• Journal of the Korea Institute of Building Construction
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• v.17 no.6
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• pp.483-492
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• 2017

Recently, the coastal area has become the popular place for infrastructure development. To provide a beautiful scenary of costal area to nearby facilities without any hinderance, and also to protect those facilities from the sea water overflow, it is necessary to develop a new type of wave dissipating block, which is a turning wave block. It is noticeable that the top of the turning wave block is flat and thus can provide spaces for various purposes. However, the unit weight of the block decreases due to the presence of pipeline that is installed for turning the direction of the waves. In order to mitigate such problem, a heavyweight concrete needs to be used to increase the resistance against tidal waves. The copper slag and magnetite were used as a source of fine and coarse aggregate, respectively. The 28 day compressive strength of concrete incorporating ordinary and heavyweight aggregate did not show significant differences. It should be noted that the chloride ion penetration resistance was evaluated using NT-BUILD 492 rather than ASTM C 1202 method because concrete incorporating magnetite as a coarse aggregate showed excessive current flow by ASTM C 1202 method. According to the results from NT Build 492 method, which uses the penetration depth of chlorine ions to obtain chloride ion diffusivity, the heavyweight concrete incorporating the copper slag and the magnetite showed the best resistance against the chloride ion penetration. Therefore, it is reasonable to say that heavyweight concrete made with copper slag and magnetite can be used for production of turning wave block.

• Journal of the Korean Chemical Society
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• v.56 no.5
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• pp.539-541
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• 2012

• Advances in concrete construction
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• v.2 no.2
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• pp.109-123
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• 2014

This paper presents chloride induced corrosion durability of reinforcing steel in geopolymer concretes containing different contents of sodium silicate ($Na_2SiO_3$) and molarities of NaOH solutions. Seven series of mixes are considered in this study. The first series is ordinary Portland cement (OPC) concrete and is considered as the control mix. The rest six series are geopolymer concretes containing 14 and 16 molar NaOH and $Na_2SiO_3$ to NaOH ratios of 2.5, 3.0 and 3.5. In each series three lollypop specimens of 100 mm in diameter and 200 mm in length, each having one 12 mm diameter steel bar are considered for chloride induced corrosion study. The specimens are subjected to cyclic wetting and drying regime for two months. In wet cycle the specimens are immersed in water containing 3.5% (by wt.) NaCl salt for 4 days, while in dry cycle the specimens are placed in open air for three days. The corrosion activity is monitored by measuring the copper/copper sulphate ($Cu/CuSO_4$) half-cell potential according to ASTM C-876. The chloride penetration depth and sorptivity of all seven concretes are also measured. Results show that the geopolymer concretes exhibited better corrosion resistance than OPC concrete. The higher the amount of $Na_2SiO_3$ and higher the concentration of NaOH solutions the better the corrosion resistance of geopolymer concrete is. Similar behaviour is also observed in sorptivity and chloride penetration depth measurements. Generally, the geopolymer concretes exhibited lower sorptivity and chloride penetration depth than that of OPC concrete. Correlation between the sorptivity and the chloride penetration of geopolymer concretes is established. Correlations are also established between 28 days compressive strength and sorptivity and between 28 days compressive strength and chloride penetration of geopolymer concretes.

• Membrane and Water Treatment
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• v.11 no.3
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• pp.201-206
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• 2020

Electrodialysis (ED) is used in wastewater treatment, during the processing and recovery of beneficial materials, to produce usable water. In this study, sulfate and chlorine ions, which are the anions majorly used for electroplating, were studied as factors affecting the recovery of copper, nickel and water from wastewater by electrodialysis. Although the removal rates of copper and nickel ions were slightly higher with the use of chlorine ions than of sulfate ions, the removal efficiencies were above 99.9% under all experimental conditions. The metal ions of the plating wastewater flowed through the ion exchange membrane of the diluate tank and the concentrate tank while all the water moved together due to electro-osmosis. The migration of water from the diluate tank to the concentrate tank was higher in the presence of a monovalent chloride ion compared to that of a divalent sulfate ion. When sulfate was the anion used, the recoveries of copper and nickel increased by about 25% and 30%, respectively, as compared to the chloride ion. Therefore, when divalent ions such as sulfate are present in the electrodialysis, it is possible to reduce the movement amount of water and highly concentrate the copper and nickel in the plating wastewater.

• Resources Recycling
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• v.12 no.2
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• pp.3-10
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• 2003

Copper oxychloride used as an agricultural fungicide has been recovered from copper-containing waste etchant by the neutralization with alkali hydroxides. Large amount of copper-containing waste etchant is generated from Printed Circuit Board industry. In an environmental and economic point of view, retrieve of the valuable natural resource from the waste is important. Recycling process of copper oxychloride from the waste etchant is discovered through the our study. In the range of reaction temp. 2$0^{\circ}C$-4$0^{\circ}C$, pH 5-7, pure copper oxychloride was able to prepare and the yield of copper oxychloride was higher than 95%. Physical properties of the sample have been characterized using SEM, XRD, TGA, ICP and Atomic absorption spectroscopy.

• Journal of the Korean Electrochemical Society
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• v.13 no.4
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• pp.270-276
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• 2010

Nickel-copper foam electrodes with pore gradient micro framework and nano-ramified wall have been prepared by using an electrochemical deposition process. Growth habit of nickel-copper co-deposits was quite different from that of pure nickel deposit. In particular, the ramified structure of the individual particles was getting clear with chloride ion content in the electrolyte. The ratio of nickel to copper in the deposits decreased with the distance away from the substrate and the more chloride ions in the electrolyte led to the more nickel content throughout the deposits. Compositional analysis for the cross section of a ramified branch, together with tactical selective copper etching, proved that the copper content increased with approaching central region of the cross section. Such a composition gradient actually disappeared after heat treatment. It is anticipated that the pore gradient nickel-copper nanostructured foams presented in this work might be a promising option for the high-performance electrode in functional electrochemical devices.

• Bulletin of the Korean Chemical Society
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• v.29 no.9
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• pp.1711-1716
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• 2008

The reaction of copper(II) chloride with phenyl-N-[(pyridine-2-yl)methylene]methaneamide (ppmma) leads to a new $\mu$ -chloro bridged dimeric [Cu(ppmma)$Cl_2$]$_2$ complex, whereas a reaction of copper(II) bromide with ppmma affords a monomeric Cu(ppmma)$Br_2$ complex. Both complexes have been characterized by X-ray crystallography and electronic absorption spectroscopy. The crystal structural analysis of [Cu(ppmma)$Cl_2$]$_2$ shows that the two Cu(II) atoms are bridged by two chloride ligands, forming a dimeric copper(II) complex and the copper ion has a distorted square-pyramidal geometry ($\tau$ = 0.2). The dimer units are held through a strong intermolecular $\pi-\pi$ interactions between the nearest benzyl rings. On the other hand, Cu(ppmma)Br2 displayed a distorted square planar geometry with two types of strong intermolecular π-π interaction. EPR spectrum of [Cu(ppmma)$Cl_2$]$_2$ in frozen glas s at 77 K revealed an equilibrium between the mononuclear and binuclear species. The magnetic susceptibilities data of [Cu(ppmma)$Cl_2$]$_2$ and Cu(ppmma)$Br_2$ follow the Curie-Weiss law. No significant intermolecular magnetic interactions were examined in both complexes, and magnetic exchange interactions are discussed on the basis of the structural features.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.2
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• pp.80-83
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• 2002

The effect of chloride content on the corrosion of reinforced bar in concrete was studied. The mixing ratio of the concrete was 1 : 1.78 : 5.35 : 4.73 (water : content : ballast : sand). The studied chloride content was in the range of 0∼3.5 wt%. The corrosion potentials were measured in every week for two years. The copper-copper sulfate electrode (CSE) was employed as a reference electrode. After two years, the corroded structure was examined and compared to measured corrosion potential. Any visible difference was founded in the specimen located indoor and outdoor. The chloride concentration enhanced rusting and reinforced bar, shifting the potential to active range. The results showed good argument with Van daveer criteria. In 3.5 wt% chloride, the potential shifted belong -350 mV after 58week. Specimen in 1.75 wt% chloride, showed the potential between -200 mV∼-350 mV. However those in free chloride solution maintained above -200 mV for the studied period. It can the concluded that the chloride enhanced corrosion of rebar in concrete and the electrochemical potential can be a promising corrosion monitoring technique.

• Resources Recycling
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• v.11 no.6
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• pp.12-17
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• 2002

Solvent extraction experiments have been performed to separate copper from $CuCl_2$-$NiCl_2$-$CoCl_2$$ solutions using Alamine336 and LIX84. The complex formation tendency between metal ions and chloride ion had a great effect on the distribution coefficients of Cu, Co and Ni ions and separation factor of Cu to Co and Ni. In the experimental ranges of chloride ion concentration from 0.5 to 4.0 M, LIX84 was superior to Alamine336 in separating copper from cobalt. When the volume percentage of LIX84 and Alamine336 was varied from 5 to 40%, LIX84 was more effective than Alamine336 in separating Cu from Co and Ni in solutions in which the chloride ion concentration was 1.0 M.

• Proceedings of the Materials Research Society of Korea Conference
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• 2000.11a
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• pp.79-79
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• 2000