A study on the effect of hydrophobically modified cationic acrylamide copolymers on flocculation properties of kaolin suspension

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dc.contributor.authorLee, Khai Ern
dc.date.accessioned2014-10-27T03:44:58Z
dc.date.available2014-10-27T03:44:58Z
dc.date.issued2009
dc.descriptionMasteren_US
dc.description.abstractA series of hydrophobically modified cationic polyacrylamides were synthesized via free radical solution copolymerization using ammonium persulphate/sodium hydrogen sulphite as the redox initiator. Epichlorohydrin, acrylamide and trialkylamine were used to synthesize the hydrophobic cationic monomer 3-acrylamido-2-hydroxypropyltriakylammonium chloride (AHPTAAC) in which the trialkyl group was trihexylamine, trioctylamine and tridodecylamine. Low concentration (1-6 mol %) of cationic monomer from each group were copolymerized with acrylamide to obtain hydrophobically modified cationic polyacrylamides. Copolymer obtained at high concentration of cationic monomer was insoluble in the aqueous medium due to its high hydrophobicity and entanglement effect. Results show that the intrinsic viscosity and molecular weight of the copolymers decreases with the increase in concentration of the hydrophobic cationic group, whereas charge density indicates the reverse behaviour. Fourier Transform Infrared (FTIR) and Transmission Electron Microscopy (TEM) were also carried out to elucidate the functional groups and structures of the copolymer respectively. A correlation analysis has been done between molecular weight and charge density of the copolymers. It was found that there is a significant inverse correlationship between molecular weight and charge density in this study. The effect of hydrophobically modified cationic polyacrylamide of varying molecular weight and charge density on flocculation of a kaolin suspension has been investigated. High molecular weight was found to be ideal in flocculating kaolin suspension. Comparison of different hydrophobic groups and monomer substitution ratio on turbidity removal was done. Hexyl group copolymer which had the highest molecular weight of 2.13x106g/mol shows the best flocculation activity and reduced turbidity by 99%. 1 mol % of hydrophobic cationic monomer concentration in copolymers was found to be the best system in flocculating the kaolin suspension. Bridging was the dominant mechanism in flocculating the kaolin suspension. Copolymer with a dodecyl group had the least water retention in the flocculated sludge compared to octyl and hexyl groups.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/152
dc.language.isoenen_US
dc.subjectBiological Scienceen_US
dc.subjectHydrophobicallyen_US
dc.subjectKaolin suspensionen_US
dc.titleA study on the effect of hydrophobically modified cationic acrylamide copolymers on flocculation properties of kaolin suspensionen_US
dc.typeThesisen_US
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