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

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 beta-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 ca-pacities for Sb species. Also, their excellent interception performances for treating Sb containing synthetic ef-fluents 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.

Automated summary

MXene-based nanocomposite membranes consisting of cellulose nanofibrils (CNFs) as functional scaffolds and in situ anchored beta-FeOOH nanorods demonstrate stable and pH-independent removal capacities for antimony (Sb) species in both static and continuous flow-through modes. These membranes also exhibit excellent self-cleaning capability through photo-Fenton degradation of adsorbed organic dye. Molecular dynamics simulations support their superior dynamic removal performance towards Sb species. This work provides insights for the design of mechanically robust MXene-based water purification membranes with favorable self-cleaning property.