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Nguyen V.K.,Chonnam National University | Tran T.,Chonnam National University | Han H.-J.,Chonnam National University | Lee S.-H.,Korea Mine Reclamation Corporation | Lee J.-U.,Chonnam National University
Journal of Geochemical Exploration | Year: 2015

There is an environmental risk of Sb becoming a major pollutant due to the quick increase in the production of Sb industry. However, there have been few investigations on interactions between Sb and microorganisms and bioremediation of Sb this paper presents an investigation on bioleaching of Sb from contaminated sediment which is collected in the vicinity of a Sb processing plant using the iron-oxidizer, Acidithiobacillus ferrooxidans. The bioleaching of Cr, Cu, Mn, Ni, and Zn in the sediment was also investigated to compare with that of sb. Duplicated batch-type experiments based on different incubation time, on the presence or absence of Fe2+ and/ or Ag+, were conducted to compare the efficiency of metal extraction. After bioleaching, 97.4% of Ni, 95.2% of Mn, 65.8% of Cr, 36.2% of Cu, 34.8% of Zn, and 2.2% of Sb were extracted from sediments. The extraction efficiency of Sb was the lowest in comparison to those of Cr, Cu, Mn, Ni, and Zn. This result indicated that Sb is difficult to solubilize by bacterial leaching. The catalytic effect of Ag+ was not observed, which could be due to the inhibition of Ag+ on the activity of A. ferrooxidans and formation of Ag jarosite precipitation on the surface of sediment particles. Though the extraction of Sb was not efficient, this study demonstrates the potential for Sb to be bioleached and a feasible technique in remediation of Sb. © 2015 Elsevier B.V.


Cui M.,Korea University | Cui M.,Jilin Institute of Chemical Technology | Jang M.,Korea Mine Reclamation Corporation | Cho S.-H.,Korea Mine Reclamation Corporation | And 2 more authors.
Journal of Hazardous Materials | Year: 2012

A series of pilot-scale tests were conducted with a continuous system composed of a stirring tank reactor, settling tank, and sand filter. In order to treat acidic drainage from a Pb-Zn mine containing high levels of heavy metals, the potential use of coal-mine drainage sludge (CMDS) was examined. The pilot-scale tests showed that CMDS could effectively neutralize the acidic drainage due to its high alkalinity production. A previous study revealed that calcite and goethite contained in CMDS contributed to dissolutive coprecipitation and complexation with heavy metals. The continuous system not only has high removal efficiencies (97.2-99.8%), but also large total rate constants (K total, 0.21-10.18h -1) for all heavy metals. More specifically, the pilot system has a much higher Zn(II) loading rate (45.3gm -3day -1) than other reference systems, such as aerobic wetland coupled with algal mats and anoxic limestone drains. The optimum conditions were found to be a CMDS loading of 280gL -1 and a flow rate of 8Lday -1, and the necessary quantity of CMDS was 91.3gL -1day -1, as the replacement cycle of CMDS was determined to be 70 days. © 2012 Elsevier B.V..


Cui M.,Korea University | Jang M.,University of Malaya | Kang K.,Korea University | Kim D.,Korea Mine Reclamation Corporation | And 2 more authors.
Chemosphere | Year: 2016

A novel and economic sequential process consisting of precipitation, adsorption, and oxidation was developed to remediate actual rare-earth (RE) wastewater containing various toxic pollutants, including radioactive species. In the precipitation step, porous air stones (PAS) containing waste oyster shell (WOS), PASWOS, was prepared and used to precipitate most heavy metals with >97% removal efficiencies. The SEM-EDS analysis revealed that PAS plays a key role in preventing the surface coating of precipitants on the surface of WOS and in releasing the dissolved species of WOS successively. For the adsorption step, a polyurethane (PU) impregnated by coal mine drainage sludge (CMDS), PUCMDS, was synthesized and applied to deplete fluoride (F), arsenic (As), uranium (U), and thorium (Th) that remained after precipitation. The continuous-mode sequential process using PASWOS, PUCMDS, and ozone (O3) had 99.9-100% removal efficiencies of heavy metals, 99.3-99.9% of F and As, 95.8-99.4% of U and Th, and 92.4% of CODCr for 100 days. The sequential process can treat RE wastewater economically and effectively without stirred-tank reactors, pH controller, continuous injection of chemicals, and significant sludge generation, as well as the quality of the outlet met the EPA recommended limits. © 2015 Elsevier Ltd.


Cui M.,Korea University | Jang M.,Korea Mine Reclamation Corporation | Cho S.-H.,Korea University | Khim J.,Korea University
Environmental Technology | Year: 2010

In this study, we investigated the application of sludge waste obtained from a coal mine drainage treatment facility that treats acid mine drainage (designated as AMD) from metal-mine water. The coal mine drainage sludge (designated as CMDS), which contained 70% goethite and 30% calcite, was utilized as a sorption material for Cu(II) and Zn(II) removal from an aqueous solution of metallic mine drainage. The equilibriums and kinetics were investigated during a series of batch adsorption experiments. The Langmuir model was used to fit the equilibrium data, resulting in the best fits. The removal efficiencies were controlled by solution pH, temperature, initial concentration of heavy metal, sorbent amount and contact time. The pseudo-second-order kinetic model was used to fit the kinetic data, providing a good correlation with the experimental data. The results of a thermodynamic study showed that the activation energies (EA) were 3.75 and 1.75 kJ mol-1 for the adsorption of Cu(II) and Zn(II) on to CMDS at pH 5.5. These values of activation energy could correspond to physisorption. The positive values obtained for both the standard enthalpy change, Δ0, and the standard entropy change, ΔS0, suggest that the adsorption of Cu(II) and Zn(II) on to the CMDS was an endothermic reaction and that randomness increased at the solid-liquid interface during the adsorption of Cu(II) and Zn(II) on to the CMDS. The adsorption process also followed a pseudo-second-order kinetic model. © 2010 Taylor & Francis.


Cui M.,Korea University | Jang M.,Korea Mine Reclamation Corporation | Lee S.,Korea University | Kweon B.,Korea University | And 2 more authors.
Japanese Journal of Applied Physics | Year: 2011

The oxidation and treatment of arsenite [As(III)] with ultrasound (US) and Fe(II) was investigated in aqueous solutions. The oxidation of As(III) into As(V), over 99.1%, was obtained by US450kHz. The kinetics of As(III) oxidation were interpreted using the modified pseudo-first-order kinetic model. The half life of As(III) was approximately 3.47 × 10-2 for the US450kHz/Fe(II)0:4mg/L reaction and depended on the iron concentration. The arsenic removal capacity of complexed and coprecipitated FeAsO4(s) was estimated to be 16.12mg per g of iron oxide. It is concluded that the sonochemical treatment of As(III) solution in the presence of Fe(II) is a simple and viable technique for the oxidation of As(III) into arsenate [As(V)] and the treatment of total arsenic. © 2011 The Japan Society of Applied Physics.


Cui M.,Korea University | Jang M.,Korea Mine Reclamation Corporation | Cho S.-H.,Korea University | Elena D.,Romanian Institute of Isotopic And Molecular Technology | Khim J.,Korea University
Ultrasonics Sonochemistry | Year: 2011

As an advanced oxidation process, the combination of sonolysis (US)/ozonolysis (O3) was investigated on the treatment of tannic acid (TA) and humic acid (HA). In this study, biodegradable chemicals were found by the molecular weight and GC-MS analysis method, and mineralization rate and synergetic effects were also studied. For the water samples prior to the treatment of US/O3, ratios of molecular size higher than 5000 and 2000 Da for HA and TA, detected by the ultra filtration method, were 90.25% and 89.53%, respectively. However, after 0.5 h of reacting, this ratio rapidly reduced to 3% and 4%, and the ratios of molecules for HA and TA less than 500 Da rapidly increased from 0.8% to 41% and from 0.65% to 39%, respectively. In the results of chemical oxygen demand (CODCr) and total organic carbon (TOC) reductions, the US/O3 process also showed synergetic effect by US/O3 for CODCr of HA and TA were 19% and 11%, and those for TOC of HA and TA were 0% and 1%, respectively. The major by-products of the oxidation process included formaldehyde, acetone, hydroxylamine, etc. Biological decomposable materials could be indirectly inferred by measuring the molecular weights and intermediates. © 2010 Elsevier B.V.


Cha J.,Korea University | Cui M.,Korea University | Jang M.,Korea Mine Reclamation Corporation | Cho S.-H.,Korea University | And 2 more authors.
Environmental Geochemistry and Health | Year: 2011

This study examines the adsorption isotherms, kinetics and mechanisms of Pb2+ sorption onto waste cow bone powder (WCBP) surfaces. The concentrations of Pb2+ in the study range from 10 to 90 mg/L. Although the sorption data follow the Langmuir and Freundlich isotherm, a detailed examination reveals that surface sorption or complexation and co-precipitation are the most important mechanisms, along with possibly ion exchange and solid diffusion also contributing to the overall sorption process. The co-precipitation of Pb2+ with the calcium hydroxyapatite (Ca-HAP) is implied by significant changes in Ca2+ and PO4 3- concentrations during the metal sorption processes. The Pb2+ sorption onto the WCBP surface by metal complexation with surface functional groups such as ≡ POH. The major metal surface species are likely to be ≡ POPb+. The sorption isotherm results indicated that Pb2+ sorption onto the Langmuir and Freundlich constant qmax and KF is 9.52 and 8.18 mg g-1, respectively. Sorption kinetics results indicated that Pb2+ sorption onto WCBP was pseudo-second-order rate constants K2 was 1.12 g mg-1 h-1. The main mechanism is adsorption or surface complexation (≡POPb+: 61.6%), co-precipitation or ion exchange [Ca3.93 Pb1.07 (PO4)3 (OH): 21.4%] and other precipitation [Pb 50 mg L-1 and natural pH: 17%). Sorption isotherms showed that WCBP has a much higher Pb2+ removal rate in an aqueous solution; the greater capability of WCBP to remove aqueous Pb2+ indicates its potential as another promising way to remediate Pb2+-contaminated media. © 2010 Springer Science+Business Media B.V.


Cui M.,Korea University | Jang M.,Korea Mine Reclamation Corporation | Cho S.-H.,Korea University | Khim J.,Korea University
Environmental Geochemistry and Health | Year: 2011

Various analyses of physico-chemical characteristics and batch tests were conducted with the sludge obtained from a full-scale electrolysis facility for treating coal mine drainage in order to find the applicability of sludge as a material for removing Zn(II) in an aqueous phase. The physico-chemical analysis results indicated that coal mine drainage sludge (CMDS) had a high specific surface area and also satisfied the standard of toxicity characteristic leaching procedure (TCLP) because the extracted concentrations of certain toxic elements such as Pb, Cu, As, Hg, Zn, and Ni were much less than their regulatory limits. The results of X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) showed that the CMDS mainly consists of goethite (70%) and calcite (30%) as a weight basis. However, the zeta potential analysis represented that the CMDS had a lower isoelectric point of pH (pHIEP) than that of goethite or calcite. This might have been caused by the complexation of negatively charged anions, especially sulfate, which usually exists with a high concentration in coal mine drainage. The results of Fourier transform infrared (FT-IR) spectrometry analysis revealed that Zn(II) was dominantly removed as a form of precipitation by calcite, such as smithsonite [ZnCO3] or hydrozincite [Zn5(CO3)2(OH)6]. Recycling sludge, originally a waste material, for the removal process of Zn(II), as well as other heavy metals, could be beneficial due to its high and speedy removal capability and low economic costs. © 2010 Springer Science+Business Media B.V.


PubMed | Korea Mine Reclamation Corporation, Korea University, University of Malaya and University of Arizona
Type: | Journal: Chemosphere | Year: 2015

A novel and economic sequential process consisting of precipitation, adsorption, and oxidation was developed to remediate actual rare-earth (RE) wastewater containing various toxic pollutants, including radioactive species. In the precipitation step, porous air stones (PAS) containing waste oyster shell (WOS), PASWOS, was prepared and used to precipitate most heavy metals with >97% removal efficiencies. The SEM-EDS analysis revealed that PAS plays a key role in preventing the surface coating of precipitants on the surface of WOS and in releasing the dissolved species of WOS successively. For the adsorption step, a polyurethane (PU) impregnated by coal mine drainage sludge (CMDS), PUCMDS, was synthesized and applied to deplete fluoride (F), arsenic (As), uranium (U), and thorium (Th) that remained after precipitation. The continuous-mode sequential process using PAS(WOS), PU(CMDS), and ozone (O3) had 99.9-100% removal efficiencies of heavy metals, 99.3-99.9% of F and As, 95.8-99.4% of U and Th, and 92.4% of COD(Cr) for 100 days. The sequential process can treat RE wastewater economically and effectively without stirred-tank reactors, pH controller, continuous injection of chemicals, and significant sludge generation, as well as the quality of the outlet met the EPA recommended limits.


Jang M.,Korea Mine Reclamation Corporation | Kwon H.,Korea Mine Reclamation Corporation
Environmental Geochemistry and Health | Year: 2011

A pilot-scale plant consisting of an oxidation basin (OB), a neutralization basin (NB), a reaction basin (RB), and a settling basin (SB) was designed and built to conduct pilot-scale experiments. With this system, the effects of aeration and pH on ferrous oxidation and on precipitation of the oxidized products were studied systemically. The results of pilot-scale tests showed that aeration at 300 L/min was optimum for oxidation of Fe(II) in the OB, and the efficiency of oxidation of Fe(II) increased linearly with increasing retention time. However, Fe(II) was still present in the subsequent basins-NB, RB, and SB. Results from pilot-scale tests in which neutralization was excluded were used to obtain rate constants for heterogeneous and homogeneous oxidation. Oxidation of Fe(II) reached almost 100% when the pH of the mine drainage was increased to more than 7.5, and there was a linear relationship between total rate constant, log (K total), and pH. Absorbance changes for samples from the NB under different pH conditions were measured to determine the precipitation properties of suspended solids in the SB. Because ferrous remained in the inflow to the SB, oxidation of Fe(II) was dominant initially, resulting in increased absorbance, and the rate of precipitation was slow. However, the absorbance of the suspension in the SB rapidly dropped when pH was higher than 7.5. © 2010 Springer Science+Business Media B.V.

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