• Journal of Microbiology and Biotechnology
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• v.9 no.5
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• pp.650-654
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• 1999

Undaria pinnatifida oxidized by nitric acid had a high capacity of Cu/sup 2+/ uptake (3.5 mmol Cu/sup 2+/g dry mass) at pH 4 and showed high affinity to Cu/sup 2+/ and Pb/sup 2+/, in a mixed-metal system, compared to Ca/sup 2+/ and Mg/sup 2+/. The IR spectrum showed increase of carboxylic acid on the surface of Undaria pinnatifida, mostly due to the effect of the oxidation reaction.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.280-291
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• 2007

Much research has been conducted in the field of phytoremediation since the discovery of the range of plants known as hyperaccumulators. Research has focused simultaneously on elucidating the mechanism of metal(loid) accumulation and development of practical techniques to enhance accumulation efficiency. To date, it is generally understood that there are five specific mechanisms employed by hyperaccumulating plant species that are either not or under utilized by non-hyperaccumulators. These include 1) enhanced metal(loid)s uptake through the root cell, 2) enhanced translocation in plant tissue, 3) detoxification and sequestration, 4) enhanced metal availability in soil:root interface, and 5) active root foraging toward metal(loid) enriched soils. Among these mechanisms, understanding of the plant-root effect on metal(loid) dynamics and subsequent plant uptake is vital to overcome the inherit limitation of phytoremediation caused by low metal(loid) solubility in soils. Plant roots can influence the soil chemistry in the rhizosphere through changes in pH and exudation of organic compounds such as low-molecular-weight organic acids (LMWOAs) which consequently change metal(loid) solubility. The decrease in soil pH by plant release of $H^+$ results in increased metal solubility. Elevated levels of organic compounds in response to high metal soil concentrations by plant exudation may also increases metal concentration in soil solution through formation of organometallic complexes.

• Journal of Environmental Science International
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• v.8 no.3
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• pp.387-391
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• 1999

$Pb^{2+}$ and $Cr^{3+}$ uptake capacity by Sargassum horneri was 185.5 mg $Pb^{2+}$/g biomass and 102.6 mg $Cr^{3+}$/g biomass, respectively. An adsorption equilibria were reached within about 0.5 hr for $Pb^{2+}$ and 1 hr for $Cr^{3+}$. The adsorption parameters for $Pb^{2+}$ and $Cr^{3+}$ were determined according to Langmuir and Freundlich model. With an increase in pH values of 2 to 5, $Pb^{2+}$ uptake was increased, however $Cr^{3+}$ uptake jwas constant. The selectivity of mixture solution showed the uptake order of $Pb^{2+}$>$Cu^{2+}$>$Cr^{3+}$>$Cd^{2+}$. $Pb^{2+}$ and $Cr^{3+}$ adsorbed by S. horneri could be recovered from 0.1M HCl, 0.1M ${HNO}_3$ and 0.1M EDTA by desorption process, and the efficiency of $Pb^{2+}$ desorption was above 98%, whereas the efficiency of $Cr^{3+}$ desorption was below 34%.

• Biotechnology and Bioprocess Engineering:BBE
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• v.2 no.2
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• pp.132-135
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• 1997

We prepared capsules containing Saccharomyces cerevisiae and Zoogloea ramigera cells for the removal of lead(II) and cadmium ions. Microbial cells were encapsulated and cultured in the growth medium. The S.cerevisiae cells grown in the capule did not leak through the capsule membrane. The dried cell density reached to 250 g/l on the basis of the inner volume of the 2.0 mm diameter capsule after 36 hour cultivation. The dry whole cell expolymer density of encapsulated Z.ramigera reached to 200 g/L. The capsule was crosslinked with triethylene tetramine and glutaric dialdehyde solutions. The cadmium uptake of encapsulated whole cell expolymer of Z.ramigera was 55mg Cd/g biosorbent. The adsorption line followed well Langmuir isotherm. The lead uptake of the encapsulated S. cerevisiae was about 30 mg Pb/g biomass. The optimum pH of the lead uptake using encapsulated S. cerevisiae was found to be 6. Freundlich model showed a little better fit to the adsorption data than Langmuir model 95 percent of the lead adsorbed on the encapsulated biosorbents was desorbed by the 1 M HCl solution. The capsule was reused 50 batches without loosing the metal uptake capacity. And the mechanical strength of the crosslinked capsule was retained after 50 trials.

• Journal of Applied Biological Chemistry
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• v.64 no.2
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• pp.159-164
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• 2021

Heavy metals exist in soils in various chemical forms including free metal ions and organo-metal complexes. The ratio of free metal ions has been known to be highly associated with the plant absorption of heavy metals. This study aims to understand the effect of free ions and organo-metal complexes on the absorption of lead (Pb) and cadmium (Cd) by plants. For this, lettuce grown in a hydroponic system for 28 days was consequently grown another 48 hours using Pb and Cd solutions. The ratios of free ion to organo-metal complexes in the solutions were adjusted at 100:0, 90:10, 70:30, 60:40 by four different organic acids (citric, oxalic, acetic, and humic acid). After that, the concentration of Pb and Cd in lettuce were analyzed. The Pb and Cd absorption by lettuce was more relied on the types of organic acids treated and the type of metals rather than the ratio of free metal ions. For example, citric acid increased the Pb absorption while it decreased the Cd absorption by lettuce. There was no significant relationship between free metal ion ratios and both Pb and Cd uptake by lettuce. It could be explained that citric acid, a relatively higher molecular weight organic acid, has higher ion binding capacity, so it forms organo-Pb complex easily due to the higher affinity of Pb on the binding site in comparison with Cd. Consequently, this complexation would assist Pb uptake by lettuce.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.627-634
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• 2016

The objectives of this study were to select optimal soil amendments through analysis of heavy metal availability in soil and uptake to Aster koraiensis Nakai for forest rehabilitation of heavy metal contaminated soil of abandoned metal mine. A. koraiensis was cultivated for 6 months at contaminated soil with several soil treatments (bottom ash 1 and 2%, fly ash 1 and 2%, waste lime+oyster 1 and 2%, Acid mine drainage sludge (AMDS) 10 and 20%, compost 3.4%, non-contaminated natural forest soil, and control). The analysis results of heavy metal concentrations in the soil by Mehlich-3 mehthod, growth and heavy metal concentrations of A. koraiensis showed that waste oyster+lime 1% and compost were more effective than the other amendments for phytostabilization. However, it is needed comprehensive review of factors such as on-site condition, slope covering to reduce soil erosion and vegetation introduction from surround forest for revegetation to apply forest rehabilitation.

• Ecology and Resilient Infrastructure
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• v.7 no.1
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• pp.63-71
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• 2020

Various types of amendments have been studied for heavy metal stabilization in soil. However, researches on the effect of amendments on alkali soil and their effects on the plants at various edible parts are insufficient. The aim of this study was to evaluate the stabilization efficiency of heavy metals and their transfer into edible parts of food crops. Abandoned mine area was selected and 3 types of amendments (lime stone, LS; steel slag, SS; acid mine drainage sludge, AMDS) was applied with 3% (w/w). in field. After 6 month aging, Chinese cabbage (leafy), bok choy (leafy), garlic (root) and red pepper (fruit) were transplanted and cultivated. For chemical assessment, total concentration and bioavailability using Mehlich-3 solution were determined. For biological assessment, fresh weight and heavy metal uptakes were analyzed. It was revealed that AMDS reduced bioavailability most effectively, resulting in the decrease in heavy metal concentration in edible parts of all crops. When explaining the heavy metal uptake of plants, the bioavailability was more appropriate than the total contents of soil heavy metals. Therefore, bioavailability-based further research and management practices should be carried out continuously for the sustainable environment management, safe crop production, and human health risk reduction.

• Fashion & Textile Research Journal
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• v.8 no.4
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• pp.458-464
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• 2006

The adsorption ability of heavy metal ions from the aqueous solution by chitosan, which it is well known natural biopolymer, has been investigated. The fundamental study in this research is focusing on the physicochemical adsorption utilizing the chitosan as a organic chelating adsorbent, adsorb especially heavy metal ions from the waste liquid solution. The adsorption ability of the chitosan between metal ions, having different characteristics with Mw of 188,600, 297,200, and 504,200 g/mol and degree of deacetylation (DD) of 86.92% and 100% were investigated targeting on the $Ni^{2+}$, $Co^{2+}$, $Zn^{2+}$, and $Pb^{2+}$ ions, respectively. The uptake of heavy metal ions with chitosan was performed by atomic absorption flame emission spectrophotometer (AAS) as conducted residual metal ions. It was found that chitosan has an strong adsorption capacity for some metals under certain conditions. Chitosan, which have 100% degree of deacetylation showed high adsorption recovery ratio and have an affinity for all kinds of heavy metals. In contrast, the molecular weight of chitosan was not completely affected on metal ion adsorption.

• Textile Coloration and Finishing
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• v.17 no.2 s.81
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• pp.10-18
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• 2005

Silk fabrics mordanted with $Fe^{2+},\;Ni^{2+},\;and\;Cu^{2+}$ were dyed with the aqueous extract of Cassia tora L. seed which was known to include water soluble colorant kaempferol, one of flavonol compounds. Kaempferol can react with free radicals and chelate transition metal ions, which is thought to catalyze processes leading to the appearance of free radicals and have antioxidant activity. In relation to the coordinating and chelating mechanism of the ions with the silk protein and kaempferol, reasonable conclusions should be made on the colorant uptake and the water fastness of the fabric. The amount of the colorant on the fabric was in the order of $Fe^{2+}>Ni^{2+}>Cu^{2+}$. In case of dyeing through coordinaiton bonds between transition metal ions and silk protein and colorants, it was thought that the ions with the smaller secondary hydration shell, the higher preference to the atoms of the ligand coordinated, and the suitable bonding stability for the substitution of primarily hydrated water molecules for colorants led to the higher colorant uptake. The water fastnsess of the fabric was in the order of $Fe^{2+}>Cu^{2+}>Ni^{2+}$. It should be reasonable to choose transition metal ions with weak and strong tendency to the ionic and the coordination bond, respectively, to the carboxylate anion of the silk protein. Although further research needs to be done, the conclusions above may be generally applied to the natural dyeing through the coordination bond mechanism between transition metal ions and colorants and substrates.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.2
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• pp.17-26
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• 2014

In this study, the adsorption efficiency of mixed heavy metals from an aqueous solution was examined using bentonite. The physical and chemical properties of bentonite was analyzed via scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR), Further, heavy metal adsorption was characterized using Freundlich and Langmuir equations. Equilibrium adsorption data were fitted well to the Langmuir model for bentonite. The adsorption uptake of heavy metals was high and followed the order $Pb^{2+}$ > $Cu^{2+}$ > $Cd^{2+}$ > $$Zn^{2+}{\sim_=}Ni^{2+}$$. The results also showed that adsorption uptake slightly increased as increasing pH from 6 to 10. The bentonite surface was observed viay SEM and FT-IR; Si-O and Si-O-Al were found to be the main functional groups by FT-IR analysis. From these results, the adsorption mechanisms of heavy metal were not only surface adsorption and ion exchange, but also surface precipitation. Thus, bentonite could be a useful adsorbent for treating heavy metal in aqueous solution.