低分子量有机酸对砖红壤表面电荷的影响

Effect of Low-molecular-weight Organic Acids on Surface Characteristics of Latosols

本文研究了4种低分子量有机酸对砖红壤表面电荷性质的影响,结果表明存在于体系中的有机酸增加了表面负电荷量,同时减少表面正电荷的量。在低有机酸加入量下,有机酸对正电荷的影响程度比其对负电荷的影响程度大得多。4种酸对土壤表面电荷影响的大小顺序为:柠檬酸>苹果酸>草酸>醋酸。有机酸对表面电荷的影响随体系pH而变化,它们对正电荷的影响程序随pH的增加而减小,而对负电荷的的影响呈相反的变化趋势。有机酸主要通过其阴离子在土壤表面的吸附来影响土壤的表面电荷性质。

In the present paper,the effect of four low-molecular-weight organic acids on surface charges of two latosols was investigated.The results showed that the presence of organic acids led to an increase in negative charges and a decrease in positive charges.At low additions of organic acids positive charges decreased to a larger extent than the increase in negative charge.The effect of different organic acids on surface charge followed the order:citrate>malate>oxalate>acetate.The effect of organic acids on surface charges changed with pH.The change of positive charges decreased with the increase in pH,while that of negative charges incereased with the increase in pH.Organic acids affected the surface charge through the adsorption of organic anions on soils.