淮河中游泥沙对磷吸附/解吸规律

选取淮河中游泥沙,通过室内静态试验,研究泥沙对磷的吸附/解吸动力学和平衡过程。吸附/解吸动力学试验结果表明:泥沙对磷的吸附/解吸动力学过程均可分为快、慢2个阶段,快速反应阶段均发生在前1.5 h,但吸附速率远大于解吸速率,约为解吸速率的16倍。吸附/解吸平衡试验结果表明:泥沙对磷的固相平衡吸附量随液相磷质量浓度的增大而增大,在低浓度区其增速较快,当液相磷浓度进一步增大时其增速逐渐变缓;泥沙对磷的固相平衡解吸量随固相平衡吸附量的增加而增大;单位质量泥沙对磷的平衡解吸量约为平衡吸附量的16%~40%,被吸附的磷不能完全解吸,吸附过程与解吸过程并非可逆过程。泥沙对磷的截留能力与单位质量泥沙固相平衡吸附量呈线性正相关,淮河中游泥沙对磷的截留率达到0.847。

Phosphorus adsorption and desorption behavior of sediments in midstream of Huaihe River

Indoor static experiments were conducted to investigate the kinetics and equilibrium processes of phosphorus(P)adsorption and desorption by sediments collected from the midstream of the Huaihe River. The results of the kinetics experiments showed that the kinetics process of the P adsorption and desorption could be divided into a fast stage and a slow stage, and that the fast stage occurred in the first 1. 5 hours, while the adsorption rate was about 16 times of the desorption rate. The results of the equilibrium experiments showed that the amount of the solid phase equilibrium absorption of P by sediments increased with the liquid phase P concentration, and the increasing speed was faster when the liquid phase P concentration was low, but gradually slowed when the liquid phase P concentration further increased. The amount of the solid phase equilibrium desorption of P by sediments increased with the increase of the amount of the solid phase equilibrium absorption of P. The amount of equilibrium adsorption and desorption of P by sediments per unit mass was 16% to 40% of the amount of equilibrium adsorption of P. The adsorbed P could not be completely desorbed, which indicated that the adsorption process and the desorption process were not reversible. There was a linear positive correlation between the P retention capacity by sediments and the amount of solid phase equilibrium adsorption of P by sediments per unit mass, and the retention rate of P by sediments was 0. 847 in the midstream of the Huaihe River.