Behavior and mechanism of perfluorooctane sulfonate (PFOS) removal from wastewater samples using bamboo powder biochar

Perfluorooctane sulfonate (PFOS) is an emerging organic pollutant that is prevalent in the environment. The high toxicity, bioaccumulation and environmental persistence of PFOS pose significant risks to ecosystems and human health, and remediation technologies are urgently needed. However, conventional treatment techniques have proven difficult, necessitating the development of more affordable alternatives to adsorbents. Biochar shows great potential as an inexpensive adsorbent for PFOS removal owing to its excellent pore structure, surface properties, and ability to generate persistent free radicals (PFRs). In this study, biochar is prepared from bamboo powder at 300, 500, and 700 °C (BP300, BP500, and BP700). BP500 showed a more developed pore structure, larger specific surface area, and higher PFR signals. The removal efficiency of PFOS on BP500 (49.45 %) was superior to that on BP300 and BP700. The influence of environmental factors (biochar dosage, pH, kinetics, isotherms, and inorganic anions) on the adsorption behavior of PFOS was determined. The removal of PFOS increased at low pH, reaching 63.77 % at pH 2, while the presence of inorganic anions in the solution inhibited PFOS removal by BP500. The presence of oxidants (H 2 O 2 and S 2 O 8 2− ) alongside BP500 in the solution improved PFOS removal efficiency. The oxidant added to biochar could degrade PFOS, as evidenced by the detection of F − , and the removal and degradation rates increased with the oxidant dosage. This study provides a new perspective for analyzing the mechanism of PFOS removal by biochar. In the future, the industrial-scale application of bamboo biochar for contaminant removal needs to be strengthened.