• 자원리싸이클링
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• 제21권5호
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• pp.50-57
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• 2012

황산동 용액중에 불순물로 존재하는 Sb, Bi 및 As를 제거하기 위해 Aminophosphosphonic acid를 관능기로 함유한 이온교환수지를 사용하여 비교 실험을 실시하였다. 이들 불순물 제거 반응에 영향을 미칠 수 있는 반응온도, 반응시간, 이온교환수지양 등에 대하여 고찰하였다. 기초 실험 결과 약 88%의 Sb 및 94%의 Bi가 이온교환수지에 흡착되어 황산동용액으로부터 제거가 가능하였다. 그러나 As의 경우는 제거율이 10% 이하로 미미하였다. 한편, Bi 와 Sb가 흡착된 수지에서 황산과 염산용액을 이용하여 선택적으로 세출이 가능하였다. 연속흡착실험 결과 Sb 와 Bi의 경우는 2BV 후에는 98.1%와 96.6%의 높은 흡착율을 보였다.

• Carbon letters
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• 제8권4호
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• pp.321-325
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• 2007

The oxygen and nitrogen enriched activated carbons were obtained from modification of commercial activated carbon by using nitric acid, sodium hydroxide and urea. Zeta-potentials of modified activated carbons were investigated in relation to copper ion adsorption. The structural properties of modified activated carbons were not so much changed, but the zeta-potentials and isoelectric points were considerably changed. The zeta-potential of nitric acid modified activated carbon was the most negative than other activated carbons in the entire pH region, and the $pH_{IEP}$ was shifted from pH 4.8 to 2.6, resulted in the largest copper ion adsorption capacities compare with other activated carbons in the range of pH 3~6.5. In case of urea modified activated carbon, copper ion adsorption was larger than that of the as-received activated carbon from pH 2 to pH 6.5 even though the $pH_{IEP}$ was shifted to pH 6.0, it was due to the coordination process operated between nitrogen functional groups and copper ion. The adsorption capacity of copper ion was much influenced by zeta-potential and $pH_{IEP}$ of carbon adsorbent.

• 한국환경과학회지
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• 제24권1호
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• pp.47-53
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• 2015

Removal characteristics of Cu(II) ions by solid-phase extractant immobilized D2EHPA and TBP in PVC were investigated. Cu(II) ion concentrations in the solution and removal capacity of Cu(II) ion according to operation time were compared. The lower the initial concentration of Cu(II) ion in aqueous solution was, the removal capacity of Cu(II) ion by solid-phase extractant was increased relatively. The bigger the initial concentration of Cu(II) ion was, the removal capacity of Cu(II) ion was increased relatively. The pseudo-second-order kinetics according to operation time was showed more satisfying results than the pseudo-first-order kinetics for the removal velocity of Cu(II) ion. The removal capacity of Cu(II) ion was 0.025 mg/g in aqueous solution of pH 2, but the removal capacity of Cu(II) ion was increased to 0.33 mg/g mg/g in aqueous solution of pH 4 according to increasing pH.

• Membrane and Water Treatment
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• 제11권3호
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• pp.201-206
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• 2020

Electrodialysis (ED) is used in wastewater treatment, during the processing and recovery of beneficial materials, to produce usable water. In this study, sulfate and chlorine ions, which are the anions majorly used for electroplating, were studied as factors affecting the recovery of copper, nickel and water from wastewater by electrodialysis. Although the removal rates of copper and nickel ions were slightly higher with the use of chlorine ions than of sulfate ions, the removal efficiencies were above 99.9% under all experimental conditions. The metal ions of the plating wastewater flowed through the ion exchange membrane of the diluate tank and the concentrate tank while all the water moved together due to electro-osmosis. The migration of water from the diluate tank to the concentrate tank was higher in the presence of a monovalent chloride ion compared to that of a divalent sulfate ion. When sulfate was the anion used, the recoveries of copper and nickel increased by about 25% and 30%, respectively, as compared to the chloride ion. Therefore, when divalent ions such as sulfate are present in the electrodialysis, it is possible to reduce the movement amount of water and highly concentrate the copper and nickel in the plating wastewater.

• Carbon letters
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• 제8권3호
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• pp.199-206
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• 2007

The activated carbon produced from rubber wood sawdust by chemical activation using phosphoric acid have been utilized as an adsorbent for the removal of Cu(II) from aqueous solution in the concentration range 5-40 mg/l. Adsorption experiments were carried out in a batch process and various experimental parameters such as effect of contact time, initial copper ion concentration, carbon dosage, and pH on percentage removal have been studied. Adsorption results obtained for activated carbon from rubber wood sawdust were compared with the results of commercial activated carbon (CAC). The adsorption on activated carbon samples increased with contact time and attained maximum value at 3 h for CAC and 4 h for PAC. The adsorption results show that the copper uptake increased with increasing pH, the optimum efficiency being attained at pH 6. The precipitation of copper hydroxide occurred when pH of the adsorbate solution was greater than 6. The equilibrium data were fitted using Langmuir and Freundlich adsorption isotherm equation. The kinetics of sorption of the copper ion has been analyzed by two kinetic models, namely, the pseudo first order and pseudo second order kinetic model. The adsorption constants and rate constants for the models have been determined. The process follows pseudo second order kinetics and the results indicated that the Langmuir model gave a better fit to the experimental data than the Freundlich model. It was concluded that activated carbon produced using phosphoric acid has higher adsorption capacity when compared to CAC.

• Carbon letters
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• 제18권
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• pp.49-55
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• 2016

Refuse-derived fuel (RDF) produced using municipal solid waste was pyrolyzed to produce RDF char. For the first time, the RDF char was used to remove aqueous copper, a representative heavy metal water pollutant. Activation of the RDF char using steam and KOH treatments was performed to change the specific surface area, pore volume, and the metal cation quantity of the char. N₂ sorption, Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), and Fourier transform infrared spectroscopy were used to characterize the char. The optimum pH for copper removal was shown to be 5.5, and the steam-treated char displayed the best copper removal capability. Ion exchange between copper ions and alkali/alkaline metal cations was the most important mechanism of copper removal by RDF char, followed by adsorption on functional groups existing on the char surface. The copper adsorption behavior was represented well by a pseudo-second-order kinetics model and the Langmuir isotherm. The maximum copper removal capacity was determined to be 38.17 mg/g, which is larger than those of other low-cost char adsorbents reported previously.

• 한국환경과학회지
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• 제23권9호
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• pp.1583-1591
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• 2014

PVA-D2EHPA/TOPO beads containing two extractants, di-(2-ethylhexyl) phosphoric acid (D2EHPA) and trioctylphoshine oxide (TOPO) were prepared for the removal of copper ions from aqueous solution. The prepared PVA-D2EHPA/TOPO beads were characterized by SEM and FT-IR. The removal characteristics of copper ions by PVA-D2EHPA/TOPO beads was investigated using batch and continuous systems. In batch experiments, the maximum removal capacity calculated from Langmuir isotherm model was 18.6 mg/g and the optimal pH was in the range of 4.5~6. The continuous experiments showed that the removal capacity of copper ions increased with increasing inlet copper ion concentrations and bed heights, but decreased with increasing inlet flow rates.

• Environmental Engineering Research
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• 제20권2호
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• pp.199-204
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• 2015

In this study, a novel phosphorus removal filter made of brass scrubber with higher porosity of over 96% was fabricated and evaluated. The brass scrubber was surface-modified to form copper hydroxide on the surface of the brass, which could be a phosphate removal filter for advanced wastewater treatment because the phosphates could be removed by the ion exchange with hydroxyl ions of copper hydroxide. The evaluation of phosphate removal was performed under the conditions of the batch type in wastewater and continuous type through filters. Filter recycling was also evaluated with retreatment of the surface modification process. The phosphate was rapidly removed within a very shorter contact time by the surface-modified brass scrubber filter, and the phosphate mass of 1.57 mg was removed per gram of the filter. The possibility of this surface-modified brass scrubber filter for phosphorus removal was shown without undesirable sludge production of existing chemical phosphorus removal techniques, and we feel that it would be very meaningful as a new wastewater treatment.

• 한국습지학회지
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• 제20권4호
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• pp.410-416
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• 2018

본 연구는 탄소나노튜브(MWCNT)와 활성탄을 이용한 니켈과 구리의 흡착특성을 평가하였다. 산성조건에서 활성탄의 제거성능이 낮은 반면, MWCNT만 니켈과 구리를 흡착 제거하는데 효율적이었다. MWCNT와 중금속의 흡착반응은 유사 일차반응식을 따랐다. 초기 pH가 중성일 때, 니켈은 MWCNT에 의해 신속히 제거되었고, 활성탄은 4시간에 각각 99.02%와 80.30%를 나타냈다. 또한, 구리이온은 초기 pH가 중성일 때 4시간내에 효율적으로 제거되었다. 흡착제 주입량을 증가함에 따라 pH가 증가하였고, 중금속 제거율도 증가하였다. 또한, 산화 전처리 공정은 MWCNT의 중금속 제거율을 증가시켰다.

• Environmental Engineering Research
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• 제7권1호
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• pp.49-57
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• 2002