ENHANCING THE FOULING RESISTANCE AND REJECTION OF CELLULOSE ACETATE [CA] /MXENE [𝑇�𝑖�3𝐶�2𝑇�𝑥�] NANOCOMPOSITE MEMBRANES

Abstract

Obstacles in the membrane-based separation field are mainly related to membrane fouling. This study synthesized a pioneering covalently crosslinked cellulose acetate anti-fouling mixed matrix membrane containing between 0 wt.% and 12 wt.% MXene (CCAM-0% to CCAM-12%) via the phase inversion process prior to formaldehyde crosslinking for ultrafiltration/nanofiltration membrane applications. The membranes’ water flux and salt, dye, and protein rejection performances were tested using DE filtration and CF filtration. The physiochemical properties of the fabricated membranes were tested using various characterization tools, including SEM, EDS, XRD, TGA, AFM, BET, and water contact angle techniques. The fabricated membranes, especially CCAM-10%, showed excellent hydrophilicity (with a contact angle of 48.06⁰), good surface roughness (with Ra=47.4 nm and Rq=60.2 nm), offering admirable permeation flux, a high surface area (124.3 m2 /g), good thermal stability, with an enhanced decomposition temperature reaching ~310℃, and high water uptake (125.3%) and porosity (72.35%). The average pore diameter and molecular weight cutoff of the CCAM-10% were ~1.73 nm and 435 Dalton, respectively. The fabricated membranes’ performances were also evaluated based on the fouling resistance ratios and separation performance, including the water flux and rejection rate. The CCAM-10% had the highest pure water flux of 522.25 L m2 bar -1 h -1 due to a CF tangential flow that had a shearing impact on the surface of the membrane, thereby inhibiting cake buildup on the membrane surface. In contrast, the DE filtration configuration endured more stress. The CCAM-10% exhibited a more than 85% rejection of methyl green and a ~96.6% rejection of BSA as well as the highest hydrophilicity, leading to increased fouling resistance performance. During the antifouling evaluation, the novel CCAM10% showed the highest flux recovery ratio of 67.3% and the lowest irreversible fouling ratio of 32.7%. These are excellent fouling resistance ratios, evidencing the good antifouling property of the membrane. In particular, the low irreversible fouling resistance ratio (Rir) of 32.7% showed that the fouling was caused by the elimination of BSA on the membrane surface, further underscoring the good antifouling performance. Hence, based on its excellent physicochemical properties as well as its separation and fouling resistance performance, CCAM-10% is highly recommended for ultrafiltration water purification applications.