Adsorption of phosphate from the Yellow River water by desert particles:Kinetics and equilibrium studies

The equilibrium and kinetic adsorption of phosphate(P) from the Yellow River water onto desert particles taken from the Ulan Buh and Kubuqi deserts were investigated.Effect of the initial concentration of P and particulate matter on the sorption was explored.The kinetic studies show that adsorption rate was faster within the 0-8th hour period,then gradually decreased at 8th-48th hour period and basically tended to a dynamic equilibrium at the 48th hour,but there exists an adsorption difference of P onto different desert particles.The uptake process of P followed the pseudo-second-order rate model and the Morris-Weber diffusion equation which indicates that the adsorption process was mainly controlled by P diffusion inside the particles.The equilibrium investigation obtained an adsorption-desorption equilibrium mass concentration(EPC0) of P from the Yellow River water on desert particles with the range of 0.010-0.042 mg/L,which is higher than present P concentration in the Yellow River.This study indicates that desert particles entering the river might release P to the Yellow River.