Removal of Amphiphilic Polymer from Tertiary Oil Recovery Wastewater Using Insoluble Cyclodextrin Polymer

Abstract

The wastewater produced by amphiphilic polymer flooding is seriously emulsified and difficult to treat. In recent years, insoluble β-cyclodextrin (β-CD) polymers were widely employed in removal and utilization of organics with specific sizes and shapes. In this paper, a new type of host β -CD insoluble polymer (HCDP) was synthesized using β -CD with tetrafluoro-phthalonitrile (TFPN) as the crosslinker. A kind of guest amphiphilic polymer (GAP) was synthesized and the inclusion performance of HCDP to GAP was studied by viscosity method. Besides, The inclusion complexes of HCDP and GAP was regenerated using washing method and the inclusion capacity of the regenerated CDP was tested for five cycles. The results showed that GAP’ s apparent viscosity increased dramatically at about 800 mg/L and it showed linear relationship (R-square was 0.99902) with polymer concentration below 400mg/L, so GAP’ s concentration can be checked by viscosity method. HCDP can rapidly adsorb GAP in aqueous solutions and reach the adsorption equilibrium in about 20 minutes in the process of inclusion, and the maximum equilibrium adsorption amount of HCDP to GAP was about 150 mg/g. HCDP showed a strong recycling capacity. After five cycles of regeneration, the adsorption capacity did not significantly reduced, and the adsorption capacity remained above 140 mg/g. All the results prove that the new type of β-CD insoluble polymer can be used to encapsulate amphiphilic polymers in EOR wastewater, the study provides a new way for the resource utilization of amphiphilic polymers in EOR wastewater.