农业环境科学学报2012，Vol.31Issue(11)：2160-2173,14.
名山河流域黄壤组分对微团聚体吸附解吸镉的影响
Effect of Yellow Soil Components on Adsorption and Desorption of Cadmium by Microaggregates in Mingshan Watershed,Sichuan Province,China
摘要
Abstract
The four kinds of old alluvial yellow soil, including woodland, paddy fields, tea garden and dry land, collected from the Mingshan River, was used to investigate the effect of yellow soil components on adsorption and desorption of Cd2+ by microaggregates with isothermal adsorption method of equilibrium liquid and desorption method of NH4OAC and EDTA. The results showed that:the distribution of soil organic matter, free iron oxide and cation exchange capacity was basically the same in bulk soil and particle size of microaggregates, being the highest of yellow soil of Woodlang. The adsorbance of Cd2i increased with the initial concentration of Cd2+ before and after removing soil components. The adsorbance was diminishing as the following sequence: (<0.002 mm)>2～0.25 mm> bulk soil>0.053～0.002 mm>0.25～0.053 mm, being significantly positively correlated with OM, free iron oxides and CEC. The size relationship of adsorption reduction was the following sequence: removal of OM>removal of free iron oxide. The contribution of OM was much more than free iron oxide. The adsorption of Cd2+ in four patterns of yellow soil was exchange adsorption mainly to complexing adsorption supplemented. Freundlich equation best fitting effect adsorption isotherm reached a significant level. Before and after removing soil components adsorbance and initial concentration of Cd2+ had showed a nonlinear correlation. The equilibrium constant K was significantly positively correlated with soil organic matter, free iron oxide and cation exchange capacity. After removing soil components, K had decreased which adsorption capacity becamed smaller. The Kd was negatively correlated with initial concentration of Cd2+. NH4OAC desorption rate increased with initial concentration of Cd2+. According to the maximum of NH4OAC desorption rate, the size relationship was the following sequence:0.25～0.053 mm>0.053～0.002 mm>bulk soil>2～0.25 mm>(<0.002 mm), but EDTA desorption rate decreased with the increase of cadmium's initial concentration, whose decreasing regularity was contrary to NH40AC desorption rate. After removing soil components NH4OAC desorption rate increased significantly, while EDTA desorption rate reduced. The desorption rate of tea garden and dry land decreased, which of woodland and paddy fields increased. After removing soil components, non-exclusive adsorption was significantly positively related to total adsorbance, while specific adsorption was significant negative correlated with total adsorption.关键词
名山河流域/微团聚体/黄壤/Cd2+/吸附解吸Key words
Mingshan watershed/ microaggregates/ yellow soil/ Cd2+/ adsorption and desorption分类
资源环境引用本文复制引用
熊东,夏建国..名山河流域黄壤组分对微团聚体吸附解吸镉的影响[J].农业环境科学学报,2012,31(11):2160-2173,14.基金项目
四川农业大学双支计划项目(2012) （2012）
