Electrospinning Device for Nanofibers| Effective PFAS removal from water using vinyltrimethoxysilane-modifiedpolyethyleneimine-aramid-banana nanocellulose aerogels

A research team led by Professors Meiling Zhang and Tong Lin from the School of Textile Science and Engineering at Tiangong University has developed a surface-modified banana stem nanocellulose-based aerogel adsorption material that can efficiently remove per- and polyfluoroalkyl substances (PFAS) from water. The material constructs a high-specific-surface-area biomimetic hierarchical porous structure by combining polyethyleneimine (PEI), aramid fibers, and hydrophobic modification with vinyltrimethoxysilane (VTMS).

Notable characteristics include:Ultra-efficient adsorption performance: Reduces various PFAS (PFOS, PFNA, PFHxS, PFBS, etc.) from an initial concentration of 1000 ppb to 2.87 ng/L (ppt) within 120-180 minutes, far below the EPA 2024 drinking water standard limits (e.g., PFOS limit of 4 ng/L).Broad-spectrum adsorption advantage: Removal rates for long-chain PFAS (e.g., PFOS, PFNA) exceed 99.9%, significantly outperforming traditional activated carbon and MOF materials.Excellent cycling stability: Maintains 92.3% adsorption capacity after 15 adsorption-desorption cycles, demonstrating outstanding mechanical and chemical stability.

This work was published in the top environmental journal "Separation and Purification Technology" under the title "Effective PFAS removal from water using vinyltrimethoxysilane-modified polyethyleneimine-aramid-banana nanocellulose aerogels". Muhammad Yousif, a Ph.D. student from the School of Textile Science and Engineering, is the first author, with Professors Zhang Meiling and Lin Tong as corresponding authors. Two international students from Soochow University, Biqees Hussain and Talha Khan, participated in the research. Tiangong University is the sole corresponding institution. The research received support from the National Natural Science Foundation of China and other sources.

The team successfully prepared porous NCAA and M-NCAA aerogels using freeze-drying and surface chemical modification techniques. SEM images showed the aerogels possess excellent porosity and pore connectivity. FTIR, XPS and XRD tests confirmed successful VTMS grafting, which enhanced the material's hydrophobicity and crystallinity. Mechanical tests showed M-NCAA has higher strength and deformation recovery capability.

Figure 1 Preparation of composite aerogel

Figure 2 Performance characterization of composite aerogel

In PFAS solutions with initial concentration of 1000 ppb, M-NCAA could reduce various PFAS concentrations to 2.87-8.9 ppt within 2-3 hours, with maximum adsorption capacity reaching 1337 mg/g (using PFOS as example), significantly outperforming unmodified NCAA. Different morphologies (hollow, flake, spherical, etc.) affected adsorption efficiency. Adding nonionic or cationic surfactants to water could enhance PFAS adsorption, while anionic types would reduce adsorption performance.The material exhibited broad-spectrum adsorption characteristics for PFAS, with Langmuir model fitting confirming a monolayer chemical adsorption process. 

Figure 3 PFAS adsorption performance of M-NCAA aerogel

Various characterizations including contact angle, Zeta potential, pH value, FTIR and XPS comprehensively demonstrated the synergistic mechanism of electrostatic adsorption, hydrogen bonding and hydrophobicity. VTMS endowed the aerogel with excellent hydrophobicity, while PEI and aramid fibers provided charge and hydrogen bonding sites respectively. After 15 adsorption-desorption cycles, M-NCAA maintained over 90% adsorption efficiency, demonstrating good recyclability and practical application potential.

Figure 4 Adsorption mechanism and cycling adsorption performance

This study designed and prepared a composite aerogel material that can achieve rapid and efficient removal of toxic PFAS from water. The material's performance not only exceeds relevant EPA standards but also significantly surpasses most reported adsorbents. The material has notable advantages including simple preparation process, low cost and environmental friendliness. Large-scale application could not only provide new solutions for PFAS pollution control in aquatic systems but also offer important support for the innovative development of sustainable water treatment technologies.

Original link: https://doi.org/10.1016/j.seppur.2025.133667