不同NaNO3浓度下可变电荷土壤铜离子解吸率的分配及影响因素  

DISTRIBUTION OF CU(Ⅱ) DESORPTION RATE IN VARIABLE CHARGE SOILS RELATIVE TO CONCENTRATIONS OF NANO_3 AND ITS AFFECTING FACTORS

作　　者：张政勤[1] 罗文贱[1] 陈勇[1] 杨少海[1] 邹献中[1] 

机构地区：[1]广东省农业科学院农业资源与环境研究所,农业部南方植物营养与肥料重点实验室,广东省养分资源循环利用与耕地保育重点实验室,广州510640

出　　处：《土壤学报》2015年第5期1188-1195,共8页Acta Pedologica Sinica

基　　金：广东省中小企业发展资金项目“农田重金属污染阻控产品的产业化与推广”资助

摘　　要：研究了江西红壤和昆明铁质砖红壤在去离子水中和在0．1molL^-1 NaNO3溶液中吸附铜离子后，依次在包括去离子水在内，浓度由低到高的NaNO3溶液中解吸时，铜离子解吸率在不同吸附pH段的分配规律。结果表明，随着吸附pH的升高，可在去离子水中解吸的铜离子解吸率变化规律与在NaNO3溶液中者完全不同。在所研究的吸附pH范围内，大致以吸附pH3．7～4．0为界，低于此值时，吸附性铜离子基本以在去离子水中解吸为主，反之则基本为交换性解吸。土壤中氧化铁含量和吸附时溶液的NaNO3浓度越高，则能被交换解吸的铜离子所占总解吸率的比例越低。其原因与不同pH段各种铜离子吸附态在不同吸附条件下的比例分配以及解吸对体系pH的影响有关。An adsorption and desorption test was conducted of two variable charge soils （Ali-Haplic Acrisol from Jiangxi and Hyper-Rhodic Ferralsol from Kunmin of Yunnan ） to explore distribution of desorption rates of pre-adsorbed Cu （ Ⅱ ） from the soils in NaNO3 solution relative to concentration of the solution and pH, at which Cu （Ⅱ） was adsorbed during the pre-adsorption phase. For the test, the soil samples were first put into de-ionized water and 0.1 mol L-1 NaNO3, separately, for pre-adsorption of Cu （Ⅱ） and then into de-ionized water and NaNO3 solutions varying in concentration gradually from low to high, sequentially, for desorption of Cu （ Ⅱ ） . Results show that with rising pH, Cu （ Ⅱ ） desorption rate varied sharply with NaNO3 solution. In de-ionized water, Cu （Ⅱ） desorption rate declined monotonously with the rise of pH in the Cu （ Ⅱ ） pre-adsorption phase; while in NaNO3 solutions, Cu （ Ⅱ ） desorption ratefollowed a peak-shaped curve, but the total Cu （ Ⅱ ） desorption rate also declined monotonously with the rise of pH in the Cu （ Ⅱ ） pre-adsorption phase. The Cu （ Ⅱ ） desorption rate was the highest in the solution of 0.1 mol L-1 NaNO3. In short, desorption rates of the Cu （Ⅱ） desorbable in de-ionized and in NaNO3 solutions were distributed mainly in the high and low sections, respectively, of the range of pH studied. Desorption rate of the Cu （ Ⅱ ） desorbable in NaNO3 was closely related to content of ferric oxide in the soils and NaNO3 concentration in Cu （ Ⅱ ） pre-adsorption, so the higher the content of ferric oxide in the soil, or the higher the NaNO3 concentration in pre-adsorption at pH 〉 4.0 - 4.5, the lower the proportion of Cu （ Ⅱ ） desorbed by NaNO3. The cause of such a phenomena is believed to be associated with the effect of ion-strength, specific weight of exchangeable Cu （ Ⅱ ） relative to adsorption condition and the effect of desorption on pH of the system. Besides, comparison was also made

关 键 词：可变电荷土壤 铜离子 解吸率分配 连续解吸 NaNO3浓度 

分 类 号：S153.2[农业科学—土壤学]