Exploration of newly-formed ferric as the coagulant

A new coagulant was synthesized by oxidizing Fe^II with H₂O₂ instantaneously. Key parameters in the preparation of the coagulant including aging time, acid volume, and n(H₂O₂)/n(Fe) were investigated through jar tests. The optimized coagulant was then compared with Fe₂(SO₄)₃ and PFS (poly-ferric sulphate) in residual turbidity, UV₂₅₄, Zeta potential to evaluate its coagulation efficiency and infer the reaction mechanism. Aging time has a little effect on coagulation efficiency. The optimized acid concentration was 0.1 mol·L^-1. Coagulation efficiency increased with n(H₂O₂)/n(Fe). 0.55 is the most economical and efficient molar ratio. The removal efficiency of turbidity of the newly-formed ferric is similar to Fe₂(SO₄)₃ or PFS. The removal efficiency of UV₂₅₄ by newly-formed ferric is higher than that by Fe₂(SO₄)₃ by 20%-44%. The Zeta potential of supernatant after being treated by newly-formed ferric gradually increased to 0 mV with the increasing coagulant dosage, indicating a strong effect of charge neutralization. The newly-formed ferric is a promising new coagulant with an extremely short aging time, a simple synthesis process, a lower cost than Fe₂(SO₄)₃ or PFS by more than 50%, and a high removal efficiency of UV₂₅₄ absorbance.