Study On Preparation And Flocculation Efficiency Of Inorganic-Organic Hybrid Polymer Flocculant

Oilfield chemical drive wastewater contains polymers,alkalis and surfactants,resulting in complex water quality components difficult to deal with.Specifically,the viscosity of the system increases,the rate of oil droplet floatation decreases;the emulsification of oil droplets is high,the surface interfacial tension decreases,and the separation of oil and water phase destabilization is difficult;the zeta potential value of the sewage system becomes large,and it is difficult for oil droplets to collide and coalesce,and the oilfield sewage system shows high stability.Therefore,in view of the difficult treatment of chemically driven oilfield wastewater,the development of a new and efficient flocculant to make oil droplets easier to destabilize and gather has become an urgent problem for oilfield water treatment.In this paper,a new inorganic-organic hybrid polymer flocculant PAC-P(AM-BA)with hydrophobic groups was prepared by aqueous free-radical micelle polymerization,using polymerized aluminum chloride(PAC),polyacrylamide(AM)and butyl acrylate(BA)as raw materials,which targeted the removal of oil droplets from oil-bearing wastewater and provided a new type of flocculant for the efficient treatment of chemically driven wastewater in oil fields.The optimal conditions for the preparation of PAC-P(AM-BA)are:the optimal synthesis conditions are:initiator mass fraction of 0.15%(of total monomer),n(AM):n(BA)=98:2,urea mass fraction of 3.00%,total monomer mass fraction of 15.06%,inorganic component(PAC)mass fraction of 1.37%,and polymerization temperature of 27.06℃.The BA of PAC-P(AM-BA)is embedded in PAM with chemical bond,and the PAC is connected to the long chain with ionic bond.The thermal decomposition temperature of PAC-P(AM-BA)is 233.93°C.The surface of hybrid flocculant is rough,and the specific surface area is 30.351 m~2/g,which has strong adsorption bridging and net sweep performance.For the oily wastewater containing about 500 mg/L of oil,1000 mg/L mass concentration of PAM,50 mg/L mass concentration of surfactant and 0.02 mol/L salt molar concentration,the optimal dosage of PAC-P(AM-BA)is 20 mg/L,the optimal stirring conditions are rapid stirring speed of 160 r/min,time of 8 min,slow stirring speed of 60 r/min,time of 8 min,temperature of 40°C,p H value of 6,settlement time of 10 h.PAC-P(AM-BA)has better flocculation efficiency than cationic polyacrylamide(CPAM)and complex flocculant(PAC+PAM),10 flocculation experiments on wastewater containing 300.0-530.0 mg/L of oil are conducted and it is learned that the adaptability to water quality fluctuations is better,and the average oil removal rate is 90.3%,which is 16.4%and 29.0%higher than that of cationic polyacrylamide(CPAM)and compound flocculant(PAC+PAM),respectively.The fractal dimension of the heterogeneous flocculant floc is 1.733,and the floc structure is dense and has good settling performance.PAC-P(AM-BA)flocculant can resist the influence of polymers and surfactants in oilfield chemical drive effluent and has good flocculation ability.PAC electrically neutralizes the surface charge of the colloid,reduces the electrostatic repulsion between the particles,the long chain of polymer PAM playes the role of adsorption bridging and netting sweeping,BA strengthen the netting sweeping effect,and finally destabilizes the pollutants to form a dense structure and easy to remove flocs,realizing the efficient separation of oil droplets and water.