등온 및 동적 흡착 실험을 통한 제강 슬래그의 비소 흡착 특성

오참뜻,이성수,Toshifumi, Igarashi,권호진,이원택,박준범 한국지반공학회 2010 한국지반공학회논문집 Vol.26 No.9

Sorption characteristics of arsenic on furnace slag were investigated to remove arsenic from groundwater using furnace slag, which is industrial waste generated from steel company. Adsorption isotherm experiments and kinetic sorption experiments were performed and the chemical characteristics of supernatants from these experiments were analyzed. Results showed that all supernatants were alkaline (above pH 9) and the highest ion concentration in the solution was found with calcium (30~50 mg/L). Results of adsorption isotherms were more adequately described by the Freundlich model than Langmuir model. From adsorption isotherms experiments, it was noted that the adsorption amount of As(V) was 87% higher than that of As(III). Results of kinetic sorption experiments were more properly fitted by pseudo second order (PSO) model than pseudo first order model. Equilibrium adsorption amount (qe) and relaxation time (tr) calculated from PSO model increased with initial concentration of arsenic. Equilibrium adsorption amount of As(V) was higher than that of As(III) and relaxation time of As(V) was shorter than that of As(III). Adsorption isotherm results could be predicted by kinetic adsorption results, since equilibrium adsorption amount calculated through PSO model generally agreed with equilibrium adsorption amount measured from adsorption isotherm.

폭기를 활용한 광산배수 내 용존 철 제거속도 향상 기작

오참뜻,임길재,정영욱,홍지혜,지상우 한국자원공학회 2014 한국자원공학회지 Vol.51 No.4

Aeration was applied on three different mine drainages to verify the removal rate enhancement of dissolved iron. Equilibrium with the atmosphere accelerated the increase in DO and decrease in DCO2 where the latter affected the eventual increase in pH level. The combined effect of the increase in both DO and pH provided a favorable environment for Fe2+ oxidation and this led to the boost in oxidation rate. Aeration, in this process, played an important role in escalating gas exchange rates by increasing the contact area between mine drainages and the atmosphere. Since Fe2+ oxidation was a rate determining step in removing dissolved iron, aeration could be an effective method to expedite the iron removal in mine drainages. In case of net acidic mine drainages, however, aeration could not boost the treatment efficiency due to lack of decarbonation effect which increases the pH of the mine drainages. 광산배수 내 용존 철 제거속도를 향상시키기 위한 방법으로 폭기를 활용하고자 서로 다른 특성을 띄는 광산배수를 대상으로 폭기실험을 수행하였다. 대기와의 평형반응을 통해 광산배수 내 DO 농도는 증가하고 DCO2 농도는 감소하게 되는데 탈기된 DCO2는 광산배수의 pH를 상승시킨다. 상승된 DO 농도와 pH 값은 Fe2+가 산화되는데 유리한 환경을 제공하여 Fe2+ 산화속도를 크게 향상시킬 수 있었다. 이 과정에서 폭기는 광산배수-대기 간 접촉면적을 증가시킴으로써 기체교환속도를 큰 폭으로 향상시키는 역할을 하였다. Fe2+의 산화반응은 용존 철 제거과정에서 속도결정단계였으므로 폭기는 광산배수 내 용존 철 제거속도를 향상시키는 효과적인 방법이 될 수 있다. 다만 순 산성을 띄는 광산배수의 경우에는 DCO2 탈기에 의한 pH 증가를 기대할 수 없어 폭기를 통해 광산배수 처리효율을 향상시킬 수 없었다.

지구화학적 평형 모델 적용을 통한 제강 슬래그의 비소제거 기작 연구

오참뜻,임길재,박준범,지상우,정영욱 한국자원공학회 2013 한국자원공학회지 Vol.50 No.2

It was performed to evaluate dominant mechanisms occurring when steel making slag removes arsenic in aqueous solution that batch experiments with initial pH and its geochemical equilibrium modeling using Visual MINTEQ. A large amount of calcium was leached from the slag in process of the chemical reaction with the arsenic solution and were precipitated as calcite or amorphous calcium carbonate due to increased solution pH by the slag removing arsenic by co-precipitation or adsorption. When the solution pH was acidic after the batch experiments, calcium precipitates could not be formed. However, it is estimated that ferric oxide, ferrous hydroxide, aluminum oxide, aluminum oxide hydroxide would adsorb arsenic in form of HAsO4 2-, H2AsO4 - instead of calcium precipitates in acidic condition. Results of geochemical equilibrium modeling using Visual MINTEQ proved its good applicability being similar with those of previous literatures. 제강 슬래그를 이용해 수용액상의 비소를 제거할 때 발생하는 주 기작을 평가하기 위해 초기 pH를 변화시킨 비소용액과 제강 슬래그의 흡착실험을 수행하고 이에 대한 지구화학적 평형을 Visual MINTEQ을 이용해 모델링하였다. 제강 슬래그와 비소의 화학반응 과정에서 다량의 칼슘이 용출되었고 이는 제강 슬래그로 인해 상승된 용액의 pH에 의해 다시 방해석 및 amorphous calcium carbonate로 침전되면서 공침, 흡착을 통해 비소를 제거하는 것으로 확인된다. 흡착반응 완료 후 용액의 pH가 산성인 경우 칼슘 침전물은 형성되지 못하는 것으로 모사되었으나 ferric oxide, ferrous hydroxide, aluminum oxide, aluminum oxide hydroxide 등이 HAsO4 2-, H2AsO4-형태의 비소를 흡착하는 것으로 판단된다. Visual MINTEQ을 통한 제강 슬래그-비소 반응의 지구화학적 평형 모델링 결과는 선행연구들과 유사한 결과를 보이며 높은 적용 가능성을 보였다.

정화토양 및 배출가스의 환경적 특성 분석을 통한 저온열탈착장치의 현장 적용성 평가

오참뜻,이용민,김용성,전우진,박광진,김치경,성기준,장윤영,김국진,Oh, Cham-Teut,Yi, Yong-Min,Kim, Young-Soung,Jeon, Woo-Jin,Park, Gwang-Jin,Kim, Chi-Kyung,Sung, Ki-June,Chang, Yoon-Young,Kim, Guk-Jin 한국지하수토양환경학회 2012 지하수토양환경 Vol.17 No.3

Geochemical and ecological properties of remediated soil and gas exhausted from a low-temperature thermal desorption (LTTD) process were analyzed to assess the environmental impact of LTTD treatment. Soil characteristics were examined with regard to the chemical (EC, CEC, and organic matter) and the ecological (dehydrogenase activity, germination rate of Brassica juncea, and growth of Eisenia andrei) properties. The exhaust gases were analyzed based on the Air Quality Act in Korea as well as volatile organic compounds (VOCs) and mixed odor. Level of organic Organic matter of the soil treated by LTTD process was slightly decreased compared to that of the original soil because the heating temperature ($200^{\circ}C$) and retention time (less than 15 minutes) were neither high nor long enough for the oxidation of organic matter. The LTTD process results in reducing TPH of the contaminated soil from $5,133{\pm}508$ mg/kg to $272{\pm}107$ mg/kg while preserving soil properties. Analysis results of the exhaust gases from the LTTD process satisfied discharge standard of Air Quality Law in Korea. Concentration of VOCs including acetaldehyde, propionaldehyde, butyraldehyde and valeraldehyde in circulation gas volatilized from contaminated soil were effectively reduced in the regenerative thermal oxidizer and all satisfied the legal standards. Showing ecologically improved properties of contaminated soil after LTTD process and environmentally tolerable impact of the exhaust gas, LTTD treatment of TPH-contaminated soil is an environmentally acceptable technology.

인공습지 내 자연유기물의 분광학적 특성평가

오참뜻(Chamteut Oh),권주혁(Juhyuk Kwon),한영수(Youngsoo Han),임길재(Giljae Yim),조용찬(Yongchan Cho),정영욱(Youngwook Cheong) 대한지질학회 2017 대한지질학회 학술대회 Vol.2017 No.10

암석 내 존재하는 황의 화학종을 고려한 산 발생량 평가

오참뜻(Chamteut Oh),유초이(Choi Yu),지상우(Sangwoo Ji),임길재(Giljae Yim),정영욱(Youngwook Cheong),이평구(Pyoungkoo Lee) 대한지질학회 2013 대한지질학회 학술대회 Vol.2013 No.10

토양 정화 방법에 따른 토양의 물리화학적 특성 변화

이용민,오참뜻,김국진,이철효,성기준,Yi, Yong-Min,Oh, Cham-Teut,Kim, Guk-Jin,Lee, Chul-Hyo,Sung, Ki-June 한국지하수토양환경학회 2012 지하수토양환경 Vol.17 No.4

Various methods are used to remediate soil contaminated with heavy metals or petroleum. In recent years, harsh physical and chemical remediation methods are being used to increase remediation efficiency, however, such processes could affect soil properties and degrade the ecological functions of the soil. Effects of soil washing, thermal desorption, and land farming, which are the most frequently used remediation methods, on the physicochemical properties of remediated soil were investigated in this study. For soils smaller than 2 mm, the soil texture were changed from sandy clay loam to sandy loam because of the decrease in the clay content after soil washing, and from loamy sand to sandy loam because of the decrease in the sand content and increase in silt content during thermal desorption, however, the soil texture remained unchanged after land farming process. The water-holding capacity, organic matter content, and total nitrogen concentration of the tested soil decreased after soil washing. A change in soil color and an increase in the available phosphate concentration were observed after thermal desorption. Exchangeable cations, total nitrogen, and available phosphate concentration were found to decrease after land farming; these components were probably used by microorganisms during as well as after the land farming process because microbial processes remain active even after land farming. A study of these changes can provide information useful for the reuse of remediated soil. However, it is insufficient to assess only soil physicochemical properties from the viewpoint of the reuse of remediated soil. Potential risks and ecological functions of remediated soil should also be considered to realize sustainable soil use.

마이크로버블 오존 산화제와 공압파쇄 장치를 연계 적용한 지중 화학적 산화법의 정화효율 평가

오승택,오참뜻,김국진,석소희,김철경,임진환,유재봉,장윤영,Oh, Seung-Taek,Oh, Cham-Teut,Kim, Guk-Jin,Seok, So-Hee,Kim, Chul-Kyung,Lim, Jin-Hwan,Ryu, Jae-Bong,Chang, Yoon-Young 한국지하수토양환경학회 2012 지하수토양환경 Vol.17 No.4

A new type of chemical oxidation technology utilizing micro bubble ozone oxidizer and a pneumatic fracturing equipment was developed to enhance field applicability of a traditional chemical oxidation technology using hydrogen peroxide as an oxidizer for in-situ soil remediation. To find an efficient way to dissolve gaseous ozone into hydrogen peroxide, ozone was injected into water as micro bubble form then dissolved ozone concentration and its duration time were measured compared to those of simple aeration of gaseous ozone. As a result, dissolved ozone concentration in water increased by 31% (1.6 ppm ${\rightarrow}$ 2.1 ppm) and elapsed time for which maximum ozone concentration decreased by half lengthened from 9 min to 33 min. When the developed pneumatic fracturing technology was applied in sandy loam, cracks were developed and grown in soil for 5~30 seconds so that the radius of influence got longer by 71% from 392 cm to 671 cm. The remediation system using the micro bubble ozone oxidizer and the pneumatic fracturing equipment for field application was made and demonstrated its remediation efficiency at petroleum contaminated site. The system showed enhanced remediation capacity than the traditional chemical oxidation technology using hydrogen peroxide with reduced remediation time by about 33%.

Optimizing the addition of flocculants for recycling mineral-processing wastewater

박진희,오참뜻,한영수,지상우 한국자원공학회 2016 Geosystem engineering Vol.19 No.2

Mineral processing requires large volumes of water, but water is limited at mining sites. Therefore, techniques to recycle mineral-processing wastewater without negative effects on recovery and flotation grade are critical. Among a number of technologies to recycle water, flocculation using an anionic polymer was tested for recycling mineral-processing wastewater, as a major issue in mineral-processing wastewater recycling is to reduce suspended particles. A batch cylinder test was employed to evaluate the optimum amount of flocculant to add and settlement rate, turbidity, and floc size were measured as indications of dewaterability. Adding increasing amounts of flocculant increased the sedimentation rate due to the increased floc size. However, turbidity did not improve by increasing the concentration of flocculant because the polymer coating on the particle surface prevented efficient bridging of particles. In addition, excess use of flocculant may degrade water quality and produce unnecessary costs. Therefore, it is important to identify the optimum flocculant concentration for treating mineral-processing wastewater based on the properties of the water.

수산화알루미늄 함유 폴리염화비닐 흡착제에 대한 비소이온 흡착거동

지상우,복송민,오참뜻,임길재,정영욱,박제현,최의규,최홍일,유경근 한국자원공학회 2016 한국자원공학회지 Vol.53 No.5

PVC-Al(OH)3 beads were prepared to remove arsenic (As) ions using aluminium hydroxide sludge for an effective re-use. The sludge was obtained from domestic treatment facilities of acid mine drainages. The absorption behavior of arsenic ion was investigated in the pH range within 2 and 12. As a result, the removal efficiencies of As(V) ion were higher than that of As(III), over the entire pH range of this study. The removal efficiencies of As(V) ion increased to 100% at neutral pHs within 500 min of reaction duration. The efficiencies were low at pH 2 and pH 12, because of the high dissolution of aluminum hydroxide at those pHs. The absorbed amount of As(V) ions increased to 200 mmol/g at 200 mmol/L initial As concentration. 국내 산성광산배수 처리장에서 회수된 수산화알루미늄 슬러지를 효율적으로 활용하기 위해서 폴리염화비닐 (PVC)과 혼합해 PVC-Al(OH)3 비드를 제조하고 비소 이온 제거를 위해 사용하고자 하였다. pH를 2에서12로 변화시키며 비소이온의 흡착거동을 조사한 결과 모든 구간에서 비소 5가 이온의 제거율이 비소 3가 이온보다 높았으며, pH가 중성영역에서 제거율은 500 분 내에 100%를 나타냈다. 비소 제거율은 pH가 2와 12에서감소하였는데, 이는 수산화알루미늄이 이 영역에서 용해되는 것이 원인으로 분석되었다. 비소 5가 이온의 경우초기 농도 200 mmol/L일 때 흡착량은 200 mmol/g까지 증가하였다.