Cu secondary adsorption by three variable charge soils collected from hubei Province and Hunan Province was investigated.The amount of Cu secondary adsorption increased with that of SO4^2- elementary adsorption and co...Cu secondary adsorption by three variable charge soils collected from hubei Province and Hunan Province was investigated.The amount of Cu secondary adsorption increased with that of SO4^2- elementary adsorption and conformed with the Langmuir,freundlich and Temkin isotherms.Desorption of secondary-adsorbed Cu indicated that the hysteresis ratio decreased as Cu secondary adsorption increased,which meant that secondry-adsorbed Cu existed not only in the exchangeable form but also in the bridge form and specifically adsorbed form.The amount of Cu secondary adsorption increased with the temperature.展开更多
The effects of sorbed phosphate on the kinetics of Cu￣2+ secondary adsorption on three major types ofsoils in southern and Central China were studied using the batch method and flow (or miscible displacement)techniqu...The effects of sorbed phosphate on the kinetics of Cu￣2+ secondary adsorption on three major types ofsoils in southern and Central China were studied using the batch method and flow (or miscible displacement)techniques. Both of the methods showed that diffusions were the ratedetermining steps in the Cu￣2+ adsorp-tion by the soils. By the flow method, the course of Cu￣2+ adsorption kinetics consisted of two steps-sn initialrapid process and a later slow process of Cu￣2+ adsorption; while by the batch method, the 90% of Cu￣2+adsorption reaction was found to finish within first 1 minute. The results obtained using the flow method alsoindicated that for red soil and yellow-brown soil, Cu￣2+ adsorptions during the initial reaction periods wererestrained when the soils sorbed phosphate, whereas the adsorption reactions were stimulated at the finaltime. For grey Chao soil, sorbed phosphate retarded the Cu￣2+ adsorption in the whole reaction period. Theresults obtained using the batch method and flow techniques all implied that the different effects of sorbedphosphate would be attributed to its effects on Cu￣2+ ion diffusion in soil solution.展开更多
基金Project supported by the Laboratory of Material Cycling in Pedosphere, Academia Sinica.
文摘Cu secondary adsorption by three variable charge soils collected from hubei Province and Hunan Province was investigated.The amount of Cu secondary adsorption increased with that of SO4^2- elementary adsorption and conformed with the Langmuir,freundlich and Temkin isotherms.Desorption of secondary-adsorbed Cu indicated that the hysteresis ratio decreased as Cu secondary adsorption increased,which meant that secondry-adsorbed Cu existed not only in the exchangeable form but also in the bridge form and specifically adsorbed form.The amount of Cu secondary adsorption increased with the temperature.
文摘The effects of sorbed phosphate on the kinetics of Cu￣2+ secondary adsorption on three major types ofsoils in southern and Central China were studied using the batch method and flow (or miscible displacement)techniques. Both of the methods showed that diffusions were the ratedetermining steps in the Cu￣2+ adsorp-tion by the soils. By the flow method, the course of Cu￣2+ adsorption kinetics consisted of two steps-sn initialrapid process and a later slow process of Cu￣2+ adsorption; while by the batch method, the 90% of Cu￣2+adsorption reaction was found to finish within first 1 minute. The results obtained using the flow method alsoindicated that for red soil and yellow-brown soil, Cu￣2+ adsorptions during the initial reaction periods wererestrained when the soils sorbed phosphate, whereas the adsorption reactions were stimulated at the finaltime. For grey Chao soil, sorbed phosphate retarded the Cu￣2+ adsorption in the whole reaction period. Theresults obtained using the batch method and flow techniques all implied that the different effects of sorbedphosphate would be attributed to its effects on Cu￣2+ ion diffusion in soil solution.
