新生态铁的混凝作用探索

Exploration of Newly-Formed Ferric as the Coagulant

利用双氧水和亚铁瞬时反应制备新生态铁作为混凝剂,采用杯罐试验确定了最优制备条件老化时间、酸的添加量、n(H2O2)/n(Fe),并且通过对比新生态铁、硫酸铁、聚合硫酸铁分别对浊度、UV254吸光度的去除效果、沉后水Zeta电位来衡量新生态铁的混凝效果并推测其可能的反应机制.结果表明,老化时间对新生态铁的除浊效果影响极小,可忽略不计;添加酸浓度为[H+]=0.1 mol.L-1时制备出的新生态铁混凝效能最佳;提高n(H2O2)/n(Fe)可显著增强新生态铁的混凝效果,最为经济有效的摩尔比值为0.55.新生态铁对浊度的去除效果与硫酸铁、聚合硫酸铁相近;对UV254吸光度有机物的去除率比Fe2(SO4)3高20%～44%;沉后水Zeta电位随新生态铁投量增加逐渐趋近于0 mV,电中和作用较强.新生态铁是一种具有开发价值的新型混凝剂,老化时间极短,过程简化,原料价格低廉,对浊度、UV254吸光度去除效果较好.

A new coagulant was synthesized by oxidizing FeII with H2 O2 instantaneously.Key parameters in the preparation of the coagulant including aging time,acid volume,and n（H2 O2）/n（Fe） were investigated through jar tests.The optimized coagulant was then compared with Fe2（SO4）3 and PFS（poly-ferric sulphate） in residual turbidity,UV254,Zeta potential to evaluate its coagulation efficiency and infer the reaction mechanism.Aging time has a little effect on coagulation efficiency.The optimized acid concentration was 0.1 mol·L-1.Coagulation efficiency increased with n（H2 O2）/n（Fe）.0.55 is the most economical and efficient molar ratio.The removal efficiency of turbidity of the newly-formed ferric is similar to Fe2（SO4）3 or PFS.The removal efficiency of UV254 by newly-formed ferric is higher than that by Fe2（SO4）3 by 20%-44%.The Zeta potential of supernatant after being treated by newly-formed ferric gradually increased to 0 mV with the increasing coagulant dosage,indicating a strong effect of charge neutralization.The newly-formed ferric is a promising new coagulant with an extremely short aging time,a simple synthesis process,a lower cost than Fe2（SO4）3 or PFS by more than 50%,and a high removal efficiency of UV254 absorbance.