• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.7
• /
• pp.445-453
• /
• 2012

An investigation for removal of 1-indanone (1-ID), which were commonly produced from the biological and/or chemical treatment and natural weathering of the PAHs-contaminated soils, via oxidative transformation mediated by birnessite in the presence of various phenolic mediators is described. This study also examines the potential effect of the natural occurring substance humic acid (HA) on the oxidative transformation. The experiment was carried out in aqueous phase as a batch test (10 mg/L 1-ID, 0.3 mM phenolic mediators, $1.0g/L\;{\delta}-MnO_2$, at pH 5). All of the 11 tested phenoilic mediators belong to the group of natural occurring phenols and are widely used as model constituents of humic substances. From the results of HPLC analysis, it is demonstrated that 1-ID was not reactive to birnessite itself, but it can be effectively removed in birnessite-mediated cross coupling reactions in the presence of the phenolic mediators. The percent removals of 1-ID after 2 day incubation were ranged from 9.2 to 71.2% depending on the phenolic mediators applied. The initial rate constant ($K_{int}$, $hr^{-1}$) values for the 1-ID removals obtained from the pseudo-first-order kinetic plots also widely ranged from 0.18 to 15.0. Results of the correlative analysis between the removal efficiencies and structural characteristics of phenolic mediators indicate that the transformation of the 1-ID was considerably enhanced by the addition of electron-donating substituents (e.g., -OH, $-OCH_3$) at the benzne ring, and much less enhanced by the addition of electron-withdrawing substituents (e.g., -COOH, -CHO). The presence of HA showed that removal efficiencies of 1-ID in the birnessite-phenolic mediator systems decreased with increasing HA concentrations. However at low concentration of HA (< 2 mg/L), it caused some enhancement in the removals of 1-ID as compared to the control.

• Clean Technology
• /
• v.11 no.2
• /
• pp.83-90
• /
• 2005

This paper is about a new method of synthesis organic tanning agent (polymer, polyphenol, polyresin) and discusses their tanning property. It was found that properties of the leather manufactured with application of organic tanning agent were similar to those applied with conventional chrome tanning agent and reducing effects of Cr, T-N, COD, SS concentrations in the effluent.

• Journal of Korea Foresty Energy
• /
• v.24 no.1
• /
• pp.33-38
• /
• 2005

To find a new use of wood tar which is obtained from the manufacturing process of wood charcoal, a resol type of phenol adhesive using wood tar was made and some adhesion tests on plywood were examined. Phenol adhesive synthesized with pine tar was almost same as an original phenol adhesive in physical properties such as solid content and viscosity and tensile-shear adhesive strength of plywood made of phenol adhesive synthesized with pine tar was not much lower than the original one in non-waterproof and waterproof tests. Phenol adhesive synthesized with oak tar, however, was different from original phenol adhesive in physical properties. Adhesive strength of plywood made of oak tar was $50\%$ lower than the original one on waterproof tests. The amount of emitted formaldehyde increased as the amount of wood tar increased.

• Korean Journal of Food Science and Technology
• /
• v.52 no.3
• /
• pp.205-211
• /
• 2020

In this study, fruit phenolics were investigated with using LC/MS and HPLC analysis in order to compare the differences between domestic ('Campbell Early', 'Kyoho', 'Heukbosuk', and 'Hongju SDS') and imported ('Crimson SDS' and 'Thomson SDS') grapes. In the case of fruit characteristics, imported grape 'Crimson SDS' and 'Thompson SDS', had lighter skin weight (300-350 mg/berry) and hard flesh (5.2-5.6 kg·f) than domestic grape cultivar. The phenolic compound contents of 'Crimson SDS' skin was higher, but resveratrol (25-29 mg/kg), quercetin (350-380 mg/kg), and myricetin (31-32 mg/kg) contents were similar in to those of 'Hongju SDS'. The anthocyanin content was different from differed between grape cultivars. 'Hongju SDS' grape was showed higher in Delphinidin-3-glucose (D3G) levels, and 'Crimson SDS' was showed higher in Peonidin-3-glucoside (P3G) levels. The contents of phenolic compounds were investigated differently for each grape berry part. Catechin, epicatechin, procyanidin B1, and B2 were found in grape seeds.

• Polymer(Korea)
• /
• v.37 no.2
• /
• pp.156-161
• /
• 2013

Phenolic antioxidants are effective stabilizers that provide excellent long-term heat stability by preventing thermo-oxidative degradation during processing and service life. However, under a selected set of circumstances, certain types of phenolics have been susceptible to discoloration due to prolonged storage in an environment containing oxides of nitrogen. It is investigated that the effect of addition of secondary antioxidant and chemical structure of primary antioxidant on discoloration of amorphous poly-${\alpha}$-olefin (APAO), which is especially prone to be decomposed in high processing temperature. From the result, it is concluded that a higher level of steric hindrance of phenolic antioxidant provided by long alkyl chain allows a more enhanced synergic effect with secondary antioxidant.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.49 no.5
• /
• pp.355-363
• /
• 2021

Heat resistance performance evaluation and thermal analysis were performed to confirm the applicability of the lyocell-based carbon/phenolic composite material for heat-resistant parts for aerospace. Heat resistance performance evaluation of carbon/phenolic was conducted by Thermal Protection Evaluation Motor (TPEM). In this paper, boundary layer integration code considering the boundary layer analysis of combustion gas and MSC-Marc 2018 considering ablation and thermal pyrolysis were used for the thermal analysis. The ablation and thermal insulation performance were analyzed by the pressure curve of test motor and the cut carbon/phenolic specimens. The thermal response of the lyocell-based carbon/phenolic material was similar to that of the rayon-based carbon/phenolic material. Based on the results through the combustion test, the applicability of heat-resistant parts for aerospace to which domestic lyocell-based carbon fibers were applied was confirmed.

• Food Science and Preservation
• /
• v.18 no.3
• /
• pp.328-334
• /
• 2011

Natural polyphenolic compounds such as catechin, epicatechin derivatives, quercetin, and resveratrol, have been reported to have a wide range of biological activities against carcinogen and reactive oxygen species. The compounds can act together in synergy or can independently affect the activity. Contents of four compounds in different grape cultivar groups with different skin color were determined through HPLC. There were not significant differences in content of four phenolic compounds among the different skin color groups of the same grape cultivar groups, but were among different grape cultivars within the same skin color groups. Totally, contents of catechin, epicatechin derivatives were much higher than those of quercetin and resveratrol. In each skin color group, Campbell Early in Black, Seneka in Green, and Benigard in Red group showed highest contents, respectively. Nothing or a very small amount of four phenolic compounds was detected in some cultivars. This information would be useful for grape breeders and manufactures.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.39 no.1
• /
• pp.20-24
• /
• 2010

This study was performed to investigate antioxidant activities of Mistletoe (MS) extracts by measuring electron donating ability (EDA), super oxide dismutase (SOD)-like activity and total polyphenol content (TPC). The extracts were obtained using supercritical carbon dioxide, hot-water and ethanol extraction. EDAs was the higher in ethanol extract (70.53%) than water (36.73%) or supercritical carbon dioxide extract (15.73% at 400 bar, $30^{\circ}C$) at concentration of 10 mg/mL. However, SOD-like activities and TPCs were the highest in the supercritical carbon dioxide extract. At concentration of 1 mg/mL, supercritical carbon dioxide extract (22.54% at 200 bar, $40^{\circ}C$) was higher SOD activity than water (7.85%) and ethanol extract (6.12%). Regarding TPCs of MS extracts, the content was the highest in supercritical carbon dioxide extract (17.57 wt% catechin equivalent at 200 bar, $50^{\circ}C$) followed by ethanol and water extract. These results suggest that it can be useful to develop functional foods using antioxidative active compounds of MS with high polyphenol contents.

• Polymer Science and Technology
• /
• v.20 no.5
• /
• pp.465-471
• /
• 2009

• Journal of Convergence for Information Technology
• /
• v.11 no.6
• /
• pp.206-212
• /
• 2021

This study aimed to maximize the efficacy of Angelica gigas by finding a more effective way to extract active compounds from Angelica gigas. After extracting Angelica gigas by hydrothermal, ethanol, and supercritical carbon dioxide extraction methods, analysis of decursin and decursinol angelate content, quantification of total polyphenol content, and evaluation of efficacy of antioxidant, whitening, and antibacterial were conducted. The content of decursin and decursinol angelate was very high at 38.65% of the supercritical carbon dioxide extract, and the total polyphenol content was high in the order of hydrothermal extract, ethanol extract and supercritical carbon dioxide extract, but the difference was relatively small. The antioxidant effects were consistent with the total polyphenol content, and the antibacterial effects were consistent with the decursin and decursinol angelate content. In other words, through this study, we found that the optimal method for extracting active compounds from Angelica gigas is the supercritical carbon dioxide extraction method.