• Mass Spectrometry Letters
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• v.5 no.1
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• pp.30-33
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• 2014

A solid phase extraction (SPE) method was optimized for the quantitative analysis of perfluorooctanoic acid (PFOA) in serum using hydrophilic-lipophilic balance SPE and LC-MS/MS. Fetal bovine serums spiked with $^{13}C_8$-PFOA before or after SPE were used as test samples for evaluation of the SPE efficiency. Simultaneous evaluation of matrix effects and absolute SPE recovery for $^{13}C_8$-PFOA in serum using different sample pre-treatments and SPE conditions allowed optimization of SPE process efficiency with minimal matrix effect and decent SPE recovery. Introduction of protein precipitation as a sample pre-treatment procedure for serum samples before SPE generally decreased matrix effect in LC-MS/MS analysis and provided more stable recovery of PFOA.

• Membrane and Water Treatment
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• v.2 no.4
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• pp.267-279
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• 2011

At steady state, the simultaneous transport of sulphuric acid and nickel sulphate through an anion-exchange membrane Neosepta-AFN (Astom Corporation, Tokyo, Japan) was investigated in a two-compartment counter-current dialyzer with single passes. The transport was quantified by the recovery yield of acid, rejection of salt and four phenomenological coefficients, which were correlated with the acid and salt concentrations in the feed. The phenomenological coefficients were determined by the numerical integration of the basic differential equations describing the concentration profiles of the components in the dialyzer. This integration was combined with an optimizing procedure. The experiments proved that the acid recovery yield is in the limits from 63 to 91 %, while salt rejection is in the limits from 79 to 97 % in the dependence on the volumetric liquid flow rate and composition of the feed.

• Applied Chemistry
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• v.16 no.1
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• pp.73-76
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• 2012

Due to the developments of communications equipment and electronic devices, lithium ion secondary battery usage is growing. Along with demand increasing, the amount of scrap has been steadily increasing. In this study, method of cobalt recovery using organic eco-friendly is proposed. Sulfuric acid, Malic acid, Citric acid at reflux device had good cobalt leaching efficiency. And Sulfuric acid, Malic acid at the autoclave increased cobalt leaching efficiency.

• Korean Chemical Engineering Research
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• v.44 no.5
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• pp.476-482
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• 2006

This paper studied the recovery of organic acid from organic acid salt by using bipolar membrane electrodialysis. Acetic acid and lactic acid was used as for organic acid. Organic acid concentration, sodium hydroxide concentration and pH values were measured at various current density. Organic acid salt was effectively converted to organic acid and sodium hydroxide. Based on the experimental results, mathematical models were developed, in which time changes in ion balance were considered. Model predictions of organic acid concentration, sodium hydroxide concentration and pH values were in good agreement with the experimental data.

• Membrane Journal
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• v.5 no.4
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• pp.137-144
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• 1995

This studies concern the separation of aqueous boric acid solution and same solution containing silica using cellulose acetate RO S/W 4040 module manufactured by Hydranautics Co. The operating conditions of the applied pressures, temperatures, and feed flow rate are also investigated to characterize the permeabilities, biroc acid recovery, and silica rejection, so that the optimum operating conditions would be found out. In the case where the operating conditions are the temperature 35$^{\circ}$C, The pressure 20atm, and the feed flow rate 2.82 l/min, for the boric acid aqueous solution, the boric acid recovery 58.7% and the permeation rate 2.82 l/min were obtained. And also the results showed the boric acid recovery 68.1% and the permeation rate 1.56 l/min at the operating conditions, 35$^{\circ}$C and 10atm. For the boric acid solution containing silica, when the feed solution are at the conditions of 35$^{\circ}$C and 3.2atm, the boric acid recovery 69.7%, the silica rejection 97.5% and the permeation rate 0.47 l/min were obtained. And the operating conditions were at 35$^{\circ}$C, 20atm and the feed flow rate 2.92 l/min, the results showed the boric acid recovery 56.4%, the silica rejection 96.1% and the permeation rate 2.72 l/min.

• Resources Recycling
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• v.7 no.5
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• pp.46-51
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• 1998

A study has been on the recovery of nitric acid and valuable metals such as Fe, Cu, Sn, Pb, from spent nitric etching solutions. The effects of extractant of extractant type, concentrations, phase raios and selectivity from Fe, Cu, Sn, Pb on nitric acid extraction were studied. The results showed that TBP as an extractant for recovering of nitric acid was more effective than Alamine336, and the optimal concentration of TBP was found to be 60~70% of organic phase. Also, the nitric acid were only extracted by TBP from the spent etching solutions and the heavy metals such as Fe, Cu, Sn, Pb were not extracted above 0.1N nitric acid in spent etching solutions, From the analysis of McCabe-Thiele diagram, the extraction of 95% nitric acid is attained at a ratio of O/A=3 with five stages by 60% TBP and the stripping of 98% nitric acid from 80 g/l nitric acid in organic phase is attained at a ratio of O/A=1 with four stages by distilled water.

• Resources Recycling
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• v.18 no.5
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• pp.44-51
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• 2009

Fundamental study has been made on the recovery of copper from the electronic scrap by hydrometallurgical process. Nitric acid was used as a leaching agent to dissolve the metals such as Cu, Sn, Pb, Fe etc. from the crushed electronic scraps. TBP was employed to extract nitric acid from the strong nitric acid leaching solutions and to reclaim nitric acid. From the experimental results, Cu was effectively leached by 3.0-4.0 M nitric acid. And 95% of nitric acid in the leaching solution was extracted by 60% TBP, and 98% of nitric acid was stripped from the loaded organic phase by distilled water and it was possible to reuse as a leaching agent.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.3
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• pp.232-240
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• 2019

Approximately 80% of the world's sea cucumbers Apostichopus japonicas are processed into dried sea cucumbers. The hot air-drying method is currently used in industry, but it has many problems, such as a short drying time, severe browning, high nutrition loss, and low recovery. In this study, the moisture absorption rate, dry recovery rate, and lipid nutrient composition of sea cucumber dried by heat pump decompression and with a hybrid dryer were investigated. The moisture absorption rates for hybrid-dried sea cucumbers at 24, 48, 72, 96, and 120 h were 241.3%, 427.7%, 652.0%, 721.0%, and 742.2%, respectively. The moisture absorption rates for hot air-dried sea cucumbers were 155.8%, 240.0%, 390.3%, 655.5%, and 667.4%, respectively. Thus, moisture absorption was faster and greater with hybrid drying than with hot air drying. The dry recovery rate at 24 h was greater for hybrid-dried sea cucumber (70.7%) than for hot air-dried sea cucumber (59.8%). Saturated fatty acid contents of the hybrid- and hot air-dried sea cucumbers were 30.0% and 37.5%, respectively. Moreover, greater ${\Sigma}n-3$ polyunsaturated fatty acid content was found in hybrid-dried sea cucumber (15.8%) than in hot air-dried sea cucumber (11.7%).

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.4
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• pp.133-142
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• 2020

Purpose : The purpose of this study was to investigate the effective recovery method of exercise-induced fatigue and muscle pain by comparing the effect of the use of illite hot mat product and general hot mat product on the recovery of muscle pain induced by high intensity exercise. Methods : To measure and analyze the changes in lactic acid, CRP, and ACR according to the high-intensity circuit training program, this study was conducted for the healthy adult men and women, who exercise st the K-region sports center. A total of 45 subjects were studied in 15 groups of 15 patients who received an illite hot-water mat recovery group (A group), 15 general hot-water mat recovery group (B group), and 15 control group (C group). The circuit training exercise program was conducted as a one-time exercise, and each exercise time consisted of 30 minutes of warm-up exercise, 5 minutes of main exercise, 20 minutes of clean-up exercise, and 5 minutes of strength exercise. The intensity setting was high intensity of subjective exercise intensity It carried out by setting to (14-16RPE). Results : Changes in Lactic Acid Concentration There was a significant difference in the lactic acid concentrations between the groups after the high intensity circuit training program (p <.05). The illite rest group (A) decreased 7.71 mmol / L and the control group decreased 4.03 mmol / L. Significantly decreased (p <.05). Changes in ACR Concentration. There was a significant difference in the ACR concentrations Significant differences were found in CRP and ACR during the recovery period after exercise. (p <.05), the elite rest group (A) decreased 2.47 mg / mmol, and the control group increased 1.63 mg / mmol. There was a significant difference (p <.05). Conclusion: The static rest on a heated mat after high-intensity exercise has an effect on changes in blood lactate and ACR levels.

• Journal of Korean Physical Therapy Science
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• v.11 no.4
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• pp.5-10
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• 2004

This study selected 10 university football male players and repeatedly treated them as sports massage group, exercise resumption group, and stability resumption. After maximum exercise, when sport massage, exercise resumption, and stability resumption were applied during recovery, blood lactic acid concentration and $LDH_5$ isozyme concentration were examined. Finally this study obtains the following conclusion 1. There was a significant difference in both lactic acid concentration and time between groups. Besides, the cross-action on group and time was significant. 2. There was a significant difference in both $LDH_5$ concentration and time between groups. Besides, the cross-action on group and time was significant. Based on the above findings, this study suggests that sport massage resumption and exercise resumption remove blood lactic acid more quickly than stability resumption to promote recovery. That means that sport massage and exercise resumption anre very effective for lowering the level of fatigue. Thus sport massage or exercise resumption treatment is considered to have a very positive effect on player's quick recovery and it should be used aggressively in a field.