Ma Jiangya,Fu Xue,Jiang Liyan,Zhu Guocheng,Shi Jun
A novel magnetic flocculant (CPAMF) was synthesized by using Fe 3 O 4 coated with cationic polyacrylamide (CPAM) for flocculation of high turbid water. The surface morphology and chemical structures of CPAMF were confirmed by Fourier transform infrared spectroscopy (FTIR) and thermo-gravimetric analysis (TGA). X-ray diffraction (XRD) was employed to verify the crystal structure of CPAMF. The magnetic property of CPAMF was compared with Fe 3 O 4 in this study. The flocculation performance by using flocculants CPAMF was evaluated in high turbid water treatment. The maximum transmittance 92.4% of kaolin suspension was achieved at corresponding optimal flocculation conditions. The result indicated that CPAMF was efficient in high turbid water flocculation. Analysis of FTIR, XRD of flocs, and zeta potential (ZP) of supernatant were accomplished for flocculation mechanism investigation. Because of low recovery factor in reflocculation under the effect of shear force on flocs, the bridging effect was found to be dominant in both acidic and alkaline conditions. Sedimentation experiments under the role of permanent magnet indicated that nano-Fe 3 O 4 could effectively improve the settling property of CPAM.
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A novel cationic polyacrylamide (PAMC) with various cationic monomer contents were prepared by copolymerizing acrylamide (AM) and methacryloxyethyl trimethyl ammonium chloride aqueous solution (DMC) through low-pressure ultraviolet (UV) initiation. The chemical structure of PAMC was determined by Fourier transform infrared (FTIR), proton unclear magnetic resonance spectrometry ( 1 H NMR), thermal gravimetric and differential analysis (TG-DTA) analysis. Flocculation performance of PAMC was tested in clarification of kaolin suspension, and flocculation kinetic and mechanism were discussed accordingly. Results showed that PAMC with 40% cationic monomer content exhibited excellent turbidity removal efficiency at pH 4.0, dosage of 0.3 mg·L −1 , stirring speed of 120 rpm, stirring time of 15 min, and sedimentation time of 40 min. Increased cationic monomer content and reduced kaolin pH level resulted in the increase of transmittance of the supernatant and decrease of optimal PAMC dosage. The determined kinetic constant ( K ) suggested that interaction of contact and collision between flocculants and kaolin particles was sufficient at the optimal PAMC dosage. ZP analytical results showed that charge neutralization and adsorption were dominant under acidic and alkaline environments, respectively.
Jiangya Ma,Jun Shi,Houcheng Ding,Guocheng Zhu,Kun Fu,Xue Fu
This work presents a preparation process and flocculation performance evaluation of a novel cationic polyacrylamide PADC synthesized by low-pressure ultraviolet (UV) initiation. Flocculant of PADC was polymerized with acrylamide (AM), diallyl dimethyl ammonium chloride (DMDAAC) and coconut diethanolamide (CDEA) in homogeneous aqueous solution under the irradiation of low-pressure UV, and 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone (Irgacure2959) was used as photo sensitizer. The factors that affect polymerization were investigated; these include monomer concentration, initiator dosage, mass ratio of m AM : m DMDAAC and irradiation time. Structures and morphologies were characterized by Fourier transform-infrared (FTIR) spectroscopy, nuclear magnetic resonance hydrogen (1H NMR) spectra, scanning electron microscope (SEM), and thermo gravimetric and differential thermal analysis (TG-DTA). The flocculation performance was evaluated by removing high turbidity kaolin suspension; flocculation mechanism was also correspondingly analyzed. Experimental results show that the PADC efficiently removes the suspended particles efficiently by charge neutralization and bridging effect in an environment with wide range of pH.
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