• 한국물환경학회지
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• 제23권6호
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• pp.966-972
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• 2007

A novel organoclay has been developed with aluminium-pillared clay modified with an amphoteric surfactant, N-Dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (DDAPS). This novel organoclay is expected to have phosphorus removal capacity as well as organic and inorganic contaminant removal capacity, due to aluminum inside the clay structure. It also exhibited less surfactant desorption than conventional cation surfactant-based organoclays. Phosphorus in water can be decreased from 0.2 mg/L to 0.0012 mg/L in 27 hours with this organoclay. Also, cadmium could removed from water using this proposed organo-clay. Experiments were performed under various pHs and amphoteric surfactants sorption capability was the highest at pH 5 when more of the amphoteric surfactant head group took on positive charges.

• 환경위생공학
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• 제11권3호
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• pp.21-27
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• 1996

Chitosan is a natural polyelectrolytic compound. Researches of adsorption capacity using chitosan have been doing actively. We prepared bead type gel, simple modifier of chitosan, And then experimented adsorption test of heavy metals (Cd etc) using it. According to the result adsorption capacity of chitosan bead was five times higher than chitosan powder. Removal rate of cadmium resulted 90% over in the test that initial concentration of Cd was 100mg/L and bead dosage was 6g/100mL. Adsorption type of heavy metals was similar to general adsorption curve. And optical pH range was 4 - 10 in the adsorption test. In the experiments of other heavy metals (Pb, Zn, Cu, Mn) adsorption types had two stages, highly removal rate-stage at the short time (20minutes) and then slow rate-stage at the after. And removal efficiency at the variable pH ranges revealed relatively good.

• Journal of Microbiology and Biotechnology
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• 제15권3호
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• pp.497-501
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• 2005

This study deals with the removal of mercury species using a packed-bed column with spherical aminated chitosan material. These adsorbents revealed a high adsorption capacity for mercury species. Experiments with feed solutions of 10 ppm Hg dissolved in distilled water showed an excellent removal with a sharp increase of the filter effluent concentration after a total throughput of 900 bed volumes of feed water. Up to $95\%$ desorption was reached by using 3 bed volumes of 0.01 N EDTA solution. EDTA could be recovered by means of sulfuric acid with about $75\%$ efficiency. Almost the same results were obtained in repeated sorption and desorption experiments at identical conditions. The experiments demonstrated that the sorbents possessed practically no sorption capacity for alkaline earth ions ($Ca^{2+}\;and\;Mg^{2+}$). Their influence on the sorption of mercury was negligible. In experiments with spiked tap water of the Karlsruhe Research Centre and a feed mercury concentration of 0.01 mg/l, the breakthrough of Hg was observed only after a total throughput of about 6,000 bed volumes of feed water.

• 자원환경지질
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• 제43권1호
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• pp.33-42
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• 2010

마을상수도 지하수의 라돈의 자연저감 정도를 파악하기 위하여 6개 지점을 대상으로 지하수공의 제원, 저수조의 크기, 지하수 사용량, 원수로부터 꼭지수까지의 거리를 측정하고 원수와 3개 꼭지수의 라돈함량을 분석하고 비교하였다. 5개 마을상수도 지하수(A-E)에서 2회에 걸친 원수와 꼭지수의 라돈 자연저감은 2006년 11월에는 26.0%, 2006년 12월에는 45.6%로 나타나 계절별 지하수 사용량에 따른 자연저감율에 차이가 있는 것으로 나타났다. 그러나 마을상수도 F에서 2007년 4월 일주일 간격으로 3회 분석된 꼭지수의 라돈함량은 원수의 44.1-49.0%로 나타나 단기간에 걸친 라돈 자연저감에는 큰 변화가 없는 것으로 나타났다. 한편 꼭지수에서의 라돈의 저감은 원수로부터의 거리, 저수조의 크기보다는 지하수의 사용량에 더 영향을 받는 것으로 나타났다.

• Korean Chemical Engineering Research
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• 제52권2호
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• pp.240-246
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• 2014

황화수소와 암모니아를 포함한 악취폐가스를 처리하기 위하여 여러 semi-pilot 바이오필터 운전 조건 하에서 Bacillus cereus DAH-1056과 Arthrobacter sp. KDE-0311를 고정한 semi-pilot 바이오필터 시스템을 운전하였다. Semi-pilot 바이오필터 운전조건에서 Thiobacillus sp. IW와 반송슬러지를 고정한 바이오필터의 황화수소 removal efficiency는 약 80%이었고 암모니아의 removal efficiency는 약 50% 정도이었던 반면에 Bacillus cereus DAH-1056과 Arthrobacter sp. KDE-0311를 고정한 본 연구에서 황화수소의 removal efficiency는 약 90%이었고 암모니아의 removal efficiency는 약 60% 정도이었다. 따라서 본 연구에서 Thiobacillus sp. IW와 반송슬러지를 고정한 semi-pilot 바이오필터의 경우를 기준으로 황화수소 및 암모니아의 removal efficiency가 각각 약 13% 및 20% 정도 제고되었다. 또한 본 연구에서는 암모니아의 최대 elimination capacity가 약 $35g/m^3/h$로서 Thiobacillus sp. IW와 반송슬러지를 고정한 semi-pilot 바이오필터의 경우보다 $3{\sim}5g/m^3/h$ 정도 제고되어 10~17% 더욱 높았다. 한편 본 연구의 황화수소의 최대 elimination capacity는 약 $63g/m^3/h$ 정도로 약 15% 증가하였다. 본 연구에서는 같은 inlet load의 황화수소라 할지라도 높은 농도의 황화수소가 낮은 농도의 황화수소보다 바이오필터의 암모니아 처리를 더 어렵게 하거나, 같은 inlet load의 암모니아라 할지라도 낮은 농도의 암모니아의 경우가 높은 농도의 암모니아보다 더 큰 removal efficiency와 elimination capacity를 갖는 것이 관찰되었다. 본 연구에서의 황화수소 최대처리용량은 황화수소와 암모니아를 동시처리 하였음에도 불구하고 황화수소만을 바이오필터로 처리한 선행연구에서의 황화수소 최대처리용량을 초과하거나 비슷하였다. 또한 본 연구에서는 바이오필터로 황화수소와 암모니아를 동시처리한 선행연구보다 더 높은 암모니아 제거용량을 보였다.

• Carbon letters
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• 제12권1호
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• pp.1-7
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• 2011

In the present study, the removal of Pb (II) ions on oxidized activated carbons (ACs) was investigated. ACs were derived from activation of indigenous cotton stalks waste with potassium hydroxide (KOH) in two-stage process. The KOH-ACs were subjected to liquid-phase oxidation with hot $HNO_3$ and one untreated sample was included for comparison. The obtained carbons were characterized by Fourier transform infrared (FTIR), slurry pH and $N_2$-adsorption at 77 K, respectively. Adsorption capacity of Pb (II) ions on the resultant carbons was determined by batch equilibrium experiments. The experimental results indicated that the oxidation with nitric acid was associated with a significant increase in mass of yield as well as a remarkable reduction in internal porosity as compared to the untreated carbon. The AC-800N revealed higher adsorption capacity than that of AC-800, although the former sample exhibited low surface area and micropore volume. It was observed that the adsorption capacity enhancement attributed to pore widening, the generation of oxygen functional groups and potassium containing compounds leading to cation-exchange on the carbon surface. These results show that the oxidized carbons represented prospective adsorbents for enhancing the removal of heavy metals from wastewater.

• 유기물자원화
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• 제15권4호
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• pp.107-114
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• 2007

다당류의 일종인 알긴산을 이용한 중금속 제거에 관한 연구가 수행되어졌다. 알긴산은 pH 4에서 480mg/g의 납 이온을 흡착하였으며 이것은 다른 생물흡착제에 비해서 약 2배 정도의 높은 흡착능이다. 납 이온에 대한 등온흡착선을 묘사하기 위하여 Langmuir model 식을 이용하였으며 실험결괴는 모델식에서 얻어진 결과와 잘 부합되었다. 온도가 증가함에 따라서 흡착능은 증가하였으며 이는 알긴산과 납 이온의 흡착은 흡열반응임을 보여준다. 납 이온의 흡착에 대한 알칼리 금속(칼슘, 마그네슘 이온)의 영향은 거의 없었으며 대부분의 흡착은 30분 내에 이루어졌다. 구리, 수은, 스트론튬, 세슘 과 같은 다른 금속 이온에 대한 흡착능도 조사되었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제15권3호
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• pp.27-33
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• 2010

The purpose of this study was in search of native plant species showing metal-resistant property and excessively accumulating heavy metals in metal-contaminated soil or abandoned mines as well as in evaluation of applicability of phytoremediation. In the study area, species showing excessively accumulating heavy metals were a shepherd´s purse, pampas grass, a Korean lettuce, a Hwansam vine, the Korean persicary, a foxtail, a goosefoot, and a water pepper. The first screened plant species in Sambo mine were as shepherd's purse, Korean lettuce and pampas grass Among them the shepherd´s purse can be excluded because it is a seasonal plant and has lower removal capacity for heavy metals. The Korean lettuce was also excluded because of having lower removal capacity for heavy metals. Pampas grass is a highly bionic plant species constantly growing from spring. However it has weak points such as little accumulation capacity for zinc as well as small values of an accumulation factor and a translocation factor. Another problem is regarded as removal of roots after the clean up if pampas grass is applied to a farmland. In Sanyang mine, wormwood and Sorijaengi were considered as adaptable species.

• Membrane and Water Treatment
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• 제13권5호
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• pp.209-217
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• 2022

In the present research, Ficus religiosa Bark (FRB) is used as an adsorbent for the removal of heavy metal Cr (VI) ions. This Ficus religiosa Bark was characterized by Scanning Electron Microscope, Fourier transform infrared Spectroscopy, Thermo Gravimetric Analyzer and the results showed that activated adsorbent have high adsorption capacity and withstand even in high temperature. Batch and Continuous experiments were conducted to determine the effect of various parameters such as pH, contact time, adsorbent dose and initial metal concentration. The biosorption followed pseudo first order kinetic model. The adsorption isotherms of Cr (VI) on Ficus religiosa fitted well with the Temkin model. In Batch study, maximum biosorption capacity of Cr (VI) was found to be 37.97 mg g^-1 (at optimal pH of 2, adsorbent dosage of 0.3 grams and concentration of Cr (VI) is100 mg L^-1). The Continuous mode of study shows that 97% of Cr (VI) ion removal at a flow rate of 15 ml min^-1. From the results, selected Ficus religiosa Bark has the higher adsorption capacity for the removal of Cr (VI) ions from wastewater.

• Journal of the Korean Wood Science and Technology
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• 제51권5호
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• pp.321-333
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• 2023

In this study, lignin, a lignocellulosic biomass, was chemically modified to produce polyethyleneimine-grafted lignin (PKL) with maximum hexavalent chromium [Cr(VI)] adsorption capacity. Changes in the physicochemical properties due to the cationization of lignin were confirmed through elemental analysis, Fourier transform infrared spectroscopy, and moisture stability evaluation. Alginate (Alg) beads containing PKL (Alg/PKL) were prepared by incorporating cationic lignin into the Alg matrix to apply the prepared PKL in a batch-type water treatment process. The optimal Alg/lignin mixing ratio was selected to increase the Cr(VI) adsorption capacity and minimize lignin elution from the aqueous system. The selected Alg/PKL beads exhibited an excellent Cr(VI) removal capacity of 478.98 mg/g. Isothermal adsorption and thermodynamic analysis revealed that the Cr(VI) removal behavior of the Alg/PKL beads was similar to that of heterogeneous chemical adsorption. In addition, the bulk adsorbent material in the form of beads exhibited adsorption behavior in three stages: surface adsorption, diffusion, and equilibrium.