Research On Construction Of Phosphorus-doped Biochar Floating Island Cathode Electrochemical System And Disinfection

Water quality disinfection is an important topic in the field of water supply and drainage and environmental science.As the epidemic spreads,the public pays more attention to water quality,and the development of new disinfection technologies has become a new trend.Electrochemical disinfection based on electro-living substances is a green cleaning A new type of disinfection technology with no secondary pollution,mild conditions,easy manipulation,and multi-functional integration,has certain development potential and application prospects.Electrochemical disinfection systems often have multiple effects such as direct disinfection of electric fields and indirect disinfection of electro-generated active oxygen substances,especially active oxygen substances represented by H₂O₂ are clean,avoiding the risk of transportation and storage,and complex anthraquinone preparation The craftsmanship has received widespread attention.In the process of electrochemical 2-electron oxygen reduction synthesis of H₂O₂,scientific problems such as low cathode electrochemistry/selectivity and precursor oxygen mass transfer have led to a low concentration of cathode electrosynthesis H₂O₂.In order to solve this problem,this research designed a heteroatom-doped porous biochar cathode to improve the reactivity/selectivity of the 2-electron ORR,supplemented by the design of floating island oxygen supply,and supplemented the lack of dissolved oxygen with the oxygen source of air.To achieve the enhancement of the oxygen mass transfer of the precursor,and ultimately the two synergize to increase the accumulation of electrosynthetic active substances.In this study,waste porous biomass was used as the precursor of porous biomass.After phosphoric acid pretreatment,high temperature pyrolysis was used to obtain heteroatom phosphorus-doped biochar cathodes with different impregnation times,impregnation ratios and three temperature gradients.Scanning electron microscopy（SEM）results show that the prepared biochar cathode preserves the complex layered pore structure and obvious surface protrusions of the original biomass;the specific surface area（BET）and pore size distribution results show that the prepared phosphorus doped biochar cathode Compared with before modification,the specific surface area is increased by nearly 20%,with more micro/mesoporous composite structure;X-ray photoelectron spectroscopy（XPS）results show that the modified cathode introduces more oxygen-containing functional groups such as C=O,C-O-C.On the surface of the resistance test value,the introduction of oxygen-containing functional groups is beneficial to improve the conductivity and electrocatalytic activity of the prepared plates;the results of cyclic voltammetry（CV）and linear scanning voltammetry（LSV）show that the prepared biochar materials have good properties The oxygen utilization capacity is conducive to the occurrence of oxygen reduction reactions.Combining the characterization method and the accumulation of H₂O₂,the optimal operating conditions were obtained,that is,the sintering temperature of biochar was 700℃,the immersion time was 5 hours,and the immersion ratio was 3:0.1.The floating island type oxygen supply method replaces the traditional immersion type,resulting in a higher accumulation of H₂O₂.Within 30 minutes,it can increase by nearly 25%,which has better oxygen utilization effect.Using oxygen in the air as the source of oxygen,combined with the hydrophobicity that facilitates the adsorption of oxygen molecules,the oxygen mass transfer efficiency has a better effect;driven by electric power and uniform stirring,the adsorbed oxygen bubbles can be spread to avoid bubble accumulation.The modified phosphorus-doped biochar cathode is loaded into an electrochemical reactor using a floating island as the oxygen supply method,which has a good effect of killing E.coli.The reactor runs for 40 minutes and can kill 99.99%rate.The heteroatom-phosphorus-doped biochar cathode prepared in this study has good electrochemical activity for the 2-electron oxygen reduction synthesis of H₂O₂.The floating island oxygen supply design strengthens the oxygen mass transfer process of the 2-electron oxygen reduction,and finally strengthens Electrochemical synthesis of H₂O₂.The electrochemical system is applied to the inactivation of E.coli,the inactivation efficiency is significant,and it has economic feasibility and application prospects.