Effective removal of arsenite from water using polylactic acid ZIF-8 biocomposite nanofiber

Water purification from As(III)-contaminated groundwater is difficult but highly needed. Herein, a new polylactic acid ZIF-8 biocomposite nanofiber mat (ZIF-8@PLA/NFM) was fabricated using an electrospinning technique for As(III) decontamination. The active component, ZIF-8 nanoparticles, are uniformly embedded in sustainable PLA fibers and can be rapidly contacted by As(III), achieving fast kinetics and high utilization of nanoparticles. The removal experiments show that the ZIF-8@PLA/NFM can effectively remove As(III), especially in combination with H2O2. The 50%-ZIF-8@PLA/NFM with 1 mM H2O2 reduced 1000 mu g/L As(III) to less than 10 mu g/L in just 5 min through the synergy of oxidation and adsorption. The maximum sorption capacity for As(III) on 50-ZIF-8@PLA/NFM was 11.61 +/- 0.99 mg/g, which increased to 39.25 +/- 3.84 mg/g with the addition of H2O2. It performed well in the pH range of 4-9. The combination of H2O2 broadened its effective pH operating range (3-10) as well as enhanced interference resistance, enabling deep removal of As(III) across a wide range of water environments. The As(III)-spiked natural water (100 mu g/L) could be purified to drinking standard level by ZIF-8@PLA/NFM within 60 min. In combination with H2O2, the removal efficiency was reduced by only 1.5% at the fifth reuse. Macroscopic experiments and microscopic characterization suggest that the adsorption follows the inner-sphere complexes mechanism. The study provides a novel approach for the fabrication of efficient, easy-to-use, and sustainable MOFs-based biocomposite for As(III) decontamination.