含磷废水中稀土除磷及沉淀剂再生

基于已有热力学数据,对稀土除磷过程及沉淀产物的再生过程分别进行了热力学计算,绘制了25℃下lg c?pH图,为含磷废水中磷的资源化利用和无害化处置提供理论支撑。结果表明:采用稀土处理含磷废水时在pH 2.70~8.66范围内沉淀,可生成稳定的LaPO4(和CePO4)沉淀,实现磷的去除;再生过程pH在14.5~16.0范围内,LaPO4(和CePO4)可转变为La(OH)3(和Ce(OH)3)实现沉淀剂的再生与磷的回收。采用La(OH)3和Ce(OH)3处理30 mg/L的含磷溶液,磷沉淀率分别为99.72%和96.33%;采用4 mol/L的NaOH溶液分解沉淀产物,反应3 h后La(OH)3和Ce(OH)3的再生率分别为30.38%和63.38%。

Removal of phosphate and precipitant regeneration from phosphorus-containing wastewater by rare earth

Based on the available thermodynamic data,the thermodynamic calculation of the phosphorus removal process with rare earth and the regeneration process of precipitation products were carried out,respectively.And the lg c?pH diagram at 25℃was drawn to provide theoretical support for the resource utilization and harmless disposal of phosphorus in phosphorus-containing wastewater.The analysis shows that stable LaPO4(and CePO4)precipitation can be generated within the pH range of 2.70?8.66 to remove phosphorus.During the regeneration process,LaPO4(and CePO4)can be transformed into La(OH)3(and Ce(OH)3)in the pH range of 14.5?16.0 to achieve precipitation regeneration and phosphorus recovery.The results show that when La(OH)3 and Ce(OH)3 were used to treat 30mg/L phosphorous solution,the phosphorus precipitation rates are 99.72%and 96.33%,respectively.After 3h reaction,the regeneration rates of La(OH)3 and Ce(OH)3 are 30.38%and 63.38%,respectively.