聚硫酸铁强化混凝除锑(V)作用机制探讨

以聚硫酸铁(PFS)为絮凝剂,考察强化混凝去除饮用水源水中五价锑(Sb(V))时原水p H值、PFS投量、共存阴离子(HCO3-和PO43-)及腐殖酸(HA)等对其去除效果影响及作用机制.结果表明,原水p H值对强化混凝过程Sb(V)存在形态及PFS的水解产物有重要影响,表现为较低p H值和较高PFS投量均有利于提高Sb(V)的去除率;由于竞争吸附作用的存在,共存阴离子与HA均对Sb(V)的混凝去除产生负面效应.此外,PFS除Sb(V)过程较为符合准二级动力学模型.

Discussion on action mechanisms of antimony(V) removal by enhanced coagulation with polymeric ferric sulphate

The impact of raw-water pH value, polymeric-ferric-sulphate (PFS) dosage, coexisting anion (i.e., bicarbonate and phosphate ions), and humic acid (HA) was explored on antimony (V) removal effect from drinking water sources by enhanced coagulation with PFS (as flocculant). In addition, the action mechanisms of removal process were also discussed. The results showed that pH value of raw water significantly affects antimony (V) existing forms and PFS hydrolysates during enhanced coagulation, reflected by an increase of antimony (V) removal efficiency with reducing pH value or increasing PFS dosage. As a result of competitive adsorption, coexsiting anion and HA have a negative influence on the removal of antimony (V) by coagulation. Moreover, antimony (V) removal process by PFS coagulation has been found to be more in line with the pseudo-second-order kinetic model.