Integrating Fenton Oxidation and Zirconium-Based Coagulation for Deep Removal of Phosphonates from Polluted Water

Abstract

Organophosphonates are a group of chemicals that are difficult to be directly removed through coagulation and are recalcitrant to conventional Fenton oxidation (pH 3.0). The excessive discharge of these chemicals into the environment can lead to severe consequences. In this study, we successfully addressed this challenge by introducing a combined approach of Fenton oxidation followed by coagulation. For the first time, Fenton oxidation was found to be effective for the degradation of a representative phosphonate, amino trimethylene phosphonic acid, at a circumneutral pH of 8.0. This pH level eliminated the requirement for repeated pH adjustment prior to and after coagulation, making the coagulation process more favorable and efficient. Following the oxidation treatment, a novel zirconium xerogel coagulant (ZXC) consistently reduced the remaining total phosphorus concentration to below the regulatory discharge limit (0.1 mg/L). In short, the combined approach of Fenton oxidation and ZXC coagulation holds significant promise in mitigating water pollution from phosphonates. The findings of this study have the potential to make a significant contribution to the field of water treatment and sustainability with the aim of protecting our precious water resources from eutrophication.