• Resources Recycling
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• v.12 no.1
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• pp.18-24
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• 2003

Reusing of electroless Ni-Cu-B waste solution was investigated in the plating time, plating rate, solution composition and deposit. Plating time of nickel-catalytic surface took longer than that of zincated-catalytic surface. Initial solution with 40% waste solution additive at batch type was possible to reusing of waste solution. Plating time of initial solution at continuous type took longer 6 times over than that of batch type. Plating time of 40% waste solution additive at continuous type took longer 2 times over than that of batch type. Component change of nickel-copper for electroless deposition was greatly affected by deposited inferiority and larger decreased plating rate.

• Resources Recycling
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• v.4 no.3
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• pp.19-25
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• 1995

A Study on the recovery of the valuable metals(Vanadium Molybdenium) was carried out using spent catalysts originated from desulfurizing process of oil refinery. Experiments consisted of pre-roasting for Sulfur and Carbon removal, soda roasting and leaching for the extraction of valuable metals, and selective precipitation of Vanadium and Molybdenium. Effects of temperature and time in roasting for Sulfur removal, of $Na_2CO_3$ concentrations in soda roasting, and of pulp density, temperature and time in leaching were investigated for the recovery of Vanadium and Molybdenium. A optimum condition having over 85% in yield of Vanadium and Molybdenium was found. In the selective precipitation, more than 98% of Vanadium and Molybdenium were obtained by the variation of pH and concentration of additives.

• Journal of Urban Science
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• v.11 no.1
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• pp.29-35
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• 2022

Waste to Energy Plant were recognized as hateful facilities, and there were many conflicts in the location due to social problems such as the NIMBY phenomenon due to problems such as damage to property in the surrounding area, odor, and image loss. Problems such as air pollution and odor are solved by the development of advanced prevention facilities such as electric dust collectors, wet cleaning systems, semi-dry reaction towers, bag filters, and catalyst towers (SCR: Selective Catalytic Reduction), and air recycling facilities in waste storage tanks. However, it is being avoided because of the perception that it is an incinerator. To resolve these conflicts, the government installs and operates resident convenience facilities to compensate residents near resource recovery facilities, provides green space and improves the environment, and supports heating expenses in accordance with the 「Waste Treatment Facility Support Act」. The purpose of this study is to derive implications through the analysis of domestic and overseas case studies for resident convenience facilities and environment improvement for the promotion of local communities in resource recovery facilities and use them as basic data for community promotion and environmental improvement when installing resource recovery facilities in the future.

• Resources Recycling
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• v.11 no.2
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• pp.3-13
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• 2002

The characteristics of cyanide decomposition in aqueous phase by hydrogen peroxide have been explored in an effort to develop a process to recycle waste water. The self-decomposition of $H_2O$$_2$at pH 10 or below was minimal even in 90 min., with keeping about 90% of $H_2O$$_2$undissociated. On the contrary, at pH 12 only 9% of it remained during the same time. In the presence of copper catalyst at 5 g Cu/L, complete decomposition of $H_2$O$_2$was accomplished at pH 12 even in a shorter time of 40 min. The volatility of free cyanide was decisively dependent on the solution pH: the majority of free cyanide was volatilized at pH 8 or below, however, only 10% of it was volatilized at pH 10 or above. In non-catalytic cyanide decomposition, the free cyanide removal was incomplete in 300 min. even in an excessive addition of $H_2$$O_2$at a $H_2$$O_2$/CN molar ratio of 4, with leaving behind about 8% of free cyanide. On the other hand, in the presence of copper catalyst at a Cu/CN molar ratio of 0.2, the free cyanide was mostly decomposed in only 16 min. at a reducedH202/CN molar ratio of 2. Ihe efnciency of HBO2 in cyanide decomposition decreased with increasing addition of H2O2 since the seu-decomposition rate of $H_2$$O_2$increased. At the optimum $H_2$$O_2$/mo1ar ratio 0.2 of and Cu/CN molar ratio of 0.05, the free cyanide could be completely decomposed in 70 min., having a self-decomposition rate of 22 mM/min and a H$_2$$O_2$ efficiency of 57%.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2349-2356
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• 2014

The recycling technology by the catalytic conversion is one of the most promising techniques for the $CO_2$ treatment of coal burning power plant flue gases. The conversion of $CO_2$ to valuable product of $CH_4$ can be used as a fuel to run the turbine for electricity generation. Through this technique, the amount of coal needed for the combustion in a gas turbine can be reduced as well as $CO_2$ emissions. Therefore, a series of catalysts based on cerium oxide doped with copper, nickel and manganese were prepared by impregnation method. From the characterization analysis, it showed that the prepared catalysts calcined at $400^{\circ}C$ were amorphous in structure with small particle size in the range below 100 nm. Meanwhile, the catalyst particles were aggregated and agglomerated with higher surface area of $286.70m^2g^{-1}$. By increasing the calcination temperature of catalysts to $1000^{\circ}C$, the particle sizes were getting bigger (> 100 nm) and having moderate crystallinity with lower surface area ($67.90m^2g^{-1}$). From the catalytic testing among all the prepared catalysts, Mn/Ce-75/$Al_2O_3$ calcined at $400^{\circ}C$ was assigned as the most potential catalyst which gave 49.05% and 56.79% $CO_2$ conversion at reaction temperature of $100^{\circ}C$ and $200^{\circ}C$, respectively.

• Applied Chemistry for Engineering
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• v.18 no.4
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• pp.303-313
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• 2007

Various commercial catalysts used in chemical related applications have been disposed as an industrial waste when the catalytic activity of catalysts is not good enough to achieve an optimum yield. In addition, the amount of disposed three way catalysts (TWC) has been continuously increased. Considering the physicochemical, environmental, and economical characteristics, the deactivated spent catalysts can be treated in several alternative ways such as regeneration, recycling, and disposal. In view of the environmental and economical matters, the spent catalyst should be regenerated and used for the various purposes, although its activity is not as good as a fresh catalyst. On the other hand, spent catalysts containing noble and metal oxides can be applicable for the catalytic oxidation of volatile organic compounds (VOCs) by applying the proper treatment method. Therefore in this review the quantity of the spent catalysts and the available regeneration methods for the spent catalysts are briefly summarized and especially the proper regeneration method for applying the catalytic oxidation of VOCs and its results are introduced.

• Applied Chemistry for Engineering
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• v.27 no.6
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• pp.555-564
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• 2016

In recent years, methanol has attracted much attention since it can be cleanly manufactured by the combined use of atmospheric $CO_2$ recycling and water splitting via renewable energy. For the concept of "methanol economy", an active methanol synthesis catalyst should be prepared in a sophisticated manner rather than by empirical optimization approach. Even though Cu/ZnO-based catalysts prepared by coprecipitation are well known and have been extensively investigated even for a century, fundamental understanding on the precipitation chemistry and catalyst nanostructure has recently been achieved due to complexity of the necessary preparation steps such as precipitation, ageing, filtering, washing, drying, calcination and reduction. Herein we review the recent reports regarding the effects of various synthesis variables in each step on the physicochemical properties of materials in precursor, calcined and reduced states. The relationship between these characteristics and the catalytic performance will also be discussed because many variables in each step strongly influence the final catalytic activity, called "chemical memory". All discussion focuses on how to prepare a highly active Cu/ZnO-based catalyst for methanol synthesis. Furthermore, the preparation strategy we deliver here would be utilized for designing other coprecipitation-derived supported metal or metal oxide catalysts.

• Journal of the Korean Ceramic Society
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• v.38 no.12
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• pp.1162-1166
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• 2001

NiZn-ferrite was synthesized from waste catalysts, which were produced from styrene monomer process and buried underground as an industrial wastes, and its magnetic properties were investigated. Nickel oxide and zinc oxide powders were mixed with finely ground waste catalysts, and spinel type ferrite was obtained by calcination at 900$\^{C}$ and sintering at 1230$\^{C}$ for 5 hours. The intial permeability was measured and reflection loss was calculated from S-parameters for the composition of Ni$\_$x/Zn$\_$1-x/Fe$_2$O$_4$(x=0.36, 0.50, 0.66). NiZn-ferrite synthesized from waste iron oxide catalyst showed a feasibility for the use as electromagnetic wave absorber in X-band.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.10a
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• pp.39-41
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• 2011

The recycling rate of recovered paper in Korea is the highest in the world, 92%, but remanufacturing yield is low due to the extremely poor quality of the paper. The poor quality, in turn, influences to the reject amount in deinking process. To increase the yield of old newspaper recycling process, hydrophobic degree of inorganic pigments of deinking stock must be reduced. To determine the hydrophobicity, Pitch Potential Deposit Tester (PDT) was newly designed and applied with respect to the SB latex property of various quality used in Korea; its hydrophobic degree according to Tg, gel content, charge and particle size of latex and optimum designing condition of SB latex. And below are the conclusions: 1. The reason of excessive reject from old newspaper deinking process for total amount of printed ink is loss of inorganic pigments. When lipase, a biochemical catalyst, was applied with the purpose of preventing inorganic pigments loss about more than 70% of total reject weight and promoting hydration of pulp for deinking, deinking process yield of pre flotation secondary stage increased remarkably without any changes of deinking efficiency. 2. Lipase improved deinking stock by cutting ester linkage on surface of hydrophobic materials to promote its hydration. From this, it reached the conclusion that hydration degree of stock exercises significant effect on flotation deinking process yield. 3. Inorganic alkali promotes hydration of deinking stock. But there have been needs for more fundamental measures other than inorganic alkali of promoting hydration for yield improvement. For this, this study intended to find out reasons of chemical properties change on surface of hydrophobic material by change of pH. 4. Pitch Deposit Test (PDT) was performed for understanding principle of why surface of coating flake from OMG is hydrophobic and why it becomes hydrophilic when pH of stock is alkaline. As a result of this test, it is determined that swelling property by change of pH of latex film, which were used as coating adhesive is the reason for hydrophobic change. 5. Hydrophilicity of coating flake increased with hydrophilic pigments. And as more of SB Latex adhesive was used and higher of calcium hardness of stock became, its hydrophilicity decreased. SB Latex adhesive film is reformed by mechanical friction. For having hydrophilicity under neutral pH, strong bruising action such as kneading is required. 6. Because swelling of adhesive film decreases as Tg of SB latex gets lower and mean diameter gets smaller, it shows hydrophobicity under neutral pH. This lowers hydrophilicity of coating flake, which leads to easy elimination with flotation reject on DIP process. Therefore, for improving future flotation yield, it is necessary to develop to use eco-friendly clean SB latex by raising Tg and increasing mean diameter for recycling, and as a result, to reduce excessive loss of coating flake as a reject from deinking process.

• Journal of the Korean Chemical Society
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• v.54 no.1
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• pp.55-58
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• 2010

Aliphatic and aromatic nitro compounds were selectively reduced to their corresponding amino derivatives in good yields using formic acid and CeY zeolite under monomode reactor. This system is found to be compatible with several sensitive functionalities. Beside the recycling result showed it had a long catalyst lifetime and could maintain activity even after being used for 20 cycles.