A polyethyleneimine-functionalized cellulose nanofiber/MXene composite aerogel: Towards highly efficient adsorption of crude oil, organic solvents, and dyes

The issue of water pollution is complex and severe, encompassing multiple facets such as crude oil, organic solvents and dyes. Multifunctional aerogels are frequently employed as environmentally friendly adsorbent materials for complex wastewaters. Herein, we successfully fabricated a polyethyleneimine/nanocellulose/MXene/loofah composite aerogel through a simple freeze-drying method using an economical loofah as the skeletal structure. A series of characterization techniques were employed, including Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Brunauer-Emmett-Teller (BET), and Scanning Electron Microscopy (SEM). With the assistance of simulated solar illumination, the aerogel showed rapid photothermal conversion performance, the temperature rose to 110.3 °C within 90 s. The aerogel was able to swiftly and efficiently adsorb heavy crude oil (20.61 g g -1 ), maintaining an impressive adsorption efficiency of 95.91 % even after the fifth adsorption cycle. Furthermore, the PCML aerogel exhibited exceptional adsorption efficacy for various organic solvents, with an adsorption capacity of 16.42 g g -1 for dichloromethane . Due to the interactions between hydroxyl and amine groups of nanocellulose , MXene , and polyethyleneimine , the PCML aerogel, after crosslinking with glutaraldehyde and ion exchange, can selectively adsorb multiple cationic (Methylene Blue, Malachite Green) and anionic dyes (Congo Red, Methyl Orange) from mixed dye systems. Additionally, the PCML aerogel demonstrated significant mechanical properties, withstanding a stress of 120 kPa at 80 % deformation and exhibiting a low bulk density of 28.15 mg cm -3 . The adsorption process deeply investigated through N 2 isothermal adsorption, pseudo-primary kinetics, pseudo-secondary kinetics, intra-particle diffusion model, and adsorption isotherms (Langmuir and Freundlich models) for CR dye. The maximum CR adsorption capacity of 2499.5 mg g -1 was achieved in 2.5 h at pH = 4 using only 10 mg of PCML aerogel. This study proposes novel strategy based on low-cost, high-efficiency composite aerogels , showing potential practical applications in various complex water pollution fields. • The composite aerogel was prepared by freeze-drying method. • The aerogel with efficient and rapid photothermal conversion performance. • Aerogel shows excellent performance in crude oil adsorption under simulated sunlight. • The aerogel can be recycled adsorption of variety organic solvents and dyes.