Effects Of Sediment Particle Size On Phosphate Adsorption Characteristics In The Lake Wuliangsuhai

Entrofication of lakes has been becoming one of the global aquatic eco-environment problems. It has been proved that phosphorus is one of the key contaminants contributing to the entrofication of lakes. It is dissolved and adsorbed in both the water body and the sediment and dynamically transport in between. It was reported that the transport processes were affected by many factors like physical, chemical, hydrogeochemical, mineralogical etc, among which the particle size of the sediment play an important role in adsorption characteristics of phosphorus.To get better understanding on the effects of the adsorption characteristics of phosphorus in the lake Wuliangsuhai, the sediment was sampled and sieved into four groups with the particle sizes of less than 63μm, 63-125μm, 125-250μm and great than 250μm individually. Lab experiments were carried out on phosphorus adsorption dynamics. The results showed that the adsorption processes were affected significantly by the particle size. The higher adsorption rates appeared in the first 45min for all the treatments with different particle sizes. Meanwhile, the rates were varied with the particle size through out the test period, the greater of the particle size the lower of the adsorption rate. The adsorption processes showed the best agreement with both the second-order equation and Langmuir model in the higher concentration solution. The amount of the phosphorus adsorption had a liner relationship with the initial substrate concentrations and the balanced concentrations. The test results also suggested that the phosphorus adsorption was an endothermic reaction, the higher of the temperature the more of the phosphorus was adsorbed. pH of the solution also affected the amount of the phosphorus adsorption, which was increased from the acid to the alkaline conditions.