Flocculation of kaolin in water using novel calcium chloride-polyacrylamide (CaCl2-PAM) hybrid polymer

The flocculation of kaolin suspension in water using a novel calcium chloride-polyacrylamide hybrid polymer has been studied. A redox initiation system - (NH4)(2)S2O8 and NaHSO3 was used to initiate free radical solution polymerization of one molar acrylamide solution at 50 C. One mole of calcium chloride was blended with polymerized acrylamide solution to synthesis a novel inorganic-organic composite polymer (CaCl2-PAM hybrid polymer). The CaCl2-PAM hybrid polymer was characterized using Fourier transform infrared spectrometer (FT-IR) and transmission electron microscopy (TEM). TEM image showed that the CaCl2-PAM hybrid has a bulky and web-like nature. The CaCl2-PAM hybrid polymer was used in flocculating kaolin suspension. A factorial design was used in screening the factors for the flocculation of kaolin suspension to study the effect of two operating parameters (pH and dosage). The kaolin suspension flocculation was found to be pH and dosage dependent. Response surface methodology was done using central composite design and showed that the CaCl2-PAM hybrid polymer was able to reduce >98.0% of turbidity. The optimal operating condition was reported between pH 2 and 2.5 and dosage between 2 and 3 mg/L. (C) 2010 Elsevier B.V. All rights reserved.