摘要
铁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,但其稳定性差,易发生自聚,形成沉淀、失去混凝效能.因此,制备一种稳定高效的铁基复合混凝剂受到广泛的研究.针对以上问题,本研究提出一种新型稳定的铁基复合混凝剂聚磷氯化铁镁钛(PFMTC)的制备方法.以氯化铁、四氯化钛、氯化镁、磷酸氢二钠为原料,单因素法确定PFMTC最优合成条件为:反应温度为50℃,n(Mg)/n(Fe)为1.0,n(Ti)/n(Fe+Mg)为0.5,n(OH)/n(Ti+Mg+Fe)为0.5,n(PO_4^(3-))/n(Fe)为0.3.Ferron逐时络合比色分光光度法分析PFMTC中Fe的形态;红外光谱、X-射线衍射、扫描电镜与能谱对PFMTC结构形貌、组成进行表征分析.Ferron逐时络合比色分光光度法研究显示,PFMTC的混凝性能的优劣受混凝剂多因素(温度、Mg、Ti、碱化度与PO_4^(3-))调控,从而影响混凝剂中Fea、Feb、Fec(Fea表示自由离子铁离子与铁的单核羟基络合物; Feb表示一系列铁的多核羟基络合物或称低聚合度铁的无机高分子; Fec表示铁的高聚物和铁的失稳溶胶或凝胶形态)三者含量的变化.表征分析显示,PFMTC是一种多羟基的铁镁钛聚合物,含有的新基团键(如Ti—P—Ti、Fe—P—Fe、Fe—O—Ti),其有助于延长PFMTC分子链提高其分子量; PFMTC结构单元呈现交联紧密的空间立体网状结构,有助于吸附架桥和网捕卷扫,增强PFMTC的混凝性能.
Iron-based coagulants are important water treatment agents used in coagulation. However, such coagulants are limited by their poor stability due to self-polymerization, precipitation formation, and low coagulation efficiency. Therefore, preparation of stable and efficient iron-based composite coagulants is important. In this study, a new stable iron-based composite coagulant named polychlorinated ferric phosphate, magnesium titanium (PFMTC) was prepared. Ferric chloride, titanium chloride, magnesium chloride, and hydrogen phosphate sodium were used as raw materials for PFMTC preparation. The optimum synthesis conditions of PFMTC were as follow:reaction temperature of 50℃, n(Mg)/n(Fe) of 1.0, n(Ti)/n(Fe+Mg) of 0.5, n(OH)/n(Ti+Mg+Fe) of 0.5, and n(PO4^3-)/n(Fe) of 0.3. The morphology of Fe in PFMTC was analyzed by Ferron timed complexometric colorimetric spectrophotometry. The structure and composition of PFMTC were characterized by FTIR spectroscopy, X-ray diffraction, scanning electron microscopy, and energy spectroscopy. Results of Ferron hourly complexometric colorimetric spectrophotometry showed that the coagulation performance of PFMTC was influenced by many factors (temperature, Mg content, Ti content, basicity, and PO43- content), which further influenced the Fea, Feb, and Fec (Fea represented iron ion and a mononuclear hydroxy complex of iron; Feb represented a series of iron polynuclear hydroxy complexes or inorganic polymers of low degree of polymerization iron; Fec standed for iron polymers and destabilized sol or gel morphology of iron) contents in the coagulant. Characterization analysis showed that PFMTC is a polyhydroxy iron magnesium titanium containing polymer with new bonds (e.g., Ti-P-Ti, Fe-P-Fe, and Fe-O-Ti) that extend the molecular chain of PFMTC and increase its molecular weight. The structural unit of PFMTC has a tightly cross-linked spatial network structure that contributes to the adsorption bridge and net scavenging and enhances the coagulation properties of PFMTC.
作者
张鹏
王雨露
赵冬琴
廖为雄
ZHANG Peng;WANG Yulu;ZHAO Dongqin;LIAO Weixiong(School of Civil Engineering, Hunan University of Science & Technology, Xiangtan, 411201, China)
出处
《环境化学》
CAS
CSCD
北大核心
2018年第12期2677-2687,共11页
Environmental Chemistry
基金
国家自然科学基金(41502331)
湖南省自然科学基金(2018JJ3174)资助.
关键词
混凝
聚磷氯化铁镁钛
浊度
Ferron光度法
coagulant
polychlorinated ferric magnesium titanium
turbidity
ferron by phase complexation colorimetric spectrophotometry
