Performance And Mechanism Of Chlorine Radical Mediated Flow-Through Electrochemical System For The Organophosphorus Degradation And Phosphorus Recovery

The use of organophosphorus pesticides in agriculture is widespread and has significant benefits for increasing productivity and income.Unfortunately,these pesticides have led to a dangerous buildup of organophosphorus in water sources,creating an urgent need for targeted treatment technologies.The crisis of dwindling global reserves of non-renewable phosphorus ore exacerbates this problem further.Despite this,there is hope in the form of electrochemically induced crystallization technology,which has been lauded for its ability to efficiently recover inorganic phosphorus resources from wastewater.However,the technology is limited in that it cannot directly recover organic phosphorus.This paper proposes a solution to this problem by combining the benefits of electrochemistry with membrane separation to create a flow-through electrochemical reaction system.This system has the potential to degrade organic phosphorus in water but also simultaneously recover phosphorus resources.To investigate the feasibility of this approach,the paper outlines several studies.Firstly,the researchers prepared titanium suboxide based membrane electrode materials using the H₂reduction technique,and then used advanced characterization techniques to investigate the materials’microscopic morphological characteristics and chemical composition.They found that titanium suboxide has a low internal resistance to charge transfer and diffusion,indicating that it could be effective in the electrochemical degradation of organic phosphorus.The performance and mechanism of electrochemical cathodic and anodic synergistic degradation of organic phosphorus and recovery of phosphorus resources were investigated using phosphorus Tetrakis（hydroxymethyl）phosphonium sulphate as the target pollutant.The results show that increasing the current density is conducive to the induced generation of chlorine radicals at the anode,accelerating the degradation reaction of the pollutant and the release rate of orthophosphate.It also helps to strengthen the local strong alkaline conditions at the cathode surface interface,promoting the migration and diffusion movement of Ca²⁺to the cathode surface,driving the precipitation process of calcium hydroxyphosphate precipitates,and ultimately facilitating the recovery of phosphorus.When the current density was increased from 10 m A·cm^-2 to 30 m A·cm^-2,the degradation efficiency of Tetrakis（hydroxymethyl）phosphonium sulphate phosphate increased from 77%to 97%and the phosphorus recovery increased from 57%to 80%.When the initial p H of the native solution was increased from 3.0 to 9.0,there was no significant change in the oxidation of phosphorus Tetrakis（hydroxymethyl）phosphonium sulphate,while the phosphorus recovery increased from 72%to 82%,indicating that alkaline conditions helped to promote the production of calcium hydroxyphosphate.The system was able to ensure the desired degradation of Tetrakis（hydroxymethyl）phosphonium sulphate phosphonium sulphate and phosphorus recovery under optimal experimental conditions,with a reaction energy consumption of only 61 k Wh·m^-3.Electron paramagnetic resonance spectroscopy confirmed the generation of chlorine radicals in the concentration range of 3.21×10^-14 M.Free radical capture experiments demonstrated that chlorine radicals are the main strong oxidation-active oxide species in the oxidation of organophosphorus at titanium suboxide electrodes.In conclusion,this paper proposes an effective strategy for the resource-based treatment of organophosphorus wastewater by means of electrochemical cathode and anode synergy,achieving efficient decomposition of organophosphorus and rapid recovery of phosphate in the electrochemical reaction.This study provides a theoretical basis for improving the shortcomings of conventional water treatment technology in the resource utilization of organophosphorus wastewater and provides technical support for the wide application of electrochemical technology in the field of wastewater treatment.