Titanium Coagulation Simplified Removal Procedure and Alleviated Membrane Fouling in Treatment of Antimony-Containing Wastewater

The removal of antimony (Sb) from textile and dyeing wastewater is a challenging task. To meet the discharge limit and the demand for water reuse, the currently available treatment process was complicated: first, coagulation with polyaluminum chloride (PAC) and polyacrylamide (PAM) prior to membrane filtration to remove turbidity and then coagulation with polyferric sulfate (PFS) after membrane filtration to remove Sb from the concentrate. Such a process is troublesome in operation and generates a large amount of hazardous sludge. Here, we report that using a titanium xerogel coagulant (TXC) prior to membrane filtration could simultaneously remove the turbidity and the residual Sb in one-step. With TXC as the coagulants, no after-membrane coagulation was needed. Moreover, the TXC coagulation significantly alleviated the membrane fouling. A 24-day running of a pilot-scale test demonstrates that addition of 60 mg/L of TXC reduced the residual Sb concentration in the effluent from 226–894 μg/L to below the discharge limit (