Natural organic matter that penetrates or does not penetrate activated carbon and competes or does not compete with geosmin
Natural organic matter that penetrates or does not penetrate activated carbon and competes or does not compete with geosmin
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DOI：
10.1016/j.seppur.2013.04.009
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发表时间：
2013-07
影响因子：
8.6
通讯作者：
Y. Matsui;S. Nakao;Tomoaki Yoshida;Takuma Taniguchi;T. Matsushita
中科院分区：
文献类型：
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作者：
Y. Matsui;S. Nakao;Tomoaki Yoshida;Takuma Taniguchi;T. Matsushita
天然有机物（NOM）对活性炭吸附2-甲基异戊烯（MIB）（一种具有泥土/发霉气味的化合物）的能力的不利影响，对于亚微米级粉末活性炭（SPAC）来说，不如常规尺寸的粉末活性炭（PAC）严重[11]。在这项研究中，NOM效应得到了证实，并通过对另一种恶臭化合物土臭素的研究来研究该效应的机制。通过简化的等效背景化合物（EBC）估计和渗透指数，NOM的性能方面的机制进行了研究。渗透指数值和尺寸排阻色谱图的分数面积之间的相关性表明，SPAC上较高的NOM负载主要与具有分子量（MW）>2kDa和发色团部分的NOM部分相关，其不扩散到吸附剂颗粒的内部区域，而是仅吸附到它们的外表面上。因此，每单位质量吸附剂具有较大比表面积的SPAC比PAC更大程度地吸附这种高MW发色NOM。然而，这种NOM不与土臭素竞争吸附位点，因为土臭素吸附到吸附剂颗粒的内表面上。相反，具有<2kDa的MW和非发色团部分的NOM穿透吸附剂颗粒并吸附在内表面上。估计的EBC浓度及其与尺寸排阻色谱图馏分和渗透指数值的相关性表明NOM与土臭素竞争的特性与MIB相似。MW <230 Da的发色NOM与土臭素和MIB竞争吸附位点。除了非发色的低MW（<2kDa）NOM之外，这种发色的极低MW NOM也渗透吸附剂颗粒并吸附在内表面上。因此，这种NOM的负载量与碳颗粒（SPAC或PAC）的尺寸无关。因此，NOM对土臭素吸附能力的影响被认为是相似的SPAC和PAC，尽管事实上，更多的NOM被加载到SPAC比PAC。极低分子量发色团NOM占整个NOM的<2%。
The adverse effect of natural organic matter (NOM) on the capacity of activated carbon to adsorb 2-methylisoborneol (MIB), a compound with an earthy/musty odor, is less severe for submicron-sized powdered activated carbon (SPAC) than for conventionally sized powdered activated carbon (PAC) [11]. In this study the NOM effect was confirmed, and the mechanism responsible for the effect was investigated by studies with another malodorous compound, geosmin. The mechanism was investigated with respect to the properties of NOM by simplified equivalent background compound (EBC) estimation and penetration index. Correlations between penetration index values and fractional areas of size-exclusion chromatogram indicated that higher NOM loading on SPAC were associated mainly with a fraction of NOM having a molecular weight (MW) >2kDa and a chromophoric moiety, which did not diffuse into the inner region of adsorbent particles and instead adsorbed only onto their external surfaces. Therefore SPAC, which has a larger specific surface area per unit mass of adsorbent, adsorbs such high-MW chromophoric NOM to a greater extent than does PAC. However, such NOM does not compete for adsorption sites with geosmin because geosmin adsorbs onto the interior surfaces of adsorbent particles. Contrariwise, NOM with a MW of <2kDa and with an nonchromophoric moiety penetrates adsorbent particles and adsorbs onto interior surfaces. The estimated EBC concentration and its correlations with both size-exclusion chromatogram fractions and penetration index values indicated the characteristics of the NOM that competes with geosmin to be similar to those of MIB. Chromophoric NOM with a MW of <230Da competes for adsorption sites with both geosmin and MIB. Beside the nonchromophoric, low-MW (<2kDa) NOM, such chromophoric, very-low-MW NOM also penetrates adsorbent particles and adsorbs onto interior surfaces. The loading of such NOM is therefore independent of the size of the carbon particles (SPAC or PAC). The NOM effects on geosmin adsorption capacity were therefore found to be similar for SPAC and PAC, despite the fact that more NOM was loaded onto SPAC than PAC. The very-low-MW chromophoric NOM accounted for <2% of the entire NOM.