Cationic polyacrylamide as coagulant aid with titanium tetrachloride for low molecule organic matter removal

摘要

This is the first attempt to use cationic polyacrylamide (PAM) as coagulant aid with titanium tetrachloride (TiCl_4) to improve the coagulation performance and floe properties. Coagulation-flocculation treatment was applied to simulated water (with fulvic acid (FA) as model organic matter) for both coagulation behavior investigation and floe characterization. The effect of PAM on floe reformation properties after cyclic breakage/regrowth was also investigated. Ultrafiltration experiments were performed to investigate the influence of PAM aided TiCU coagulation on the membrane fouling. The results showed that organic removal was enhanced by PAM addition at low TiCU doses. Floe growth rate and floe size were significantly affected by dosing sequence. TiCU-PAM significantly improved the floe strength factors (S_f) and recovery factors (R_f). The dosing sequence of TiCU and PAM significantly influenced the floe structure. Characterization of the flocculated sludge indicated that TiO_2 with anatase structure and high photocatalytic activity could be obtained from the TiCU-PAM flocculated sludge.