黑土对冻融有机质的吸附作用

Adsorption of Dissolved Organic Matter Treated with Freeze-Thaw on Black Soil

用批次实验方法研究黑土对冻融溶解性有机质(DOM,来源于秸秆和污泥)的吸附作用.结果表明,在DOM平衡质量浓度范围内,多数情况下DOM不仅未被黑土吸附,反而促进黑土有机质的解吸释放.与未冻融DOM相比,冻融DOM对黑土有机质的解吸释放作用更强.冻融DOM对黑土有机质的解吸释放作用受体系pH值、离子强度和离子类型影响较大:DOM对黑土有机质的解吸作用随pH值的增加和离子强度的降低而增加;当离子类型为二价阳离子Ca2+时,DOM对黑土有机质的解吸作用大于离子类型为一价阳离子的情形;在不同阴离子条件下,DOM对黑土有机质的解吸作用为Cl->SO24->NO3-.

Batch experiments were conducted to investigate the sorption of dissolved organic matter（DOM） derived from straw and sludge treated with freeze-thaw on black soil.The results showed that in most cases,the DOM that can not be adsorbed onto the black soil facilitated the release of the organic matter from black soil in the range of the equilibrium concentration of DOM.Compared with the DOM from non-frozen straw and sludge,the DOM from the straw and sludge treated by freeze-thaw increased the desorption and release of the organic matter of black soil obviously,and it was greatly affected by the pH value,ion strength and ion type of the solution system.The desorption of the organic matter of black soil by DOM increased with the increase of pH and the decrease of ion strength.When the ion type was CaCl2 of divalent cation,the desorption of the organic matter of black soil by DOM was greater than that when the ion type was monovalent cation.In the presence of the different anions,the desorption order of the organic matter of black soil by DOM was Cl^-〉SO4^2-〉NO3^-.