Phosphorylated polysaccharide derivatives as efficient separation agents for zinc and ferric oxides particles from water

• Phosphorylated polysaccharides were studied as flocculants for zinc and ferric oxide particles.
• Optimum dose and the flocculation window depended on the polysaccharide type.
• Particles flocculation is determined by charge neutralization/patch mechanisms.
• Intrinsic viscosity values were determined by Wolf equation.

The separation efficiency of some anionic polysaccharides, namely phosphorylated derivatives of dextran and cellulose, in model zinc oxide (ZnO) and ferric oxide (hematite, Fe2O3) particle suspensions has been evaluated by turbidity and zeta potential measurements. The investigation was performed with respect to the polyanion dose, the polysaccharide nature and molar mass. The turbidimetric results showed higher separation efficacy in case of polyanions based on dextran than that based on cellulose. Possible reasons for this finding have been discussed. The zeta potential values at optimum polymer dose (either close to zero in the presence of the dextran derivative or negative in the presence of the cellulose one) suggest the contribution from charge neutralization/charge patch mechanisms in the destabilization of both oxide particle suspensions. The viscosity behavior of the polymers was also examined and the experimental data were plotted in terms of the Wolf method.