Multifunctional underwater superoleophobic cellulose-based composite aerogel with oil/water separation, dye adsorption, and antibacterial activities

Developing multifunctional materials with oil/water separation, dye adsorption, and antibacterial activities presents an enticing prospect for wastewater treatment. In this paper, a three-dimensional (3D) porous cellulose (CE)/quaternized cellulose (QCE) composite aerogel with super-wettability through co-deposition of polydopamine (PDA) and polyethylenimine (PEI) is reported. The PDA/PEI coating endows the aerogel with superhydrophilicity (WCA = 0°), and the QCE act as an anionic dye sorbent at the same time, endowing the material with antimicrobial activity against Escherichia coli (E. coli). Oil/water mixtures can be separated on an as-prepared aerogel with high efficiency (>99%), even when the filtration was repeated 10 times, and the as-prepared aerogel can also separate oil-in-water emulsions. Moreover, the as-prepared aerogel exhibited excellent adsorption performance for alizarin red, with a calculated maximum adsorption capacity of 454.545 mg g−1. Besides, our modification also endowed the aerogel with antibacterial and anti-oil-fouling activities. The inhibition zone test verified the efficient elimination of E. coli. This work may open a new avenue for designing versatile aerogel with multiple functions for waste water remediation.