• Journal of Soil and Groundwater Environment
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• v.20 no.7
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• pp.135-147
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• 2015

Remediation of metal(loid)s-contaminated sites is crucial to protect human and ecosystem. Solidification and stabilization of metal(loid)s by the binder amendment is one of the cost-effective technologies. In this study, metal (loid)s in various field-contaminated soils obtained from steel-making, metal refinery and mining tillage were immobilized by the application of single binders such as diammonium phosphate (DAP), lime, and ladle slag. The efficiency of solidification and stabilization was evaluated by Toxicity Characteristic Leaching Procedure (TCLP) and the Standard, Measurements and Testing programme of European Union (SM&T) extraction processes. In terms of TCLP extraction, the binder was effective in order of lime > DAP > ladle slag. All binders were highly effective in the immobilization of Pb, Zn, Cu, Ni, and Cd. The increased immobilization efficiency is attributed to the increase in the Step III and IV fractions of the SM&T extraction. Lime and ladle slag were highly effective in the immobilization of the metal(loid)s, however, As release increased with DAP due to competition between the phosphate originated from DAP and arsenate. A further study is needed for the better immobilization of multi metal(loid)s using binary binders.

• Journal of Soil and Groundwater Environment
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• v.7 no.4
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• pp.31-39
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• 2002

Pollutants from industry, mining, agriculture, and other sources have contaminated sediments in many surface water bodies. Sediment contamination poses a severe threat to human health and environment because many toxic contaminants that are barely detectable in the water column can accumulate in sediments at much higher levels. The purpose of this study was to make optimal treatment and disposal plan o( sediment for water quality improvement in small-scale resevoir based on an evaluation of degree of contamination. The degree of contamination were investigated for 23 samples of 9 site at different depth of sediment in small-scale J river. Results for analysis of contaminated sediments were observed that copper concentration of 4 samples were higher than the regulation of hazardous waste (3 mg/L) and that of all samples were exceeded soil pollution warning levels for agricultural areas. Lead and mercury concentration of all samples were detected below both regulations. Necessary of sediment dredge was evaluated for organic matter and nutrient through standard levels of Paldang lake and the lower Han river in Korea and Tokyo bay and Yokohama bay in Japan. The degree of contamination for organic matter and nutrient was not serious. Compared standard levels of Japan, America, and Canada for heavy metal, contaminated sediment was concluded as lowest effect level or limit of tolerance level because standard levels of America and Canada was established worst effect of benthic organisms. The optimal treatment method of sediment contained heavy metal was cement-based solidification/stabilization to prevent heavy metal leaching.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.1
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• pp.27-36
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• 2012

Metal chloride waste is generated as a main waste streams in a series of electrolytic processes of a pyrochemical process. Different from carbonate or nitrate salt, metal chloride is not decomposed into oxide and chlorine but it is just vaporized. Also, it has low compatibility with conventional silicate glasses. Our research group adapted the dechlorination approach for the immobilization of waste salt. In this study, the composition of SAP ($SiO_2-Al_2O_3-P_2O_5$) was adjusted to enhance the reactivity and to simplify the solidification process as a subsequent research. The addition of $Fe_2O_3$ into the basic SAP decreased the SAP/Salt ratio in weight from 3 for SAP 1071 to 2.25 for M-SAP( Fe=0.1). The experimental results indicated that the addition of $Fe_2O_3$ increased the reactivity of M-SAP with LiCl-KCl but the reactivity gradually decreased above Fe=0.1. Also, introducing $B_2O_3$ into M-SAP requires no glass binder for the consolidation of reaction products. U-SAP ($SiO_2-Al_2O_3-Fe_2O_3-P_2O_5-B_2O_3$) could effectively dechlorinate the LiCl-KCl waste and its reaction product could be consolidated as a monolithic form without a glass binder. The leaching test result indicated that U-SAP 1071 was more durable than other SAPs wasteform. By using U-SAP, 1 g of waste salt could generated 3~4 g of wasteform for final disposal. The final volume would be about 3~4 times lower than the glass-bonded sodalite. From these results, it could be concluded that the dechlorination approach using U-SAP would be one of prospective methods to manage the volatile waste salt.

• Economic and Environmental Geology
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• v.37 no.1
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• pp.99-106
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• 2004

Pollution reduction and/or control technology becomes one of the pressing post-semiconductor research field to lead an advanced industrial structure. Soil/groundwater remediation techniques may act as a core technology which will create many demands on pollution reduction areas. A plenty numbers of abandoned metal mines were left without any remediation action in Korea, and it may be potential sources of heavy metal and As contamination in the ecosystem. In order to bring this soil contamination to a settlement, the emerging soil/groundwater remediation techniques should be introduced. Main research topics in the United States and Europe move towards the clean remediation technology without any secondary impact and the feasible application of developing technique into the field scale study. With these advantages, several soil/groundwater techniques such as electrokinetic soil processing, permeable reactive barrier, stabilization/solidification, biosorption, soil flushing with biosurfactant, bioleaching and phytoremediation will be summarized in this paper.

• Analytical Science and Technology
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• v.8 no.1
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• pp.91-99
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• 1995

One of alternative conventional technologies used for treatment of livestock wastes is composting process, and recently some mechanical composting processes are being practiced. It is, however, recognized the composting process also has its own limitations such as longer time requirement, and difficulties to estimate the degree of decomposition, etc. The incomplete compost contains potentially harmful materials to crops and public health due to instabilized organic contents and pathogenic organisms. The purpose of this investigation is to develop an innovative system whereby anxious livestock wastes are thoroughly stabilized and disinfected. Thus the overall management scheme should meet the following requirements. 1. A system should be in a cost-effective and environmentally sound manner. 2. Sludges must be chemically stabilized and bacteriologically safe. 3. Odor-free by product should be applied to crop land. 4. Sludges are sources of fertilizer nutrients and/or soil amendments to enhance crop production. 5. And they can be used as potential pH adjusting agent of the acidified soils. Overall effectiveness of the developed system is experimentally tested to satisfy the preset criteria and requirements. Major experiments are divided into four categories: they are 1. chemical stability test, 2. optimal condition test of stabilization process, 3. bacteriological examination and disinfection tests, and 4. deodorization tests The stabilization process is consisted of the stabilizing reaction process and the drying process. Stabilized wastes is dried by both sun dryer and rotary dryer. It is shown that an additive dosage of about g/kg solid in wastes with a minimum of 5-minutes reaction would be necessary for effective stabilization reaction. The stabilization process is consisted of the stabilizing reaction process and drying process. Stabilized wastes are dried by both sun dryer and rotary dryer. It is shown that an additive dosage of about 300g/kg solid in wastes with a minimum of 5-minutes reaction would be necessary for effective stabilization reaction. In the stabilization reaction process, the pH of wastes is lowered from initial values of 12.3 to 8.6. High pH prevents odor production and kills pathogenic organisms. Organic matter contents in the stabilized wastes are about 50% and the sum of contents of fertilizer elements such as total nitrogen, $P_2O_5$ and $K_2O$ are about 5.3%. The livestock wastes that are stabilized chemically and hygienically can be used as a good soil conditioner and/or organic fertilizer.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.1
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• pp.21-26
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• 2002

The behavior of the biological water treatment process on start-up operation was evaluated in the integrated recirculating aquaculture system consisting of a double drain type rearing tank ($2.5 m^3$), a sedimentation tank, a floating bead filter, a foam separator and a rotating biological contactor. A system was stocked with nile tilapia (Oreochromis niloticus) at an initial rearing density of $2\%$ for 2 weeks for acclimated rotating biological contactor. The total ammonia nitrogen (TAN) level increased to $13.6 g/m^3$ on day 4 after adding feed and was decreased to $0.3 g/m^3$ on day 7. The total suspended solid was completely removed during overall experimental period.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.2 s.51
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• pp.141-146
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• 2005

Unstable cosmetic active ingredients could rapidly break down in chemical and photochemical process. Therefore, it has become a very important issue to encapsulate active ingredient for the stabilization. 7-Dehydrocholesterol (7-DHC), a precursor of vitamin $D_3$, has been shown to increase levels of protein and mRNA for heat shock protein in normal human epidermal keratinocytes. However, topical dermal application of 7-DHC is restricted due to its poor solubility and chemical unstability. In this study, 7-DHC was incorporated into nano-emulsion (NE), solid lipid nano-particle (SLN), and chitosan coated solid lipid nano-particle (CASLN), respectively. In order to prepare NE and SLN dispersion, high-pressure homogenization at temperature above the melting point of lipid was used Hydrogenated lecithin and polysorbate 60 were used as stabilizer for NE and SLN. CASLN was prepared by high speed homogenizing after adding chitosan solution to the SLN dispersion and showed positively charged particle properties. Decomposition rate of 7-DHC in NE, SLN and CASLN was studied as a function of time at different temperature. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies were performed to characterize state of lipid modification. It appeared that CASLN is the most effective to stabilize 7-DHC and may be used for a useful topical dermal delivery system.

• Applied Chemistry for Engineering
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• v.25 no.6
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• pp.592-597
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• 2014

The graphite/$SiO_2$ composites as anode materials for lithium-ion batteries were prepared by sol-gel method to improve the graphite's electrochemical characteristics. The prepared graphite/$SiO_2$ composites were analysed by XRD, FE-SEM and EDX. The graphite surface modified by silicon dioxide showed several advantages to stabilize SEI layer. The electrochemical characteristics were investigated for lithium ion battery using graphite/$SiO_2$ as the working electrode and Li metal as the counter electrode. Electrochemical behaviors using organic electrolytes ($LiPF_6$, EC/DMC) were characterized by charge/discharge, cycle, cyclic voltammetry and impedance tests. The lithium ion battery using graphite/$SiO_2$ electrodes had better capacity than that of using graphite electrodes and was able to deliver a discharge capacity with 475 mAh/g at a rate of 0.1 C. Also, the capacity retention ratio of the modified graphite reaches 99% at a rate of 0.8 C.

• Resources Recycling
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• v.20 no.3
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• pp.28-39
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• 2011

This review investigated theoretical principals and practical application examples on recirculation system of soil washing-wastewater treatment-treated water recycling. As for technologies which have attempted to remediating metals-contaminated soil in and around country, there are reactive barriers, encapsulation, solidification/stabilization, soil washing, and phytoremediation. Among those, in particular, this review covers soil washing technology which physicochemically removes contaminants from soils. The major drawbacks of this technology are to generate a large amount of wastewater which contains contaminants complexed with ligands of washing solution and needs additional treatment process. To solve these problems, many chemical treatment methods have been developed as follows: precipitation/coprecipitation, membrane filtration, adsorption treatment, ion exchange, and electrokinetic treatment. In the last part of the review, recent research and field application cases on soil washing wastewater treatment and recycling were introduced. Based on these integrated technologies, it could be achieved to solve the problem of soil washing wastewater and to enhance cost effective process by reducing total water resources use in soil washing process.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.1
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• pp.141-148
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• 2012

The objective of this study is to remove arsenate from artificially contaminated wastewater using CaAl-ettringite and CaAl-monosulfate which were synthesized in laboratory. The study was carried on the basis of solidification/stabilization of waste using cement. Monosulfate and ettringite are constituents of cement paste. The CaAl-ettringite has a chemical formula of $Ca_6Al_2O_6(SO_4)_3{\cdot}32H_2O$ and has a needle like morphology. Whereas CaAl-monosulfate $Ca_4Al_2O_6(SO_4){\cdot}12H_2O$ has layered double hydroxide structure (LDH) in which the mainlayer consists of Ca and Al and S as interlayer. Ettringite and monosulfate were synthesized by reaction of tricalcium aluminate and gypsum and hydrating this mixture at elevated temperature. The synthesized mineral were characterized by PXRD and FESEM to ensure purity. It was found that concentrations of As(V) in contaminated water were reduced from initial concentration of 1.335 mmol/L to 0.054 mmol/L and 0.300 mmol/L by CaAl-monosulfate and CaAl-ettringite respectively. The post experimental results of PXRD and FESEM analysis indicate that arsenate removal was by ion exchange.