摘要：
As one of the most important water treatment agents,polysilicate coagulant,has been playing an important role in co-agulation-flocculation,but it is prone to lose stability due to self-polymerization and the forming of silica gel.Therefore,re-search on the preparation of stable polysilicate coagulant has attract great attention.A new method to prepare a stable polysili-cate coagulant (PSPF),was proposed in this paper.Its structure and morphology were characterized by using Fourier transform infrared (FTIR)spectroscopy and scanning electron microscopy (SEM)respectively.Fe species in PSPF was analyzed via Fe-Ferron complexation timed spectrophotometric method.The performance of PSPF was assessed by measuring micro-polluted wa-ter treatment efficiency.Primary chemicals,such as ferrous sulfate,sodium silicate,potassium dihydrogen phosphate,sodium carbonate,were used.The influence of those parameters affecting the preparation of PSPF,such as n Si Fe ,n P Fe and n OH Fe molar ratios were examined.The results showed that n Si Fe of 1 ∶4,n P Fe of 1 ∶6 and n OH Fe of 1 ∶ 10 under 60 °C water bath for 30 min was the optimum condition for preparation.The FTIR spectrum indicated that PSPF was a kind of high molecu-lar polymer,containing new groups (e.g.,Si—O—Si and Fe—O—Si),which could increase the molecular weight,molecular chain and coagulation-flocculation efficiency.PSPF presented a cluster appearance similar to a network structure,which was conductive to adsorption-bridging capacity and precipitation sweeping.The increase of Fe(b)and Fe(c)as a result of Si increas-ing in PSPF improved the polymerization and solidification.The coagulation behaviors of PSPF that were largely affected by the coagulant dosage and pH,indicated that for pH and dosage at 6 and 8 mg·L-1 ,respectively,the residual turbidity and UV254 removal efficiency could achieve 0.33 NTU and 58.6%,respectively.%聚硅酸基混凝剂是重要的水处理剂之一,在混凝过程中扮演重要的作用,但易于产生自聚反应、形成硅胶、失去稳定性。因此,制备稳定的聚硅酸基混凝剂受到广泛关注。为获得一种稳定的聚硅酸基混凝剂,提出一种新型稳定的固体硅酸基混凝剂(PSPF)的制备方法。采用红外光谱与扫描电镜表征 PSPF 的结构与形貌；Ferron 逐时络合比色分光光度法分析 PSPF 中 Fe 的形态；通过微污染源水的处理评估 PSPF 的混凝性能。以硫酸亚铁、硅酸钠、磷酸二氢钾、碳酸钠等为原料,确定硅铁摩尔比(n Si／n Fe )、磷铁摩尔比(n P／n Fe )与碱化度(n OH／n Fe )对 PSPF 的制备影响。结果显示在60°C水浴30 min 条件下,PSPF 最优合成条件为：n Si／n Fe 为1∶4,n P／n Fe 为1∶6与 n OH／n Fe 为1∶10。表征分析显示,PSPF 是一种高分子聚合物,含有的新基团键(例如,Si—O—Si 与 Fe—O—Si),其有助于增大 PSPF 分子量与分子链与增强 PSPF 的混凝性能；PSPF 形貌团簇,呈网状结构,有助于吸附架桥和网捕卷扫；Si 含量增加提高了 PSPF 中 Fe(b)和 Fe(c)的含量,增强了 PSPF 的聚合度与固化效果。PSPF 的混凝性能受 PSPF 投加量与水环境 pH 影响显著；在 pH 为6与投加量为8 mg·L-1时,残余浊度和 UV254去除率分别可达0.33 NTU 与58.6%。实验研究显示,混凝剂多因素(Si,Fe 与 P)调控对增强固体聚硅酸基混凝剂的固化效果、稳定性以及混凝性能具有良好的效果。
