黄河中下游沉积物对磷酸盐的吸附动力学研究

研究了黄河中下游10个不同表层沉积物在黄河水体中对磷酸盐（P）的吸附动力学及其影响因素和吸附机理。结果表明：（1）不同黄河沉积物对P的吸附能力各不相同,但吸附量随时间的变化具有相同的变化趋势,吸附速率均在前8h内较快,以后逐渐趋缓,在48h时基本达到吸附平衡。不同黄河沉积物对P的吸附量均随P初始质量浓度的增加而增大,随沉积物含量增大而减小;（2）不同沉积物在不同P初始质量浓度下对P的吸附动力学均符合Lagergren二级吸附动力学模型及Weber-Morris扩散方程,求得二级吸附速率常数和扩散速率常数分别在11.9866～157.55g·mg^-1·h^-1和0.0005～0.0119mg·g^-1·h^-1/2之间,吸附过程由P在沉积物内扩散控制。

Adsorption kinetics of phosphate onto sediments from the middle and lower reaches of the Yellow River

The adsorption kinetics and its influencing factors,and adsorption mechanism of phosphate（P） onto 10 different sediments from the middle and lower reaches of the Yellow River in the Yellow River water were investigated.The results showed that：（1） The adsorption abilities of different sediments to P were different,but the change of P adsorption amount onto different sediments with time had the same trend,and adsorption rates were all faster within 0-8 h,then gradually getting slowly within 8-48 h and the adsorption tended to the dynamic equilibrium at 48 h.Both of initial P concentration and sediment concentration had certain impact on P adsorption kinetics,and P adsorption amount on different sediments increased with initial P concentration increasing and decreased with sediment content increasing.（2） At different initial P concentration,P adsorption kinetics onto different sediments all followed second-order adsorption kinetic model and Weber-Morris diffusion equation which second-order adsorption rate constants and diffusion rate constants obtained by were in ranges of 11.986 6-157.55 g·mg^-1·h^-1 and 0.000 5-0.011 9 mg·g^-1·h^-1/2,respectively.The P adsorption process was controlled by the intra-particle diffusion.