PFOA ADSORPTION KINETICS ON NATIONAL ACTIVATED CARBON: PRELIMINARY STUDY (Atena Editora)

Abstract

The present work exposes the problem of water contamination by a class of anthropogenic chemical substances known as per- and polyfluoroalkyl substances (PFAS) that have been widely used in various industrial processes since the 1940s. The use of PFAS in the production of textiles, Non-stick coatings, stain-resistant materials and firefighting foam result in significant environmental contamination, especially in areas where these products are manufactured and used due to the ability of PFAS to bioaccumulate in organisms, leading to toxic effects. Although conventional water treatment techniques can remove many contaminants, PFAS are not effectively removed by these methods and even the use of advanced oxidative processes has been shown to be ineffective at removing PFAS from water. Faced with this challenge, research has focused on the use of powdered activated carbon (PAC), a common adsorbent for removing contaminants in water. The study describes experiments conducted on a bench scale at ``Universidade de Brasília`` (UnB) using commercial pulverized activated carbon produced from the endocarp of the babassu coconut (CAP Babassu) aiming to evaluate the adsorption kinetics of perfluorooctanoic acid (PFOA) on carbon in a matrix of ultrapure water given that there are few studies on the removal of PFAS in Brazil. The initial characterization of the coal was carried out using thermogravimetric analysis and PCZ pH test. Quantification of the analyte was carried out using a Shimadzu Total Organic Carbon analyzer. The study evaluated the adsorption kinetics of perfluorooctanoic acid (PFOA) using pseudo-first and pseudo-second order models. The results were analyzed using the linear regression technique and plotted on graphs representing the model equations. In the end, activated carbon from babassu coconut endocarp proved to be a potential adsorbent for use in the removal of PFOA (qe = 120 mg PFOA/g CAP Babassu), following a pseudo-second order kinetic model, suggesting the predominance of chemical adsorption and coexisting with physical adsorption.