砷酸根对砖红壤中铜吸附和解吸影响的初步研究

研究了加砷酸根对砖红壤吸附铜及随后吸附性铜的解吸的影响.结果表明,加砷后土壤对铜的吸附量和解吸量均增加.随砷加入量的增加,土壤对铜的吸附量和吸附性铜的解吸量均增加.在pH值为3 4至5 2范围内,砷对铜吸附的促进作用随pH值的增加而增加,约在pH值为4 5时达最大,然后逐渐减小.表面电荷的测定结果和铜的解吸实验结果均说明砷酸根主要通过自身的吸附来增加土壤的表面净负电荷,从而增加土壤对铜的吸附量.

Preliminary study on effect of arsenate on adsorption and desorption of Cu2+ by a latosol

The effect of arsenate on the adsorption and desorption of Cu~(2 ) by a latosol was investigated in this study. The results showed that the presence of arsenate induced the increase in the adsorption of Cu~(2 ) and the desorption of adsorbed Cu~(2 ), and the effect increased with increasing amounts of arsenate added. In the pH range from 3.4 to 5.16, the enhanced Cu~(2 ) adsorption by arsenate increased with increasing pH and reached the maximum effect at about pH4.5, followed by a decrease. The results from the desorption of adsorbed Cu~(2 ) and a separate investigation on surface charge demonstrated that the enhanced Cu~(2 ) adsorption by arsenate was mainly resulted from the increase in net negative surface charge of the soil due to the specific adsorption of arsenate. The determination of surface charge of the soil before and after the adsorption of arsenate showed that the presence of arsenate caused a decrease in positive surface charge and an increase in negative surface charge of the soil.