Removal of Fluorotelomer Alcohol from water matrix

Per- and polyfluoroalkyl substances (PFAS) are a large group of synthetic organofluorine compounds used in firefighting foams, surface coatings, textiles, and food packaging. Their exceptional chemical and thermal stability, derived from the strong carbon fluorine bond, makes them resistant to natural degradation, leading to their global persistence in the environment and earning them the name “forever chemicals.” Exposure to PFAS has been linked to developmental, reproductive, and immunological effects, as well as increased cancer risk [1]. Among PFAS, fluorotelomer alcohols (FTOHs) have gained particular attention as precursors of persistent perfluoroalkyl acids (PFAAs). 6:2 Fluorotelomer Alcohol (6:2 FTOH) can undergo oxidative degradation to form PFCAs, including long-chain species (e.g., PFHxA, PFOA) and ultra-short ones such as trifluoroacetic acid (TFA), which are highly mobile and difficult to remove from water [2]. The increasing detection of both long- and short-chain PFAS in surface, ground, and even drinking waters highlights the urgent need for efficient and sustainable adsorbent materials. However, traditional materials such as activated carbon and ion-exchange resins often show limited performance toward volatile precursors like FTOHs, mainly due to differences in polarity, molecular size, and hydrophobicity. In this work, mesoporous MCM-41 was synthesized from a low-cost, waste-derived silica source and subsequently functionalized with four types of surface modifiers [3]. Different functionalization ratios were investigated to identify the best compromise between surface coverage and accessibility of adsorption sites. A non-functionalized MCM-41 reference synthesized under identical conditions was also included for comparison [3;4]. Adsorption isotherms of 6:2 FTOH were obtained in batch mode The equilibrium concentrations were determined by headspace gas chromatography–mass spectrometry (GC-MS-HS). This technique allows to quantify 6:2 FTOH, minimizing matrix effects; analyses were conducted with an isotopically labelled internal standard. The analytical method exhibited excellent linearity (R2 > 0.999) within the 0–200 ppb range, enabling reliable quantification of 6:2 FTOH at trace levels. The results demonstrated that functionalized materials achieved significantly higher adsorption capacities compared to the non-functionalized MCM-41, confirming the beneficial effect of surface modification. This study highlights the potential of waste-derived mesoporous silica as a sustainable platform for PFAS remediation and provides new insights into the interaction mechanisms of volatile fluorinated compounds with tailored silica surfaces.