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Polyamide thin-film composite (TFC) was fabricated on polysulfone (PS-20) base by interfacial polymerization of aqueous m-phenylenediamine (MPD) solution and 1,3,5-benzenetricarbonyl trichloride (TMC) in hexane organic solution. Multi-wall carbon nanotubes (MWCNT) were carboxylated by heating MWCNT powder in a mixture of HNO 3 and H 2 SO 4 (1:3 v/v) at 70°C under constant sonication for different periods. Polyamide nanocomposites were prepared by incorporating MWCNT and the carboxylated MWCNT (MWCNT-COOH) at different concentrations (0.001-0.009 wt%). The developed composites were analyzed by Fourier transform infrared spectroscopy-attenuated total reflection, scanning electron microscopy, transmission electron microscopy, contact angle measurement, determination of salt rejection and water permeate flux capabilities. The surface morphological studies displayed that the amalgamation of MWCNT considerably changed the surface properties of modified membranes. The surface hydrophilicity was increased as observed in the enhancement in water flux and pure water permeance, due to the presence of hydrophilic nanotubes. Salt rejection was obtained between 94 and 99% and varied water flux values for TFC-reference membrane, pristine-MWCNT in MPD, pristine-MWCNT in TMC and MWCNT-COOH in MPD were 20.5, 38, 40 and 43 L/m 2 h. The water flux and salt rejection performances revealed that the MWCNT-COOH membrane was superior membrane as compared to the other prepared membranes.

Reverse osmosis (RO) membranes modified withSnO2nanoparticles of varied concentrations (0.001–0.1 wt.%) were developed via in situ interfacial polymerization (IP) of trimesoyl chloride (TMC) andm-phenylenediamine (MPD) on nanoporous polysulfone supports. The nanoparticles dispersed in the dense nodular polyamide on the polysulfone side. The effects of IP reaction time andSnO2loading on membrane separation performance were studied. The modified reverse osmosis membranes were characterized by scanning electron microscopy (SEM), X-ray diffractometer (XRD), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), contact angle measurement, and atomic force microscopy (AFM). The synthesizedSnO2nanoparticles size varies between 10 and 30 nm. The results exhibited a smooth membrane surface and average surface roughness from 31 to 68 nm. Moreover, hydrophilicity was enhanced and contact angle decreased. The outcomes showed that an IP reaction time was essential to form a denserSnO2-polyamide layer for higher salt rejection, the developed reverse osmosis membranes with the incorporation of theSnO2nanoparticles were examined by measuring permeate fluxes and salt rejection, and the permeate flux increased from 26 to 43.4 L/m2·h, while salt rejection was high at 98% (2000 ppm NaCl solution at 225 psi (1.55 MPa), 25°C).

The present work is focused on developing a suitable chemical membrane with polyamide, incorporating co-solvents. There are many benefits of using a membrane technique. It is cost-effective and can be fabricated easily and its materials have less effect on the environment. Therefore, the general membrane techniques have been used for the desalination of ocean water as a worldwide strategy to meet the demand for clean water. But in some cases the use of this membrane becomes limited when pore size, distribution of pores and low selectivity for pollutants/contaminants are considered. The fabrication of such a membrane with co-solvents is expected to lead to a solution to address some of these problems. In this study, a polyamide thin-film composite membrane was developed by interfacial polymerization in non-polar heptane solvent, using acetone as a co-solvent medium. The modified membranes were characterized by different techniques. Scanning electron microscope and atomic force microscopy images showed a smooth membrane surface. Thermo-gravimetric analysis indicated that these developed membranes possessed high thermal stability. High contact angles were observed in the presence of acetone as a co-solvent in the polyamide membrane. Similarly, high fluxes were observed with low salt rejection ability.

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