• Economic and Environmental Geology
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• v.51 no.4
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• pp.371-379
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• 2018

In many countries, recycling coal ashes as backfill materials for subsided lands, abandoned mine tunnels, and road pipeline constructions by making low-strength concretes with minimal amounts of cement is frequently considered for massive treatment of coal ashes. This study investigates the variation of heavy metals in the concrete test pieces prepared for the cases of using only Portland cement as binding material, fly ash as a replacement of the cement, sand as aggregates, and disposed ashes in the ash ponds as a replacement of aggregates. Heavy metal contents were measured based on the aqua regia extraction technique following the Korean Standard for Fair Testing of Soil Contamination and the influences of each materials on the total heavy metal contents were also assessed. Results show that the cement has the highest Cu, Pb, and Zn concentrations than any other materials. Therefore, the test pieces show significant concentration decreases for those metals when the cement was replaced by fly ash. Ponded ash shows low concentrations relative to fly ash in most of the parameters but shows higher Cu and Ni, and lower Pb levels than the sand aggregate. In overall, heavy metal levels of the test pieces are regulated by mixing among the used materials. Test pieces prepared during this study always show concentrations much lower than the Worrisome Level of Soil Contamination (Area 1), which was designated by the Soil Environment Conservation Act of Korea.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.5
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• pp.535-541
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• 2005

Peat humin(p-Humin) extracted from Canadian Sphagnum peat moss was packed in a column and removal of heavy metal ions such as Cd, Cu and Pb from aqueous solution under flow conditions was studied. The metal ions were removed not only from single-element solutions but also from a multi-metal solution. Column kinetics for metal removal were described by the Thomas model. For single-component metal solutions, the maximum adsorption capacities of the p-Humin for Pb, Cu and Cd were 138.8, 44.66 and 41.61 mg/g, respectively. The results of multi-component competitive adsorption showed that adsorption affinity was in the order of Pb $\gg$ Cu > Cd. The adsorbed metal ions were easily deserted from the p-Humin with 0.05 N $HNO_3$ solution. It is apparent that 95% of the heavy metal ions were recovered from the saturated column. This investigation provides possibility to clean up heavy-metal contaminated waste waters by using the natural biomass, p-Humin as an environmentally friendly and cost-effective new biosorbents.

• Journal of the Korean Geotechnical Society
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• v.22 no.11
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• pp.5-11
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• 2006

The purpose of this study was to examine the proper mixing ratio of ordinary portland cement and Bottom Ash to recycle the Bottom Ash, which is an industrial waste. After the evaluation, the compressive strength and durability were assessed using the mixture of completely weathered soil (Hwangto), weathered granite soil, and Bentonite. Then environmental friendliness of this mixed material was examined through heavy metal leaching method. It was found out that proper mixing ratio is 6:4, and that the 6% mixture quantity of completely weathered soil (Hwangto), weathered granite soil, and Bentonite is the most effective for compressive strength and durability It was also found out through heavy metal leaching method that the Bottom Ash could be below the standard of the Clean Water Law.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.8
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• pp.808-816
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• 2008

In the present paper, a study has been performed on remediating mine tailings around abandoned mine contaminated with high concentrations of arsenic and heavy metals using the technique of soil washing. Through the removal experiment of arsenic, the optimal conditions in the type and concentration of washing reagent, mixing ratio of mine tailings and washing reagent, and washing time were derived. Results showed that the most effective washing reagents to remove arsenic from mine tailings were oxalic acid(72% removal efficiency) and phosphoric acid(65%), while the oxalic acid(89%) was the most effective in removing the heavy metals containing Cu. In addition, the most economical and efficient washing concentration was 0.25 M and the most suitable washing time was 30 minutes. The optimal mixing ratio of mine tailings and washing reagent was 1 : 20(mass/vol) from the viewpoint of minimization of wastewater produced after the washing, as well as the washing effectiveness. Although the mixture of washing reagents did not help in removal of arsenic, it could lead to much elevated synergy effect on removing Cu and Zn, compared with the single reagent.

• Journal of Environmental Science International
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• v.6 no.1
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• pp.61-67
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• 1997

Heavy metal adsorption by microbial cells is an alternative to conventional methods of heavy metal removal and recovery from metal-bearing wastewater The waste Sac-chuomyces cerevisiae is an inexpensive, relatively available source of biomass for heavy metal biosorption. Biosorption was investigated by free and immobilized-S. cerevisiae. The order of biosorption capacity was Pb>Cu>Cd with batch system. The biosorption parameters had been determined for Pb with free , cells according to the Freundlich and Langmuir model. It was found that the data fitted reasonably well to the Freundlich model. The selective uptake of immobilized-S. cerevisiae was observed when all the metal ions were dissolved in a mixed metals solution(Pb, Cu, Cr and Cd). The biosorption of mixed metals solution by immobilized-cell was studied in packed bed reactor. The Pb uptake was Investigated in particular, as it represents one of the most widely distributed heavy metals in water. We also tested the desorption of Pb from immobilized-cell by us- ing HCI, $H_2SO_4$ and EDTA.

• Journal of Navigation and Port Research
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• v.38 no.3
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• pp.269-275
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• 2014

In this study, the adsorption efficiency of mixed heavy metals in aqueous solution was investigated using steel slag. Moreover, heavy-metal stabilization treatment of contaminated marine sediment was achieved using steel slag as stabilizing agents. Heavy metal adsorption was characterized using Freundlich and Langmuir equations. The equilibrium adsorption data were fitted well to the Langmuir model in steel slag. The adsorption uptake of heavy metals were higher in the order of $Pb^{2+}$ > $Cd^{2+}$ > $Cu^{2+}$ > $Zn^{2+}$ > $Ni^{2+}$. The steel slage was applied for a wet-curing duration of 150 days. From the sequential extraction results, the exchangeable, carbonate, and oxides fractions of Ni, Zn, Cu, Pb, and Cd in sediment decreased by 13.0%, 6.0%, 1.3%, 17.0%, and 50.0%, respectively.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.413-416
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• 2004

매립장 침출수로 인해 오염된 매립장 주변 지하수 정화를 위한 실내실험을 실시하였다. 오염물로는 대표적 염화용제인 TCE와 PCE, 그리고 중금속인 As, Cd, Cr, Pb에 대하여 Air-sparging, 오존 산화법, 화학적 처리방법에 의한 정화효율 실험을 실시하였다. Air-sparging은 TCE, PCE에서 높은 제거효율을 가졌으며, 오존 산화법은 Cr, Pb에서 제거 효율이 좋았다. 반응제를 첨가한 공침방법의 경우, 모든 중금속에 대하여 소석회 첨가시 매우 높은 제거효율을 보였으며, As는 황산제일철에서, Cd, Cr, Pb는 탄산칼슘과 제올라이트 첨가시 높은 제거효율을 나타내었다. 실험결과로부터, 유기오염물과 중금속이 혼합되어 나타나는 매립장 주변 오염 지하수의 경우 휘발성 유기오염물의 제거를 위해서는 폭기방법이, 중금속의 경우에는 공침방법에 의해 수산화물, 탄산염으로 만들어 고형물로 처리하는 방법이 제거효과가 좋은 것으로 나타났다.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.330-334
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• 2005

본 연구에서는 유해 중금속을 다량 함유하고 있는 산업폐기물의 고화 처리에 사용되는 칼슘설포알루미네이트(4CaO $3Al_2O_3\;SO_4$ 이후부터 CSA로 기입)의 제조를 위해 철강부산물인 압연 슬러지를 활용하여 그 특성에 대해 조사하였다. 본 연구에서는 철강 부산물인 압연슬러지 외에 석회석 미분물, 인산부산 석고를 혼합하여 칼슘알루미네이트 상을 합성하였다. 합성 결과 소성온도 $1250^{\circ}C$에서부터 CSA가 합성되었고, 이와 함께 칼슘실리케이트$(2CaO\;SiO_2)$와 칼슘알루미노페라이트($4CaO\;Al_2O_3\;Fe_2O_3$)도 함께 합성되었다. CSA 합성에 미치는 중금속 영향을 관찰한 결과 원료의 중금속이 CSA 합성 온도를 낮추는 효과가 있는 것으로 나타났다. CSA를 이용한 철강산업 폐기물의 중금속 고용 처리 연구에서도 본 실험에서 합성된 CSA가 폐기물의 중금속 고화 처리에 효과가 있는 것으로 나타났다.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.4
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• pp.81-90
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• 2009

About 35 domestic incinerators are being operated currently. There is waste management policy to reuse waste efficiently and reduce waste through incineration which include reuse, recycling and energy recovery. However, there is a critical social issue that some heavy metals(Cu, Pb) were found in bottom ash from incineration of waste. After incineration, bottom ash is treated with chemicals to prevent second pollution of heavy metals from bottom ash and increase efficiency of heavy metal stabilization.

• Journal of the Korean Ceramic Society
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• v.39 no.8
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• pp.728-734
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• 2002

Stabilization behavior of Cr, Cd, Cu, Pb, Fe and Zn heavy metals in the EAF dust was investigated by adding EAF dust to clay or white clay, respectively, up to 50 wt% with 10 wt% intervals and sintering at temperatures between 200 and $1200^{\circ}C$ with $200^{\circ}C$ intervals with an aid of ICP-AES followed by TCLP test to evaluate heavy metal cation exchange capacity of the clay or the white clay. The clay or the white clay had a better Cr ion exchange capacity than that of zeolite. The TCLP leaching test for the sintered specimens showed that Cr and Fe were rarely detected for all the specimens and the concentration of Cd and Zn decreased with increasing sintering temperature and decreasing EAF dust contents respectively. When the clay or the white clay were mixed with EAF dust, cation exchange may occur between the clay and the EAF dust so that the first stabilization of the mixtures containing semistabilized heavy metals may happen. Stabilization of heavy metals in the ceramic bodies was further completed probably due to the eutectic reaction caused by the sintering of semi-stabilized mixtures. It was conceivable that the white clay rather than the clay may be a better stabilizer for the EAF dust containing heavy metals.