Synthesis and application of polyferric chloride–poly (epichlorohydrin–dimethylamine) composites using different crosslinkers

By the premixing of polyferric chloride (PFC) and poly-epichlorohydrin–dimethylamine (DAM–ECH), a novel composite material (PFC–DAM–ECH) was prepared and then utilized for the coagulation treatment of simulated reactive brilliant red dye wastewater in this study. The influence of OH/Fe molar ratio (B value), Fe to DAM–ECH mass ratio (Mr value) and cross-linker type (ethylenediamine, diethylenetriamine, and triethylenetetramine denoted as EDM, DTM and TTM, respectively) on color removal efficiency and zeta potential was extensively investigated as functions of flocculants dosage and dye wastewater pH. The decolorization performance and charge neutralization ability of composite PFC–DAM–ECH flocculant were studied in comparison with those achieved by single use of PFC and DAM–ECH. Experimental results indicated that synergic effect of PFC and DAM–ECH improved the color removal efficiency and charge neutralization ability of composite PFC–DAM–ECH. At the conditions of lower B value, higher Mr value and TTM as cross-linker, PFC–DAM–ECH provided higher decolorization effect and stronger charge neutralization effect. In addition, decolorization effect with the composite material is quite effective within the pH range of 6–7.5 for simulated dye wastewater treatment. Furthermore, PFC–DAM–ECH is proved to be more suitable and effective for simulated reactive brilliant red dye wastewater treatment than conventional metal coagulants and organic polymers.

► A novel composite material PFC–DAM–ECH is synthesized for dye wastewater treatment.
► Lower B value and higher Mr value are beneficial to the dye wastewater treatment.
► PFC–DAM–ECH exhibits better coagulation effect at weak acid or neutral pH range.
► Synergic effect of PFC and DAM–ECH improved coagulation property of PFC–DAM–ECH.
► PFC–DAM–ECH provides higher decolorization characteristic with TTM as cross-linker.