| The energy becomes less and less in our country today and how to use oil in a reasonable way has caused people's great attention. Enhanced Oil Recovery (EOR) has become an important topic in oil exploitation. Polymer flooding accounts for an important position in EOR of tertiary oil recovery. Hydrophobically associating polymer has become one of the most important research directions in the development of salt-tolerant and thermal-resistant polymer which was used in EOR.With the scarcity of fresh water resource and the importance of environmental protection, wastewater treatment played more and more important roles all over the world. Cationic polyacrylamide as an effective polymer flocculant is used very widely in water treatment. Hydrophobically associating cationic polyacrylamide is a water-soluble polymer which is introduced some hydrophobic group on the hydrophilic chain of polyacrylamide. Flocculation performance and sludge dewatering performance are improved because of the effect of hydrophobic group and cationic group. It has broad applications in the field of sewage treatment.Micellar polymerization is a common method to prepare hydrophobically associating polymer, but the post-processing is very complicated and the molecular weight is not high. We chose aqueous solution polymerization because the hydrophobic monomer 2-vinylpyridine which we used in this paper has small water-solubility in the polymerization. Hydrophobically associating cationic polyacrylamide P(AM-DAC-2VP) was synthesized using acrylamide, acryloyloxyethyl trimethyl ammonium chloride and 2-vinylpyridine as monomer, azo initiator HYAM-01 and potassium persulfate as composite initiator. The structure of the copolymer was characterized by FTIR spectrum and1H-NMR spectrum.The influences of the factors, such as monomer concentration, composite initiator dosage, initiation temperature and pH on the intrinsic viscosity of copolymer were studied. The obtained optimum reaction conditions were as follows:monomer mass fraction 35%, composite initiator dosage 0.07%, initiation temperature 30℃, pH 5.0, urea dosage 5.0%. The intrinsic viscosity enhanced with the mass fraction of 2-VP and DAC increased within a certain range.The effect of copolymer concentration, NaCl concentration, temperature and share rate on the solution properties of P(AM-DAC-2VP) had been investigated. The results showed that the solution viscosity would rise sharply when P(AM-DAC-2VP) concentration was higher than critical associating concentration(CAC). P(AM-DAC-2VP) represented good salt tolerance, temperature resistance and shear thinning behavior.The flocculation performance of P(AM-DAC-2VP) was studied. The results indicated that the flocculation efficiency of P(AM-DAC-2VP) was higher than that of P(AM-DAC), and it increased with the increasing hydrophobic monomer 2-VP content in a certain range. At the same content of 2-VP, the optimum flocculation capability was obtained when cationic mass fraction was 30.0%. The flocculation performance was best when sludge pH was 5.0. The obtained optimum conditions were hydrophobic monomer mass fraction 1.0%, cationic monomer concentration 30.0%, copolymer dosage 25 mg/L, sludge pH 5.0. Under above conditions, the transmittance of clear liquid was 92.1%. The specific resistance of sludge was decreased owing to introducing 2-vinylpyridine in P(AM-DAC-2VP). P(AM-DAC-2VP) had lower dosage and stronger sludge dewatering performance than P(AM-DAC) which was synthesized in the same conditions. |
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