研究论文
薛含斌,符岩,汤鸿霄.镉与天然固体表面络合物的条件稳定常数[J].环境科学学报,1986,6(1):50-57
镉与天然固体表面络合物的条件稳定常数
- CONDITIONAL STABILITY CONSTANTS OF THE SURFACE COMPLEXES OF CADMIUM AND NATURAL SOLIDS
- 摘要：本文研究天然固体、伊利土和湘江悬浮沉积物从水中吸附极低浓度（ppb级）的镉时吸附量随pH的变化;同时研究不同pH值时的吸附等温线。根据简单的表面络合模式,利用线性关系及其分配系数,求取不同pH值时的天然固体与镉形成的表面络合物的条件稳定常数。条件稳定常数随pH值的上升,分为两个区域而呈线性增长。据此求得表面络合反应的条件络合常数。镉与伊利土和湘江悬浮沉积物的表面络合物条件稳定常数分别为3.0—1.8×102和0.8—2.5×102（pH5.0—8.5）.低pH区
- Abstract：The adsorption of cadmium (in ppb order) on illite and sediment collected from Xiangjiang River was examined. The adsorption isotherms at different pH were constructed. The conditional stability constants of cadmium and the solids complexes at given pH were obtained based on a simple surface complex model. The plots of the conditional stability constant against pH value could be divided into two regions in which the constants were linearly correlated to pH. Conditional complexation constants were derived from those plots and were independent of pH. The conditional stability constants of the cadmium and illite complex were 3.0-1.8×102 and the cadmium and the sediment complex were 0.8-2.5×102 in the pH range from 5.0 to 8.5. The conditional complex constants for two complexes were 3.3×10-2 and 2.8×10-2 respectively in the low pH region and were 5.6×10-5 and 8.5×10-8 respectively in the high pH region.
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