Cellulose acetate-nanoMOF beads: a safe, sustainable and scalable solution for Pb remediation in complex water systems

Abstract

Pb [Pb(II)] contamination poses a critical environmental and public health challenge, necessitating innovative and sustainable remediation strategies. This study presents cellulose acetate (CA)-BNMG-1 nanoMOF beads, synthesised via a green, water-based process without hazardous chemicals. By embedding this nanoMOF into a CA polymer matrix, the beads achieve remarkable Pb(II) removal efficiencies exceeding 80% in complex aqueous systems, including canal water and artificial seawater, even with competing ions and naturally occurring microbial contaminants in canal water. The beads exhibit significantly enhanced selectivity for Pb(II), with separation factors (SFs) improving from 2.5 to 350 for Pb/Mn, 57.4 to 220.6 for Pb/Ni, and 150.6 to 314 for Pb/Cd compared to the parent BNMG-1 nanoMOF. Structural stability is ensured, with Cu(II) leaching reduced to below 5% at higher and less than 1% at lower Pb(II) concentrations (5 bead per mL). Furthermore, the beads demonstrate outstanding reusability, retaining over 95% Pb(II) removal efficiency after three cycles. The CA matrix enhances nanoMOF stability, facilitating bead recovery via simple filtration, addressing challenges in scalability and sustainability. This work aligns with safe and sustainable by design (SSbD) framework, providing an eco-friendly and scalable solution for heavy metal remediation, advancing sustainable water treatment technologies for real-world applications.