Membrane separation processes are an essential technology in advancing water reuse. However, membrane fouling and associated energy demands for fouling control remain a major barrier to full-scale implementation. In response to these concerns, novel membrane materials and/or fouling mitigation strategies need to be explored to improve the environmental and economic efficiency of water reuse. Piezoelectric polymers are one option that have been gaining interest as a membrane material due to their ability to convert electrical energy to mechanical energy as a vibrational response. Harnessing this material’s unique property within membranes subjected to high fouling environments could reduce energy demands for fouling control. Polyvinylidene fluoride (PVDF) is a common polymer for conventional flat-sheet membranes that also has piezoelectric potential, particularly when electrospinning is used to generate nanofiber membranes. Three solvents, dimethylformamide (DMF), dimethylsulfoxide (DMSO), and N-methyl-2-pyrrolidone (NMP) were tested to elucidate the solvent’s effect on the electrospun membranes’ properties and filtration performance. The PVDF beta phase fraction, thickness, contact angle, average fiber diameter, and average pore area of the fabricated membranes were characterized using FTIR, a goniometer, and SEM imaging (Figure 1). Currently, piezoresponse force microscopy (PFM) is being explored as a characterization method to quantify the piezoelectric mechanical response of the membranes’ polymer fibers. Membrane performance was also evaluated by continuously filtering a solution mimicking biofouling (2 g/L sodium alginate with 1 mM calcium addition for crosslinkage). Ongoing work is evaluating performance of the electrospun membranes in a bench-scale anaerobic membrane bioreactor system alongside commercial flat-sheet PVDF membranes treating synthetic domestic wastewater at ambient temperatures. The performance results will be used to determine the fouling mitigation effectiveness of the piezoelectric response under a more realistic biochemical environment prone to severe membrane fouling. Additional characterization from the PFM testing and preliminary data from these ongoing experiments will be presented at the 256th ACS National Meeting in Boston.

Electrospinning polymeric nanofiber membranes for piezoelectric fouling mitigation in separation processes

256th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.