Effective PFAS removal from water using vinyltrimethoxysilane-modified polyethyleneimine-aramid-banana nanocellulose aerogels

Abstract

The persistent toxicity and ubiquitous presence of per- and polyfluoroalkyl substances (PFAS) in the environment require advanced solutions for their removal from water, especially at trace levels. This study presents an innovative aerogel adsorbent that addresses this challenge through synergistic material design. The aerogel was prepared using a lyophilization technique combining banana cellulose, polyethyleneimine (PEI), and aramid, followed by surface functionalization with vinyl trimethoxysilane (VTMS). It achieved unprecedented PFAS removal efficiency. From an initial concentration of 1000 ppb, it reduced PFAS levels to 4 ppt in 2–3 h, exceeding EPA standards and outperforming most reported adsorbents. Morphological parameters such as sheet thickness (optimal at 1 mm) and structural porosity critically influence adsorption kinetics, with hollow configurations maximizing performance. Adsorption efficiency was influenced by pH and surfactant type. Nonionic and cationic surfactants improved PFAS uptake, while anionic surfactants and competing anions reduced it. The aerogel exhibits broad-spectrum PFAS affinity, particularly for long-chain compounds, driven by a synergistic interplay between VTMS (imparting hydrophobicity), PEI (facilitating electrostatic interactions), and aramid (enabling hydrogen bonding). Remarkably, the aerogel retains >90 % adsorption capacity over 15 consecutive adsorption–desorption cycles, demonstrating robust reusability. This work establishes VTMS-modified PEI-banana aramid aerogels as a scalable, high-performance solution for mitigating PFAS contamination in aquatic systems, with implications for sustainable water treatment technologies.