다양한 산으로 처리한 활성탄의 암모니아 흡착성능

박창원 ( Chang Won Park ),김기중 ( Ki Joong Kim ),안호근 ( Ho Geun Ahn ) 조선대학교 공학기술연구원 2008 공학기술논문지 Vol.1 No.1

Activated carbon was treated with various acids (CH3COOH, HNO3, HCI, H2SO4, H3PO4), to remove ammonia efficiently. The surface area, pore volume, and average pore size of modified activated carbons was investigated by means of adsorption experiments with nitrogen gas. Surface states of modified activated carbons observed by SEM. Functional groups on the surface of phosphoric acid were analyzed from FT-IR spectra. Removal performance was calculated on basis of breakthrough curves obtained from a flow system under atmospheric pressure. The surface area and pore volume of modified activated carbons were greatly varied with type of acids. The surface area and pore volume of activated carbons modified with phosphoric acid was decreased with increasing the modified contents. The amounts of ammonia adsorbed were depended on the functional groups formed chemically on the surface by the modification with phosphoric acid. Activated carbon modified with phosphoric acid of 20wt% showed the maximum amount of ammonia ad orbed was obtained.

Effects of Organic Acids Mix and Modified Atmosphere Packaging on the Storage Quality of Sliced Bacon

Muhlisin,강선문,최원희,이근택,정성희,이성기 한국축산식품학회 2011 한국축산식품학회지 Vol.31 No.5

The effects of organic acids mix (0.4%) and modified atmosphere packaging (MAP) on the storage quality of sliced bacon were investigated. Pork bellies were treated with or without organic acids at the curing stage. The organic acids mix comprised 35% sodium acetate, 25% salt, 15% calcium lactate, 11% trisodium citrate, 7% ascorbate, and 7% citric acid. The cured pork bellies were smoked and packaged with 50% CO_2 + 50% N_2 (50% CO_2-MAP) and 100% N_2 (100% N_2-MAP), and stored at 5℃ for 14 d. The 50% CO_2-MAP showed a higher pH value (p<0.05) up to 10 d, a lower protein deterioration (p<0.05) as measured by volatile basic nitrogen (VBN) from 6 to 14 d, and a higher color value of lightness (CIE L^*) compared to 100% N_2-MAP. The development of lipid oxidation measured by thiobarbituric acid reactive substance (TBARS)values seemed to be effectively controlled throughout the storage period in both 50% CO_2-MAP and 100% N_2-MAP regardless of the application of organic acids. The 50% CO_2-MAP inhibited the growth of aerobic and anaerobic bacteria (p<0.05) both in non-added and bacon added with organic acids mix. The 50% CO_2-MAP alone seemed to be effective in delaying the growth of bacteria since the use of organic acids mix gave no additional effects. The addition of organic acids mix lowered the pH value (p<0.05), effectively retarded the protein deterioration (p<0.05), and showed a higher color value of lightness (CIE L^*) value (p<0.05) and lower color value of redness (CIE a^*) value (p<0.05). In conclusion, 50% CO_2-MAP showed better quality and self-life of sliced bacon during storage. However, the beneficial effect of organic acids mix was not noticed in the concentration used in this experiment.

Effects of Organic Acids Mix and Modified Atmosphere Packaging on the Storage Quality of Sliced Bacon

Muhlisin, Muhlisin,Kang, Sun-Moon,Choi, Won-Hee,Lee, Keun-Taik,Cheong, Sung-Hee,Lee, Sung-Ki Korean Society for Food Science of Animal Resource 2011 한국축산식품학회지 Vol.31 No.5

The effects of organic acids mix (0.4%) and modified atmosphere packaging (MAP) on the storage quality of sliced bacon were investigated. Pork bellies were treated with or without organic acids at the curing stage. The organic acids mix comprised 35% sodium acetate, 25% salt, 15% calcium lactate, 11% trisodium citrate, 7% ascorbate, and 7% citric acid. The cured pork bellies were smoked and packaged with 50% $CO_2$ + 50% $N_2$ (50% $CO_2$-MAP) and 100% $N_2$ (100% $N_2$-MAP), and stored at $5^{\circ}C$ for 14 d. The 50% $CO_2$-MAP showed a higher pH value (p<0.05) up to 10 d, a lower protein deterioration (p<0.05) as measured by volatile basic nitrogen (VBN) from 6 to 14 d, and a higher color value of lightness (CIE $L^*$) compared to 100% $N_2$-MAP. The development of lipid oxidation measured by thiobarbituric acid reactive substance (TBARS) values seemed to be effectively controlled throughout the storage period in both 50% $CO_2$-MAP and 100% $N_2$-MAP regardless of the application of organic acids. The 50% $CO_2$-MAP inhibited the growth of aerobic and anaerobic bacteria (p<0.05) both in non-added and bacon added with organic acids mix. The 50% $CO_2$-MAP alone seemed to be effective in delaying the growth of bacteria since the use of organic acids mix gave no additional effects. The addition of organic acids mix lowered the pH value (p<0.05), effectively retarded the protein deterioration (p<0.05), and showed a higher color value of lightness (CIE $L^*$) value (p<0.05) and lower color value of redness (CIE $a^*$) value (p<0.05). In conclusion, 50% $CO^2$-MAP showed better quality and self-life of sliced bacon during storage. However, the beneficial effect of organic acids mix was not noticed in the concentration used in this experiment.

Physicochemical Properties of Job’s Tears (Coix lachryma-jobi L.) Starch Modified with Different Levels of Acid Hydrolysis

Hye Won Kim,Kwang Yeon Lee,In Young Bae,Soo Jin Jun,Ji Yeon Lee,Hyeon Gyu Lee 한국식품과학회 2009 Food Science and Biotechnology Vol.18 No.5

Physicochemical properties of native and acid-modified Job’s tears (Coix lachryma-jobi L.) starches were investigated. Starch extracted from Job’s tears was treated with 2.2 N hydrochloric acid for different length of time (3, 6, 12, and 18 hr). The hydrolysis pattern of starches with the acid proceeded rapidly up to 12 hr and then the approached constant values. The swelling power of acid-modified starches measured at all temperatures was lower than that of its native counterparts and the water solubility index increased as temperature and hydrolysis time increased. Rapid visco analyzer viscograms of acid-modified starches demonstrated a very low viscosity as compared with that of native starch. However, Xray diffraction did not show any significant alteration in the crystallinity after acid-modification.

친환경 착제가 적용된 modified Fenton 공정을 이용한BTEX로 오염된 지하수의 복원

권용재 ( Yong Jae Kwon ),조영훈 ( Young Hoon Jo ),정재구 ( Jae Gu Jung ),공성호 ( Sung Ho Kong ) 한국화학공학회 2014 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.52 No.5

The effect of in-organic chelating agents with Fe(II) and Fe(III) in modified Fenton was evaluated to degradationBTEX (benzene, toluene, ethylbenzene, xylene). Citric acid and pyrophosphate were used in experimentals andan optimum chelating agent for BTEX degradation was determined. In H2O2/Fe(III)/citric acid, degradation of BTEXwas decreased when concentration of citric acid was increased. In H2O2/Fe(III)/pyrophosphate, degradation of BTEXwas increased when concentration of pyrophosphate was increased and degradation for BTEX was relatively high comparedwith H2O2/Fe(III)/citric acid. In H2O2/Fe(II)/chelating agents, degradation for BTEX was high and pH variationwas minimized when molar ratio of Fe(II) and citric acid was 1:1. Optimum molar concentration of Fe(II), citric acidand H2O2 were 7 mM, 7mM and 500 mM for degradation of 100 mg/L of benzene to obtain best efficiency of H2O2,least precipitation of iron and best degradation.

Natural deep eutectic solvents for enhancing the solubility of two B vitamins in aqueous solutions: Experimental study and thermodynamic aspects

Shima Taheri Vardanjani,Aliakbar Roosta,Jafar Javanmardi 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.12

Natural deep eutectic solvents (NADESs) as green solvents have substantial potential for enhancing the solubility of pharmaceuticals in aqueous solutions. In this work, the solubility of two B vitamins (nicotinic acid and 4aminobenzoic acid) in aqueous solutions of two NADESs was measured at temperatures between 298.15 K and 313.15 K and different concentrations of NADESs. The studied NADESs were prepared by mixing dried choline chloride with urea or malonic acid with molar ratios of 1 : 2 and 1 : 1, respectively. Based on the results, chloride+malonic acid was more effective on the solubility of the pharmaceuticals in aqueous solutions. Furthermore, the DESs increased the aqueous solubility of 4aminobenzoic acid more than that of nicotinic acid. The experimental solubility data were modeled with the van Laar activity model as well as the modified Apelblat equation to correlate the solubility of the pharmaceuticals to the temperature and NADESs concentration. The molar enthalpy of dissolution (hd) and the molar enthalpy of mixing (hmix) of the pharmaceuticals in the aqueous solutions of the NADESs were calculated. These parameters showed that all the dissolution processes were endothermic, while the mixing process as a part of the dissolution process was exothermic.

Assessment of durable press performance of cotton finished with modified DMDHEU and citric acid

Guneet Dhiman,J. N. Chakraborty 한국의류학회 2017 Fashion and Textiles Vol.4 No.1

Cotton apparels possess inherent tendency to form wrinkles under external stress. Conventionally selective cross-linking agents in presence of specific catalyst are applied on cotton to supress formation of creases or wrinkles via pad-dry-cure technique at high curing temperature under acidic conditions imparting stability and elasticity to the fabric. Extensive research carried out in this field identifies invariable deterioration in mechanical properties of finished cotton. In this study, two different cross-linking agents, i.e. modified DMDHEU and citric acid working on etherification and esterification crosslinking reaction with cellulose respectively were applied on cotton through selection of factors using Box Behnken experimental design in conjunction with response surface analysis and regression methods to study their DP ratings as well as other mechanical properties. Significant factors were further drastically narrowed down to reach to most specific concentrations of cross-linker, catalyst as well as other chemicals along with finishing parameters. It was found that modified DMDHEU performed better in terms of DP rating as well as overall physical properties as compared to those obtained with citric acid.

Detection of Oleic Acid Biodegradation by Fungi

HAN, DONG-WOOK,SUH, HWAL,LEE, DONG HEE,PARK, BONG JOO,TAKATORI, KOSUKE,PARK, JONG-CHUL 한국미생물 · 생명공학회 2002 Journal of microbiology and biotechnology Vol.12 No.3

To investigate oleic acid biodegradation, 47 fungal strains were tested with modified Czapek Dox broth media containing oleic acid, and their biodegradative activities were assayed by measuring the release of [^14C]CO_2 from the ^14C- labeled oleic acid. After 72 h of cultivation, Aspergillus flavus, Aspergillus ochraceus, and Alternaria species metabolized approximately 25% to 35% of the supplied oleic acid. The relationship between the fungal degradation of oleic acid and the fungal growth was also examined using 7 strains of Aspergillus niger. A. niger YMC 0100 and YMC 0322 degraded about 26% of the oleic acid after 72 h, while their germination ratios were more than 30%.

Carbon supported palladium-copper bimetallic catalysts for promoting electrochemical oxidation of formic acid and its utilization in direct formic acid fuel cells

양종원,양승원,정용진,권용재 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.1

Carbon supported palladium-copper (Pd-Cu) bimetallic catalysts (PdxCuy/Cs) are fabricated by modified polyol method to enhance the reaction rate of formic acid oxidation reaction (FAOR) and the performance of direct formic acid fuel cell (DFAFC) through weakening the bond with the intermediate of formic acid. According to the evaluations, when the ratio of Pd and Cu is 3 : 1 (Pd3Cu1/C), catalytic activity is best. Its maximum current density is 1.68-times better than that of commercial Pd/C. Even from the optical and spectroscopic characterizations, such as TEM, EDS, XPS and XRD, Pd3Cu1/C shows an optimal particle size and a higher degree of alloying. This is because in Pd3Cu1/C catalyst, the d-band center that induces the weakening in adsorption of formate anion groups to Pd surface is most positively shifted, and this positive shift promotes the reaction rate of FAOR, which is the rate determining step. When the performance of DFAFCs using the PdxCuy/C catalysts is measured, the maximum power density (MPD) of DFAFC using Pd3Cu1/C catalyst is 158mW cm2, and this is the best MPD compared to that of DFAFCs using other PdxCuy/C catalysts. In addition, in a comparison with commercial Pd/C catalyst, when the same amount of catalyst is loaded, MPD of DFAFC using Pd3Cu1/C catalyst is 22.5% higher than that of DFAFC using commercial Pd/C.

Effect of boron content on 1,4-butanediol production by hydrogenation of succinic acid over Re-Ru/BMC (boron-modified mesoporous carbon) catalysts

Kang, K.H.,Han, S.J.,Lee, J.W.,Kim, T.H.,Song, I.K. Elsevier 2016 Applied Catalysis A Vol.524 No.-

<P>A series of Re-Ru bimetallic catalysts supported on mesoporous boron-modified carbon (denoted as Re-Ru/xBMC, x= B/C molar ratio) were prepared by a single-step surfactant-templating method and a subsequent incipient wetness impregnation method, and they were used for liquid-phase hydrogenation of succinic acid to 1,4-butandiol (BDO). The effect of boron addition on the catalytic activities and physicochemical properties of Re-Ru/xBMC catalysts was investigated. It was found that the addition of boron into carbon support affected surface area, metal dispersion, and reducibility of rhenium and ruthenium species in the Re-Ru/xBMC catalysts. It was also observed that boron species in carbon framework existed in several different phases such as substituted boron, partial oxidized boron, and boron oxide. In particular, the amount of substituted boron species was closely related to the hydrogen adsorption behavior of Re-Ru/xBMC catalysts. The amount of weak hydrogen-binding sites increased with increasing the amount of substituted boron species of the catalysts. Yield for BDO in the hydrogenation of succinic acid showed a volcano-shaped trend with respect to B/C molar ratio. This result was in good agreement with the amount of weak hydrogen-binding sites of the catalysts. It was revealed that TOFBDO increased with increasing the amount of weak hydrogen-binding sites of Re-Ru/xBMC catalysts. Among the catalysts, Re-Ru/0.04BMC with the largest amount of weak hydrogen-binding sites served as an efficient catalyst in the selective formation of BDO by hydrogenation of succinic acid. (C) 2016 Elsevier B.V. All rights reserved.</P>