Removal of phosphate from polluted water by lanthanum doped vesuvianite

The adsorption capacities of vesuvianite and lanthanum doped vesuvianite were studied. The effects of different mass ratios of La/vesuvianite at different contact times, pHs, and temperatures on adsorption capacity were also studied. It was found that lanthanum doped vesuvianite exhibited higher adsorption capacity than undoped one due to the reaction of bounded lanthanum with phosphate. The adsorption capacity of lanthanum doped vesuvianite for phosphate removal increased with the increase of La/vesuvianite mass ratio. The Freundlich and Langmuir models were used to simulate the sorption equilibrium, and the results indicate that the Langmuir model had a better correlation with the experimental data than the Freundlich model did. When the initial phosphate concentration was 1 mg P/L, the adsorptive capacity rate would be 1.32 mg P/g lanthanum doped vesuvianite (La/vesuvianite mass ratio ≥0.14) at pH between 6 and 9 after 40 h. The concentrations of residual lanthanum ions in solution at different conditions were measured. Lanthanum doped vesuvianite was also used for the removal of phosphate in a polluted river water and it could be easily recycled once without losing its activity to a greater extent.     

改性火山石-PAC复合絮凝剂处理城镇生活污水试验研究

利用改性火山石作为助凝剂处理城镇生活污水,在聚合氯化铝(PAC)的投加量为70 mg.L-1的条件下考察了改性火山石的投加量、反应时间及反应pH对各污染物的去除效果。正交试验L9(33)结果表明,当改性火山石投加量为4 g.L-1,反应时间为20 min及pH为8.5时,对TN、TP、COD的去除效果较好,分别为48.15%、82.25%和92.57%;当改性火山石投加量为8 g.L-1,反应时间为60～70 min、pH为8.5～9.0时,对氨氮的去除率达到最大26%～30%。