Preparation Of Magnetic Demulsification-flocculant And Its Application In Tight Emulsified Oily Wastewater

The oil and gas wastewater produced by the offshore oil and gas enterprises in the offshore oil exploitation or transportation is seriously emulsified and the effective treatment has become an urgent problem.Therefore,this paper analyzes the properties of an emulsified oily wastewater,studies the process of flocculating polyaluminium chloride?PAC?and polyacrylamide?PAM?flocculation,and briefly discusses the flocculation mechanism.The results show that the wastewater is a kind of tight emulsified high concentration oily wastewater?oil particle weighted average particle size is about 440nm,chemical oxygen demand?COD?is 9600.0mg/L?.PAC and PAM show synergistic effect when treating the wastewater,when the fast stir to add 150mg/L PAC,slow stirring and then add 3mg/L PAM,the removal rates of oil,COD and turbidity were 84.5%,57%and 96.1%,respectively.It is speculated that the effect of PAC and PAM in the treatment of tight emulsified oily wastewater is not too high?lower than ordinary emulsion?,the reasons may be:PAM and PAC in the water can be formed not easy to settle the small floc,small floc and fine emulsified oil accumulation of oil floc is not easy to settle.To speed up the floc settlement speed,to achieve non-toxic,green and reusable purposes,in this paper,two kinds of reusable novel magnetic flocculants are available.In this paper,homemade Fe₃O₄ as the core,after surface treatment,the introduction of temperature-sensitive monomer polyisopropylacrylamide?PNIPAAm?,prepared thermosensitive magnetic flocculant M-PNIPAAm,the samples were analyzed by infrared spectroscopy?FTIR?,X-ray diffraction?XRD?,thermogravimetric analysis?TGA?and transmission electron microscopy?TEM?,and were used to treat simulated emulsified oily wastewater.The results show that the particle size of M-PNIPAAm is about 28.32nm,and the phase transition temperature is 32?,which is sensitive to temperature and magnetic response.At the temperature of 32°C and p H of 7,when the ordinary simulated emulsion was treated with 80.84mg/L M-PNIPAAm,the light transmittance was 90.2%,and could be reused seven times.When the emulsified simulated wastewater was treated with91.52mg/L M-PNIPAAm,the light transmittance was 78.7%.To meet the special requirements?such as offshore platform?on the high demand for wastewater treatment and improve the flocculation effect.In this paper,pH/temperature sensitive magnetic flocculant M-P?NIPAAm-Co-DMAEMA?was prepared by introducing methacrylic acid dimethylaminoethyl ester?DMAEMA?with p H response at the same time,they were characterized by FTIR,XRD,TGA and TEM,and were used to treat simulated emulsified oily wastewater.The results show that the particle size of M-P?NIPAAm-Co-DMAEMA?is about 15.03nm,and the phase transition temperature is34?,which is both p H,temperature and magnetic triple response.Under conditions of a temperature of 34°C and a p H of 7.5,when the M-P?NIPAAm-Co-DMAEMA?dosage was120mg/L to deal with ordinary simulated emulsion,the light transmittance was92.4%.When the amount of M-P?NIPAAm-Co-DMAEMA?was 150mg/L to deal with fine emulsified simulated wastewater,the light transmittance was 80.7%.In this paper,based on M-PNIPAAm and M-P?NIPAAm-Co-DMAEMA?flocculation treatment of an actual emulsified oily wastewater,and the mechanism of the two flocculants is explored.The results show that under the condition of temperature 32?and neutral condition,when the dosage of M-PNIPAAm is 210mg/L,the transmittance is 72.0%.Under the condition of temperature 34?and neutral condition,When the dosage of M-P?NIPAAm-Co-DMAEMA?is 240mg/L,the transmittance is 77.2%.The two flocculants can not only achieve rapid separation of oil and water?<10min?,and the action of floc settling speed?<1min?under the magnetic field,and oil,water resources can be recycled,flocculant failure recovery can also be recycled,with non-toxic,green and reusable features.