Preparation of Polyaniline Modified Cellulose Filter Paper and Its Application in Detecting 23 Per- and Polyfluoroalkyl Substances

Per- and polyfluoroalkyl substances (PFAS) are a widely used class of synthetic chemicals that pose a significant global environmental and health threat due to their persistent and bioaccumulation toxicity caused by strong C-F bonds in their structures. PFAS usually exist in trace concentrations in environmental water bodies, which poses great challenges for environmental analysis. In this study, environmentally friendly cellulose was modified with polyaniline through in situ oxidative polymerization, and used as the filter paper for solid-phase extracting 23 PFAS in water. Characterization techniques such as scanning electron microscope, Fourier transform infrared spectroscopy, X-ray photoelectron spectrometer, and thermogravimetric analysis indicated the successful synthesis of structurally stable polyaniline-modified cellulose filter paper (PANI/CFP). Then, a high-performance liquid chromatograph-triple quadrupole mass spectrometry determination method was established for 23 PFAS from water using PANI/CFP extraction. The optimal adsorption occurred at a solution pH of 3.0-5.0, and the best elution efficiency can be achieved using methanol with 2% added ammonia water. The adsorption mechanism of 23 PFAS by PANI/CFP can be considered as the result of synergistic effects between physical and chemical adsorption. The recovery rates for 23 PFAS in groundwater, surface water, and wastewater ranged from 65.8% to 105%, with limits of detection and quantification from 0.44 to 36.5 ng/L. After being reused five times, PANI/CFP can still maintain a good extraction recovery rate for PFAS. This study successfully prepared PANI/CFP and established an experimental method flow for its application in the extraction and detection of 23 PFAS in water. The PANI/CFP has the characteristics of stable structure and properties, and easy operation.