Synergetic influence of F-MWCNTS on polyvinylpyrrolidone sodium alginate composite membrane for reverse osmosis

Abstract

In this study, novel composite membrane of functionalized multi-walled carbon nanotubes (F-MWCNTs) polyvinyl pyrrolidine (PVP) and sodium alginate (Na-Alg) with unique characteristics were synthesized for the application of reverse osmosis (RO) desalination. The MWCNTs in different amounts were systematically and uniformly dispersed in PVP/Na-Alg polymer matrix during the synthesis of membranes by dissolution casting method. The effect of F-MWCNTs content in the performance of the composite membrane was investigated for RO desalination process compared to PVP/Na-Alg blended membrane. The spectral studies were carried out by Fourier transform infrared spectroscopy (chemical bonding) and scanning electron microscopy (surface morphology). The thermogravimetric analysis (TGA) of membranes also recommended that composite membrane with the highest content of F-MWCNT has more excellent thermal stability compared to PVP/Na-Alg blended membrane and other modified membrane samples. The most striking experimental results show that the incorporation of F-MWCNTs improved the general RO performance of the composite membranes. The modified composite membrane surface became rough as compared to the PVP/Na-Alg blend membrane surface. The PVP/Na-Alg blended membrane shows a maximum permeation flux of 5.5 L/m2h and high-water content. This experimental analysis also presented that tethered F-MWCNTs/PVP/Na-Alg polymer matrix membrane, with stronger F-MWCNTs/polymer matrix interactions, enhanced the composite membrane's salt rejection performance by 85.4% for the highest content of F-MWCNTs. Therefore, it can be concluded that all the membrane samples presented excellent capacity to resist the growth of gram-negative E. coli bacteria.