Enhanced antimony removal within lamellar nanoconfined interspaces through a self-cleaning MXene@CNF@FeOOH water purification membrane

Abstract

MXenes as two dimensional nanocarriers are promising candidate materials for advanced water purification membranes. Nevertheless, the practical applications of MXene-based membranes are hindered by their poor mechanical strength and widespread fouling issue. Herein, we report a free-standing nanocomposite membrane for the adsorptive separation of antimony (Sb) species from wastewater. Cellulose nanofibrils (CNFs) are adopted as functional scaffolds to assemble with Ti3C2Tx MXenes by forming interlocked structures that significantly promote the mechanical strength and toughness of the membrane, meanwhile, the in situ anchored β-FeOOH nanorods in the nanoconfined interspaces offer abundant active sites for enhanced pollutants removal. The as-prepared MXene@CNF@FeOOH (MCF) membranes demonstrate stable and pH-independent static removal capacities for Sb species. Also, their excellent interception performances for treating Sb containing synthetic effluents are confirmed in continuous flow-through modes, presenting a rapid wastewater purification with allowable emission standards under a high feeding flux of 102.3 L m−2h−1 bar−1. More importantly, the MCF membranes exhibit unique self-cleaning capability via photo-Fenton degradation of the adsorbed organic dye by 90% within 1 h. Molecular dynamics simulations further support their superior dynamic removal performance toward Sb species. This work sheds light on designing mechanically robust MXene-based water purification membranes with favourable self-cleaning property.