Fabrication of nanofiltration membranes based on polyethersulfone and modified with silica and carbon nanofillers to increase the efficiency of flux and removal of pollutants from wastewater

Nanofiltration technology is a type of pressure-based membrane process that has been considered due to its cost and environmental compatible to remove organic dyes, heavy metals, and salts from wastewater. In this study, nanofillers of PMO-PPD silica and carbon CQDs used in the fabrication of membranes to compare their efficiency in the nanofiltration system. By successful analysis of FE-SEM, TEM, XRD, FTIR, contact angle, porosity, and measurement of pore radius, the successful synthesis of nanofillers and their presence in the fabricated membranes were confirmed. Fabricated membranes with a weight percentage of 0.5% with values of 47.1 and 43.8 L/M2h for PMO-PPD and CQDs nanofillers, respectively, higher flux than membrane without nanofillers (PES Bare) with a value of 17.6 L/M2h and show better hydrophilicity of these nanofillers. Antifouling parameters showed that both nanofillers improved the antifouling properties of the membrane. Removal of pollutants were for the membranes of Bare PES (21.5% NaCl, 61.5% MO, and 63.2% Pb), PES-PMO-PPD 0.5 wt.% (24.8% NaCl, 85.2% MO, and 1 71.1% Pb), and PES-CQDs were 0.5 wt.% (27.93% NaCl, 72.93% MO, and 89.76% Pb). The percentage of pollutants removal in nanofiller membranes was higher than PES Bare. The different characteristics of flux, antifouling, and removal of pollutants from the wastewater for comparison of PMO-PPD and CQDs nanofillers were due to the difference in the type of functional groups in these two nanofillers. The results showed that the fabricated membranes for nanofiltration technology were very effective in improving the flux and removing pollutants from the wastewater.