土壤及其主要化学组分对五氯酚吸附特征研究

Adsorption of pentachlorophenol on soil and its major components

研究了土壤原样及其去锰氧化物、去铁氧化物、去有机质和去水溶性有机质(DOM)土壤样品对五氯酚(PCP)的吸附规律,分析了土壤及其主要化学组分对PCP的吸附机制。实验结果表明,Langmuir方程可较好地描述PCP在各土壤样品上的热力学吸附过程。PCP在土壤上的吸附行为与自身性质和土壤理化性质密切相关,有机质和铁氧化物对PCP的吸附起到促进作用,而锰氧化物和DOM则能在一定程度上抑制PCP的吸附。通过Langmuir方程得到的拟合结果,可判断PCP在各土壤样品上的最大吸附量为去锰氧化物土壤样品>去铁氧化物土壤样品>去DOM土壤样品>土壤原样>去有机质土壤样品。

Adsorptive capacities of a soil sample and its Mn-oxides,Fe-oxides,organic-matters and water soluble organic matters （DOM） components for PCP were determined by the batch adsorption isotherm experiments employing the raw soil sample and 4 prepared soil samples with one of the four major components removed from the raw soil sample in the preparation step. The experimental adsorptive capacity vs. equilibrium concentration data of PCP adsorption on the soil samples were well represented by the Langmuir adsorption isotherm model. The isotherms were dependent on physical and chemical properties of both PCP and the soil samples. PCP was adsorbed primarily on the organic matters and Fe oxides components of the soil; however,Mn oxides and DOM components inhibited the adsorption process. The order of adsorptive capacity for PCP was： Mn-oxides-removed soil〉Fe-oxides-removed soil〉DOM-removed soil〉original soil〉organic-matter-removed soil.