Effects of different polymerisation conditions using hybrid polymer on high turbidity suspensions

Abstract

Purpose In this study, new hybrid polymers composed of Zinc chloride (ZnCl2), acrylamide and chitosan were prepared at different ratios and temperatures. The effects of pH and polymer dosage were examined for different polymers to observe their efficiency in the removal of turbid water. The polymers’ zeta potential, morphology, elemental composition and functional groups were also identified and studied. Design/methodology/approach The free-radical polymerisation process was executed in the presence of N, N’-Methylene bis-acrylamide and potassium persulphate in one molar acrylamide solution. ZnCl2 and chitosan (CO) were later introduced into the suspension under nitrogen gas flow. Ratio and temperature were varied during polymerisation. The hybrid polymer produced, termed Polyacrylamide + chitosan oligosaccharide + zinc chloride (PAMCOZ), was analysed using Fourier transform infra-red spectroscopy attenuated total reflectance and scanning electron microscope with energy dispersive X-ray. The hybrid PAMCOZ was experimented with in high turbid kaolin suspension using jar testing analysis to see its ability as a coagulant. Findings The coagulation process using PAMCOZ with a ratio of 11 (3:2) at 70°C surrounding temperature showed a 100% reduction at pH 4 with 50 mg/L of the polymer. The functional groups present in ratio 11 polymer were hydroxyl, carbonyl, amide and methyl groups. In addition, several elements were spotted on the surface of PAMCOZ, such as zinc (Zn), carbon (C), chlorine (Cl), nitrogen (N) and oxygen (O). The effect of pH also demonstrated that PAMCOZ was unfavourable in an alkaline turbid water environment. Research limitations/implications Due to the research methodology approach, the research results may lack actual wastewater application. Therefore, researchers are encouraged to test the hybrid coagulant on raw wastewater, such as pulp and paper mill effluent with a high turbidity value similar to this study. Originality/value The polymerisation between zinc chloride, acrylamide and chitosan has not yet been applied. The different ratios and effects of temperature were analysed on PAMCOZ to see the turbidity removal. PAMCOZ showed better turbidity removal in acidic conditions.