沙漠颗粒物对磷酸盐的吸附动力学研究

Adsorption Kinetics of Phosphate on Desert Particles

研究了乌兰布和沙漠和库布齐沙漠颗粒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/解吸平衡质量浓度(EPC0值)。结果表明:①不同沙漠颗粒物对P的吸附能力各不相同,但吸附速率均在前8h内较快,以后逐渐趋缓,在48h时基本达到吸附平衡。磷初始浓度和颗粒物浓度均对颗粒物吸附P有一定影响;②颗粒物对P的吸附过程均符合准二级吸附动力学模型及Weber-Morris扩散方程,吸附过程主要由P在颗粒物内的扩散过程控制;③入河沙漠颗粒物在黄河水体中对P的吸附过程存在一个吸附/解吸平衡点,该点对应的不同颗粒物对P的EPC0值为0.010～0.042mg.L-1,且其值均大于相应黄河水体中的P浓度,说明沙漠颗粒物入河后有向水体释磷的趋势。

The adsorption kinetics and influencing factors,and adsorption-desorption equilibrium mass concentration（EPC0） of phosphate（P） on desert particles taken from the Ulan Buh Desert and the Kubuqi Desert were investigated,respectively.Results showed that：（1） adsorption of P on different desert particles was different,but the adsorption rates were faster within the 0—8th hour time,then gradually get slow at 8—48th hour time and basically tended to a dynamic equilibrium at the 48th hour;Both initial P concentration and desert particle concentration had some impact on P adsorption;（2） The adsorption of P on different desert particles followed the pseudo-secend order adsorption kinetic model and the Weber-Morris diffusion equation,and the adsorption process was mainly controlled by the P diffusion process in particles;and（3） Adsorption-desorption balance point of P on desert particles in the Yellow River were different and their EPC0 were in the range of 0.010 to 0.042 mg·L-1,which were higher than the P concentration in the Yellow River.The study indicates that there is release of P for desert particles to the Yellow River.