Aerogels For The Separation Of Asphalt-containing Oil-water Mixtures And The Effect Of Asphalt Stabilizer

Oil-water separation has become one of the key means to solve global environmental protection and energy waste because of repeated crude oil leakage accidents,an increasing number of industrial and domestic oily wastewater,and the need for oil-water separation in the process of oil extraction and refining.Filtration and adsorption are one of the most commonly used methods in oil-water separation.The search for ideal filter materials is still an urgent problem.As a special porous material with excellent physical and chemical properties such as low density,high porosity,high surface area and adjustable surface chemistry,aerogel has shown great application potential in the field of oil-water separation.However,in the current aerogel application research,the oil phase is usually composed of simple reagents or edible oils,and the influence of complex components of crude oil on filtration has not been studied in depth.In this work,asphalt,the most polar component of crude oil,is selected as an example.Hydrophilic and lipophilic aerogel membranes are prepared for the filtration and separation of asphalt-containing oil-water mixtures.By adding the asphalt stabilizer,poly(styrene-co-N-octadecyl maleimide)(SNODMI),to the asphalt-containing oil-water mixture,the adverse effects brought by asphalt are supresssed.The effects of asphalt and asphalt stabilizers on the filtration of asphalt-containing oil-water mixtures by lipophilic aerogel membranes were first investigated.The first generation Grubbs catalyst were used to catalyze Dicyclopentadiene(DCPD)to prepare polydicyclopentadiene(PDCPD)gels through ring-opening metathesis polymerization.PDCPD aerogels were prepared by solvent replacement and supercritical drying.PDCPD aerogels with different pore structures were prepared by using PDCPD gels with appropriate concentration ranges.The aerogel structure was characterized by FTIR test,surface contact angle test,and SEM test.The PDCPD aerogel membrane was used as a filtration membrane for oil-water separation.It was found that the PDCPD aerogel membrane can successfully separate simple oil-water mixtures,oil-water emulsions containing emulsifiers,and oil-water mixtures containing asphalt.However,the presence of asphalt decreased the separation efficiency by blocking the pores and acting as an emulsifier.An asphalt stabilizer,SNODMI,was then employed to reduce the asphalt particle size and reduce the blockage of flow passage,consequently improving the filtration speed and the asphalt content in the filtrate.The combination of PDCPD aerogel film with asphalt stabilizer has great application prospects for separating asphalt-containing oil-water mixture.The effects of asphalt and asphalt stabilizers on the filtration of asphalt-containing oil-water mixtures by hydrophilic aerogel membranes were also studied.Cellulose chitosan composite aerogel membrane(CECS)was prepared by sol-gel method and freeze-drying method.CECS aerogel membranes with different pore structures were prepared by using cellulose solutions with appropriate concentration range.The aerogel structure was characterized by FTIR,surface contact angle test,and SEM.The CECS aerogel was used as a filtration membrane to separate the oil-water mixture.It was found that the CECS aerogel membrane can successfully separate simple oil-water mixtures with the highest speed reaching 9315 kg·h-1·m-2.In a continuous filtration device,CECS aerogel membranes show stable filtration performance during continuous filtration for 30 minutes.The CECS aerogel films with different hole sizes were able to maintain a filtration rate of about 90%of the initial filtration rate.CECS aerogel can also successfully separate asphalt-containing oil-water mixtures.However,the filtration speed continued to decrease after adding asphalt,and a large number of asphalt particles were adhered to the aerogel membrane surface.After the addition of SNODMI,the decreasing trend of the filtration speed was greatly slowed down.It was found in the SEM images that the number of asphalt particles adhering to the surface of the used aerogel membrane was greatly reduced.The size of the asphalt paticles was also reduced.The combination of CECS aerogel membrane and asphalt stabilizer has huge application potential in the field of asphalt-containing oil-water separation.