptake of Cu(II) and phosphate, pseudo second order is more suitable. On comparison with the value of adsorption rate constant (k), phosphate kinetic was 2-4 times faster than that of Cu(II) at any experimental condition indicating the electrostatic interaction between ${NH_3}^+$ and phosphate is dominated at the presence of single component. However, when Cu(II) and phosphate simultaneously exist, the value of k for phosphate was sharply decreased and then the difference was not significant. Both diffusion models confirmed that the sorption rate was controlled by film mass transfer at the beginning time (t < 3 hr) and pore diffusion at next time section (t > 6 hr).

• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.23-28
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• 1997

The adsorption characteristics of ammonia-Cu(II) complex on activated carbon were studied. Firstly, the specific surface area of the activated carbon was measured by using the BET adsorption apparatus. Secondly, the characteristics of the removal copper(II) ion from aqueous ammonia solution by forming a complex with ammonia and then by the adsorption of the complex on the activated carbon were studied. It was found that the specific surface area increases with decreasing the mesh number of the activated carbon, and the optimum pH for the adsorption of the Cu(II) ion on she activated carbon was found to be approximately 6. It was also found that the adsorbed Cu(II)-ammonia complexes on the activated carbon in the aqueous ammonia solution have two types, depending on the concentration of the solution ; i.e. $[Cu(NH_3){_2}]^{2+}$and $[Cu(NH_3){_3}]^{2+}$ for $2.25{\times}10^{-4}(mol/{\ell})$and $2.25{\times}10^{-3}(mol/{\ell})$, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.37 no.4
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• pp.177-186
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• 2023

Perfluorooctanoic acid(PFOA) was one of widely used per- and poly substances(PFAS) in the industrial field and its concentration in the surface and groundwater was found with relatively high concentration compared to other PFAS. Since various processes have been introduced to remove the PFOA, adsorption using GAC is well known as a useful and effective process in water and wastewater treatment. Surface modification for GAC was carried out using Cu and Fe to enhance the adsorption capacity and four different adsorbents, such as GAC-Cu, GAC-Fe, GAC-Cu(OH)₂, GAC-Fe(OH)₃ were prepared and compared with GAC. According to SEM-EDS, the increase of Cu or Fe was confirmed after surface modification and higher weight was observed for Cu and Fe hydroxide(GAC-Cu(OH)₂ and GAC-Fe(OH)₃, respectively). BET analysis showed that the surface modification reduced specific surface area and total pore volumes. The highest removal efficiency(71.4%) was obtained in GAC-Cu which is improved by 17.9% whereas the use of Fe showed lower removal efficiency compared to GAC. PFOA removal was decreased with increase of solution pH indicating electrostatic interaction governs at low pH and its effect was decreased when the point of zero charges(pzc) was negatively increased with an increase of pH. The enhanced removal of PFOA was clearly observed in solution pH 7, confirming the Cu in the surface of GAC plays a role on the PFOA adsorption. The maximum uptake was calculated as 257 and 345 ㎍/g for GAC and GAC-Cu using Langmuir isotherm. 40% and 80% of removal were accomplished within 1 h and 48 h. According to R², only the linear pseudo-second-order(pso) kinetic model showed 0.98 whereas the others obtained less than 0.870.

• Journal of Korean Society on Water Environment
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• v.38 no.2
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• pp.82-94
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• 2022

In this study, chemically modified biochar (NSBP500, KSBP500, OSBP500) derived from starfish was utilized to improve the adsorption ability of the SBP500 (Starfish Biochar Pyrolyzed at 500℃) in a solution contaminated with heavy metals. According to the biochar modification performance evaluation batch tests, the removal rate and adsorption amount of NSBP500 increased 1.4 times for Cu, 1.5 times for Cd, and 1.2 times for Zn as compared to the control sample SBP500. In addition, the removal rate and adsorption amount of KSBP500 increased 2 times for Cu, 1.8 times for Cd, and 1.2 times for Zn. The removal rate and adsorption amount of OSBP500 increased 5.8 times for Cu. The FT-IR analysis confirmed the changes in the generation and movement of new functional groups after adsorption. SEM analysis confirmed Cu in KSBP500 was in the form of Cu(OH)₂ and resembled the structure of nanowires. The Cd in KSBP500 was densely covered in cubic form of Cd(OH)₂. Lead(Pb) was in the form of Pb₃(OH)₂(CO₃)₂ in a hexagonal atomic layer structure in NSBP500. In addition, it was observed that Zn was randomly covered with Zn₅(CO₃)₂(OH)₆ pieces which resembled plates in KSBP500. Therefore, this study confirmed that biochar removal efficiency was improved through a chemical modification treatment. Accordingly, adsorption and precipitation were found to be the complex mechanisms behind the improved removal efficiency in the biochar. This was accomplished by electrostatic interactions between the biochar and heavy metals and ion exchange with Ca²⁺.

• Journal of the Korean Geotechnical Society
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• v.16 no.4
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• pp.157-170
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• 2000

In this study, we conducted a combined adsorption-sequential extraction analysis(CASA) to investigate temperature effects of single and competitive adsorption of zinc and copper on natural clays. As a result, it was found out that in a single adsorption of zinc, the adsorption was mostly in the exchangeable phase, with increase n temperature. In a competitive adsorption of zinc, this trend was so strong that the exchangeable phase adsorption increase up to 80~90%. On the other hand, about 50% of copper was adsorbed in the carbonate occluded phase in single and competitive adsorptions. In the single adsorption the adsorption of carbonate occluded phase increased by 5% with the temperature increase and in the competitive adsorption the increase rate is about twice. The adsorption of zinc and copper on natural clays is an endothermic reaction with the exception of exchangeable phase adsorption.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.547-556
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• 2000

A study have been conducted for the adsorption and desorption characteristics of Cu ion using manganese nodule as adsorbent. For 100 ppm Cu ion solution, the adsorbed amount of Cu ion was more than 90 % at equilibrium state. Adsorption was equilibrated in 42 hours the adsorption reaction was shown to be first order reaction. For the desorption reaction of Cu ion in the region of solution pH 3.5~9.5, the desorption was completed in the acidic region, but it has been decreased as the pH was raised. Also, the desorption rate was higher in the acidic region compared with alkaline region. The desorbed amount was decreased as the reaction temperature increased, therefore, the desorption reaction was thought to be exothermic. Also, several thermodynamic properties were calculated based on experimental results and compared with theoretically driven values. To see the effect of complexing agent on the desorption of Cu ion, EDTA was introduced and the des orbed amount increased in the presence of EDTA.

• Analytical Science and Technology
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• v.13 no.2
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• pp.131-135
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• 2000

We studied adsorption isotherm, surface properties and antibacterial activity of Cu treated activated carbon fiber (ACF). The BET surface area of Cu treated ACF are distributed to $688.2-887.8m^2/g$. The adsorption results show that BET surface areas move gradually to lower value with increasing treated Cu mole concentration. Using t-method, the specific micropore volumes and average pore size were obtained. From the SEM study, it is also observed that many of micropores in activated carbon fiber are blocked surface after the treatment. And we also observed that the activity of E. coli in kind of colon bacillus increases gradually to larger range with increasing Cu mole ratio. From these results, we suggest the antibacterial mechanism for metal treated ACF.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.147-150
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• 2011

A copper-based metal organic framework (MOF) named Cu-BTC, also known as HKUST-1, was successfully synthesized by using a solvothermal method. The properties of the Cu-BTC sample were characterized with Powder X-ray diffraction (XRD) for phase structure, Thermogravimetric analysis (TGA) for thermal stability, Scanning electron microscopy (SEM) for crystal structure, and Nitrogen adsorption-desorption for pore textural structure. The analysis results displayed that the Cu-BTC sample exhibited a good crystal structure with uniform size of octahedral particles. The BET data revealed a high surface area of $1457 \;m^2g^{-1}$ and a pore volume of $0.60\; cm^3g^{-1}$. The Cu-BTCs ample was also studied for $CO_2$ adsorption and exhibited a maximum $CO_2$ adsorption capacity of 170 mg/g of the sorbent (3.8 mol/kg) at $25^{\circ}C$.

• Journal of Soil and Groundwater Environment
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• v.22 no.5
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• pp.128-134
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• 2017

This work presents the adsorption capability of green tea and ginseng leaves to adsorb heavy metals such as Cd(II), Cu(II), and Pb(II) in aqueous solution. FT-IR analysis indicates the presence of oxygen containing functional groups (carboxyl groups) in two kinds of leaves. High pH condition was favorable to the adsorption of heavy metal ions due to the enhanced electrostatic attraction and the precipitation reaction of metal ions. The adsorption of Cd(II), Cu(II), and Pb(II) reached equilibrium within 10 min, achieving high removal efficiencies of 80.3-97.5%. The adsorption kinetics data of heavy metal ions were fitted well with the pseudo-second-order kinetic model. The maximum adsorption amounts of Cd(II), Cu(II), and Pb(II) ions were 8, 3.5, and 15 mg/g, respectively, in the initial concentration range from 0.15 to 0.75 mM. Based on the fitting data obtained from isotherm models, heavy metal adsorption by green tea and ginseng leaves could occur via multi-layer sorption.

• Journal of environmental and Sanitary engineering
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• v.21 no.3 s.61
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• pp.52-60
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• 2006

The ion exchange resins have been synthesized from chlormethyl styrene-1,4-divinylbenzene(DVB) with 1%, 2%, and 20%-crosslinking and macrocyclic ligand of cryptand 21 by copolymerization method and the adsorption characteristics of uranium(VI), copper(II) and dysprosium(III) metallic ions have been investigated in various experimental conditions. The synthesis of these resins was confirmed by content of chlorine, element analysis, and IR-spectrum. The effects of pH, equilibrium time, dielectric constant of solvent and crosslink on adsorption of metallic ions were investigated. The metal ion was showed fast adsorption on the resins above pH 3. The optimum equilibrium time for adsorption of metallic ions was about two hours. The adsorption selectivity determined in ethanol was in increasing order uranium$(UO^{2+}_2)\;>\;copper(Cu^{2+})\;>\;dysprosium(Dy^{3+})$ ion. The adsorption was in order of 1%, 2%, and 20% crosslink resin and adsorption of resin decreased in proportion to order of dielectric constant of solvents.