Sorption of selected organic compounds from water to a peat soil and its humic-acid and humin fractions: Potential sources of the sorption nonlinearity
Sorption of selected organic compounds from water to a peat soil and its humic-acid and humin fractions: Potential sources of the sorption nonlinearity
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DOI：
10.1021/es990261c
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发表时间：
2000-04-01
影响因子：
11.4
通讯作者：
Boyd, SA
中科院分区：
文献类型：
--
作者：
Chiou, CT;Kile, DE;Boyd, SA
测定了水中二溴乙烷（EDB）、敌草隆（DUN）和3，5-二氯苯酚（DCP）在泥炭土腐殖酸和胡敏素组分上的吸附等温线，以及在腐殖酸上的吸附等温线。的数据进行了比较，与整个泥炭的腐殖酸（HA）和胡敏素（HM）馏分的衍生和溶质的吸附表现出不同程度的非线性能力在低相对浓度（C-e/S-w）的溶质。通过密度分级方法制备的HA级分相对较纯，并且可能不含高表面积碳质材料（HSACM），该材料被认为是导致观察到的非极性溶质（例如，EDB）在泥炭上;相反，如BET-（N-2）表面积比整个泥炭高得多所表明的，所制备的碱不溶性HM级分被认为富含HSACM。EDB在HA上的吸附没有表现出明显的非线性效应，而在HM上的吸附表现出增强的非线性效应。HA和HM对极性DUN和DCP的吸附表现出与整个泥炭相当的非线性效应，这种效应比非极性EDB更显著。这些结果符合的假设，吸附到少量的强吸附HSACM是主要负责非极性溶质在土壤上的非线性吸附，并与土壤有机质的活性基团的额外的特定的相互作用是负责一般较高的非线性吸附的极性溶质。
The sorption isotherms of ethylene dibromide (EDB), diuron (DUN), and 3,5-dichlorophenol (DCP) from water on the humic acid and humin fractions of a peat soil and on the humic-acid of a muck soil have been measured. The data were compared with those of the solutes with the whole peat from which the humic-acid (HA) and humin (HM) fractions were derived and on which the sorption of the solutes exhibited varying extents of nonlinear capacities at low relative concentrations (C-e/S-w). The HA fraction as prepared by the density-fractionated method is relatively pure and presumably free of high-surface-area carbonaceous material (HSACM) that is considered to be responsible for the observed nonlinear sorption for nonpolar solutes (e.g., EDB) on the peat; conversely,the base-insoluble HM fraction as prepared is presumed to be enriched with HSACM, as manifested by the greatly higher BET-(N-2) surface area than that of the whole peat. The sorption of EDB on HA exhibits no visible nonlinear effect, whereas the sorption on HM shows an enhanced nonlinearity over that on the whole peat. The sorption of polar DUN and DCP on HA and HM display nonlinear effects comparable with those on the whole peat; the effects are much more significant than those with nonpolar EDB. These results conform to the hypothesis that adsorption onto a small amount of strongly adsorbing HSACM is largely responsible for the nonlinear sorption of nonpolar solutes on soils and that additional specific interactions with the active groups of soil organic matter are responsible for the generally higher nonlinear sorption of the polar solutes.