• 한국지하수토양환경학회지:지하수토양환경
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• 제9권2호
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• pp.28-40
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• 2004

토양증기추출(Soil Vapor Extraction)법을 이용하여 대표적 휘발성 오염물질(VOCs)인 가솔린을 토양으로부터 제거하는 박스실험을 실시하였다. 아크릴수지로 제작된 65 cm${\times}$20 cm${\times}$30 cm 규모의 박스를 제작하여, 인공적인 토양 환경을 설정한 후, 직경 1 cm인 스테인레스 재질의 관에 0.2cm 간격으로 하부에서 15cm까지 스크린 된 스테인레스 재질의 주입정(2개)과 추출정(1개)을 설치하여 SVE를 실시하였으며, 추출정으로부터 배출되는 가스를 제거하는 후처리 공정을 연결하여 SVE로부터 배출되는 가스의 가솔린 농도와 후처리 공정 후 배출되는 가솔린 농도를 비교 분석하였다. 가솔린 100g을 토양 내 주입한 경우 0.03 L/min 조건의 박스실험에서는 SVE에 의해 약 560L (13일 경과) 가스 추출 후 주입된 가솔린의 95%가 제거되었으며, 주입 가솔린양이 250 g이고 추출 가스량이 0.2 L/min 조건에서는 약 1440L(5일 경과)가스 추출 후 주입 가솔린의 92% 이상이 제거되어, SVE가 토양 내 휘발성 오염물질을 제거하는데 매우 효과적인 방법임을 입증하였다. 가솔린으로 오염된 토양에서 SVE 공정으로부터 배출되는 가스를 과립상 활성탄 흡착탑과 바이오필터를 이용하여 제거하는 실험을 실시하였다. SVE로부터 배출된 가스의 후처리 공정으로 활성탄의 흡착탑을 이용한 제거 공정과 바이오필터를 이용한 제거 공정의 효율을, 후처리 공정으로 주입되는 가스내 가솔린량에 대한 운전 시간별 제거 효율로 나타내었다. 제거 효율은 후처리 공정에 주입되는 가솔린의 농도와 관계 없이 평균 94%의 높고 안정적인 효율을 나타내었고, 후처리 후 배출되는 가스의 농도 자체도 매우 낮게 나타남으로서, 실제 오염지역에서 토양증기추출법과 결합 된 하나의 VOCs 제거공정으로서 효과적으로 사용될 수 있음을 입증하였다. 활성탄 흡착탑과 바이오필터에 유입되는 가솔린의 부하량에 대한 제거 용량은, 주입되는 가솔린의 농도가 상당히 높음에도 불구하고 주입되는 가솔린의 농도가 높을수록 선형적으로 증가하였다. 이러한 결과들은 후처리 공정들이 SVE에서 배출되는 가스의 VOCs 농도가 다양한 환경에서도 광범위하게 적용할 수 있으며, 특히 고농도의 가스상을 처리하는 데에도 매우 효과적으로 사용될 수 있음을 입증한다.

• Environmental Engineering Research
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• 제19권1호
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• pp.15-22
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• 2014

In this study, the performances of various adsorbents-red mud, zeolite, limestone, and oyster shell-were investigated for the adsorption of multi-metal ions ($Cr^{3+}$, $Ni^{2+}$, $Cu^{2+}$, $Zn^{2+}$, $As^{3+}$, $Cd^{2+}$, and $Pb^{2+}$) from aqueous solutions. The result of scanning electron microscopy analyses indicated that the some metal ions were adsorbed onto the surface of the media. Moreover, Fourier transform infrared spectroscopy analysis showed that the Si(Al)-O bond (red mud and zeolite) and C-O bond (limestone and oyster shell) might be involved in heavy metal adsorption. The changes in the pH of the aqueous solutions upon applying adsorbents were investigated and the adsorption kinetics of the metal ions on different adsorbents were simulated by pseudo-first-order and pseudo-second-order models. The sorption process was relatively fast and equilibrium was reached after about 60 min of contact (except for $As^{3+}$). From the maximum capacity of the adsorption kinetic model, the removal of $Pb^{2+}$ and $Cu^{2+}$ were higher than for the other metal ions. Meanwhile, the reaction rate constants ($k_{1,2}$) indicated the slowest sorption in $As^{3+}$. The adsorption mechanisms of heavy metal ions were not only surface adsorption and ion exchange, but also surface precipitation. Based on the metal ions' adsorption efficiencies, red mud was found to be the most efficient of all the tested adsorbents. In addition, impurities in seawater did not lead to a significant decrease in the adsorption performance. It is concluded that red mud is a more economic high-performance alternative than the other tested adsorption materials for applying a removal of multi-metal in seawater.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권6호
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• pp.402-409
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• 2001

Different bioligands carrying synthetic adsorbents have been reported in the literature for protein separation, We have developed a novel and new approach to obtain high protein ad-sorption capacity utilizing 2-methacrylamidohistidine(MAH) as a bioligand. MAH was synthe-sized by reacting methacrylocholride and histidine, Spherical beads with an average size of 150-200㎛ were obtained by the radical suspension polymerization of MAH and 2-hydrosyethyl-methacrylate(HEMA) conducted in an aqueous dispersion medium. p(HEMA-co-MAH) beads had a specific surface area of 17.6㎡/g . Synthesized MAH monomer was characterized by NMR. p(HEMA-co-MAH) beads were characterized by swelling test, FTIR and elemental analysis. Then Cu(II) ions were incorporated onto the beads and Cu(II) loading was found to be 0.96 mmol/g.These affinity beads with a swelling ration of 65% and containing, 1.6 mmol MAH/g were used in the adsorption/desorption of human serum albumin(HSA) from both aqueous solutions and hu-man serum. The adsorption of HSA onto p(HEM-co-MAH) was low(8.8 mg/g). Cu(II) chelation onto the beads significantly increased the HSA adsorption (56.3 mg/g). The maximum HSA ad-sorption ws observed at pH 8.0 Higher HSA adsorption was observed from human plasma(94.6 mgHSA/g) Adsorption of other serum proteins were obtained as 3.7 mg/g for fibrinogen and 8.5mg/g for γ-globulin. The total protein adsorption was determined as 107.1mg/g. Desorption of HSA was obtained using 0.1 M Tris/HCl buffer containing 0.5 M NaSCN, High desorption rations(up to 98% of the adsorbed HSA) were observed. It was possible to reuse Cu(II) chelated-p(HEMA-co-MAH) beads without significant decreases in the adsorption capacities.

• 공업화학
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• 제34권2호
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• pp.199-205
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• 2023

Arsenic is a highly toxic element, and its contamination is widespread around the world. The natural materials with high selectivity and efficiency toward pollutants are important in wastewater treatment technology. In this study, the mesoporous synthetic hectorite was synthesized by facile hydrothermal crystallization of gels comprising silica, magnesium hydroxide, and lithium fluoride. Additionally, the naturally available clay was modified using zirconium at room temperature. Both synthetic and modified natural clays were employed in the removal of arsenate from aquatic environments. The materials were fully characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transform-infrared (FT-IR) analyses. The synthesized materials were used to remove arsenic (V) under varied physicochemical conditions. Both materials, i.e., Zr-bentonite and Zr-hectorite, showed high percentage removal of arsenic (V) at lower pH, and the efficiency decreased in an alkaline medium. The equilibrium-state sorption data agrees well with the Langmuir and Freundlich adsorption isotherms, and the maximum sorption capacity is found to be 4.608 and 2.207 mg/g for Zr-bentonite and Zr-hectorite, respectively. The kinetic data fits well with the pseudo-second order kinetic model. Furthermore, the effect of the background electrolytes study indicated that arsenic (V) is specifically sorbed at the surface of these two nanocomposites. This study demonstrated that zirconium intercalated synthetic hectorite as well as zirconium modified natural clays are effective and efficient materials for the selective removal of arsenic (V) from aqueous medium.

• 분석과학
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• 제17권3호
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• pp.199-210
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• 2004

Amberite XAD-16 다공성 수지에 4,5-dihydroxynaphthalene-2,7-disulfonic acid (chromotropic acid, CTA)를 화학적으로 결합시켜 XAD-16-CTA형 새로운 킬레이트 수지를 합성하고, 적외선분광법과 원소분석법으로 확인하였다. 이 킬레이트 수지에 대한 금속마감 산업과 관련 있는 9개 금속이온을 포함하는 Cr(III) 및 Cr(VI) 이온들의 흡착 및 탈착 특성을 뱃치법과 용리법으로 조사하였다. XAD-16-CTA 킬레이트수지는 1~5 M의 HCl, $HNO_3$ 및 NaOH 등의 산과 염기 용액에서 매우 안정하였다. pH 2에서 Cr(VI) 이온과 Cr(III) 이온이 공존하는 혼합용액으로부터 Cr(VI) 이온만을 선택적으로 분리할 수 있음을 확인하였으며, Cr(VI)의 최대 흡착용량은 1.2 mmol/g 이었다. 또한 Cr(VI) 이온의 흡착에 미치는 공존 음이온의 영향을 검토한 결과 음이온인 $F^-$, $SO{_4}^{2-}$, $CN^-$, $CH_3COO^-$, $NO{_3}^-$ 이온은 흡착율을 감소시켰으며, $PO{_4}^{3-}$와 $Cl^-$는 흡착에 큰 영향을 미치지 않았다. pH 2에서 킬레이트 수지에 의한 돌파점용량과 총괄용량으로부터 얻은 금속이온의 용리순서는 Cr(VI)>Sn(II)>Fe(III)>Cu(II)>Cd(II)${\simeq}Pb(II){\simeq}Cr(III){\simeq}Mn(II){\simeq}Ni(II){\simeq}Al(III)$이었다. 한편 $HNO_3$, HCl 및 $H_2SO_4$ 등의 탈착제에 의한 Cr(VI) 이온의 탈착특성을 조사한 결과 3 M HCl에서 높은 탈착효율을 나타내었다. 결과적으로, XAD-16-CTA 킬레이트 수지는 여러 가지 금속이온이 혼합된 금속마감산업 인공폐액 중 Cr(VI) 이온의 선택적 분리, 농축 및 회수에 매우 유용함을 알 수 있었다.

• 대한화학회지
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• 제52권2호
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• pp.155-163
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• 2008

유기-실리카 이용한 잔유 구리(II)의 양을 빠른 추출을 위한 간단하고 재현성을 가지는 방법과 불꽃원자 흡수분광법으로의 검출에 대해 연구하였다. 공통으로 존재하는 이온은 분리와 검출에 간섭받지 않았다. 예비농축인자는 100 ml시료 용량에 대해 100 (1 ml 추출용량) 이 였다.제안된 방법의 검출한계는 1.0 ng ml-1이다. 최적조건하에서 흡착제의 최고흡수용량은 5 mg 구리/g 흡착제 였다. 최적조건하에서 상대표준편차는 2.8% (n=10)을 얻었다. 다양한 양의 구리(II)이온은 스파이크한 자연수와 합성수를 시험 시료로 하여 정확도 등을 시험하였다.

• Membrane and Water Treatment
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• 제11권3호
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• pp.189-193
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• 2020

In this study, electrokinetic remediation equipment was used to remove cesium (Cs) from clay soil and waste solution was treated with sorption process. The influence of electrokinetic process on the removal of Cs was evaluated under the condition of applied electric voltage of 15.0-20.0 V. In addition to monitoring the Cs removal, electrical current and temperature of the electrolyte during experiment were investigated. The removal efficiency of Cs from soil by electrokinetic method was more than 90%. After electrokinetic remediation, Cs was selectively separated from soil waste solution using sorbents. Various adsorption agents such as potassium nickel hexacyanoferrate (KNiHCF), Prussian blue, sodium tetraphenylborate (NaTPB), and zeolite were compared and KNiHCF showed the highest Cs removal efficiency. The Cs adsorption on KNiHCF reached equilibrium in 30 min. The maximum adsorption capacity was 120.4 mg/g at 0.1 g/L of adsorbent dosage. These results demonstrated that our proposed process combined electrokinetic remediation of soil and waste solution treatment with metal ferrocyanide can be a promising technique to decontaminate Cs-contaminated fine soil.

• 한국농공학회논문집
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• 제56권3호
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• pp.11-17
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• 2014

We investigated the applicability of steel slag as a capping material in order to minimize phosphorus(P) release into seawater. Steel slag is a byproduct from the iron and steel industries and the use of steel slag has some advantages in respect of both cost and environmental concern. P removal by steel slag were studied in a batch system with respect to changes in contact time and initial concentration. Kinetic adsorption data were described well by pseudo 2nd order model, indicating rate limiting step for P adsorption to steel slag is chemical sorption. Equilibrium adsorption data fitted well to Langmuir isotherm model which describes for single layer adsorption. The maximum P adsorption capacity of steel slag was 7.134 mg-P/L. Increasing the depth of steel slag produced a positive effect on interruption of P release. More than 3 cm of steel slag was effective for blocking P release and 5 cm of steel slag was recommended as the depth for capping of P contaminated marine sediments. Increasing P concentration and flow rate had a negative effect on P removal ratio. It was concluded that the steel slag has a potential capping material for blocking P release from marine sediments.

• Advances in environmental research
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• 제6권4호
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• pp.301-315
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• 2017

An Amberlite XAD-4 resin impregnated with di(2-ethylhexyl)phosphoric acid was prepared and its adsorption-desorption behaviors with Sr(II) ions under various conditions was examined. The resin was characterized by fourier transform infrared and thermal analysis techniques. The effects contact time, temperature, pH, interfering ions and eluants were studied. Results showed that adsorption of Sr (II) well fitted with pseudo-second-order kinetic model. The equilibrium adsorption data of Sr (II) on the impregnated resin were analyzed by Jossens, Weber-van Vliet, Redlich-Peterson and Fritz-Schlunder models to find out desirable equilibrium condition. Among them, the Fritz-Schlunder model best fitted to the experimental data. The maximum sorption capacity of impregnated resin amounted to 0.45 mg/ g at pH 8.0 and $20^{\circ}C$.

• 상하수도학회지
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• 제23권1호
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• pp.113-119
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• 2009

The feasibility of using cork oak bark for phosphorus removal from wastewater was evaluated in this study. Recently, development of more cost-effective media while maintaining high efficiency in pollutants removal has received concern. Barks have a negative surface charge and, hence, tend to show a high affinity to bind cations, and they need to undergo chemical modification to increase their adsorption capacity of anions. Bark was hydrolyzed by HCl solution and it received modification using an aqueous solution of high molecular weight polyethylenimine(PEI). Surface modification with HCl and PEI resulted in a decrease of specific surface area of the bark from $1.932 m^2/g$ to $1.094 m^2/g$. The adsorption experiments were carried out in batch tests and the data were fitted to the Langmuir isotherm and Freundlich isotherm equations. Phosphate removal rate was higher at the lower solution pH possibly due to the form of phosphate ion in solution. For the initial phosphate concentration of 10 mg/L, maximum adsorption was 20.88 mg P/g at pH 3 and 12.02 mg P/g at pH 5. Mechanism of phosphorus sorption onto the HCl-PEI bark was examined through FT-IR spectrometer. Ion exchange between $NH^+$ and $H_2PO_4{^-}$ appeared to be a key mechanism of phosphate adsorption onto the HCl-PEI bark surface.