• Journal of Environmental Science International
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• v.11 no.4
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• pp.361-366
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• 2002

Several effects on Pb$^{2+}$ removal by crab shell from aqueous solution were investigated. As the increase of initial Pb$^{2+}$ concentration and decrease of initial crab shell concentration, the time required to reach an equilibrium state and the residual Pb$^{2+}$ concentration increased. In our experimental ranges, the optimum initial Pb$^{2+}$ concentration and crab shell concentration were below 103 mg/$\ell$ and over 0.5 mg/$\ell$, respectively. Also, in order to investigate the mechanism of Pb$^{2+}$ removal by crab shell in aqueous solution, the crab shell was compared with chitosan and chitin on aspects of Pb$^{2+}$ removal capacity and Pb$^{2+}$ removal rate. The Pb$^{2+}$ removal by crab shell was greater than that by chitin and chitosan. The role of chitin was not so great in Pb$^{2+}$ removal by crab shell. The Pb$^{2+}$ removal by chitosan was not exactly correlated to the molecular weight of chitosan. weight of chitosan.

• Applied Chemistry for Engineering
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• v.24 no.4
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• pp.428-432
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• 2013

From the forest areas in Chungbuk, large amounts of wood wastes by pruning are generated, however most of them considered as by-products are not treated properly with no disposal options. In this work, among diverse wood wastes such as Quercus variabillis, Juniperus chinensis, Larix kaemoferi, and Pinus densiflora, Juniperus chinensis was found to be more effective biosorbent for the removal of lead ions than other wood wastes. Also, the enhancement of lead removal efficiency from the aqueous phase was investigated using Juniperus chinensis waste. It was observed that the optimal initial pH to increase the removal efficiency of 20 mg/L lead ions was 4.0 and the optimal dosage concentration with regard to the biosorbent for the enhanced removal of 50 mg/L lead ions was 0.6 g/100 mL. In addition, chemical treatment of Juniperus chinensis waste with sulfuric acid was required to improve the adsorption capacity for high lead concentrations (over 100 mg/L). When Juniperus chinensis waste was chemically treated with 6 M sulfuric acid, the adsorption quantities of lead ions were 180, 340, and 425 mg/g with regard to 200, 400, and 500 mg/L lead ions concentrations, respectively. These results indicate that the practical biosorbent technology developed in this study is a highly efficient method to treat the lead ion from an aqueous solution.

• Journal of Soil and Groundwater Environment
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• v.18 no.7
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• pp.41-53
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• 2013

The study is to propose the optimal separation technique of heavy metals (Pb and Zn) contaminated in soil for improving the removal efficiency by various applicable techniques. The heavy metal contaminated soil samples near abandoned mine X-1 and X-2 were used for the study. Firstly, the wet classification process was shown more than 80% of removal efficiency for lead and zinc. Meanwhile, the magnetic separation process was shown low removal efficiency for lead and zincs because those heavy metals were non-magnetic materials. For the next step, the flotation separation process was shown approximately 24.4% of removal efficiency for zinc, while the gravity concentration process was shown approximately 57% of removal efficiency for lead, and 19.9% of removal efficiency for zinc, respectively. Therefore, zinc contaminated in soil would be effectively treated by the combination technique of the wet classification and the flotation technique. Meanwhile, lead contaminated in soil would be effectively treated by the combination technique of the wet classification process and the flotation process. Furthermore, the extraction of organic matter was shown more effective with aeration, 3% of hydrogen peroxide and 3% of lime such as calcium hydroxide.

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.2
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• pp.81-88
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• 2007

A study on the removal of heavy metals using sawdust was performed. Among heavy metals such as lead, copper and cadmium ions, uptake capacity of lead ions was the highest as about 0.22 mmol/g-dry mass at pH 4. The surface condition and existence of lead ions onto the sawdust was confirmed by the FT-IR, SEM (Scanning Electron Microscopy), and EDX (Energy Dispersive X-ray) instrumental analyses. When 0.5g of sawdust was added to initial lead solution (100ppm) removal efficiency was approximately 90%. Isothermal adsorption curve for lead ions was described by the Langmuir model equation and experimental data well fitted to model equation. Most adsorption for lead ions was also completed within 60min and pH of lead solution from 5.8 to 4.5 decreased with time.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1999.10a
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• pp.12-15
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• 1999

Soils collected from an agricultural field in Youngdong, Chungbuk province were intentionally: contaminated with lead and copper. The efficiencies of soil washing with HCl, SDS and Tween 80 were investigated through the column mode experiments. Washing with 0.1 N HCl obtained the best result for lead and copper removal (95.04 %, 95.94 %). In case of SDS, lead and copper removal rate was such poor as 7.1 % and copper was 24.04 %, respectively. Meanwhile, washing of contaminated soil with Tween 80, did not show any significant removal effect. It was found that the washing efficiency was dependent on pH of washing agent.

• Journal of Soil and Groundwater Environment
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• v.13 no.1
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• pp.60-66
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• 2008

Laboratory soil washing experiments with HCl or EDTA were conducted to remediate lead-contaminated soil in a firing range. After lead bullets were removed by standard sieve #18 (1.0 mM), Pb concentrations were measured by EPA Method 3050B (9,443 mg/kg) and Korea Standard Test (4,803.5 mg/kg). The results of the batch test showed that the removal efficiency curve was logarithmic and approximately 90% of lead in soil was removed, when HCl was used. In case of EDTA, the removal efficiency increased proportionally to the concentration of EDTA, up to 98% lead removal with 0.1M EDTA. High mixing strength resulted in increase of removal efficiency and kinetics showed that the most lead was extracted in 10 min.

• Journal of Environmental Health Sciences
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• v.24 no.1
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• pp.98-103
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• 1998

A study on the removal of mercury and lead by microorganisms, Saccharomyces cerevisiae and Aureobasidium pullulans, was performed, in which the comparison of adsorption model between these two heavy metals was done. The amounts of mercury removed were more than those of lead in both microorganisms. In case of mercury, the adsorption isotherm of S. cerevisiae was accorded with Langmuir model but A. pullulans was followed to Freundlich model. In the case of lead, however, the adsorption isotherm had opposite results. The adsorption rate of mercury to S. cerevisiae was faster than that of A. pullulans, but in the case of lead, it revealed contrary results. It seems, therefore, that the type of microorganisms used as biosorbents should be selected differently with the type of heavy metals removed for applying these to real adsorption process.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.740-744
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• 1994

This study was undertaken to prove the suppressing effect of green tea on the intestinal absorption of heavy metals using in vitro membrane filtration system. From drinking water contaminated with 10 and 100 times level of water quality standard for heavy metals, the removal ratio of lead (Pb) was $50{\sim}70%$ by green and black teas, and $30{\sim}40%$ by roasted barley tea. The removal ratio of cadmium (Cd) was $30{\sim}40%$ by green tea and black teas, and $10{\sim}20%$ by roasted barley tea. The removal effect from drinking water contaminated with both lead and cadmium was lower than that from water contaminated singly with lead or cadmium. It appears that tea components and filter membrane compete toward the adsorption of two heavy metals. Among the extraction conditions of raw tea materials at $70^{\circ}C$, 2 minutes and $95^{\circ}C$ , 10 minutes, the removal ratios of heavy metals were similar.

• Environmental Engineering Research
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• v.10 no.5
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• pp.205-212
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• 2005

The study was conducted to investigate the removal of heavy metals by using Hydroxyapatite(HAp) made from waste oyster shells and wastewater with high concentration of phosphorus. The maximum calcium concentration for the production of HAp in this study was released up to 361 mg/L at pH of 3 by elution experiments. When the pH was at adjusted 6, the maximum calcium released concentration was 41 mg/L. During the elution experiment, most of the calcium was released within 60 minutes. This reaction occurred at both pH levels of 3 and 6. The result of the XRD analysis for the HAp product used in this study shows the main constituent was HAp, as well as OCP. The pH was 8.6. As the temperature increased, the main constituent did not vary, however its structure was crystallized. When the pH was maintained at 3, the removal efficiency decreased as the heavy metal concentration increased. The order of removal efficiency was as follows: $Fe^{2+}$(92%), $Pb^{2+}$(92%) > $Cu^{2+}$(20%) > $Cd^{2+}$(0%). Most of these products were dissolved and did not produce sludge in the course of heavy metals removal. As the heavy metal concentration increased at pH of 6, the removal efficiency increased. The removal efficiencies in all heavy metals were over 80%. From the analysis of the sludge after reaction with heavy metals, the HAp was detected and the OCP peak was not observed. Moreover, lead ion was observed at the peaks of lead-Apatite and lead oxidant. In the case of cadmium, copper and iron ions, hydroxide forms of each ion were also detected.

• Environmental Analysis Health and Toxicology
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• v.7 no.1_2
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• pp.53-57
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• 1992

Amount of lead burden in a tissue reflects poisoning of lead in that tissue, so is the removal of lead directly connected to curement of lead poisoning. The purpose of present study was to investigate the relative effects of penicillamine and thiamine tetrahydrofurfuryl disulfide (TTFD) or thiamine propyl disulfide (TPD) in the removal of lead from rat brain tissue treated with excessive lead. Wistar rat pups of both sexes were used in this experiment. Within 1 day of parturition, experimental mothers nursing their pups as well as rat pups were given drinking water containing 0.2% lead acetate, TTFD 20mg/1.2 L (2 mg/kg/day), TPD 20 mg/1.2 L (2mg/kg/day), penicillamine 40 mg/1.2 L (40 mg/kg/day), 0.2% lead acetate+TTFD 20mg/1.2 L (2 mg/kg/day), 0.2% lead acetate+ TPD 20 mg/1.2 L (2 mg/kg/day) or 0.2% lead acetate+ penicillamine 40 mg/1.2 L (40 mg/kg/day) ad libitum, throughout the entire period of experiment. Rat pups in the control group received normal tap water. The animals were sacrificed by decapitation on the day when they become 2 or 8 weeks of age. Brains were dissected into five regions: telencephalon, diencephalon, midbrain, pons/medulla and cerebellum. The dissected brain tissues were lyophillized and then solubilized by acid mixture (nitric acid + sulfuric acid). Lead levels in the solubilized brain tissues were measured by the inductively coupled plasma. In lead-exposed rats, lead levels were significantly higher than those of control group in all brain legions, lead levels in brain regions of TTFD or TPD group were generally lower than those of control group. The simultaneous administration of lead with TTFD or TPD to animals caused significant decrement of lead from all brain regions. In the elimination of lead from brain regions, effectiveness of TTFD or TPD was equivalant to penicillamine.