Bioinspired and dual-functional nanocellulose aerogels for water disinfection and heavy metal removal

Treating water resources contaminated by pathogenic microorganisms and heavy metals is a great challenge because of the difficulties in developing efficient strategies for water treatment. Traditional adsorbent materials have the drawbacks of high cost, low adsorption efficiency, secondary pollution creation, and a lack of adaptability in removing a wide variety of pollutants. In this study, inspired by the hierarchical fibrous structure and antibacterial property of the natural silkworm cocoon, we developed a guanidine-functionalized sericin/nanocellulose aerogel (GSNA) with a biomimetic skeletal architecture, which holds great promise for achieving hybrid water disinfection and heavy metal removal. The nanocellulose (CNC) fibers integrated into a robust building block with an interconnected structure and mechanical stability. The grafted polyhexamethylene biguanide (PHMB) endows the biomimetic aerogel with exceptional bactericidal activity (7 log reduction against Escherichia coli within 30 min). Benefiting from the abundant surface functional groups on sericin and CNC-PHMB, the obtained aerogel also exhibits superior heavy metal adsorption capacity (571.5 mg/g for Cu). These compelling merits enable the aerogel to disinfect water and remove heavy metal ions simultaneously as a membrane filter. The synthesized GSNA can be a promising candidate for water disinfection and purification because of its facile preparation, cost-effectiveness, and environmentally friendly characteristics.