Li-juan Wang, Jian-Ping Wang, Shu-juan Zhang
Jun 15, 2009
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Influential Citations
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Journal
Separation and Purification Technology
Abstract
abstract A water-soluble cationic flocculant, the copolymer of acrylamide (AM) and acryloylamino-2-hydroxypropyl trimethyl ammonium chloride (AMHP), has been synthesized through dispersionpolymerizationinaqueousammoniumsulfate((NH 4 ) 2 SO 4 )solution.Thepolymerizationwasinitiatedbypotassium persulfate (KPS) using poly(2-methylacryloylxyethyl trimethyl ammonium chloride) (PDMC)asthestabilizer.ThecopolymerobtainedwascharacterizedusingFourier-transforminfrared(FTIR)spec-troscopy, nuclear magnetic resonance (NMR) spectroscopy, colloidal titration and optical microscopy. Itsflocculation properties were evaluated with 0.25wt% kaolin suspensions using a standard jar test. Thezetapotentialofthesupernatesatdifferentflocculantdosageswasmeasuredsimultaneously.Theresultsdemonstrate the superiority of the copolymer over the commercial polyacrylamide as a flocculant.© 2009 Elsevier B.V. All rights reserved. 1. Introduction Flocculation is an efficient and cost-effective method for waterandwastewatertreatment[1–3].Flocculantsareclassifiedintotwocategories, i.e., inorganic and organic ones [4–7]. Inorganic floc-culants are usually salts of multivalent metals like aluminium oriron. Compared with the organic flocculants, they have several dis-advantages such as greater dosage, larger volume of sludge andpH sensitivity [8]. On the other hand, synthetic organic polymershave some advantages, such as inertness to pH changes, formationof large cohesive flocs and versatile tailor ability [9]. Among theorganic polymer flocculants, cationic ones present better floccula-tion ability, as they can work efficiently through both bridging andcharge neutralization [10–14].The water-soluble cationic flocculants could be preparedthrough solution polymerization [15–17], emulsion polymeriza-tion [18], and microemulsion polymerization [19]. However, thereare some shortcomings in these processes. In order to producehigh-molecular-weightpolymerswiththesolutionpolymerizationmethod, the monomer concentration has to be kept over 10wt%.This will result in a gelatinous and crosslinking polymer, whichis difficult to transport and dissolve in water. The emulsion poly-merizationcouldcauseenvironmentalpollutionproblems,becausethis process needs a large amount of organic solvents. Similar tothe emulsion polymerization, microemulsion polymerization also