Nanomembranes from Polymeric Waste for Produced Water Treatment

AbstractObjectives/ScopeIn the oil&gas sector, the produced water is the most significant waste stream. Among different possible materials including ceramic, polymers, carbon nanomaterials used for water filtration, polymeric nanofibers can be considered unique solution that can be used as a membrane and/or adsorbent. In this work we prepared polymeric nanofibers from polystyrene-waste to show a win-win approach to re-use polymer waste and clean produced water from organic contaminations.Methods, Procedures, ProcessThe polystyrene waste dissolved in the dimethylformamide (DMFA) was used as a feedstock for the preparation of nanofibrous membranes by using the electrospinning process. Electrospinning is one of the simplest methods for the preparation of nanofibers with diameters ranging from micrometers down to nanometers. It uses strong electrostatic forces overcoming the surface tension of a polymer solution. We studied the electrospinning of polystyrene solutions with a range of concentrations from 10 to 30 (w/v %) and tested different solvents, including chloroform, acetone, dimethylformamide (DMFA), and ethyl acetate, and their binary mixtures.Results, Observations, ConclusionsSEM revealed that the samples prepared with ethyl acetate solutions were thin and with numerous defects. In contrast the layers obtained by electrospinning of polystyrene waste dissolved in the DMFA exhibited homogeneous nanostructure if the voltage and concentration were properly adjusted. The beads-free homogenous nanofibers were synthesized for the solution with the concentrations from 15 to 25 w/v % at the voltage 20𠄻28 kV. The artefacts were suppressed by increasing the polystyrene concentration and electrospinning voltage. The wettability of the obtained nanofibers was evaluated by water contact angle (WCA) measurements. All samples were superhydrophobic with the WCA values from 115 to 145°. The obtained nanomembranes exhibited high efficiency for separation of water/hydrocarbon mixtures.Novel/Additive InformationThe utilization of dissolved polystyrene waste for the preparation of nanomembranes for separation of hydrocarbon pollutants from the wastewater streams potentially can be green win-win approach allowing to clean water and utilize abundant expanded polystyrene waste.