• Progress in Superconductivity and Cryogenics
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• v.22 no.2
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• pp.1-6
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• 2020

Large-scale civil engineering works discharge a large amount of soil suspension contaminated with natural heavy metals. Most of the heavy metal ions due to industrial activities and minings are accumulated in the soils and the sediments of lakes and inner bays through the rivers. It is necessary to remove heavy metals from the soils and the sediments, because some of these heavy metals, such as arsenic and cadmium, have significant biological effects even in small amounts. This study proposes a new volume reduction method of the contaminated soils and sediments by superconducting magnetic separation. Our process can remove the specific minute minerals selectively, which adsorbs heavy metals depending on pH. As a fundamental study, the adsorption behaviors of arsenic and cadmium on minute minerals as a function of pH were investigated, and the adsorption mechanism was discussed based on the crystal structure and pH dependence of surface potential in each minute minerals.

• Journal of environmental and Sanitary engineering
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• v.24 no.2
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• pp.31-39
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• 2009

In this research, I carried out the adsorption and removal test of Pb, Ni, Co and Cu ions using organic substances spread out any where in the nature which can be obtained easily from our neighbor-such as Paulownia coreana, Pinus densiflora, Juniperus chinesis, Quercus dentata, Magnolia kobus, Platanus occidentalis, Gingko biloba, Diospyros kaki leaves. As the result of the research to find the best optional condition for the adsorption and removal, shows that the adsorption and removal ratio of Pb ion by a Paulownia coreana raw leaves is 99% at $70^{\circ}C$, those of Ni ion and Co ion by Magnolia kobus formalin treatment leaves are 79% at $70^{\circ}C$, 97% at $40^{\circ}C$ respectively. And that of Cu ion by Platanus occidentalis treatment leaves is 97% at $50^{\circ}C$ in mixed solution. As the result of comparing the removal ratio by raw leaves and formalin treatment leaves, the removal ratio of treatment is 30~90% more effective than raw leaves in most cases. And I concluded Pb > Cu > Co > Ni ion in multiple solution and Co > Ni > Cu >Pb ion in single solution after testing adsorption and removal ratio of mixed solution separately as time goes by. In general, the reactions were completed within first 5 minutes. The test result of measuring the hydrolysable tannin content of each leaf shows that an overcup Quercus dentata is 11.36%, a Diospyros kaki is 10.81% and the rest of them are 2.49~4.12% in raw leaves cases. In treatment leaves cases, an overcup Quercus dentata is 3.23% and the others are less than 1%.

• Journal of the Korean Wood Science and Technology
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• v.28 no.2
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• pp.49-56
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• 2000

This study was designed to investigate the adsorption of heavy metal ions by untreated bark according to the treatment conditions of aqueous solution. The effect of temperature and pH of aqueous solution, particle size of bark, addition of light metal ions on the adsorption was examined, and the competition in adsorption among heavy metal ions was also evaluated. te The adsorption ratio of $Cu^{2+}$ and $Zn^{2+}$ increased with increasing themperature of solution from $-5^{\circ}C$ to $10^{\circ}C$ however, it was relatively constant at temperatures between $10^{\circ}C$ and $55^{\circ}C$. The adsorption ratio of $Cr^{6+}$ increased continuously with increasing the temperature of solution. The maximum adsorption ratio of $Cu^{2+}$, $Zn^{2+}$, and $Pb^{2+}$ was noted at pHs ranged 6 to 7; however, the adsorption ratio declined sharply on either sides of the optimum. The adsorption ratio of $Cr^{6+}$ decreased continuously with increasing the pH of solution. The adsorption ratio increased as decreasing the particle size of bark, and there was little differences in adsorption tendency between pine and oak bark. By the addition of $Ca^{2+}$ or $Mg^{2+}$(10~25 ppm), the adsorption ratio of $Cu^{2+}$ and $Zn^{2+}$ increased. An increase of the adsorption ratio was higher in oak bark than in pine bark. However, the adsorption ratio of $Pb^{2+}$ and $Cr^{6+}$ was not affected by the addition of light metal ions. As the mixed solution of 2 or 3 kinds of heavy metal ions($Cu^{2+}$, $Zn^{2+}$, $Pb^{2+}$) was treated with the untreated bark, the adsorption of $Zn^{2+}$ decreased considerably because of the competitive adsorption among heavy metal ions. Also the adsorption of $Cu^{2+}$ was more and less reduced. However the adsorption of $Pb^{2+}$ was not affected by the presence of other heavy metal ions.

• Membrane Journal
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• v.29 no.3
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• pp.123-129
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• 2019

Environmental pollution caused by the presence of heavy metal ion from growing industrialization or from leaching is increasing area of concern. There are several area of water purifications but among them adsorption on the functionalized polymer fibers is efficient and cost-effective method. Polyacrylonitrile (PAN) is exciting polymer due to the presence of excessive functional group which can be easily transformed for metal ion adsorption. PAN can be easily electrospun to prepare nanofiber that have higher surface area leading to better metal ion removal. Composite PAN fiber is yet another type of polymer covered in this review for waste water treatment.

• Environmental Engineering Research
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• v.19 no.1
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• pp.15-22
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• 2014

In this study, the performances of various adsorbents-red mud, zeolite, limestone, and oyster shell-were investigated for the adsorption of multi-metal ions ($Cr^{3+}$, $Ni^{2+}$, $Cu^{2+}$, $Zn^{2+}$, $As^{3+}$, $Cd^{2+}$, and $Pb^{2+}$) from aqueous solutions. The result of scanning electron microscopy analyses indicated that the some metal ions were adsorbed onto the surface of the media. Moreover, Fourier transform infrared spectroscopy analysis showed that the Si(Al)-O bond (red mud and zeolite) and C-O bond (limestone and oyster shell) might be involved in heavy metal adsorption. The changes in the pH of the aqueous solutions upon applying adsorbents were investigated and the adsorption kinetics of the metal ions on different adsorbents were simulated by pseudo-first-order and pseudo-second-order models. The sorption process was relatively fast and equilibrium was reached after about 60 min of contact (except for $As^{3+}$). From the maximum capacity of the adsorption kinetic model, the removal of $Pb^{2+}$ and $Cu^{2+}$ were higher than for the other metal ions. Meanwhile, the reaction rate constants ($k_{1,2}$) indicated the slowest sorption in $As^{3+}$. The adsorption mechanisms of heavy metal ions were not only surface adsorption and ion exchange, but also surface precipitation. Based on the metal ions' adsorption efficiencies, red mud was found to be the most efficient of all the tested adsorbents. In addition, impurities in seawater did not lead to a significant decrease in the adsorption performance. It is concluded that red mud is a more economic high-performance alternative than the other tested adsorption materials for applying a removal of multi-metal in seawater.

• Journal of the Korean Ceramic Society
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• v.46 no.6
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• pp.668-672
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• 2009

Heavy metal ion immobilization properties of microporous ettringite (3Ca$O{\cdot}Al_2O_3{\cdot}3CaSO_4{\cdot}32H_2$) body were examined using standard solutions of typical heavy metals. Microporous Ettringite body with desirable shape for an ionic adsorbent was obtained by the self hardening of the paste prepared from the mixture of tricalcium aluminate($C_3$A) and gypsum(CaS$O_4{\cdot}2H_2$O). Crushed grains of ettringite were soaked in each standard solutions of Pb, Co, Cd, Mn and Cr concentrated at 200 ppm. In order to evaluate the ionexchange and immobilization ability, the ionic concentration of the filtrate solution as well as the solution obtained after leaching test was measured. As a result, for the heavy metal ions excepting Cr, porous ettringite body was revealed to be excellent in ionic exchange and immobilization properties though some ions eluted at the severe condition of pH 2. The adsorption and keeping capacity for four heavy metals showed the order of $Pb{>}Co{>}Cd{>}$Mn.

• Journal of Korean Society on Water Environment
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• v.23 no.3
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• pp.314-318
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• 2007

The feasibility of the employment of waste oyster shell as an adsorbent for fluoride ion has been tested by considering the effect ionic condition on the adsorption of fluoride ion on oyster shell. The adsorption capacity of oyster shell for fluoride ion was found not to be significantly influenced by the ionic strength of aqueous environment. The existence of complexing agent such as nitrilotriacetic acid in wastewater decreased the adsorbed amount of fluoride ion by forming a stable complex of $CaT^-$ and the adsorption reaction of fluoride ion on oyster shell was examined to be endothermic. The coexisting heavy metal ionic adsorbate in wastewater hindered the adsorption of fluoride ion, however, its adsorbed amount was increased as the particulate size of adsorbent was decreased. Finally, a serial adsorption column test has been conducted for a practical application of adsorption process and the breakthrough of the column adsorption was observed in 22 hours under the experimental condition.

• Journal of the Korean Wood Science and Technology
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• v.28 no.2
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• pp.75-79
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• 2000

To improve the adsorption of heavy metal ions in aqueous solutions. sawdust and bark of pine (Pinus densiflora) and oak(Quercus accutisima) were phosphorylated. The phosphorylated sawdust and bark contained phosphorous of 1.2~1.3% in the treatment for 1 hr and 1.4~1.7% for 2 hrs regardless of species and tree segments. The sawdust indicated considerable increase in the adsorption ratio of $Cu^{2+}$, $Zn^{2+}$ and $Cd^{2+}$, however the adsorption of $Pb^{2+}$ was a little increased. The pine sawdust was more effective in the adsorption of heavy metal ions than that of oak. While the bark indicated little adsorption efficiency of heavy metal ions.

• Journal of the Korean Society of Clothing and Textiles
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• v.12 no.1 s.26
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• pp.27-35
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• 1988

In order to investigate a practical application of the fibrous adsorbent to heavy metal ions, acrylic fibers were treated with the hydroxylamine solution that was producted by hydroxylamine hydrochloride and potasium hydroxide in a condition of strong alkaline and $70^{\circ}C$. The adsorption mechanism of copper(2) ion on the fibrous adsorbent, that is hydroxylaminated acrylic fibers, was studied. The adsorption of copper(2) ion was explained in terms of the activated adsorption that are formed the complex with the ligand, such as C=N, N-H, NHOH, on the surface of the adsorbent. The activation energy was evaluated to be 3.8 Kcal/mol. and the times of adsorption equilibrium was approximately 10 minutes. The uptake of copper(2) ion was found to be effected with the increase of temperatures and the pH dependence.

• Journal of Environmental Science International
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• v.20 no.10
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• pp.1337-1345
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• 2011

The removal performances of divalent heavy metal ions ($Pb^{2+}$, $Cu^{2+}$, $Cd^{2+}$, $Sr^{2+}$ and $Mn^{2+}$) were studied using the Na-P1 zeolite synthesized from Jeju scoria in the batch and continuous fixed column reactor. The uptakes of heavy metal ions by synthetic Na-P1 zeolite decreased in the order of $Pb^{2+}$ > $Cu2^{2+}$ > $Cd^{2+}$ > $Sr^{2+}$ > $Mn^{2+}$ based on the selectivity of each ion to ionic exchange site of Na-P1 zeolite for single and mixed solutions in batch or continuous fixed column reactor. For mixed solution, each heavy metal ion uptake was lower than that in single solution, and especially the uptake for $Mn^{2+}$ decreased greatly. In batch reactor, the uptakes of heavy metal ions by synthetic Na-P1 zeolite were described by Freundlich or Langmuir equation, but they followed the former better than the latter. In continuous fixed column reactor, the maximum ion exchange capacity obtained for each of heavy metal ions, was about 90----- of that in batch reactor. The uptakes of heavy metal ions by synthetic Na-P1 zeolite increased with the increase of initial heavy metal concentration and solution pH, and the decrease of the amount and particle size of synthetic zeolite.