Recently, Advanced water treatment facilities with Ozone are being introduced domestically. However, waterproofing/corrosion prevention construction method of concrete structure for existing advanced water treatment makes waterproofing/corrosion prevention materials and concrete deteriorated because of strong oxidation of ozone. Therefore, in this study, As a one of studies for improving durability of advanced water treatment plant applied by metal spray system, electrochemical corrosion protection of metal spraying film according to surface treatment in pH 5 acid solution which is similar to pH concentration in real ozone treatment was evaluated..
In this paper, the heavy metal leaching of mortar substituted the crushed waste glass as fine aggregate are evaluated. From the results, when the heavy weight waste glass substitution ratio increase, leching quantities of heavy metal is increased. Therefore, it is needed that the characteristics of heavy metal leching according to waste glass substitution ratio in mortar specimens.
Development of appropriate construction technology at frozen soil environments for developing resources is essential. However, cathodic protection technology using monitoring at frozen soil environments is lack. In this study, we want to build a real-time monitoring system at frozen soil environments through corrosion monitoring using type of gavanic metal
In this study, the leaching characteristics of magnesium from mine residue by acid leaching method was studied. First, It was confirmed the effect of the particle size. The particle size was selected 80 mesh in consideration of the leaching amount and recycling rate of Mg. And after, It was compared to the leaching characteristics of magnesium by H2SO4, HCl and HNO3. Among them, leaching efficiency of H2SO4 was best. After the experiments were conducted with H2SO4. The effect of various parameters such as acid concentration, reaction temperature, and liquid/solid ratio on the leaching process were investigated. It was determined that the leaching amount of magnesium increased with reaction acid concentration, temperature, and liquid/solid ratio, and decreasing particle size. Maximum leaching amount of magnesium was obtained at the condition of particle size blow 80 mesh, temperature 80oC, 6 M H2SO4, 10/1 liquid/solid ratio, 6 h of reaction time and 180 rpm.
The amount of food waste is generated every year in Korea. Despite food waste contain a large amount of valuable organic resources, The rate of recycling is low because of high moisture contents and sodium. It proposed a solution to the problem is the Hydrothermal carbonization (HTC) technology. The Bio-char is produced by HTC allows to increase the recycling uses. The agents of heavy metal adsorption are mainly used with lime and activated carbon. However, these have difficulties such as low economical feasibility and solubility. This study focused on the application of the adsorbent. It is expected to have advantages in heavy metal waste water like Acid Mine Drainage (AMD) or industrial effluent. In this study, the adsorption capacity of bio-char was measured with the conditions of the time and the amount of bio-char inputs to remove in the artificial AMD. Artificial waste water 10 ppm and 100 ppm was prepared using Cu, Pb, Cd, As, and analyzed a batch-test to find the optimum condition. The experimental results showed The optimal blending ratios with activated bio-char and contaminated water were 1 : 20 for high concentration (100 ppm), 1 : 100 for low concentration (10 ppm). As the results, the absorption efficiency of the heavy metals, shows more than 99% except for arsenic.
This study was performed to find the effect of Enteromorpha prolifera as a biosorbent on the removal of heavy metals such as lead, copper, zinc and cadmium from the synthetic wastewater. The biosorption experiment was conducted using biomass of dried Enteromorpha prolifera, which has caused environmental pollution issues in oceans and lakes. To find the physico-chemical characteristics and adsorption capacity, parameters such as biosorbent dosage, initial heavy metal concentration, pH value of solution, contact time which influence the effects on heavy metals removal were changed and the optimum values were found through batch test. The experimental results showed that the sequence for adsorption capacity of heavy metals by Enteromorpha prolifera was Pb2+> Cu2+> Cd2+> Zn2+. The optimum conditions of pH, contact time and dosage of biosorbent were pH 5.0, 60 min. and 0.5 g/L, respectively. As initial heavy metal concentration increased, the adsorption capacity increased up to 17.53 mg/g for Pb with 98% removal efficiency. From the adsorption thermodynamic and kinetic analysis, the biosorption pattern of Pb, Cu, Zn and Cd was well described using Freundlich and Langmuir sorption isotherm with their R2 values of 0.99 and 0.97, respectively. The sorption kinetics followed pseudosecond order kinetic models and thus supported chemical sorption rather than internal diffusion. The work clearly indicates the potential of using Enteromorpha prolifera as an excellent adsorbent for heavy metal removal in industrial wastewater.
This study evaluates heavy metal(Cu and Cr) adsorption characteristics produced from food waste charcoal extracted in an optimal operation condition after analyzing activated charcoal of iodine adsorption and heavy metals that derived from an activation process of carbide by the developed by-products of food waste treatment facility using the methods from previous studies. As experiment apparatus, this study used a tube-shaped high temp furnace. The mixing ratio of by-products of food waste treatment facility, carbide, and activation component(ZnCl2) was 1:1. The experiment was proceeded as adjusting the activation temperature from 400 to 800℃ and activation time from 30 to 120 minutes. The optimal activation condition for iodine absorption was 90 minutes at 700℃ and by using the produced food waste charcoal, this study conducted an experiment on absorption of heavy metals (Cu and Cr) as changing pH of artificial wastewater and stirring time. As a result, pH 7 showed the highest heavy metal decontamination ratio and in terms of stirring time, it revealed balance adsorption after 10 minutes. This result can be particularly applied as basic data for recyclability of high concentration organic waste, by-products of food waste treatment facility, as an food waste charcoal.
The response of the freshwater microalga, Chlorella vulgaris, to heavy metal stress was examined based on chlorophyll fluorescence analysis to assess the toxic effects of heavy metals in freshwater ecosystems. When toxic effects were analyzed using regular chlorophyll fluorescence analysis, photosystem II activity(Fv/Fm) decreased significantly when exposed to Cu2+ and Hg2+ for 12 h, and decreased in the order of Hg2+ > Cu2+ > Cd2+ > Ni2+ when exposed for 24h. The effective photochemical quantum yield(Φ′PSII), chlorophyll fluorescence decrease ratio(RFd), minimal fluorescence yield(Fo), and non-photochemical quenching(NPQ), but not photochemical quenching(qP), responded sensitively to Hg2+, Cu2+, and Cd2+. These results suggest that Fv/Fm, as well as Φ′PSII, RFd, Fo, and NPQ could be used to assess the effects of heavy metal ions in freshwater ecosystems. However, because many types of heavy metal ions and toxic compounds co-occur under natural conditions, it is difficult to assess heavy metal toxicity in freshwater ecosystems. When Chlorella was exposed to heavy metal ions for 12 or 24h, Fv/Fm and maximal fluorescence yield(Fm) changed in response to Hg2+ and Cu2+ based on image analysis. However, assessing quantitatively the toxic effects of several heavy metal ions is challenging.
The aim of this study was to examine the morphological responses of Hosta longipes, an ornamental plants for heavy metal contaminated soils in urban landscaping, to heavy metals Cd, Pb, and Zn. Plants were grown in artificial soil amended with Cd, Pb, and Zn at concentation of 0, 100, 250, and 500 mg/kg. Plant height, leaf length, leaf width, total leaf number, deaf leaf number, new leaf number, chlorophyll contents, and ornamental value were monitored from May to August. At 4 months after planting, the survival and morphological responses of H. longipes grown in soil amended with Cd at concentrations ≥ 100 mg/kg were severely affected compared to those grown in the control soil. Relative leaf length rate and relative leaf width rate were significantly decreased when the concentration of Pb was increased. Total leaf number, chlorophyll contents, and ornamental value were the lowest value in plants grown in soil amended with Pb at level of 500 mg/kg. Relative leaf length rate and relative leaf width rate, total leaf number, dead leaf number, new leaf number, and ornamental values had a tendency of decrease when plants were grown in soils amended with Zn. However, no significant difference was found among treatments except for plants were grown in soils amended with 500 mg/kg Zn. Therefore, Hosta longipes might be useful for phytoremediation of Zn contaminated sites as herbaceous ornamental plants.
According to a report ‘2012 Present Condition of National Household Refuse Resource Recovery Facility’, about 582,178 tons/year of household refuse were processed in the incineration plant, and 465,087 tons/year of bottom ash and 117,091 tons/year of fly ash were produced respectively. As incineration ash contains many kind of heavy metals such as soluble salt, copper and lead, it may lead to the leaching potential of heavy metals according to the environmental change, so it requires special care in landfill and recycling. In this study CO2 was injected into the bottom ash, so that environmental stability such as leaching of heavy metals was reduced and increased the possibility of CO2 fixation ability of the bottom ash was analyzed. Bottom ash of the household refuse incineration plant of I City was used as the sample of the fixation ability particle size was divided into 3 sections to analyze its components before and after carbonation using XRF. Stability of the sample was identified by the leaching test through KSLT and TCLP, and CO2 fixation ability by the DT-TGA analysis. Test results of the fixation ability shows that stabilization of the bottom ash produced in the household refuse incineration plant by carbonation is evaluated as there is little environmental problem caused by heavy metals when it is utilized into the recycled aggregate, and economic profits can be expected due to securing new agents of the supply and demand for the recycled aggregates, the greenhouse gas emission reduction by CO2 fixation.
본 연구에서는 폐금속 광산에 특화된 인체위해성평가 방법을 제시하고, 국내 폐금속 광산지역 으로부터 도출된 다양한 노출인자 값을 적용하여 폐금속 광산지역의 주민(성인 남자, 성인 여자, 어린 이)에 대하여 인체위해성평가를 수행하였다. 또한 인체위해성평가의 결과로부터 중금속 오염에 의한 주민의 건강이 우려되는 경우, 위해성에 기반한 각 매체(토양, 지하수, 지표수)별 복원기준을 제시하고 자 하였다. 본 연구 결과, 발암위해도와 비발암위해도를 지시하는 총 초과발암위해도(TCR)와 위험지 수(HI)는 지하수섭취와 농작물섭취에 의한 경로로 노출되는 비소에 의해 각각 허용 가능한 수준인 1.00E-6과 1을 크게 초과하는 것으로 나타나서 연구대상 지역의 인체위해성이 큰 것으로 평가되었다. 위해도 저감을 위한 복원농도 산정 결과, 발암위해도 기준 계산 시 As 6.83~6.85 mg/kg, Pb 18.41~18.46 mg/kg, 비발암위해도 기준 계산 시 Cu 17.38 mg/kg, As 9.13 mg/kg의 수준으로 토양정 화가 필요한 것으로 나타났다.
국내 경상북도 포항 지역에서 채취한 6종의 천연 제올라이트를 X-선 회절, X-선 형광분석, 열 시차 분석, 열중량 분석 및 양이온교환능 분석을 통해 특성분석을 수행하였다. 이들 제올라이트의 주 성분은 구룡포A (Ku-A), 구룡포B (Ku-B), 구룡포C (Ku-C), 동해A (Dh-A), 동해B (Dh-B), 동해C (Dh-C) 모두 모데나이트, 알바이트 및 석영이 함유되어 있었다. 6종의 제올라이트는 Si, Al, Na, K, Mg, Ca, Fe을 함유하고 있었으며 구룡포C (Ku-C) 제올라이트의 양이온 교환능이 다른 지역의 제올라 이트 보다 높게 나타났다. 6종의 천연 제올라이트를 이용하여 Pb2+, Cd2+ 및 Cu2+ 등의 중금속 이온을 제거하는데 소요되는 반응 시간의 효과를 비교하였다. 6종의 천연 제올라이트 모두 Pb2+, Cd2+ 및 Cu2+ 제거율이 매우 낮게 나타났다. 이는 6종의 천연 제올라이트에 함유된 제올라이트의 함량이 매우 낮기 때문으로 판단된다. 본 연구 결과는 제올라이트 광석의 중금속 흡착능력은 제올라이트의 함량, 즉 광석의 품위에 크게 의존되는 경향을 보여주고 있다.
however, these elements can limit plant growth. This study selected a heavy metal-tolerant plant by analyzing seed germination and biomass of alfalfa (Medicago sativa), canola (Brassica campestris subsp. napus var. nippo-oleifera), Chinese corn (Setaria italica), and a sorghum-sudangrass hybrid (Sorghum bicolor × S. sudanense), and determined heavy metal uptake capacity by analyzing biomass, chlorophyll a fluorescence, and heavy metal contents under high external copper or zinc levels. The seed germination rate and biomass of the sorghum-sudangrass hybrid were higher under copper or zinc stress compared to the other three plants. The plant biomass and photosynthetic pigment contents of the sorghum-sudangrass hybrid seedlings were less vulnerable under low levels of heavy metals (≤ 50 ppm copper or ≤ 400 ppm zinc). The maximum quantum yield of PSII (Fv/Fm) and the maximum primary yield of PSII (Fv/Fo) decreased with increasing copper or zinc levels. Under high copper levels, the decline in Fv/Fm was caused only by the decline in Fm, and was accompanied by an increase in non-photochemical quenching (NPQ). The Fv/Fm declined under high levels of zinc due to both a decrease in the maximum fluorescence (Fm) and an increase in the initial fluorescence (Fo), and this was accompanied by a marked decrease in photochemical quenching (qP), but not by an increase in NPQ. Accumulations of copper and zinc were found in both aboveand below-ground parts of plants, but were greater in the below-ground parts. The uptake capacity of the sorghum-sudangrass hybrid for copper and zinc reached 4459.1 mg/kg under 400 ppm copper and 9028.5 mg/kg under 1600 ppm zinc. Our results indicate that the sorghum-sudangrass hybrid contributes to the in situ phytoremediation of copper or zinc polluted soils due to its high biomass yield.
산업단지, 철도부지, 사격장 및 폐광산 등 중금속으로 오염된 토양부지의 복원을 위하여 토양 세척법, 세정법, 동전기법 등의 기술이 사용되며, 이들 기술의 적용을 위해서는 강한 산 또는 화학적 산화제의 사용이 불가피하다. 화학적 세척제의 사용은 처리수의 정화 및 처리 토양의 생태 독성 제거 등 후처리가 필요하다. 한편, 휴믹산은 자연 토양 내 많이 존재하는 자연기원 유기물로서, 비료로 사용되거나 토양 개질에도 많이 이용된다. 이러한 휴믹산은 구조가 매우 복잡하며, 중금속과 배위결합이 가능한 카르복실기, 페놀기 등을 다량 보유한다고 알려져있다. 휴믹산 중금속 제거를 위한 킬레이트제로 친환경적 토양 세척법으로의 적용이 가능하다. 본 연구는 표준 휴믹산을 정제하여 용산 철도부지의 현장오염토양을 대상으로 구리, 납, 아연의 제거를 위한 토양 세척법의 적용 가능성을 평가하였다. 농도 및 pH 조건을 달리한 실험 결과 농도는 1000 ppm에서, pH 조건 10에서 각 중금속의 제거 효율이 가장 높게 나타났다. 중금속 제거용 킬레이트제의 대조군으로 EDTA를 사용하였으며, 휴믹산의 중금속 제거율은 EDTA 대비 구리, 납, 아연 각각 20.44%, 4.58%, 19.55%으로 나타났다. 토양 세척 시의 고액 비, 반응 온도, 등 다른 환경인자에 따라 중금속 제거 효율을 증대 시킬 수 있을 것으로 판단된다.
최근 산업의 발달로 산업폐수가 다량으로 발생됨과 더불어 방류수내 유독성 중금속으로 인해 수생태계에 악영향을 미치고 있으며 또한 인체 내에 축적되는 성질을 가지고 있다. 이러한 중금속 제거에 관한 연구가 활발히 진행되고 있으나 효과적인 처리에는 한계점을 나타내고 있다. 지금까지 가장 널리 사용되고 있는 방법으로는 화학첨전법, 이온교환법 등이 이용되고 있으나 완전한 중금속 제거가 어렵고 많은 약품이 필요하며 고독성의 슬러지가 발생하는 단점이 있다. 생물흡착제로서 미세 해양 조류, 미생물 및 효모 등을 이용한 중금속 흡착연구가 진행되어 왔는데, 이중에서도 조류를 이용한 방법이 가장 경제적이고 효율적인 것으로 알려져 있다. 본 연구에서는 해양에 널리 분포성장하고 있는 조류 중 감태를 이용하여 중금속 흡착실험을 수행하였는데, 이러한 조류 감태는 최근 기후변화 및 부영양화 현상으로 인하여 2007년부터 여름철에 한국과 중국 연해인 황해에서 대량 번식하여 2014년에도 감태 최대 분포면적이 50,000 km²에 이르는 것으로 보고되고 있다. 현재 감태는 식용을 제외하고 일부 가축 사료로도 활용되지만 대부분 폐기물로 처리되고 있는 실정이다. 따라서 본 연구에서는 감태(Enteromorpha prolifera)를 이용한 중금속 흡착능을 평가하여 대부분 폐기물로 처리되고 있는 감태의 활용방안을 모색하고자 하였다. 비활성 감태의 물리화학적 특성 파악 및 금속이온 공존상태에서의 흡착능을 검토하기 위해서 감태를 건조한 후 분말로 만들어 batch test를 하였으며, Pb2+, Cu2+, Zn2+, Cd2+ 등 4종의 중금속을 대상으로 흡착 실험을 수행하여 적정 투입량, pH, 온도 및 반응시간변화에 따른 최적 조건을 도출하고자 하였다. 또한 해조류 중 다시마 등과의 흡착능을 비교해 보았다. 흡착실험결과, pH는 1~11변화에 따른 흡착능을 비교해 본 결과, pH 5에서 가장 높은 흡착효율을 나타내었으며, 온도는 10~30℃ 범위내에서 실험해 본 결과, 최적 흡착 조건은 20℃로 나타났다. 또한 생물흡착제의 종류에 따라 금속의 흡착율 뿐만 아니라 금속의 선택적인 흡착까지도 명확하게 다른 것으로 나타났다. 중금속 종류별 흡착능력은 Pb2+>Cu2+>Cd2+>Zn2+순이었으며, 감태는 Pb2+, Cu2+이온에 대한 흡착율이 최대 95% 및 82%로서 높은 제거효율을 보였으며, 다시마는 각각 92%, 77%의 흡착율을 나타내었다. Zn2+과 Cd2+이 함유되어 있는 폐수에 대해서는 다시마가 감태보다 오히려 흡착능 효율이 더 좋은 것을 알 수 있었다. 이상의 결과로부터 생물흡착제 감태의 중금속 흡착 제거 효과가 우수한 것을 확인할 수 있었으며, 조류의 활용과 더불어 생물흡착제로서 중금속 흡착제거에 활용될 수 있을 것으로 판단된다