• 한국환경보건학회지
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• 제31권6호
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• pp.483-488
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• 2005

The waste seashells were used for the removal of hydrogen sulfide from a hot gas stream. The sulphidation of waste seashells with $H_{2}$S was studied in a thermogravimetric analyzer at temperature between 600 and $800^{circ}C$. The desulfurization performance of the waste seashell sorbents was experimentally tested in a fixed bed reactor system. Sulfidation experiments performed under reaction conditions similar to those at the exit of a coal gasifier showed that preparation procedure and technique, the type and the amount of seashell, and the size of the seashell affect the $H_{2}$S removal capacity of the sorbents. The pore structure of fresh and sulfided seashell sorbents was analyzed using mercury porosimetry, nitrogen adsorption, and scanning electron microscopy (SEM). Measurements of the reaction of $H_{2}$S with waste seashells show that particles smaller than 0.631 mm can achieve high conversion to CaS. According to TGA and fixed bed reactor results, temperature had influenced on $H_{2}$S removal efficiency. As desulfurization temperature increased, desulfurization efficiency increased. Also, maximum desulfurization efficiency was observed at $800^{circ}C$. Desulfurization was related to calcinations temperature.

• 자원환경지질
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• 제53권4호
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• pp.337-346
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• 2020

본 연구는 국내 휴·폐금속광산 주변의 수은이 함유된 광물찌꺼기 처리 또는 수은으로 오염된 고형물질(토양, 퇴적물 등)의 정화를 위한 세척공법 적용성 평가를 위해 수행되었다. 이를 위해 수은을 함유한 광물찌꺼기에 대하여 입도분석과 단계별 추출시험을 실시하여 물리·화학적 특성을 고찰하고, 세척공법 적용성 평가를 위해 염산(HCl), 질산(HNO₃), 요오드화칼륨(KI) 및 티오황산나트륨(Na₂S₂O₃) 세척액을 활용한 실험실 규모의 세척시험을 실시하였다. 광물찌꺼기 시료의 입도분포는 #40 이하로 집중되며, #200 이하의 입도가 가장 높은 비율을 차지하였다. 단계별 추출시험 결과, 광물찌꺼기에는 원소 수은이 69.12%로 가장 높은 비율을 차지하고 있으며, 강한 결합 형태가 15.25%, 유기결합 및 잔류 형태 형태가 11.97%의 비율을 각각 차지하고 있었다. 광물찌꺼기에 함유된 수은의 세척 적용성을 검토한 결과, 질산(HNO₃)과 티오황산나트륨(Na₂S₂O₃)의 경우, 세척공법 적용성이 낮은 것으로 분석되었다. 염산(HCl)의 경우 #200 이상의 입도에서 수은 제거가 가능한 것으로 분석되어 물리적 선별 공정이 필요한 것으로 판단되었다. 요오드화칼륨(KI)은 모든 농도와 입도에서 우수한 화학적 세척효율 보였다. 특히, 미세입자에서도 우수한 수은 제거 효율이 확인되어 세척공법 적용성이 가장 높은 것으로 평가되었다.

• 한국산학기술학회논문지
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• 제22권5호
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• pp.1-6
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• 2021

한번 배출된 수은은 소멸되지 않고 자연환경에 축적 및 순환되며 생태계 및 인류보건에 심각한 위해를 준다. 미국에서는 수은의 인위적 배출량의 약 32 %를 차지하는 것으로 알려진 석탄 화력발전소의 배출가스의 증기수은 제거를 위해 황점착 활성탄 사용을 고려하고 있다. 본 연구애서는 석탄 연소설비 배출가스 중의 증기상의 원소수은을 저감하기 위한 고효율의 다공성 수은흡착 소재를 개발하여 소재의 수은 흡착 특성을 조사하였다. 30℃에서 증기수은 흡착능 조사결과 수은흡착용으로 상용화된 활성탄 Darco FGD 대비 실리카 나노소재인 MCM-41의 경우는 약 35 %에 불과하였으나 황을 1.5% 함침한 경우 133 %까지 증가하였고, 폐동 재생공정에서 회수한 용광로 비산재의 경우는 523 %의 효율을 보였다. 또한 30 ℃, 80 ℃ 및 120 ℃의 온도에서 흡착능을 조사한 결과 80 ℃에서 가장 우수한 흡착성능을 나타냈다. MCM-41은 실리카 나노튜브로 구조가 견고해 여러 번 재사용할 수 있을 뿐더러 활성탄을 사용할 경우 우려되는 열점형성으로 인한 화재 가능성이 없어 추가적인 장점까지 지니고 있다.

• 동력기계공학회지
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• 제13권6호
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• pp.76-81
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• 2009

Thermal desorption systems are designed to remove organic compounds from solid matrices such as soils, sludges and filter cakes without thermally destroying them. It is a separation technology, not a destruction technology. Since it is a thermal process, there is a common belief that temperature is the only significant parameter to be monitored. While it is true that better removal efficiencies are usually achieved at higher temperatures, other factors must be considered. Since the process is governed by mass transfer, heating time and the amount of mixing are also key parameters in optimizing removal efficiency. Thermal desorption have been successfully used for just about every organic contaminant found to date. It has also been used to remove mercury. In the present study, the numerical simulation has been performed to investigate the characteristics of heat transfer of LTTD(low temperature thermal desorption). The commercial software, AMESIM was applied for analyzing the heat transfer process in the LTTD.

• 한국환경보건학회지
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• 제36권2호
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• pp.136-140
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• 2010

The integrated gasification combined cycle (IGCC) is one of the most promising proposed processes for advanced electric power generation that is likely to replace conventional coal combustion. This emerging technology will not only improve considerably the thermal efficiency but also reduce or eliminate the environmentally adverse effects normally associated with coal combustion. The IGCC process gasifies coal under reducing conditions with essentially all the sulfur existing in the form of hydrogen sulfide ($H_2S$) in the product fuel gas. The need to remove $H_2S$ from coal derived fuel gases is a significant concern which stems from stringent government regulations and also, from a technical point of view and a need to protect turbines from corrosion. The waste seashells were used for the removal of hydrogen sulfide from a hot gas stream. The sulphidation of waste seashells with $H_2S$ was studied in a thermogravimetric analyzer at temperature between $600^{\circ}C$ and $800^{\circ}C$. The desulfurization performance of the waste seashell sorbents was experimentally tested in a fixed bed reactor system. Sulfidation experiments performed under reaction conditions similar to those at the exit of a coal gasifier showed that preparation procedure and technique, the type and the amount of seashell, and the size of the seashell affects the $H_2S$ removal capacity of the sorbents. The pore structure of fresh and sulfided seashell sorbents was analyzed using mercury porosimetry, nitrogen adsorption, and scanning electronmicroscopy.

• Bulletin of the Korean Chemical Society
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• 제34권7호
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• pp.2176-2182
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• 2013

A novel sol-gel method was implied to prepare CuO-doped ZnO nanoparticles. XRD and SEM techniques were used to characterize the CuO-doped ZnO sample. The photocatalytic degradation of Lidocaine HCl was investigated by two methods. The degradation was studied under different conditions such as the amount of photocatalyst, pH of the system, initial concentration, presence of electron acceptor, and presence of anions. The results showed that they strongly affected the photocatalytic degradation of Lidocaine HCl. The photodegradation efficiency of drug increased with the increase of the irradiation time. After 6 h irradiation with 400-W mercury lamp, about 93% removal of Lidocaine HCl was achieved. The degree of photodegradation obtained by Taguchi method compatible with the trial-and-error method showed reliable results.

• Korean Chemical Engineering Research
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• 제45권5호
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• pp.460-465
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• 2007

엔도설판류(${\alpha}$, ${\beta}$, sulfate)를 UV 및 초음파에너지를 조사하여 분해하였다. 물질의 분해과정은 가스크로마토그래프(GC)와 총유기탄소(TOC)를 분석하여 검토되었다. UV 원으로서 low pressure mercury multilamp(8Wx2)와 초음파발생기를 이용하였으며, 초기농도는 10 mg/L로 하였다. 단일성분에서의 실험결과 엔도설판류(${\alpha}$, ${\beta}$, sulfate)의 UV 광분해도는 순서대로 48.2%, 50.0%, 76.5%였으며, 초음파를 이용한 분해에서는 각각 66.9%, 55.8%, 72.7%였다. 3성분 혼합용액에서는 단일성분용액의 분해효율과 달리 엔도설판-sulfate의 분해속도가 급감하여 가장 낮았고 엔도설판 -${\alpha}$, -${\beta}$들은 두드러진 차이를 보이지 않았다. 혼합용액에서 엔도설판-sulfate의 분해속도 감소로부터 엔도설판-${\alpha}$, -${\beta}$와 엔도설판-sulfate 사이의 낮은 평형상수값을 갖는 가역적 반응을 가정할 수 있었다. TOC 분석자료는 엔도설판류의 무기질화가 약 20%~40% 수준으로 진행되었음을 보여주며, 동시에 두 고도처리법이 라디칼분해반응을 유도하면서 상당한 분율의 중간산물을 생성함을 추정할 수 있었다. 또한 엔도설판류의 분해는 유기물 및 TOC 분석자료에 의거하면 모두 겉보기 1차 속도식과 잘 부합되었다.

• 산업기술연구
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• 제20권A호
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• pp.51-56
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• 2000

The Photocatalytic decolorization and degradation of commercial dyes were studied using a batch reactor. Degussa P25 titanium dioxide and $H_2O_2$ were used as the photocatalyst and proved to be effective for dyes degradation when they were irradiated with UV light. The light source was a 20W low pressure mercury lamp. Three different kinds of dyes, such as direct dye(congo red), acid dye (acid black) and disperse dye(disperse blue) were tested. Extending the UV only treatment up to 120min, direct dye was decolorized to 60% and degraded to 30% as COD. On the other side, acid and disperse dyes were eliminated less than 10% as color and COD. But, color and COD were eliminated about 90% for all of the three dyes by $UV/H_2O_2$ system. And then the most effective decolorization was done for direct dye with 96% removal efficiency by $UV/TiO_2$ system at 120min with 500mg/L of $TiO_2$.

• 한국대기환경학회지
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• 제33권2호
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• pp.87-96
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• 2017

In this study, 4 gases containing typical chlorinated volatile organic compounds (VOCs) were treated by ultraviolet (UV) irradiation. The typical chlorinated VOCs are dichloromethane (DCM), trichloromethane (TCM), carbon tetrachloride (CTC) and trichloroethylene (TCE). The removal efficiency (RE) and the products of chlorinated VOCs by UV irradiation are investigated. At this time, 2 types of background gas (air and nitrogen) were used to figure out the RE by photooxidation and photolysis. The specification of UV-lamp used in this study was low-pressure mercury lamp emitting wavelength of 185~254 nm. The experimental conditions were set as initial VOC concentration of $180{\pm}10ppm$, empty bed retention time (EBRT) of 53 s, temperature of $23{\pm}2^{\circ}C$ and relative humidity of $65{\pm}5%$. In the photolysis condition with nitrogen ($N_2$) as background gas, the averaged RE of the 4 types of chlorinated VOCs was about 24% higher than that with photooxidation; and the REs of VOCs except CTC were confirmed as >99%. The composition of off-gases after UV photooxidation in air was investigated and several intermediates from DCM, TCM and TCE were detected by GC/MS. Among them, phosgene which is a toxics was detected as an intermediate of TCM. In addition, the concentration of carbon dioxide ($CO_2$) in the off-gases was measured to calculate the mineralization rate (MR). With the photooxidation, TCE showed the highest RE (>99%) while MR was the lowest (17%); and the MR of DCM was the highest (86%). In addition, particulate matters (PM) in the off-gases was also detected and high concentrated $PM_{10}$ ($21,580{\mu}g{\cdot}m^{-3}$) and $PM_{2.5}$ ($6,346{\mu}g{\cdot}m^{-3}$) were detected in TCE off-gas. More than 99% of the chlorinated VOCs could be removed using UV254-185 nm lamp, while it is necessary to conduct further studies on the production and treatment of secondary pollutants.

• Environmental Engineering Research
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• 제14권4호
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• pp.212-219
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• 2009

Emission characteristics of air pollutants from three commercially operating cement kilns co-burning waste were investigated. The major heavy metals emitted were mercury (Hg), zinc (Zn), nickel (Ni), chromium (Cr), lead (Pb), cadmium (Cd), and arsenic (As) Removal efficiency of the bag filter was above 98.5% for heavy metals (except Hg), and above 60% for Hg. Higher fractions of heavy metals entering the bag filter were speciated to cement kiln dust. On average, 3.3% of the -heavy metals of medium and low toxicity (Pb, Ni, and Cr) entering the bag filter were released into the atmosphere. Among highly toxic heavy metals, 0.14% of Cd, 0.01% of As, and 40% of Hg entering the bag filter were released into the atmosphere. In passing through the bag filter, the proportion of oxidized Hg in all cases increased. Emission variations of hazardous air pollutants in cement kilns tested were related to raw materials, fuel, waste feed and operating conditions. Volatile organic compounds detected in gas emissions were toluene, acrylonitrile benzene, styrene, 1,3-butadiene, and methylene chloride. Although hazardous air pollutants in emissions from cement kilns co-burning waste were within the existing emission limit, efforts are required to minimize their levels.