Composite flocculants based on magnesium salt–polydiallyldimethylammonium chloride: characterization and flocculation behaviour

Abstract

This study describes preparation, characterization and examines the flocculation characteristics of novel magnesium salt polydiallyldimethylammonium chloride (polyDADMAC) composite flocculants. Five different compositions have been prepared by physical blending between synthesized polyDADMAC and magnesium salt. Fourier transform infrared spectroscopy (FTIR), intrinsic viscosity and zeta potential measurements were conducted to characterize the properties of the composite flocculants produced. Meanwhile jar tests and photometric dispersion analyses (PDA) were carried out to correlate the flocculation behavior and flocs aggregation. The intrinsic viscosity and zeta potential of the composite flocculants increase with increasing polyDADMAC composition. Composite flocculants (sample B and C) show better turbidity removal compared to polyDADMAC alone. In this system, magnesium salt acts as a secondary destabilizer, while polyDADMAC as a primary destabilizer also enhances the bridging mechanism, thus improving the aggregating capacity.