磷酸盐对不同铝混凝剂混凝处理过程中铝水解和Al(OH)_(3)聚集的影响  

Effect of phosphate on aluminum hydrolysis and Al(OH)_(3) aggregation during coagulation treatment with different aluminum coagulants

作　　者：赵博 季蒙 宋永会[2] 孟晓光[1] ZHAO Bo;JI Meng;SONG Yonghui;MENG Xiaoguang(Center of Environmental Systems,Stevens Institute of Technology,Hoboken,NJ 07030,USA;State Key Laboratory of Environmental Criteria and Risk Assessment,Chinese Research Academy of Environmental Sciences,Beijing 100012)

机构地区：[1]史蒂文斯理工学院环境系统中心,霍博肯,新泽西州07030,美国 [2]中国环境科学研究院,环境基准与风险评估国家重点实验室,北京100012

出　　处：《环境科学学报》2023年第12期16-25,I0006,共11页Acta Scientiae Circumstantiae

摘　　要：通过批次实验、透射电子显微镜(TEM)、^(31)P核磁共振(NMR)及傅立叶红外(FTIR)等多种方法,系统研究了硫酸铝(Alum)、聚合氯化铝(PACl)及预混凝硫酸铝(PPA)对磷酸盐的去除效率及其水解团聚过程中磷的影响.结果表明,Alum在磷去除效率上优于PACl和PPA. Alum和PACl能在数分钟内达到磷去除平衡,而PPA则需44 d.相较于预混凝,混凝过程中磷酸盐吸附与铝聚合的竞争作用限制了铝(氢)氧聚合物的生长,从而导致絮体粒径较小,结晶度较差,提供了更高的比表面积和去除效率.这种竞争作用来源于磷酸根与铝(氢)氧聚合物之间形成的稳定Al—O—P键. ζ电位分析证明了混凝过程中磷酸盐被掺入铝(氢)氧聚合物内部,这也提高了Alum组的磷去除效率.而在用PACl和PPA时,初始高度聚合的铝(氢)氧聚合物降低了磷去除能力.在长达44 d的老化过程中,磷酸根导致絮体先部分溶解再聚合,其中,磷酸盐被进一步吸附(Alum和PPA组)或始终固定在絮体内(PACl组),从而减少磷释放风险.本研究为含磷废水处理的混凝剂选择和机制理解提供了重要的科学依据.The phosphate removal efficiency of aluminum sulfate(alum),poly aluminum chloride(PACl)and pre-precipitated aluminum sulfate(PPA)and the effects of phosphate on their hydrolysis and aggregation were systematically evaluated using batch experiments,transmission electron microscopy(TEM),^(31)P nuclear magnetic resonance(NMR),and Fourier-transform Infrared(FTIR)spectroscopy.The results showed that alum outperformed PACl and PPA in phosphate removal.Phosphate removal by alum reached equilibrium within minutes,whereas it took 44 days for PPA to reach phosphate removal equilibrium.The competition between phosphate adsorption on aluminum hydroxides and the polymerization of aluminum hydroxide during the coagulation process limited the growth of aluminum hydroxide polymers,resulting in smaller aluminum hydroxide flocs with poorer crystallinity,higher specific surface area,and higher phosphate removal efficiency.The phosphate competition was attributed to the formation of stable Al—O—P bonds.ζpotential analysis showed that the incorporation of phosphate into the aluminum hydroxide polymer increased the phosphate removal efficiency of alum.On the other hand,the high degree of polymerization of aluminum hydroxide polymer in PACl and PPA reduced their phosphate removal capacities.During 44 days of aging period,the flocs underwent partial dissolution and re-aggregation,and phosphates were further adsorbed(in alum and PPA treatment)or immobilized(in PACl treatment)in the aluminum hydroxide flocs,minimizing phosphate release risk.This study provides important scientific basis for coagulant selection and mechanism understanding in the treatment of phosphorus containing wastewater.

关 键 词：混凝 除磷 硫酸铝 聚合氯化铝 氢氧化铝 

分 类 号：X131.2[环境科学与工程—环境科学] X703