Ultrafast Removal of Ni(Ii) Ions Over a Bio-Based Antibacterial Adsorbent

Efficiently removing heavy metal ions and preventing bacterial growth were meaningful for wastewater purification, which still faced a long-term problem requiring the development of sustainable antibacterial adsorbent with both high uptake capacity and ultrafast adsorption rate. We fabricated a low-cost yet strong bio-based adsorbent using simple supramolecular self-assembly of tannic acid (TA) and polyethyleneimine (PEI) for fast and highly reversible absorption of Ni(II) ions. This adsorbent displayed an interconnected nanoparticle morphology, and its average size was similar to 41 nm. Benefiting from the abundant catechol/amine groups and meso-/ macro-porous channel as well as high surface area (86.5 m(2)/g), this bio-based adsorbent could trap Ni(II) ions by rapidly forming Ni-O and Ni-N coordination bonds, thereby reaching adsorption equilibrium within 5 min, which almost exceeded most reported adsorbents by 6-330 times. Simultaneously, these structural merits also endowed this bio-based adsorbent with a high adsorption capacity (269.6 mg/g), superior to most other adsorbents. Furthermore, we discovered that the formed supramolecular nanostructure and the positive-charged surface of this bio-based adsorbent with bicomponent TA and PEI provided TA-PEI with about 100 % antibacterial activities against Escherichia coli and Staphylococcus aureus.