Sustainable and reusable antibacterial aerogels constructed from surface-quaternized cellulose nanofibrils for effective oil-water separation

Severe environmental risks from oil extraction leaks and solvent-containing wastewater have created an urgent need for efficient oil-water separation materials. Cellulose nanofibril (CNF) aerogels are regarded as promising candidates for oil-water separation owing to their low weight, high porosity, and excellent adsorption capabilities. However, the limited surface functionality of CNF restricts their development in functional aerogel materials. Herein, three types of surface-quaternized CNF (CCNF-Q 16 , CCNF-Im 8 , and CCNF-BnMe 2 ) were synthesized via surface chloroacetylation, followed by quaternization with different tertiary amines. Antibacterial results showed that all the prepared quaternized CNFs possessed excellent antibacterial activity, and the antibacterial rate of CCNF-Q 16 achieved 100% against both Escherichia coli and Staphylococcus aureus . CCNF-Q 16 was cooperated with sodium alginate to fabricate an aerogel, which was further hydrophobically modified using methyltrimethoxysilane. The aerogel exhibited low density (0.027 g cm −3 ), high mechanical strength (138.2 kPa), and excellent adsorption capacity for oils (up to 48.1 g g −1 ). Moreover, it had long-term antibacterial activity and retained an antibacterial rate of 94.3% even after 15 consecutive oil-water separation cycles. This work provides a new strategy for synthesizing surface-quaternized CNFs and highlights the potential of the modified CNFs as sustainable and reusable antibacterial aerogel materials for oil-water separation and environmental remediation.