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        검색결과 4

        1.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Engineering of activated carbons (ACs) through chemical activation of organic precursors has been extensively studied for a wide variety of biopolymers, biomasses, wastes and other fossil-based precursors. Despite huge efforts to engineer evermore performant and sustainable ACs, “searching-for-the-best-recipe” type of studies are more the rule than the exception in the published literature. Emerging AC applications related to energy and gas storage require strict control of the AC properties and a better understanding of the fundamentals underlying their engineering. In this study, we provide new insights into the K2CO3 chemical activation of plant-based polyphenols—lignins and tannins—through careful thermoanalytical and structural analyses. We showed for the the first time that the reactivity of polyphenols during K2CO3 chemical activation depends remarkably on their purity and structural properties, such as their content of inorganics, OH functionalities and average molecular weight. We also found that the burn-off level is proportional to the K2CO3/ lignin impregnation ratio (IR), but only within a certain range—high impregnation ratios are not needed, unlike often reported in the literature. Furthermore, we showed for the first time that the K2CO3 chemical activation of different carbon surfaces from lignins and tannins can be modelled using simple global solid-state decomposition kinetics. The identified activation energies lay in the range of values reported for heterogenous gas-carbon surface gasification reactions ( O2-C, H2O- C, or CO2- C) in which the decomposition of C(O) surface complexes is the common rate-limiting step.
        4,900원
        4.
        2005.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        감 껍질 추출물을 Sephadex LH-20 및 MCI-gel CHP 20 column을 이용하여 2개의 주요 탄닌을 분리할 수 있었으며, NMR, IR, FAB-mass 등을 이용한 구조 동정 결과(+)-catechin, (+)-gallocatechin으로 확인되었다. 소석회와 보조응집제로 정제 탄닌을 처리할 때 얻어진 탁도, T-N, T-P 및 CODcr 제거율은 gallocatechin이 catechin보다 우수한 것으로 나타났으며, 이는