Isotope Microscopy Visualization of the Adsorption Profile of 2-Methylisoborneol and Geosmin in Powdered Activated Carbon
Isotope Microscopy Visualization of the Adsorption Profile of 2-Methylisoborneol and Geosmin in Powdered Activated Carbon
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DOI：
10.1021/es5024515
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发表时间：
2014-09-16
影响因子：
11.4
通讯作者：
Yurimoto, Hisayoshi
中科院分区：
文献类型：
--
作者：
Matsui, Yoshihiko;Sakamoto, Asuka;Yurimoto, Hisayoshi
减小粉末活性炭的粒度可以提高其对小分子和微污染物（如2-甲基异戊烯（MIB）和土臭素）以及大分子和天然有机物的平衡吸附能力。壳吸附，其中吸附物不完全渗透的吸附剂，而是优先吸附在吸附剂的外表面附近，可以解释这种平衡吸附容量的增强。在这里，我们使用同位素显微镜和氘掺杂的MIB和土臭素直接可视化的MIB和土臭素在碳颗粒中的固相吸附物浓度分布。氘/氢比，我们用作为MIB和土臭素的固相浓度的指数，是在壳区域比在碳颗粒的内部区域更高。从氘/氢比获得的MIB和土臭素的固相浓度大致与等温线数据的壳吸附模型分析预测的一致。微污染物吸附物在活性炭颗粒中的定位的直接可视化提供了壳吸附的直接证据。
Decreasing the particle size of powdered activated carbon may enhance its equilibrium adsorption capacity for small molecules and micropollutants, such as 2-methylisoborneol (MIB) and geosmin, as well as for macromolecules and natural organic matter. Shell adsorption, in which adsorbates do not completely penetrate the adsorbent but instead preferentially adsorb near the outer surface of the adsorbent, may explain this enhancement in equilibrium adsorption capacity. Here, we used isotope microscopy and deuterium-doped MIB and geosmin to directly visualize the solid-phase adsorbate concentration profiles of MIB and geosmin in carbon particles. The deuterium/hydrogen ratio, which we used as an index of the solid-phase concentration of MIB and geosmin, was higher in the shell region than in the inner region of carbon particles. Solid-phase concentrations of MIB and geosmin obtained from the deuterium/hydrogen ratio roughly agreed with those predicted by shell adsorption model analyses of isotherm data. The direct visualization of the localization of micropollutant adsorbates in activated carbon particles provided direct evidence of shell adsorption.