• Applied Chemistry for Engineering
• /
• v.31 no.4
• /
• pp.438-442
• /
• 2020

Studies on the recovery conditions and optimization process for valuable metal recovery through chemical treatment from detoxified asbestos-containing waste composed of calcium silicate, larnite, merwinite, and akermanite were conducted. The main components, Si, Ca, and Mg, of detoxified asbestos-containing waste (DACW) were separated and recovered in the form of SiO₂, CaSO₄, and Mg(OH)₂ compounds, respectively. Each separated component was confirmed through X-ray diffraction (XRD) and inductively coupled plasma spectrometer (ICP) analysis. The recovery conditions for each component were first treating them with an acid to separate SiO₂ and subsequently with H₂SO₄ to recover Ca in the form of sulfate, CaSO₄. The remaining Mg was recovered by precipitation with Mg(OH)₂ under strong basic conditions. This study suggested that it is possible to convert existing treatment process of asbestos waste by landfill through recovering the components into a resource-recycling green technology.

• KSBB Journal
• /
• v.20 no.3
• /
• pp.142-148
• /
• 2005

Succinic acid is an important material in industries producing biodegradable polymers, food and pharmaceutical products, and green solvents. Furthermore, succinate fermentation is a novel process due to the fixation of $CO_2$ into succinate during fermentation. However, the impurities in fermentation broth make the separation process of succinic acid be difficult. Reactive extraction has been proposed to be an effective primary separation step of succinic acid from dilute fermentation broth. This article presents the principles of reactive extraction along with the characteristics of tertiary amino extractants. A brief overview on the current research on reactive extraction of succinic acid is presented. Finally, for the succinic acid separation, reactive extraction as a primary step is suggested in the whole downstream process for succinic acid from fermentation broth.

• KSBB Journal
• /
• v.14 no.3
• /
• pp.358-364
• /
• 1999

The effect of hydrogen peroxide on pretreatment of oakwood was investigated. Reaction temperature was $170^{\circ}C$ and reaction solutions used in pretreatment were aqueous ammonia, sulfuric acid and pure water. When 10% ammonia solution was used, the extents of delignification and hemicellulose recovery were 55% and 26%, respectively. These values were significantly higher as delinigfication and lower as hemicellulose recovery than those of acid hydrolysis. To overcome this problem, hydrogen peroxide was added into ammonia solution stream to increase hemicellulose recovery. But delignification and hemicellulose recovery were not increased as much as hydrogen peroxide loading was increased. And as hydrogen peroxide loading was increased, the decomposition of sugars solubilized from hemicellulose and cellulose were increased. So there were significant differences between the total amount in solid residue and liquid hydrolyzate, and the total amount in the original biomass. It was found that hydrogen peroxide added was reacted with substrate packed mostly in the front part of reactor. In order to increase hemicellulose recovery, it was necessary to treat with acidic solution than with alkali solution. Effect of hydrogen peroxide was higher in water than acid solution.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2003.11a
• /
• pp.632-635
• /
• 2003

For the disposal of low-level radwaste from nuclear power plant need the determination of levels of radio nuclides in radwaste. These nuclides include the difficult-to-measure nuclides, so indirect methodology for the determination of the difficult-to-measure nuclides have to be developed. In this work, for the determination of $^129I(t_{1/2}=1.57{\times}10^7 years)$ in low-level radwaste from nuclear power plant is investigated. Recovery of Iodide in simulated waste($UO_2$ pellet) as a soluble and radwaste(resin, woolen fabric)as a insoluble samples are measured. After pretreatment of sample, $I_2$ are extracted from aqueous solution with $CCl_4$. Then I are extracted from $CCl_4$ with 0.1M $NaHSO_3$ aqueous solution. iodide in aqueous solution are determined by ion chromatography. The overall recovery yield is 76.7 (RSD 1.7%) for mixed-acid digestion method. Incase of woolen fabrics, overall recovery yield is 74.3 (RSD 2.2%) and recovery of iodide in resin 56.5(RSD 5.6%) for alkaline fusion method.

• Resources Recycling
• /
• v.31 no.6
• /
• pp.18-24
• /
• 2022

Dry reduction using natural gas was proposed to recover tin from waste tin oxide generated in a tin bath that was used for controlling the smoothness of architectural glass during production, and the reduction behavior was investigated. The utilized vertical natural gas dry reduction system is capable to process 4 L or 20 kg depending on input raw materials. The system was established by applying the upper intake and lower discharge method. The recovery rate was 97.2% at 800 ℃ and 4 sccm flow rate and increased with the amount of input gas. Hydrogen accounted for 23% of the discharge gas, showing a 16.6% hydrogen conversion rate. The reaction behavior of tin recovered via natural gas reduction provides basic data on the new waste resource reduction/recovery technology.

• KSBB Journal
• /
• v.11 no.1
• /
• pp.15-21
• /
• 1996

Purification of hyaluronic acid produced by Streptococcus equi was carried out to obtain clinical grade hyaluronic acid. The removal method of the bacteria was selected as filtration because filtration was the most effective method in removing impurities such as protein and nucleic acid of the fermentation broth. The removal efficiencies of protein and nucleic acid of hyaluronic acid solution were increased to 75% and 67%, respectively, by filtration with adding 0.6% of activatied carbon and 1.0% colite. Hyaluronic acid solution was precipitated by mixing with 2 volumes of ethanol. Effects of pH and conductivity on ethanol preciptation of hyaluronic acid were investigated. Protein and nucleic acid of hyaluronic acid were remained almost constant regardless of pH and conductivity, and the recovery of hyaluronic acid was optimum as about 85% at pH 7 and l00mS of conductivity Protein of hyaluronic acid was completly removed by three serial filtration and ethanol precipitation, however, nucleic acid was not removed. Hyaluronic acid solution was passed through a column of Duolite A7 to remove its nucleic acid, where 65% of nucleic acid was removed at pH 7 and 40mS of conductivity. The residual nucleic acid of hyaluronic acid solution was completly removed by treatment of 0.2% hydroxyapatite and the clinical grade hylauronic acid could be obtained.

• Korean Journal of Food Science and Technology
• /
• v.22 no.5
• /
• pp.520-525
• /
• 1990

A modified method of urea adduct formation, in which water and organic solvent were used as the wetting agent and the reaction medium. respectively, is suggested to obviate methanolysis and to ease recovery in the separation of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish oil. With the new method the fraction in which the total content of EPA. DHA and their precursors is more than 80% could be obtained. Although the total content of precursors in the concentrate was hardly affected by the kind of the wetting agent or the organic solvent, the content of EPA and DHA varied significantly depending on the organic solvent. This finding made it possible to selectively enrich the desired components. After DHA-enriched fraction (I)HA is 50%) was obtained by using pentane, EPA-enriched fraction ( EPA is 53%)) could be obtained from the residue of DHA-enriched fraction by using heptane.

• KSBB Journal
• /
• v.10 no.1
• /
• pp.1-8
• /
• 1995

A lot of water soluble proteins and lipids are released from minced mackerel meat and lost into the washing waste during the leaching process of Kamaboko or surimi manufacture. The removed proteins and lipids are not only an edible things but also a big burden for treating the wastewater. In order to recover the proteins from the effluent and to use as food stuff, the "pH-shifting" treatment, a modified isoelectric point precipitation method, was tried. This method is based on a myogen-aggregation phenomenon, which occurs when a solution of sarcoplasmic proteins is acidified or alkalified beyond the critical pH zone of 2∼3 or 12∼13 respectively and then neutralized. The maximum amount of precipitation was obtained by shifting the pH of the wastewater from original pH to isoelectric point (pH 4) or alkali pH 12 and then changing to neutral pH. The precipitates were easily collected by filteration or centrifuging at 10,000rpm. The oils which were only floating in the washing wastewater are easily recovered by seperating with oil separator after pouring. The recovered proteins were slightly denaturated during this pH shifting precipitation process, while the composition of amino acids was good balance as a food.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.28 no.2
• /
• pp.157-162
• /
• 1995

When fish meat is washed for the processing of surimi, about 50ff of lipid in the fish meat is removed from the fish meat to the effluent. The removed lipid was easily recovered by centrifugation or filteration of wastewater washed fish meat. Then, the recovered lipid was utilized as a material of mayonnaise sauce processing. The major fatty acids in the recovered lipids are $C_{16:0},\;C_{18:0},\;C_{16:1},\;C_{20:5},\;and\;C_{22:6}$ Polyenoic fatty acids were composed of $33.6\%$ to total fatty acids. When the recovered lipid was substituted for soybean oil in processing of mayonnaise sauce, the maximum percentage of substitution ratio presumed to be $30\%$ according to viscosity, color difference, and emulsion stability evalution for the substituted ones.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.36 no.2
• /
• pp.80-87
• /
• 2003

Recovery conditions and characteristics of a high molecular soluble protein from surimi processing wastewater in marine manufacture using calcium powder of cuttle bone treated with acetic acid (ATC) were examined. Judging from results of total-N, pH, COD, turbidity and yields, optimal treatment concentration of ATC for recovery of high molecular soluble proteins from wastewater was $1.0\%.$ The protein recovered from seafood waste (PRW) was macromolecule weight. The COD value in the wastewater treated with ATC was very high. The PRW had a $78.4\%$ in moisture, $1.0\%$ in crude lipid and $5.7\%$ in crude ash. The proximate composition, except the crude ash, of the PRW was similar to that of commercial surimi. The PRW showed white index and similar in the content and in the composition of total amino acid to those of commercial surimi. From the results of sensory evaluation on white index and texture, the heat-induced surimi gel prepared with $5\%$ subsititution of the PRW for bulking agent of commercial surimi was not significantly different compared to that prepared with the original commercial surimi.