氧化程度不同的土壤对芘的吸附作用

Sorption of Pyrene on Soils with Different Chemical Oxidation Degree

将北京东灵山和云南曲靖采集的山地土壤样品分别用芬顿试剂和次氯酸钠梯度氧化后,进行芘的批量吸附实验.用O/C极性指数和TOC覆盖指数并辅助电镜扫描图对吸附系数进行拟合和解释.次氯酸钠氧化后云南土壤的O/C指数在高平衡浓度下(c=0.1cs,c=0.5cs)与lgKOC显著相关,R2达到0.752 7和0.859 9.次氯酸钠氧化的东灵山和云南土壤以及芬顿试剂氧化的云南土壤的TOC覆盖指数在高平衡浓度下对lgKOC也有很好的预测能力,R2介于0.221 5～0.887 8之间.芬顿试剂和次氯酸钠对土壤的氧化效果存在差异,芬顿试剂趋于将土壤表面的疏松结构氧化消减,使颗粒外表面更平滑,次氯酸钠溶液趋于将土壤表面氧化成更疏松的表观形态,增加表面积.土壤母质、有机质含量、组成和分布以及土壤氧化导致的疏松有机质的裸露等原因都可能成为影响土壤吸附芘的原因.

Mountain soil samples collected from Beijing Dongling Mountain and Yunnan Qujing were oxidated by Fenton reagent and sodium hypochlorite into gradients,respectively.Batch adsorption experiments for pyrene were carried out.The O/C polarity index,TOC coverage index and secondary electron microscope scan were used to fit and interpret the adsorption coefficients.The O/C polarity index could predict the single-point absorption coefficient of Yunnan soil（oxidized by sodium hypochlorite） well under two equilibrium concentrations（c=0.1cs,c=0.5cs）,and the R2 were 0.752 7 and 0.859 9,respectively.The TOC coverage index predicted single-point absorption coefficient well of Yunnan soil（both oxidized by sodium hypochlorite and Fenton regent） and Dongling soil（oxidized by sodium hypochlorite） for higher concentrations with R2 between 0.221 5 and 0.887 8,respectively.Fenton reagent and sodium hypochlorite presented different soil oxidation effects.Fenton reagent tended to decrease loose surface structure and smooth the outer surface of soil particles,while sodium hypochlorite solution tended to change soil surface into looser shape and increase surface area.Laboratory oxidation conditions control,soil type,content and distribution of soil organic matter,bareness of loose organic surface caused by the oxidation could affect the adsorption of pyrene on soil.