MXene–PVA composite for arsenic removal from industrial wastewater: a combined DFT and experimental study

Abstract

Arsenic pollution in industrial effluent presents significant environmental and health hazards worldwide. Although Ti₃C₂T_x MXene demonstrates potential for arsenic adsorption, its actual use is constrained by structural instability and aggregation in aqueous conditions. This research combines density functional theory (DFT) computations with experimental verification to create MXene-polyvinyl alcohol (PVA) composites for efficient arsenic elimination. DFT simulations indicated an increased As(V) adsorption energy of −2.58 eV due to synergistic hydrogen bonding between the hydroxyl groups of PVA and the surface terminations of MXene. The synthesized MXene–PVA composite (20 wt% MXene) attained a maximum adsorption capacity of 135.2 mg g⁻¹ for As(V), adhering to pseudo-second-order kinetics and the Langmuir isotherm model. The composite exhibited 85% selectivity in the presence of competing ions (PO₄³⁻, SO₄²⁻) and preserved 85% capacity following eight regeneration cycles. Actual wastewater treatment from electroplating facilities lowered arsenic levels from 8.2 mg L⁻¹ to 0.008 mg L⁻¹, thereby complying with WHO requirements. XPS study verified that bidentate As–O–Ti complexation is the predominant process, corroborating DFT predictions. This study illustrates a feasible approach for industrial arsenic cleanup using an integrated computational-experimental design.