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숯의 유해물질과 이들의 연소 중 상변화에 대한 열분석 연구
윤혜온 ( Hye On Yoon ),김기현 ( Ki Hyun Kim ) 한국광물학회 2011 광물과 암석 (J.Miner.Soc.Korea) Vol.24 No.2
숯은 제조 및 활용과정에서 연소를 통해 함유된 성분들을 방출한다. 연소는 숯의 화학조성뿐만 아니라 숯의 표면 물성변화를 초래하고 다른 성분을 흡착하기 쉬운 상태로 변형시키기도 한다. 본 연구에서는 국내에서 시판되는 4종 숯에 대하여 화학적, 열적안정성과 중금속 및 유기유해물질의 거동 연구를 수행하였다. 상온에서 400℃까지 열중량분석(TGA)과 시차주사열량계를 이용한 연소에 따른 중량변화와 관련된 물질거동 연구를 수행하였다. TGA 분석결과 대부분 시료에서 200℃ 이전 약 10% 중량이 감소하였으며, 200℃ 이전에 잔류유기물과 가스상 물질이 소실되는 것을 알려준다. 열분석에 의한 질량 감소는 천연숯과 인공숯에서 다르게 측정되었다. 천연숯 K1, C1에서는 400℃까지의 가열 반응결과 약 15% 중량 감소가 있었으며, 인공숯 K2, C2의 경우 약 20%의 중량 감소가 있는 것으로 검출되었다. 가열에 의한 400℃ 이하 중량감소는 주요 유기물과 VOC의 소실에 기인하는 것으로 나타났다. 화학조성분석에 근거한 X-선 회절분석을 실시하였다. 분석결과 첨가제인 Ba이 Ba(NO3)2 및 BaCO3 등의 형태로 NaNO3와 함께 숯에 다량 존재하는 것으로 분석되었다. Charcoal burning in the process of manufacture and ordinary use often release many constituent chemical species. As a result of open burning, the chemical composition as well as the physical properties of original material changes through the modification of surface properties of charcoal. Surface modification could be more responsible toward the outside elements for surface adsorption, it becomes easy to adsorb more toxic elements through surface adsorption. In this study, four kinds of commercially available charcoal were studied against the chemical and thermal stability along with the heavy metals and organic hazardous substances. Thermo gravimetric analysis (TGA) and differential scanning calorimetry, from room temperature to 400℃, were performed to study the weight loss and the changes in the behavior of those substances. According to TGA analysis, about 10% of weight loss was happened before 200℃. It was found that related weight loss of this temperature region may responsible to the gas phase organic matter. Natural charcoal, K1 and C1 show 15% of loss during the reaction heated to 400℃, while the artificial charcoal K2, C2 show the weight loss of about 20% was found. This is consistent with the main organic matter and VOC analysis results shown. Chemical composition based on the x-ray diffraction analysis was carried out. X-ray diffraction analysis reveals the existence of chemical additive in the forms of Ba(NO3)2, BaCO3, and NaNO3.
윤혜온(Hye On Yoon),(Richard J. Reeder) 한국광물학회 2002 광물과 암석 (J.Miner.Soc.Korea) Vol.15 No.2
The sorption of Cd^2+ on calcite was studied in aqueous solutions of several electrolytes. The Cd^2+ concentration, 10^-8 M, was kept well below saturation with respect to CdCO_3(s). Sorption behavior of Cd^2+ in different ionic strengths of NaClO_4 solutions shows that sorption is independent of ionic strength. This result suggests that Cd^2+ sorption on calcite surface is of a specific nature, and adsorption is controlled by an inner-sphere type of surface complex. Two stages in the sorption behavior could be identified: an initial rapid uptake, followed by slower uptake reaching a maximum steady state by 145 hrs. No evidence was observed for surface precipitation, although it can not be entirely ruled out. Desorption of Cd^2+ from the calcite surface after resuspension into Cd-free solution is initially very rapid, but depends partly on the previous sorption history. Desorption behavior of Cd^2+ show that an initial rapid desorption followed either by slow uptake reaching a maximum, as in the adsorption experiments, or slowing desorption to reach a steady state minimum. This irreversible behavior of Cd^2+ sorption and desorption may act as one of the controls for regulating the mobility of dissolved Cd^2+ in natural aqueous systems. Calculated adsorption partition coefficients suggest that overall sorption and desorption process in the concentration range are controlled by a single mechanism.
폐기물 매립가스 중 황화합물과 원소성 수은의 배출특성연구
조상희,김기현,마흐무드 라만,윤혜온 한국냄새환경학회 2011 실내환경 및 냄새 학회지 Vol.10 No.3
In this study, the emission characteristics of landfill gas (LFG) were investigated with respect to reduced sulfur compounds (RSC) and elemental mercury. To describe their emission characteristics accurately, methane and dilution-to-threshold (D/T) ratio were also analyzed as reference. LFG samples were collected in three different pathways; (1) old landfill (LF), (2) new LF, and (3) composite from both LFs. Differences in RSC concentrations between two LFG samples were relatively insignificant in the case of H2S, CS2, and SO2. On the other hand, a significant reduction in CH3SH and DMS concentrations was observed from old landfill. The concentration data of Hg and methane showed a similar spatial trend between new and old LF, as seen from RSC. In general, a large quantity of trace gas pollutants came out from new rather than old LF. The correlation analysis indicated strong relationship between most sulfur compounds, while it is not for other components including Hg, CH4, and D/T ratio. It suggests that trace composition of LFG comply well with the maturity of landfill.