• Korean Journal of Environmental Agriculture
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• v.29 no.1
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• pp.61-65
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• 2010

Phytoextraction is a method of phytoremediation using plants to remediate metal-contaminated soils. Recently, various chelating agents were used in this method to increase the bioavailability of metals in soils. Even though phytoextraction is an economic and environment-friendly method, this cannot be applied in highly metal-contaminated areas because plants will not normally grow in such conditions. This research focuses on identifying chelating agents which are biodegradable and applicable to highly metal-contaminated areas. Lead (Pb) as a target metal and cysteine (Cys), histidine (His), citrate, malate, oxalate, succinate, and ethylenediamine (EDA) as biodegradable chelating agents were selected. Ethylenediamine tetraacetic acid (EDTA) was used as a comparative standard. Plants were grown on agar media containing various chelating agents with Pb to analyze the effect on root growth. Cys strongly increased the inhibitory effect of Pb on root growth of plants, while, His did not affect on it significantly. The inhibitory effect of oxalate is weak, and malate, citrate, and succinate did not show significant effects. Both EDTA and EDA diminished the inhibitory effect of Pb on root growth. The effect of EDA is correlated with decreased Pb uptake into the plants. In conclusion, as biodegradable chelating agents, EDA is a good candidate for highly Pb-contaminated area.

• Carbon letters
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• v.3 no.1
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• pp.13-16
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• 2002

The modification of coal-tar pitch has been carried out by heat treatment of pitch at different temperatures in the range ($300^{\circ}-400^{\circ}C$) for different times (2-5 hrs) in air and nitrogen. The pitch heat treated in air at lower temperature ($300^{\circ}C$) exhibit increase in softening point by $20^{\circ}C$ as compared to only $2^{\circ}C$ when treated in nitrogen. The changes are faster in air than in pure nitrogen. Pitch as such as well as after heat treatment were further treated with metal complexes by solution route. Silver intake has been found to increase from 0.5 to 0.8 % in nitrogen treated pitch while the uptake is found to decrease for pitches treated in air at $350^{\circ}C$ for 5 hrs. Experiments have also been made to incorporate silver into PAN and PAN-ox fibers through solution route. The metal intake has been found to be more in PAN-ox fibers than in PAN as such. Metal loaded carbon composites have been made by using metal loaded fibers as well as cokes. These composites as such exhibit higher surface oxygen complexes but decrease after activation.

• Korean Journal of Ecology and Environment
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• v.40 no.4
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• pp.537-545
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• 2007

The heavy metal removal capacity of filamentous green alga Cladophora sp. cultured together with wet-mixed solidified soil (loess) was tested. A Cladophora sp. was cultured for 5d, with added Chu No. 10 medium, in stream water contaminated by high concentration of heavy metals from a closed mine effluent. Heavy metal ion concentrations of the medium and in algal tissue were measured every day during the experiment. Dissolved metals (Al, Cd, Cu, Fe, Mn, Zn) in medium were rapidly removed (over 90% elimination) within 1-2d when alga and loess were added. Dissolved heavy metals dropped by only 10% when algae were cultured without loess. The Cladophora sp. accumulated much more heavy metals when cultured with loess than when the alga was cultured alone. Cladophora sp. exhibited a maximum uptake capacity for Al ($17,000{\mu}g^{-1}$ algal dry weight). The metal bioremoval capacities of the algae were in the order Al, Fe, Cu, Mn, Zn and Cd. The heavy metal removal capacity of Cladophora sp. showed significant increases when wet-mixed solidified soil was added to culture media.

• Journal of the Korean Society of Safety
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• v.19 no.3 s.67
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• pp.57-64
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• 2004

This is the study for the removal of a toxic heavy metal ions and the recycling of expanded polystyrene wastes. Thus expanded polystyrene wastes collected from the packing materials of TV or chemicals and dissolved by $80wt.\%$ solvent(N, N-Dimethylacrylamide), electrospun in DC 20kV by power supply. Generally, the electrospinning is a process of manufacture to the fibers of nanosize from polymer solution. Manufactured nanofiber mats by electrospinning were sulfonated by cone.-sulphuric acid with $Ag_2S_O_4$ catalysts for the exchange capacity of heavy metal ions and the properties of structure with sulfonated time investigated by FESEM(Feild Emission Scaning Electron Microscope). The ion exchange capacity of light metal$(Na^+)$, Cd(II) and Ni(II), and by a nanofiber mats were 1.94[mmo1/g-dry-mat), 1.72(mmol/g-dry-mat), 1.24(mmol/g-dry-mat), respectively., and water uptake content showed a similar trend with IEC. and The selectivity coefficients $K^M_H$ of Cd(II), Ni((II) ions showed 0.324, 0.228. respectively.

• The Korean Journal of Ecology
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• v.5 no.4
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• pp.176-186
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• 1982

Uptake and effects of treated Cd and Pb in rose moss and tomato were studied in pot cultures. Three horticulural plants on the roadside were tested to determine the contents of heavy metals in plant parts. Yields of rose moss were increased by the increase Pb concentrations in soil. Yields of rose moss by Cd treatment were decreased in 1, 000 ppm group, but increased in 500 ppm group. Portulaca grandiflora Hook. proved to be tolerent of Pb and Cd added in soil. Yields of tomato were decreased by an incrase of Pb concentration in soil, and tomato proved to be weak for Pb added in soil. Pb contents in root, stem, leaf, and flower and seed of rose moss were increased by an in crease of Pb concentration in soil Pb content in root was the highest among them. Pb content was the highest in root of tomato, but the lowest in the stem. Among the heavy metal contents metal contents of three horticultural plants collected by roadside, it was the Chrysanthemum which had the highest contents of heavy metal among them. The heavy metal contents in stem were less than in the other plnat parts in all three plants. The number of flowers in rose moss was decreased by an increase of Pb, and Cd concentration in soil, but in tomato it was increased by an increase of Pb concentration in soil. Amount of rose moss seeds which were collected after cultivation was decreased by Pb, and Cd treatment in soil.

• Applied Biological Chemistry
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• v.44 no.3
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• pp.185-190
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• 2001

Alginate, a well-known biopolymer, is universally applied for immobilization of microbial cells. Biosorption characteristics of lead by waste biomass of immobilized A. niger beads, used in fermentation industries to produce citric acid, were studied. The immobilized A. niger beads, prepared via capillary extrusion method using calcium chloride, were applied in the removal of lead. Pb uptake was the highest in A. niger beads cells grown for 3 days with medium producing citric acid (12% sucrose, 0.5% $NH_4NO_3$, 0.1% $KH_2PO_4$, and 0.025% $MgSO_4$). Lead uptake by the immobilized A. niger beads and free A. niger mycellia beads increased sharply with time. However, while uptake by the immobilized A. niger beads continued to increase slowly, that by free A. niger mycellia beads stopped after 30 min. The optimum pH and temperature of lead uptake were found to be 6 and $35^{\circ}C$, respectively. The maximum uptake of lead was achieved with $50{\sim}100$ beads and 50 ml lead solution in a 250-ml Erlenmeyer flask, while, at over 100 beads, uptake of the lead decreased. The order of biosorption capacity for heavy metals was Pb>Cu>Cd. Pb uptake capacity of the immobilized A. niger beads treated with 0.1 M $CaCI_2$, 0.1 M NaOH, and 0.1 M KOH decreased compared to the untreated beads. On testing the desorption of Pb from the immobilized A. niger beads, re-uptake of Pb was found possible after desorption of the binding metal with 0.1 M HCI.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.158.2-159
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• 2003

Cadmium is well known as a toxic metal and has insulin mimicking effects in rat adipose tissue. To investigate the effect of CdCl2 on glucose transport and its mechanism, this study was performed in 3T3-L1 adipocytes. 10 and 25mM of CdCl2 exposed to cells for 12 hours increased 2-deoxyglucose uptake to 2.2 and 2.8 fold, respectively. Nifedipine, a calcium channel blocker, inhibited the 2-deoxyglucose uptake stimulated by CdCl2. (omitted)

• KSBB Journal
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• v.13 no.4
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• pp.444-448
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• 1998

Biosorption of Pb and Cu was evaluated for 23 species of marine algae collected from a Korean coast. Among a variety of species for biosorbent potential, Hypnea charoides showed the highest capacity for Pb. An adsorption equilibrium was reached in about 2 hr for Pb and 30 min for Cu. The uptake capacity was 192.8 mg Pb/g biomass and 256 mg Cu/g biomass, respectively. The adsorption parameters for Pb and Cu were determined according to Langmuir model. With an increase in pH value, more negative sites are becoming avaliable for adsorption of pH and Cu, thus the removal of Pb and Cu increases at alkaline conditions. The selectivity of mixture solution shows the uptake order of Pb>Cu>Cr>Cd. When Ca concentration increases in Pb solution, Pb was selectively adsorbed.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.2
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• pp.106-114
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• 2017

There is an increasing concern over heavy metal(loid) contamination of soil in agricultural areas including paddy soils. This study was conducted to determine the bioconcentration factor (BCF) for heavy metal(loid)s to brown rice grown in paddy soils vulnerable to heavy metal(loid)s contamination, for the quantitative health risk assessment to the residents living nearby the metal contaminated regions. The samples were collected from 98 sites nationwide in the year 2015. The mean and range BCF values of As, Cd, Cu, Ni, Pb, and Zn in brown rice were 0.027 (0.001 ~ 0.224), 0.143 (0.001 ~ 2.434), 0.165 (0.039 ~ 0.819), 0.028 (0.005 ~ 0.187), 0.006 (0.001 ~ 0.048), and 0.355 (0.113 ~ 1.263), respectively, with Zn showing the highest. Even though the relationship between heavy metal(loid) contents in the vulnerable soils and metal contents in brown rice collected at the same fields was not significantly correlated, the relationship between log contents of heavy metal(loid)s in the vulnerable soils and BCF of brown rice wes significantly correlated with As, Cd, Cu, and Zn in rice. In conclusion, soil environmental risk assessment for crop uptake should consider the bioconcentration factor calculated using both the initial and vulnerable heavy metal(loid) contents in the required soil and the crop cultivated in the same fields.

• Journal of Environmental Science International
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• v.8 no.3
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• pp.399-409
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• 1999

The three domestic natural zeolites(Yong dong-ri (Y), Daesin-ri (D), Seogdong-ri (S)) harvested in Kyeongju-shi and Pohang-shi, Kyungsangbug-Do, were pretreatd with each of the NaOH, $Ca(OH)_2$ and NaOH following HCl solutions, and the removal performances of divalent haevy metals(Cu, Mn, Pb, and Sr) for natural and pretreated zeolites were investigated and compared in the single and mixed solutions. The natural zeolite-heavy metal system attained the final equilibrium plateau within 20 min, irrespective of initial heavy metal concentration. The heavy metal uptakes increased with increasing initial heavy metal concentration and pH. The heavy metal uptakes for natural zeolites decreased in the following sequences : D>Y>S among the natural zeolites; Pb>Cu>Sr>Mn among the heavy metals. The pretreated zeolites showed higher heavy metal removal performances than natural zeolites and decreased in the order of NaOH, NaOH following HCl, $Ca(OH)_2$ treatment among the pretreatment methods. The heavy metal ion exchange capacity by natural and pretreated zeolites was described either by Freundlich equation or Langmuir equation, but it followed the former better than the latter. The heavy metal uptakes for natural zeolites decreased in the mixed solution, in comparing with those in the single solution and especially, the manganese uptake decreased greatly in the mixed solution. The pretreated zeolites showed the improved removal performances of heavy metals in the mixed solution than in the single solution and the heavy metal uptakes by those in the mixed solution showed the same trends in the single solution among the chemical treatment methods and heavy metals.