| Cationic polyacrylamide is widely used in industry as an organic polymer flocculant.The polymerization method initiated by low-pressure ultraviolet light has the advantages of short reaction time,less amount of initiator,simple operation and environmental protection.Therefore,it is of great significance to initiate polymerization of a new type of cationic polyacrylamide flocculant with high efficiency and environmental protection.In this paper,hydrophobic modified cationic polyacrylamide flocculants with high intrinsic viscosity and positive charge density were prepared by low-pressure UV initiated polymerization.The structure and morphology were analyzed by modern characterization technology.Finally,the flocculant was used to remove high turbidity kaolin suspension and simulated oily wastewater.（1）Synthesis and optimization of hydrophobic modified cationic polyacrylamide flocculant.In this paper,hydrophobic modified cationic polyacrylamide flocculant was synthesized by polymerization of acrylamide（AM）,acryloxyethyl trimethylammonium chloride（DAC）and alkyl glycoside（APG）as monomers initiated by low pressure UV light.The effects of the total monomer mass concentration,m AM:m DAC,initiator concentration,solubilizer concentration and other factors on the intrinsic viscosity and positive charge density were investigated by single factor experiments,and the optimum synthesis conditions were obtained as follows.The total mass concentration of monomer was 35.0%,the concentration of initiator was 0.2%,the concentration of solubilized urea was 3.0%,the reaction system p H was 6.0,the light duration was 90 min,the ratio of monomer m AM:m DAC was 3:1,the mass concentration of hydrophobic monomer was 2.0%.Finally,the flocculant with the characteristic viscosity and cationic charge density of 1384.8 ml·g-1 and 5.09mmol·g-1 were obtained.（2）Structure,composition and morphology characterization.FT-IR,1HNMR,SEM,TGA-DSC and organic element analyzer were used to analyze the functional group structure,morphology,thermal stability and element composition of the synthetic flocculant.（3）The flocculant was used to study the flocculation ability of high turbidity kaolin suspension,and the effects of experimental on the flocculation efficiency were investigated.Flocculant was used in the flocculation study of high-turbidity kaolin suspension to investigate the influence of various experimental steps on flocculation efficiency.The results showed that the optimal dosage was 7 mg·L-1.Flocculant maintained high flocculation efficiency in a wide range of p H.Flocculation efficiency is higher under neutral and weak acid and weak base conditions,and the optimal p H is 6.0.The optimal standing time is 20 min.The optimum stirring speed is 80 rpm.The optimal stirring time was 10 min,and the flocculation mechanism of kaolin was investigated at the end of the chapter.（4）The flocculation experiment of simulated oily wastewater with the prepared flocculation.The results showed that the optimal monomer ratio was cationic monomer concentration of 40%and hydrophobic monomer concentration of 30%,with the highest oil removal efficiency of 93.9%and the turbidity removal rate of 97.52%.Then the factors in the flocculation process were investigated.When the concentration was 30 mg·L-1,the oil removal efficiency could reach 96.56%.The optimum speed of flocculation is 375 rpm.The flocculating efficiency of flocculant is higher than that of basicity under neutral acidic condition.At last,the flocculation mechanism was analyzed by infrared spectrum. |
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