Dual-layered ultrafiltration membrane with MgO nanoparticles via co-casting technique for arsenate removal

Conventional membrane technologies for arsenic removal often struggle with inefficiencies due to arsenic neutrality, high-pressure needs, low water flux, limited contact area, and scaling issues. To address these challenges, we introduce a novel dual-layered flat sheet adsorptive membrane via a co-casting technique, incorporating thermally activated MgO nanoparticles (MgO_650°C) into the selective layer. This co-casting technique enables both strong adhesion and enhanced adsorption performance. The membrane with MgO_650°C: 2.0 ratio exhibited excellent performance, combining an arsenate adsorption capacity (184.56 mg/g), efficient water permeability (167.39 L/m².h.bar), and rejection efficiency of over 99 %. The adsorption behavior followed a pseudo-second-order kinetic model, implying that chemisorption is the dominant mechanism. The application of four adsorption isotherm models with kinetic analysis provides a comprehensive understanding of the adsorption mechanism. This is further supported by EDX elemental mapping, which confirmed the formation of As-O-Mg complexes on the membrane surface. Additionally, the membrane can be easily regenerated using a 0.1 M NaOH solution coupled with the ability to maintain performance over multiple cycles, underscoring its reusability. This work presents a scalable, regenerable, and highly adsorptive membrane platform, establishing a new benchmark for arsenic removal efficiency in membrane-based water treatment systems.