Study On Demulsification Technology Of Oil-in-water Emulsion Based On The Multi-phase Interfacial Reaction

It is difficult to demulsify the emulsion and remove the turbidity of surfactant-stabled O/W emulsified wastewater separately,due to the stable oil-water interface and complex emulsifier components.Usually,it needs complex process flow,occupies more structures or requires a variety of combined technologies.Therefore,the necessity calls for simple,economic and efficient techniques of simultaneous demulsification,so as to realize the oil and turbidity removal and finally explore its micro interfacial reaction mechanism.In this study,the technology of microbubble pretreated ion exchange resin,magnetic demulsifier MMZ-CDs,metal inorganic salt associated with ozonation applied for demulsification were studied.The direction of this paper is to explore the actual demulsification and oil removal effects of various technologies,as a result,revealing the micro reaction mechanism at different demulsification reaction interfaces.It is proved that demulsification and oil removal can be carried out efficiently and rapidly in the solid,liquid and gas multi-phase system from a large number of single factor experiments,multi-factor comparative experiments,emulsion water sample analysis,characterization of demulsifers from many aspects and relevant literature support.Finally,from the point of view of solid-liquid and gas-liquid interface reaction,the destruction of oil-water interface and the way of demulsification are explained.The experimental results show that microbubbles can effectively remove the impurities in the resin and achieve a better demulsification effect.Compared with the traditional industrial application of acid or base solution pretreatment resin method,this method greatly reduces the secondary pollution.The pretreated resin can be used to treat emulsions with oil content of 1000mg/L and obtain a demulsification oil removal rate of 97%.The resin which is utilized for five cycles still retains more than70%of the demulsification oil removal capacity.From the demulsification experiment,water sample analysis and resin characterization results,it is proposed that the emulsion can be demulsified by ion exchange,adsorption,surface modification and other paths to make the stable oil-water interface transfer to the resin.The experimental results of demulsification and oil removal with MMZ-CDs magnetic demulsifier show that the demulsifier with zeolite powder as the base,Fe₃O₄as the coating,MgSO₄ and cyclopaste as the fixative can complete the demulsification within 30s-50s,and the emulsion with initial turbidity of more than 2000ntu can be reduced to less than 10ntu.Otherwise,MMZ,MM-CDs and MZ-CDs demulsifiers were also obtained by loading different components on zeolite powder.In the comparative experiment,MMZ-CDs obtained the most superior demulsification and turbidity removal effect.After repeated use for 5 times,the demulsification and turbidity removal ability was still about 75%,and the iron loss rate of single use was less than 0.5%,ensuring the magnetic separation effect.It is proposed that the rapid and efficient demulsification ability of MMZ-CDs is due to the simultaneous action of zeolite ion exchange,cyclodextrin adsorption on organic molecules,flocculation of magnesium ion and anti-ion effect,which eventually leads to the transfer of oil-water interface and the collision and aggregation of oil droplets and demulsification.The experimental results of the demulsification and degreasing of metal inorganic salts combined with ozonation technology show that the emulsion containing a lot of surfactants is easy to foam under aeration and increase the difficulty of processing.So an improvement of the aeration device needs to be carried out to solve this problem.The reactions in three systems of ozone demulsification,magnesium sulfate demulsification and ozone magnesium sulfate co-demulsification were studied respectively.It takes more than 40 minutes for ozone to achieve 91.6%turbidity removal rate and 95.8%turbidity removal rate in 30 minutes when the dosage of magnesium sulfate is more than 200 mg/L.However,when magnesium sulfate co-ozonation demulsification is adopted,it can reach nearly 100%turbidity removal rate in 5 minutes,and finally,the water gets clear.In addition,the addition of magnesium sulfate greatly increased the instantaneous hydroxyl production and made the demulsification reaction complete quickly.Finally,the interaction between ozone and the interaction with magnesium sulfate was proposed to produce everfount active substances in a steady stream.The surfactant was degenerated by attacking oil-water interfacial film,and the demulsification was achieved fundamentally.