• 에너지공학
• /
• 제26권4호
• /
• pp.74-83
• /
• 2017

Coal-fired power plants supply roughly 50 percent of the nation's electricity but produce a disproportionate share of electric utility-related air pollution. Coal combustion technology can facilitate volume reduction of up to 90%, with the inorganic contaminants being captured in furnace bottom ash and fly ash residues. These disposal coal ash residues are however governed by the potential release of constituent contaminants into the environment. Accelerated carbonation process has been shown to have a potential for improving the chemical stability and leaching behavior of bottom ash residues. The aim of this work was to quantify the volume of $CO_2$ that could be sequestrated with a view to reducing greenhouse gas emissions and stabilize the contaminated heavy metals from bottom ash samples. In this study, we used PC boiler bottom ash, Kanvera reactor (KR) slag and calcined waste lime for measuring chemical analysis and heavy metals leaching tests were performed and also the formation of calcite resulting from accelerated carbonation process was investigated by thermo gravimetric and differential thermal analysis (TG/DTA).

• Journal of Ecology and Environment
• /
• 제32권2호
• /
• pp.109-113
• /
• 2009

Tree-ring width analysis has been used to assess the effects of air pollution on tree growth around industrial complexes. Our study was conducted to elucidate the effect of air pollutants on annual ring growth in black pines (Pinus thunbergii) of age 41$\sim$48 years around Ulsan Metropolitan City. The growth data were analyzed by multiple regression and the results are as follows: 1. The annual ring increment of black pines increased with tree age until age 40 years and then decreased gradually after age 40 years. 2. The increment of annual ring width of black pines was affected more by precipitation and evapotranspiration than air temperature. An annual ring decline appeared in the years 1968$\sim$1983, when annual ring indices below zero were observed. Decreased annual ring growth during this period may have been due to air pollution. 3. The heavy metal with the strongest effect on annual ring growth of black pines in the experimental stand was lead (Pb). The concentration of lead in the stand was estimated as over 6 ppm. 4. The technique of tree-ring width analysis may be useful for estimation of the extent of pollution in forest areas near industrial complexes.

• 한국환경과학회지
• /
• 제16권8호
• /
• pp.913-920
• /
• 2007

Hydrochloride acid salts of new $N_2O_2$ tetradentate ligands containing amine and phenol N,N'-bis(2-hydroxybenzyl)-o-phenylenediamine(H-BHP), N,N'-bis(5-bromo-2-hydroxybenzyl)-o-phenylenediamine(Br-BHP), N,N'-bis(5-chloro-2-hydroxybenzyl)-o-phenylene-diamine(Cl-BHP), N,N'-bis(5-methyl-2-hydroxybenzyl)-o-phenylene-diamine (Me-BHP) and N,N'-bis(5-methoxy-2-hydroxybenzyl)-o-phenylenediamine(MeO-BHP) were synthesized. The ligands were characterized by elemental analysis, mass and NMR spectroscopy. The elemental analysis showed that the ligands were isolated as dihydrochloride salt. The potentiometry study revealed that the proton dissociation constants$(logK_n{^H})$ of ligands and stability constants $(logK_{ML})$ of transition and heavy metals complexes. The order of the stability constants of each metal ions for ligands was Br-BHP < Cl-BHP > H-BHP < MeO-BHP < Me-BHP.

• 한국결정성장학회지
• /
• 제14권2호
• /
• pp.37-46
• /
• 2004

The electrochemical adsorption of the Ag ions from aqueous solution on pelletized activated carbon monolith was investigated over wide range of operation time. The adsorption capacities of pelletized activated carbon monolith are associated with their internal porosity and are related properties such as surface area, pore size distribution. The chemical industry generates wastewater that contains toxic matters like heavy metals in small concentrations so that their economic recovery is not feasible. But, the method using activated carbon monolith can be used to withdrawal of heavy metals in waste water. After the electrochemical treatment, the quantitative properties in Ag ion solutions are also examined by pH concentration and studied elemental analysis by ICP-Atomic Emission Spectrometer and Energy Disperse X-ray (EDX) spectra. It is consider that the pH is very important factor at the reason of water pollutant with increasing acidity in industrial field. The result of quantitative analysis using Inductively Coupled Plasma-Atomic Emission Spectrometer of metal after electrochemical reaction in Ag ions solution depending on time are shown that the amount of Ag ions deposited was decreased with growth of Ag particles on the carbon surfaces as increasing electrochemically treated time. And, surface morphologies are investigated by scanning electron microscopy (SEM) to explain the changes in adsorption properties.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제23권1호
• /
• pp.63-73
• /
• 2018

Rice is a staple food source in Asian countries. In paddy field, rice plant can take up toxic elements through its roots from contaminated soils, and its leaves and grain can absorb the toxic elements deposited on the soil surface. A totla of 40 soil and polished rice samples were collected around four abandoned metal mines in Korea and analyzed for As, Cd, Cu, Pb and Zn by atomic absorption spectrophotometer (AAS). The average contents of As, Cd, Cu, Pb and Zn in rice grain grown on the contaminated soils were 0.247, 0.174, 4.694, 0.804 and 16.78 mg/kg, respectively. These levels are higher than worldwide average concentrations. Assuming the rice consumption of 169 g/day by overall households in Korea, the estimated daily intakes from the rices were found to be 33, 48, and 63% for As, Cd, and Pb, respectively, of the acceptable daily intake (ADI) suggested by the FAO/WHO Joint Food Additive and Contaminants Committee.

• 한국군사과학기술학회지
• /
• 제14권2호
• /
• pp.264-270
• /
• 2011

This paper focuses on possibility to design and fabrication new combination of bullet core to substitute current toxic material of heavy metal such as lead by environment-friendly ones. The core is designed as dual structure to manipulate the core center of gravity easily by combining materials, which of basis is tungsten of low cost and easily acquired. Those combinations are W-M series such as W-Cu, W-Sn, W-Cu-Sn, and W-Cu-Ni to target the density of lead, $11.34g/cm^3$ through powder-metallurgy. Out of four, combination of W-Cu-Ni shows the highest compression density of 96% and is confirmed as the most suitable substitution for lead due to the excellent property of matter and sintering. All combination samples is simulated on the PRODAS software for designing and structure analysis by adjusting the center of gravity of dual core samples forward and backward. The simulations confirm the similarity of current bullet core with respect to properties of mass, aero dynamics, and flying stability.

• 대한한의학방제학회지
• /
• 제24권2호
• /
• pp.71-79
• /
• 2016

Objectives : To verify the equivalence between Atractylodis Rhizoma Alba herbal prescription(HP-ARA) and Atractylodis Rhizoma Alba herbal sub stance(HS-ARA). Methods : Safety tests by microbial regulation and heavy metal analysis (total heavy metal, Pb, As) and a stability test by long term shelf test for HP-ARA according to notification of the Ministry of Food and Drug Safety were carried out. Then, multi component profile of HP-ARA and HS -ARA were analyzed by HPLC. Results : The safety and stability of HP-ARA confirmed by several tests. Correlation coefficient of equivalence of HP-ARA and ARA-HS showed 0.992. Conclusion : Based on this result of equivalence between HP-ARA and HS-ARA, HP-ARA can substitute HS-ARA used to make herbal medicines (herbal decoction, pills and powder).

• 공업화학
• /
• 제30권5호
• /
• pp.536-545
• /
• 2019

An experiment was conducted to evaluate the adsorptive removal of Pb(II) from an aqueous solution using a mixture of spent coffee grounds and chitosan on beads (CC-beads). Various parameters affecting the adsorption process of Pb(II) using CC-beads were investigated. Based on the experimental data, the adsorption kinetics and adsorption isotherms were analyzed for their adsorption rate, maximum adsorption capacity, adsorption energy and adsorption strength. Moreover, the entropy, enthalpy and free energy were also calculated by thermodynamic analysis. According to the FT-IR analysis, a CC-bead has a very suitable structure for easy heavy metal adsorption. The process of adsorbing Pb(II) using CC-beads was suitable for pseudo-second order kinetic and Langmuir model, with a maximum adsorption capacity of 163.51 (mg/g). The adsorption of Pb(II) using CC-beads was closer to chemical adsorption than physical adsorption. In addition, the adsorption of Pb(II) on CC-beads was exothermic and spontaneous in nature. CC-beads are economical because they are inexpensive and also the waste can be recycled, which is very significant in terms of the continuous circulation of resources. Thus, CC-beads can compete with other adsorbents.

• 대한환경공학회지
• /
• 제27권6호
• /
• pp.626-634
• /
• 2005

본 연구에서는 강원도내 4개의 폐금속광산에서 발생되는 광미와 주변 토양의 중금속 오염현황 및 오염도를 평가하였다. 광미와 주변 토양의 오염정도는 총 중금속농도 기준으로 원동>제2연화>신예미${\fallingdotseq}$상동 순이었으며, 이들 광미는 배경토양 및 Kloke 값보다 각각 $1.2{\sim}78.2$와 $1.1{\sim}80.6$배가 높은 농도로서 주변 토양을 오염시키고 있었다. 광미내 대다수 중금속의 화합물형태는 잔류성이 대부분이었다. 비잔류형태 화합물에서는 상당부분이 환원성과 산화성이어서 장기간에 걸쳐 산화환경조건에 따라 중금속이 유출될 것으로 보이며 특히, 제2연화의 Cd은 교환성과 탄산염 화합물이 쉽게 유출되어 단기간에 주변 환경을 오염시킬 가능성이 클 것으로 판단된다. 우리나라 토양오염기준치의 초과여부 검토결과 많은 시료에서 토양환경보전법의 우려기준 및 대책기준 이상인 것으로 나타나 이에 대한 처리대책이 필요하였다. PI에 의한 오염도평가에서는 4개의 광산지역 모두 1.0 이상보다 훨씬 높아 오염정도가 심각하였으며 복원시 최우선 광산은 원동이었다. 또한, DI에 의한 복원수준정도 평가결과에서 원동광산은 단기간에 유출 가능한 교환성부터, 나머지 광산은 중 장기간에 걸쳐 유출되는 환원성부터 우선적으로 제거해야 할 것으로 나타났다.

• 한국식물학회:학술대회논문집
• /
• 한국식물학회 2002년도 춘계학술발표대회:발표눈문요지록
• /
• pp.62-72
• /
• 2002

This study has investigated the biosynthesis and function of the heavy metal binding peptides, the phytochelatins, in plants. PCs are synthesised enzymatically from glutathione by the enzyme PC synthase in the presence of heavy metal ions. Using Arabidopsis thaliana as a model organism cadmium-sensitive, phytochelatin-deficient mutants have been isolated and characterised in previous studies. The cadl mutants have wildtype levels of glutathione, are PC deficient and lack PC synthase activity. Thus, the CADl gene has been proposed to encode PC synthase. The CADl gene was isolated by a positional cloning strategy The gene was mapped and a candidate identified. Each of four cadl mutants had a single base pair change in the candidate gene and the cadmium-sensitive, cadl phenotype was complemented by the candidate gene. This demonstrated the CADl gene had been cloned. A homologous gene in the fission yeast, Schizosaccharomyces pombe was identified through database searches. A targeted-deletion mutation of this gene was constructed and the mutant, like cadl mutants of Arabidopsis, was cadmium-sensitive and PC-deficient. A comparison of the redicted amino acid sequences reveals a highly conserved N-terminal region Presumed to be the catalytic domain and a variable C-terminal region containing multiple Cys residues proposed to be involved in activation of the enzyme by metal ions. Similar genes were also identified in animal species. The Arabidopsis CADl/AtPCSl and S. pombe SpbPCS genes were expressed in E. coli and were shown to be sufficient for glutathione-dependent, heavy metal activate PC synthesis in vitro, thus demonstrating these genes encode PC synthase enzymes. Using RT-PCR, AtPCSl expression appeared to be independent of Cd exposure. However, at higher levels of Cd exposure a AtPCSl-CUS reporter gene construct appeared to be more highly expressed. Using the reporter gene construct, AtPCSl was expressed most tissues. Expression appeared to be greater in younger tissues and same higher levels of expression was observed in some regions, including carpels and the base of siliques. AtPCS2 was a functional gene encoding an active PC synthase. However, its Pattern of expression and the phenotype of a mutant (or antisense line) have not been determined. Assuming the gene is functional then it has clearly been maintained through evolution and must provide some selective advantage. This implies that, at least in some cells or tissue, it is likely to be the dominant PC synthase expressed. This remains to be determined