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Water-resistant Lignin/Poly(vinyl alcohol) Blend Fibers for Removal of Hexavalent Chromium
곽효원,우희창,김의화,이기훈 한국섬유공학회 2018 Fibers and polymers Vol.19 No.6
Lignin is the second most abundant renewable biomass-derived natural resource that has been used to replace traditional petrochemical-based materials. However, fabricating the lignin component into the various forms required for practical application is still challenging. In this work, we fabricated water-resistant lignin/poly(vinyl alcohol) (PVA) blend fibers by wet spinning and glutaraldehyde crosslinking methods. The effect of the lignin/PVA blend ratio and glutaraldehyde crosslinking process on the physicochemical properties of wet-spun lignin/PVA blend fibers were studied using maximum draw ratios, hydrolytic degradation profiles, and mechanical properties. Furthermore, the hexavalent chromium [Cr(VI)] removal behavior of lignin/PVA blend fibers was investigated according to the effect of pH, initial Cr(VI) concentration, and contact time. The wet-spun lignin/PVA blend fiber achieved excellent water stability through glutaraldehyde crosslinking and exhibited notable Cr(VI) adsorption capacity (350.87 mg/g) and good regeneration ability. These findings demonstrate that glutaraldehyde-crosslinked lignin/PVA blend fibers could be promising adsorbents for the remediation of heavy metal species containing textile wastewater.
윤해성,우희창,이기훈,Yun, Haesung,Woo, Hee Chang,Lee, Ki Hoon 한국섬유공학회 2016 한국섬유공학회지 Vol.53 No.6
The removal of heavy metals from various kinds of waste water is important not only for environmental protection, but also for reduction of potential negative effects on human health. In this study, fibers that exhibit significant heavy metal adsorption were prepared by blending lignin with polyvinyl alcohol (PVA). These PVA/lignin fibers could be prepared by wet spinning using dimethyl sulfoxide (DMSO) as the solvent and ethanol as the coagulant. Stable spinning was achieved at a lignin content of 40%. However, lignin reduced the mechanical properties of PVA fibers due to its low molecular weight. Cr(VI) was used as a model heavy metal ion, and the presence of lignin improved the Cr(VI) adsorption almost 1.6 times. The results show the possibility of PVA/lignin blend fiber for Cr(VI) adsorption.
김덕모 ( Dug Mo Kim ),우희창 ( Hee Chang Woo ) 한국지역언론학회 2008 언론과학연구 Vol.8 No.4
This study examines the supporting system of local newspapers and its policy assessment model, and also offers the way to improve its overall policy. This study is important because it is the first attempt in Korea to evaluate the policy assessment model in supporting local newspapers. Currently, the supporting system is an independent funding model in terms of managing its fund, a direct support model in its form, and a selective support model in its method respectively. The result shows that this type of supporting system has a certain merit in achieving its goals in terms of journalistic and managerial aspects. However, the system requires far more focused and intensive supporting policies to alleviate the tendency of oligopoly by a few influential newspaper conglomerates, that has been the most crucial issue in the Korean newspaper market recently. Furthermore the system requires stronger policy measures as an alternative for the highly competitive market structure, such as distributing the govern-mental advertising selectively. The role distribution between the various supporting institutions and the consistency of policy will be another critical issue. There is a certain limitation in evaluating the funding system in Korea since it merely utilizes a goal-oriented model and a broad evaluation model. Although the Local Newspaper Development Committee set the credibility and satisfaction of local newspaper as evaluating index, this may not be suitable for assessing the wide variety of public opinion, balanced local development and the improvement of local democracies. This study thus suggests that the assessment model should incorporate the market share index to supplement the credibility and satisfaction index in order to properly assess the increasing plurality of the public opinion. In addition to this, the study also found that the model has a limitation in evaluating the direct impact to see the improvement of managing environment. Finally, the study raises an issue that the credibility and satisfaction index are only useful in assessing a single newspaper, while they significantly lack effective measures to compare the newspaper companies with the governmental support and the companies without it. Therefore, we suggest that a new model replacing an unrealistic policy evaluation model is necessary.