Coagulation Performance and Sludge Properties of A Coagulant Containing Titanium Derived from Titanium Dioxide Waste

A new coagulant, poly-Ti-Fe (M-PTF), was prepared using a kind of waste acid filter cake (WAFC) which was derived from production process of titanium dioxide as raw material. The microscopic characteristics of M-PTF were characterized by SEM, XRD and FTI. And coagulation performance and sludge properties of M-PTF in treating a domestic wastewater were studied using Jar test and fluorescence microscope (FM), compared with those of poly aluminum chloride (PAC). The results showed that the surface of M-PTF was composed of irregular and crystalline-like structures, and appeared to be rough and polymorphous networks having larger surface area. At a dosage of 2 mmol/L, M-PTF gave 29% higher organic matter (chemical oxygen demand, CODCr) removal than PAC, and had far greater sludge settling rate at starting point (44 mL/min) than PAC (2 mL/min). M-PTF sludge was a sort of fluffy and closely-connected catkins-like/cotton-like images with well-defined boundary and lower water content, while PAC sludge almost was a sort of transparent loose flocs without well-defined boundary. In addition, the sludge volume of M-PTF was much smaller than that of PAC, the water content of M-PTF sludge was lower 1.11%~2.41% than that of PAC sludge, corresponding to its sludge reduction of 71.28%~84.38% based on the sludge volume of PAC, which was largely beneficial to subsequent concentrating and dewatering. © 2019, Editorial Office of FINE CHEMICALS. All right reserved.