新型聚镧混凝剂的制备及其在低温低浊水中的深度除磷性能

Preparation of novel lanthanum coagulants and their deep phosphorus removal properties in low temperature and turbidity water

针对铁铝盐混凝剂在低温低浊水中深度除磷性能欠佳的问题,基于镧和磷酸根具有特异性亲和力的特性,选用溶胶-凝胶法以不同镧源、有机配体和原料(酸、碱、醇、水)配比制备了一系列聚镧混凝剂(LXC),所得材料中镧的质量分数均为30%~33%,混凝絮体颗粒尺寸达1600μm,且在5 min内即可完成沉降过程。以LaCl_(3)和聚氯化铝(PAC)为对照样品,评估了LXC对学校河水[温度为4~6℃,磷质量浓度为(1.0±0.1)mg/L]、阳澄湖水[温度为4~6℃,磷质量浓度为(0.1±0.3)mg/L]和石湖水[温度为4~6℃,磷质量浓度为(0.8±0.2)mg/L]的深度除磷、除浊性能。结果表明,相同投加量下LXC对不同水样的除磷效果均优于LaCl_(3)和PAC,适宜条件下混凝出水中残余磷质量浓度低于0.02mg/L,均达到深度除磷效果。该研究为深度除磷、缓解水体富营养化提供新的解决思路。

In view of the poor performance of Fe and Al coagulants in deep phosphorus removal in low temperature and low turbidity water,based on the specific affinity of lanthanum and phosphate,a series of polylanthanum coagulants(LXC)were prepared by sol-gel method with different lanthanum sources,organic ligands and raw materials(acid,alkali,alcohol,water).The mass fraction of lanthanum in the obtained materials was 30%~33%,and the particle size of the coagulation floc reached 1600μm.And the settlement process could be completed within 5 minutes.The deep phosphorus removal and turbidity removal performance of LXC on university river water[temperature of 4~6℃,phosphorus concentration of(1.0±0.1)mg/L],Yangcheng Lake water[temperature of 4~6℃,phosphorus concentration of(0.1±0.3)mg/L],and Shihu Lake water[temperature of 4~6℃,phosphorus concentration of(0.8±0.2)mg/L]were evaluated using LaCl_(3) and polyaluminum chloride(PAC)as control samples.The results showed that under the same dosage,LXC had better phosphorus removal performance on different water samples than LaCl_(3) and PAC.Under suitable conditions,the residual phosphorus concentration in the coagulated effluent was less than 0.02 mg/L,achieving deep phosphorus removal performance.This study provided new solutions for deep phosphorus removal and alleviating eutrophication in wave.