摘要
对三种不同类型土壤———棕红壤、黄棕壤、灰潮土在特定条件下的电荷零点(PZC) :ck—PZC(无硼 )、ads—PZC(硼吸附 )和des—PZC(硼解吸 )的研究发现 ,棕红壤和黄棕壤的ads—PZC与其ck—PZC相比 ,都有较为明显的下降。灰潮土 ,由于本身碳酸盐的缓冲作用 ,其ads—PZC与ck—PZC几乎相等。在硼吸附发生后 ,3种供试土壤的des—PZC较之它们的ads—PZC ,改变甚小 ,但这时灰潮土却保持强劲吸附电位离子的趋势 ,其吸附H+离子数量是棕红壤和黄棕壤的 2倍 ,表明在灰潮土上 ,原先被土壤胶体吸附的硼这时才显示利于电位离子的吸附。研究还表明 ,硼在酸性土壤中的吸附会引起 1
Three types of Point of Zero Charge (PZC), i. e . ck PZC (Without B), ads PZC(B adsorption) and des PZC(B desorption),were measured in brown red soil, yellow brown soil and calcareous alluvial soil collected from Hubei Province. The ads PZC, compared with its ck PZC, decreased by 0.9 pH unit for the brown red soil, and only by 0.3 pH unit for the yellow brown soil, but the corresponding adsorbed H + (the potential ion) increased by 3.3 cmol?kg -1 and 3.5 cmol?kg -1 , respectively. Therefore, if specific adsorption of B occurred, the buffering capacity of the yellow brown soil for environmental acid was higher than that of the brown red soil. The ads PZC of the calcareous alluvial soil was nearly equal to its ck PZC, and its adsorbed H + varied within 1.0 cmol?kg -1 . Most of the potential ion in electrolyte did not react with surface functional groups of soil colloid, but with calcium carbonate. Though the change in des PZC to ads PZC was small, the calcareous alluvial soil retained strong trend to adsorb H + at B desorption. The amount of adsorbed H + was two folds as much as that in the brown red soil or the yellow brown soil, which suggested that the accelerating effect of adsorbed B on H + adsorption by the calcareous alluvial soil just appeared at that time. The amount of B adsorbed changed with pH variation, which is connected with surface characteristics of soil colloids and B types. In lower pH range, net negative charge of soil surface was small, but B could combine with positive ion as ion pair, which was adsorbed on soil surface. The result also showed that the adsorption of B caused a ten fold increase of the adsorption of proton in acid soils.
出处
《土壤学报》
CAS
CSCD
北大核心
2002年第2期145-151,共7页
Acta Pedologica Sinica
基金
国家自然科学基金资助课题 (批准号 :3 9670 42 5 )
关键词
土壤胶体
表面性质
电位离子
硼
吸附
解吸
Soil colloid, Adsorption desorption of B, Surface properties, Potential ion
