| The adsorption behavior of organic pollutants in the geological environment is animportant factor that can directly affect the migration, transformation and fate oforganic pollutants. The adsorption is not only the main reason of contaminationmigration lag with aqueous migration lag with aqueous migration, but also is thecause of different form and distribution of contamination in the undergroundenvironment, thus it produce some affect to the processes of volatilization, dissolvingleach, biological or abiotic degradation, plant utilization and other effects in differentdegree. Based on batch experiments, this study investigated the adsorption behaviorsof TCE in the different ion bridge bonds and organic/mineral ratio complexes whichwere prepared by montmorillonite and humic acid, the composite ways and content ofdifferent kinds of complexes and their effects on organic matters adsorption behaviorwere studied as well. The research results are mainly as follows:(1) For the concentration of TCE in this study, adsorption of source MMT andsource humic acid on TCE are better fitted by the linear isothermal adsorptionequation and Freundlich isothermal adsorption equation. The adsorption of mineral onTCE was mainly relied on the surface adsorption and internal pore structure, while theadsorption of organic matter on TCE is a linear distribution process and the adsorptionrate is very fast.(2)The adsorption ability increased when ion bridge bonds presented, while theadsorbent-water partition coefficient Kdof Ca-MMT、Fe-MMT and Al-MMT samplesare increased from0.1204to0.2607、0.2546and0.2819respectively. The differenceamong the three samples is mainly caused by the size the three ions, while theadsorption capacity of Ca-MMT and Fe-MMT is more similar on TCE.(3)For different ion bridge bonds complexes, the BET and the hydrophobicregions of adsorbents are changed because of different combination ways of humicacid and mineral and the different ion bridge bonds, thus the adsorption of adsorbentson TCE is affected. The order of adsorption abilities of the four complexes are:Ca-M-HA complex>H2O-M-HA complex>Al-M-HA complex> Fe-M-HA complex.(4)Compared to the same series samples of the ion bridge bond, differentadsorption characteristics of the three ion bridge bond complexes which wereprepared gradually on TCE are showed. The order of the adsorption ability about Ca2+series samples is Ca-M-HA complex（0.4180）>M+HA mixture（0.2629）>Ca-MMTsample（0.2607）>source MMT（0.1204），which is determined by Kdvalue. But thereare not obvious pattern about the Fe3+and Al3+series samples.(5) In TCE adsorption experiments about mixtures and complexes with differentorgano-mineral ratio, Kdvalue changed when the humic acid content increased, whileKomvalue decreases. The reason is that organic matter of organo-mineral complex did not evenly cover the mineral surface but distributed irregularly on the adsorption pointof mineral surface, and there is selected adsorption for organic matters. Meantime, theadsorption characteristics were affected by the interaction of organic matters andmineral, in which the transformation of soft carbon to hard carbon happened.(6)When the organo-mineral complex is formed by the organic matters andminerals in the soil/sediment, organic matter will further be polymerized, and thenformed to the condensation, which contained lots of pore structure. With the contentof organic matters increases, condensation became more closed, which caused thepore size in the complex smaller, thus affected the adsorption of organic matter for theorganic pollutants in complex. |
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