摘要

Aluminum formate (AF), a degradable and non-corrosive coagulant, was synthesized from aluminum hydroxide and formic acid. Polyamidine (PA), as a coagulation aid, was combined with AF for dye wastewater treatment. AF was characterized by XPS, FT-IR, viscosity, zeta potential, mass spectrum and XRD, and the flocculation properties of the dual-coagulation system were characterized by FT-IR and SEM. The results showed that COOH, Al2O3-Al and O-2-Al bonds were formed in the AF synthesis process, and AF had a higher molecular weight and higher charge neutralization ability than PAC. The hydrolysates of AF were determined to contain Al-13 Al-11 and Al-2, and the components of AF were confirmed to comprise a mixture including aluminum formate (C3H3AlO6) and its hydrate. When the color removal efficiency reached 100% in jar tests, the optimized dosage of AF/PA was 18.91/0.71 mg/L, while the optimized dosage of PAC/PA was 21.19/0.91 mg/L. According to the variance analysis, the interaction between AF/PA and PAC/PA were insignificant in macroscopic view. FT-IR spectrum indicated AF captured pollutant by means of C=C=O bond, PAC captured pollutant by delta =CH, -C=C- and delta =CH. Overall, although the coagulation mechanism of AF was different from that of PAC, AF/PA showed better coagulation efficiency than PAC/PA in dye wastewater treatment.