Tunable Coordination-Responsive Metal-Phenolic Membranes for Selective and Efficient Pb(II) Remediation with Low-Chemical Regenerant in Actual Wastewaters

Abstract

Heavy metal contamination in industrial wastewater, particularly lead (Pb(II)), poses significant environmental and health challenges. Conventional membrane technologies, like nanofiltration and ultrafiltration, struggle with selectivity and separation recovery in complex wastewater streams. To address this, we present an advanced metal-phenolic network (MPN) membrane that leverages the tunable coordination chemistry of Tannic Acid (TA) and metal complexes to address these limitations. The TA-MPN membrane demonstrates exceptional performance, achieving 6-15 times higher selectivity for Pb(II) than commercial polyamide membranes, even in the presence of competing ions such as Cd(II), Zn(II), Cr(VI) and Ni(II). In electroplating wastewater applications, the membrane reduces Pb(II) levels to below 0.1 mg/L with a capacity of 80 L/m² and removal efficiency exceeding 95%, meeting stringent GB21900-2008 standards. Furthermore, the membrane exhibits outstanding regenerability, maintaining consistent performance over 10 regeneration cycles using extremely low doses of 0.1% HCl. An economic analysis reveals a preparation cost of 22.6 USD/m² and a treatment cost of 0.227 USD per ton of wastewater, demonstrating its cost-effectiveness. The findings establish the TA-MPN membrane as a scientifically robust solution for selective and cost-effective Pb(II) remediation and recovery, effectively addressing the limitations of conventional membranes while advancing scalable and sustainable technologies for heavy metal treatment.