Smart membranes engineered by surface-initiated ATRP polymer-grafting of carbon nanotubes and analyzed with RSM modelling

Membrane technology is progressively used to address the challenges of water purification around the world. Still, membrane-based technology remains unavoidably constrained by membrane fouling. Polymer membranes with functionalized carbon nanotubes (CNTs) combine the unique properties of nanotubes with the benefits of membrane separation technology, improving the performance, and fouling resistance of membrane systems. In this study, polyacrylic acid (PAA) polymer brushes were grafted onto the surface of CNTs via surface-initiated atom transfer radical polymerization (SI-ATRP). Polyacrylic acid-modified CNTs (CNT-PAA) were then added to polyether sulphone (PES) membranes, and the performance of the resulting nanocomposites was evaluated. Among all membranes, the one with 0.5% CNT-PAA demonstrated superior hydrophilicity, with a contact angle of 37° and a flux rate of 65 L/m²h. Furthermore, the functionalized membrane also exhibited high antifouling properties, with flux recovery of 78% and dye rejection of 70 to 75%. By the application of response surface methodology (RSM) based on a central composite design (CCD), the effects of pH and transmembrane pressure on the membrane’s performance were analyzed and optimized. This modified membrane also possesses the ability to alter its properties based on pH, rendering it a smart material for water treatment applications. The findings from this work have the potential to contribute to the development of novel and smart membranes designed for wastewater treatment.