Elucidating adsorption mechanism of super-fine powdered activated carbon by isotope-imaging

研究了土臭素和2-甲基异龙脑（MIB）吸附量与活性炭粒径的关系。利用同位素显微镜系统和装载有氘掺杂的MIB和土臭素的碳颗粒，得到了以氘氢比为基准的MIB和土臭素的同位素图。对于吸附MIB和土臭素的吸附能力随着碳粒径的减小而增大的碳，靠近颗粒外表面的外区氘/氢比高于内区。结果表明，超细粉末活性炭吸附MIB和土臭素的能力高于普通粒径粉末活性炭，这与壳吸附机制有关。当MIB和土臭素在活性炭颗粒的内部孔隙中吸附时，由于碳粒径的减小，天然有机物（NOM）的吸收量增加，而这些化合物与天然有机物（NOM）之间的吸附竞争并不会增加。

Geosmin and 2-methylisoborneol (MIB) adsorption capacity dependency on activated carbon particle size was investigated for two carbons. By using the isotope microscope system and carbon particles loaded with deuterium-doped MIB and geosmin, isotopic maps for deuterium/hydrogen ratio as a maker of MIB and geosmin were obtained. For a carbon in which the adsorption capacity to adsorb MIB and geosmin increased with decreasing carbon particle size, deuterium/hydrogen ratio was high on the exterior region close to the particle outer-surface compared with inner region. The result indicated the higher MIB and geosmin adsorption capacities on super-fine powdered activated carbon than on normal-size powdered activated carbon is explained by the shell adsorption mechanism. When MIB and geosmin adsorbs in internal pores of activated carbon particles, adsorption competition between natural organic matter (NOM) and these compounds does not increase when NOM uptake increased due to carbon size reduction.