Cellulose Modified with Poly(ionic liquid)s via SI-ATRP as an Efficient Demulsifier for Breaking Water-in-Crude-Oil Emulsions at Room Temperature

Chemical demulsifiers represent an effective strategy for breaking water-in-crude-oil (W/O) emulsions. In this study, we report the synthesis and application of innovative, ecologically friendly, and effective demulsifiers based on microcrystalline cellulose (CEL) functionalized with imidazolium-based poly(ionic liquid)s for breaking the W/O emulsions at ambient temperature. Two ionic liquid (IL) monomers ([VIm-Trz-C6][Br] and [VIm-Trz-C6][BF 4 ]) were synthesized and grafted onto the CEL@SiPBr macroinitiator using the surface-initiated atom transfer radical polymerization (SI-ATRP) technique. The degree of crystallinity dropped from 70% for CEL to 41% for CEL@P[VIm-Trz-C6][BF 4 ]. In the range of 1000–4000 ppm, the synthesized compound was utilized as a demulsifier for the demulsification of 10:90 and 30:70 v/v% W/O emulsions. The CEL@P[VIm-Trz-C6][BF 4 ] at 3000 ppm showed the maximum dehydration efficiency (DE), according to the bottle test results. A significant reduction in interfacial tension (IFT) was achieved using the demulsifier CEL@P[VIm-Trz-C6][BF 4 ]. These new demulsifiers, based on microcrystalline CEL modified with imidazolium-based poly(ionic liquid)s, demonstrated high effectiveness in breaking water-in-oil emulsions while offering economic and environmental advantages. The use of CEL as a sustainable base material combined with a low ratio of ionic liquid ensures cost-efficiency and minimizes ecological impact, positioning these materials as promising candidates for crude oil emulsion treatment.