Preliminary study on effect of arsenate on adsorption and desorption of Cu2+ by a latosol
砷酸根对砖红壤中铜吸附和解吸影响的初步研究

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.