title: Preparation and coagulation efficiency of polyaluminium ferric silicate chloride composite coagulant from wastewater of high-purity graphite production.
abstract: The aim of the present work was to produce a polyaluminium ferric silicate chloride (PAFSiC) coagulant from acidic and alkaline wastewater of purifying graphite by roasting, and subsequently to evaluate coagulation efficiency of the reagent by treating surface water from the Yellow River as well as municipal wastewater in comparison with the conventional coagulant polyaluminium chloride (PAC). The PAFSiC coagulant was prepared by co-polymerization. The effects of (Al+Fe)/Si molar ratio, OH/(Al+Fe) molar ratio (i.e., y value), coagulant dosage and pH value of test suspension on the coagulation behavior of FAFSiC and the stability of the PAFSiC were also examined. Results showed that PAFSiC performed more efficiently than PAC in removing turbidity, chemical oxygen demand (COD), and total phosphate (TP). The PAFSiC with a y value of 2.0 and (Al+Fe)/Si ratio of 5 (PAFSiC 2.0/5) showed excellent coagulation effect for both turbidity and COD, while PAFSiC 1.0/5 was the best for TP. The optimum coagulation pH range of PAFSiC 2.0/5 was 5.0-9.0, slightly wider than that of PAC (6.0-8.0). The process can be easily incorporated into high-purity graphite production plants, thereby reducing wastewater pollution and producing a valuable coagulant.
authors: Henan Provincial Key Laboratory of Surface and Interface Science, School of Materials and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450002, China. niuxx@eyou.com
authors: Xiaoxia
authors: X
authors: Niu
authors: Xili
authors: X
authors: Li
authors: Jihong
authors: J
authors: Zhao
authors: Yigang
authors: Y
authors: Ren
authors: Yanqin
authors: Y
authors: Yang
mesh_terms: D000536:Aluminum Hydroxide / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D017640:Silicates; D000536:Aluminum Hydroxide; D006108:Graphite