Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals with thermal stability and lipid- and water-repelling properties. They are extensively used in aqueous film-forming foams (e.g., fire-fighting foams) as well as household products. Once released into the environment, PFAS can lead to adverse human health effects. In practice, adsorption has been proven and identified as one of the most cost-effective processes of PFAS removal. As a low-cost carbon material, biochar is an ideal sorbent for PFAS decontamination because of its cost effectiveness, thermal stabilities and high specific surface area. Biochar is a carbon-enriched and stable material derived from the energy conversion process of pyrolysis, during which organic materials (such as crop stubble, wood chips, and biosolids) are heated in the complete or near absence of oxygen. In previous study, biochar was engineered by Fe2O3 and Al2(SO4)3 impregnation to enhance the electrostatic interaction and coating with carbon nanotubes and graphite oxide (GO) to enhance the hydrogen bonding with PFAS. Engineered biosolid biochar exhibited great adsorption of both PFOA and POFS. Isotherm experiments proved that the electrostatic interaction and the porous size play important roles on PFAS adsorption. Langmuir isotherm model well described the most of PFAS adsorption on engineered biochar except biosolid biochar (R2 &lt; 0.5). In this study, the major objective is to compare the consistency between the isotherm experiments and column experiments. Dispersion and convection transport model, which can well define solute transport, has been introduced to describe the PFAS transport when various engineered biochar served as porous media. Deposition coefficient and retardation factor determined from the breakthrough curves further explain the PFAS adsorption behavior in the porous media. Consistent findings were obtained when conducted both isotherm and column experiments.

Investigation of PFOA and PFOS adsorption on engineered biochar using column and batch experiments

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.