New polymeric membranes containing mesoporous carbons doped with nitrogen and sulfur: A viable option for heavy metal removal from real electroplating effluents

Polymeric membranes containing adsorbent nanomaterials are a promising strategy for wastewater treatments, but few studies address chemical and morphological modifications in the polymer and related them to the performance of the membrane in real effluent treatment. In this study, for the first time, three-dimensional adsorbents were applied in the removal of heavy metals from a real electroplating wastewater. The prepared membranes were made from polyacrylonitrile (PAN) and mesoporous carbon doped with nitrogen and sulfur (NS-MPC). NS-MPC exhibited a three-dimensional porous structure with a high surface area (960.0 m 2 .g ̶1 ) and a pore volume of 3.43 cm 3 . g−1 The presence of NS-MPC in membranes resulted in the formation of irregular surfaces, increased porosity, square roughness (126 nm), and reduced hydrophilicity (12.05 o ). SEM images revealed the expansion of the fibrillary porous sublayers, mainly for hPAN@NS-MPC-10. This membrane showed the highest porosity and the best adsorptive performance toward heavy metals. The hPAN@NS-MPC membrane was selective for the removal of Al, Cr, Cu, Fe, and Pb, to the detriment of Ni, Zn, and Mn ions, when the concentrated electroplating bath was treated. When the electroplating effluent was used, hPAN@NS-MPC was able to remove Al, Cr, Cu, Fe, Pb, Ni, Zn, and Mn, with removal percentage between 57.6-93.8%. The hPAN@NS-MPC-10 has a comparable removal capacity to other powdered adsorbents. The pseudo-second-order and the intraparticle diffusion kinetic models were found to be the most suitable, indicating that chemisorption governs the mechanism for copper uptake. The hPAN@NS-MPC-10 exhibited 85.5% of removal for copper in filtration assays. • NS-MPC increased surface roughness and porosity of the hPAN@NS-MPC membranes; • NS-MPC provided a tridimensional fibrillary porous sublayer improving metals removal; • hPAN@NS-MPC exhibited high removal for Cu, Ni, Fe from an electroplating effluent; • 85.5% removal for Cu was achieved in filtration assays; • The complexation between Cu and hPAN@NS-MPC is the main mechanism;