The pyromellitic dianhydride (PMDA) crosslinked poly(vinyl alcohol) (PVA) was coated on top of the PAN ultrafiltration membrane to form a PVA/PAN composite PV membranes for wastewater desalination. The composite membranes have high application value in industrial wastewater treatment. By varying the membrane fabrication parameters including the weight percent (wt%) of the PMDA, the crosslink temperature and duration, membrane with the best desalination performance was obtained. The composite membrane with a 2-μm-thick PVA selective layer containing 20 wt% of PMDA and being crosslinked at 100 °C for 2 h showed the highest NaCl rejection of 99.98% with a water flux of 32.26 L/(m 2 h) at 70 °C using the 35,000 ppm NaCl aqueous solution as feed. FTIR spectroscopy, wide-angle X-ray diffraction, thermogravimetric analysis and scanning electron microscope have been used to characterize the structures and properties of both the crosslinked PVA dense films and PVA/PAN composite membranes. The effects of the concentrations of PMDA, the crosslinking time and temperature to the membrane water contact angle, swelling degree, salt rejection and water flux were systematically studied.
Zihan Liu,Junwen Ding,Shirong Li,Longfeng Hu,Heng Liang,Langming Bai
Desalination of textile wastewater is an effective measure to reduce environmental pollution and realize resource reuse. Graphene oxide (GO) membrane is regarded as one of the first choices for textile wastewater desalination due to its chemical resistance, strong mechanical properties, and adjustable interlayer channels. Here, we propose a polyaniline (PANI) particle incorporation strategy and use the dedoping effect of polyaniline to provide an additional permeation pathway through one-step alkali treatment to accelerate water molecule transport. Polyaniline (PANI) doped with polystyrene sulfonic acid (PSS) nanoparticles were synthesized and incorporated into GO membranes, followed by crosslinking of glutaraldehyde (GA) for stability and alkali treatment for more porosity generation. The as-prepared BGO/PANI-PSS membrane with 30% PANI-PSS addition displayed a flux of 70.4 LMH/bar, 99.3%, and 4.8% rejection for Congo red and NaCl, respectively, exhibiting 5.9 times higher permeability than that of GO membrane with similar dye rejection. This work provides a facile strategy for designing GO composite membranes for dye/salt separation.
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