低分子量有机酸对砖红壤动电性质的影响  

EFFECTS OF LOW-MOLECULAR-WEIGHT ORGANIC ACIDS ON ELECTROKINETIC PROPERTIES OF LATOSOLS

作　　者：李成保[1] 徐仁扣[1] 季国亮[1] 

机构地区：[1]中国科学院南京土壤研究所,南京210008

出　　处：《土壤学报》2004年第5期676-680,共5页Acta Pedologica Sinica

基　　金：国家自然科学基金 (No .40 2 710 62 );中国科学院知识创新工程领域前沿项目 (ISSASIP0 10 8);南京市科技计划项目 (2 0 0 3ZB0 10 3 )资助

摘　　要：研究了 5种低分子量有机酸 ,即醋酸、柠檬酸、马来酸、苹果酸和草酸 ,对昆明和徐闻两种砖红壤动电性质的影响。结果表明 ,在试验条件下 ,两种砖红壤的 ζ电位随醋酸浓度的递增逐渐正移 ,而后 ζ电位正移速率显著增大 ,再后 ζ电位渐趋稳定 ;两者的 ζ电位随柠檬酸浓度的增加向更负的方向移动 ,在试验浓度范围 (0～ 0 .1 5mmolL-1 )内 ,负移的速率没有明显差别。在pH 3.2至 6 .0之间 ,含有不同有机酸的两种砖红壤悬液的ζ电位均具有如下顺序 :醋酸 >马来酸 >苹果酸 >柠檬酸 >草酸 ;含同一有机酸的悬液在相同pH下的 ζ电位 ,昆明砖红壤总是高于徐闻砖红壤。在不同有机酸存在下 ,两种砖红壤悬液等电点的顺序与上述的 ζ电位顺序相同 ;对于相同处理来说 ,昆明砖红壤的等电点高于徐闻砖红壤者 0 .5～ 1 .0pH单位。Effects of five low-molecular-weight organic acids, i.e., acetic acid, citric acid, maleic acid, malic acid, and oxalic acid, on electrokinetic properties of two latosols-Kunming latosol and Xuwen latosol were investigated in this work. The results showed that under the experimental conditions with the increase in the concentration of acetic acid, the ζ potentials of Kunming latosol and Xuwen latosol were gradually shifting to the positive direction, and then the movement increased in velocity significantly, till the ζ potential leveled off. With the increase in the concentration of citric acid, however, the ζ potentials of Kunming latosol and Xuwen latosol moved towards a further negative direction, with the velocities being more or less the same between the two latosols within the range (0～0.15 mmol L -1) of the tested concentration. With the pH value ranging between 3.2 and 6.0, the ζ potentials of the two latosol suspensions containing different organic acids showed a decreasing order of acetic acid > maleic acid > malic acid > citric acid > oxalic acid; and the ζ potentials of suspensions containing the same organic acid were always higher for Kunming latosol than for Xuwen latosol. In the presence of different organic acids the isoelectric point (IEP) of the two latosols followed the same order as that of ζ potentials mentioned above; and as for the same treatment, IEP of Kunming latosol was 0.5～1.0 pH unit higher as compared with that of Xuwen latosol.

关 键 词：低分子量有机酸 砖红壤 动电性质 影响因素 

分 类 号：S153.2[农业科学—土壤学]