Study On The Performance Of Biomass Carbon Electrocatalytic Degradation Of Organic Pollutants And Its Application In Self-powered System

A remarkable sign of the rise of industrial civilization is that a large amount of organic matter?especially benzene-containing organic compounds?enters the process of industrial production to the benefit of the mankind,nevertheless,it also brings about an increasingly serious problem of water pollution.How to quickly and efficiently achieve the treatment of highly toxic and refractory organic pollutants is gradually becoming a matter of major social concern.Among the multitudinous organic pollutant treatment methods,electrochemical oxidation is one of the most efficient methods.However,traditional electrochemical oxidation treatment of organic pollutants still has various problems such as low catalytic activity of electrode materials and excessive energy consumption during the reaction process,seriously hindering its widespread usage.The electrode currently selected in the system of electrochemical oxidation degradation of organic pollutants still uses the traditional catalytic material with high price and complicated preparation process,so it is urgent to explore a catalytic material with inexpensive,preparation simple and widely applicable advantages.Additionally,to a certain extent,the problem of large energy consumption has been solved with the origin of triboelectric nanogenerator?TENG?.Based on this,we focus on solving the constrained factors of traditional electrochemical oxidation technology for the treatment of organic pollutants,and makes full use of the work of our group on oxygen reduction electrocatalysis?including two-electron reduction and four-electron reduction?for many years.The following research works were carried out by constructing a low-cost and simple preparation of catalytically degradable organic pollutant electrode materials and exploring a self-powered degradation system:?1?We innovatively fabricate biomass-derived carbon electrode materials from bean curd to self-power degradation persistent methyl red?MR?.MR is degraded to CO₂ with the carboxyl cleavage from the benzene ring of it through the indirect oxidation process induced by HOCl/Cl₂?produced at the anode interface?.Such an electrochemical degradation mechanism is proposed based on the cyclic voltammogram?CV?,gas chromatograph-mass spectrometer?GC-MS?and mass spectrometer?MS?.By analyzing the structure-activity relationship between the structure and degradation properties of a series of obtained carbon materials,it is concluded that the specific surface area and nitrogen content play a vital role in the electrochemical degradation performance.Utilizing the multilayer linkage triboelectric nanogenerator?ML-TENG?with the maximum power density of 7.4 W m^-2?load resistance:500 K??as power source,persistent MR can be indirectly degraded.This research innovatively applied biomass-derived carbon materials to electrochemical degradation of organic pollutant systems,providing material support for the construction and practical application of self-powered electrochemical degradation systems.?2?To further exert the advantages of the above catalytic materials,and overcome the problem thatthe anodic oxidation method may be accompanied by the electrolysis of water and the high toxicity and low utilization of highly active species generated by the anode.Using carbon materials derived from magnolia flowers as the cathode,a self-powered electro-Fenton?EF?system is constructed to degrade basic orange 2?BO2?.BO2 can be efficiently degraded to CO₂ by hydroxyl radical?·OH?generated during EF process,which is systematically demonstrated by CV,GC-MS and the H₂O₂ measurement.Considering the high efficiency,simple setup and low voltage of the S-cell,the electrochemical treatment of BO2 in S-cell is more valid,preferable,and feasible here.Based on the structure-activity relationship,it can be clearly found that the specific surface area and N content accompanied with hydrophilicity play an important role in the EF degradation performance of the biomass-derived carbon material.A robust and flexible multilayer triboelectric nanogenerator?RFM-TENG?has constructed,and the instantaneous power density reaches the maximum peak value of 5.5 W m^-2 at a resistance of 1 M?.Driven by this RFM-TENG,persistent BO2 can be efficiently degraded.Thus,the above results make up for the shortcomings in the traditional electrochemical anodization process,and provide a guidance for the selection of EF degradation devices,and realize the self-driving EF degradation of organic pollutants for the first time.?3?To promote EF degradation process,the synthesis of H₂O₂ is a key factor.Besides specificsurface area,nitrogen content and hydrophilicity,pore size distribution of carbon materials was also critical to their electrocatalytic oxygen reduction to synthesize H₂O₂ according to literature research.Therefore,we innovatively prepared biomass-derived carbon material with controllable porous structure by using ethylenediaminetetraacetic acid disodium salt?EDTA-2Na?as porogen,and the pore size of the synthesized material is around 1.5 and 3.5 nm?The decomposition into H₂O,CO₂ and NO_x during the calcination process of EDTA-2Na is favorable for forming hierarchical pores.?.Moreover,the micropores ensure the density of oxygen reduction active sites of carbon materials,mesopores are beneficial to increase the transfer of oxygen-related substances?O₂,H₂O₂,etc.?and the number of active sites exposed,and the micro/mesopor coexistence structure can simultaneously ensure mass transfer and the number of active sites.Additionally,a double layer rotary disc-structured triboelectric nanogenerator(the maximum output power density was 1.36 W m^-2 when the load was 1 M?)is herein designed and constructed to powerfully drive EF?using above micro/mesoporous carbon material as the cathode?degradation of methylene blue.Briefly,this work not only provides guidance for the controllable synthesis cathodic electrocatalytic materials of EF system,but also promotes the application of self-powered EF technology in organic pollutant treatment.Based on the solid work of biomass-derived carbon materials in electrocatalytic applications,weinnovatively fabricated carbon-based materials from biomass as an electrochemical anodized electrode to degrade persistent pollutions.Then,we constructed a cathodic EF degradation system to compensate for the shortcomings?accompanying the electrolysis of water and the high toxicity and low utilization of highly active species generated by the anode?of traditional electrochemical anodization.Moreover,the specific surface area,nitrogen content and hydrophilicity of the carbon material,especially the pore size distribution,affect its degradation performance.The porogen-regulated micro/mesopore coexisting carbon material can simultaneously ensure the mass transfer and the number of active sites and improve the catalytic performance of the two-electron oxygen reduction.Therefore,the above study explore a viable path for the controlled synthesis of cathodic electrocatalytic materials in the EF system.The research on degradation mechanism not only explores the degradation path of organic pollutants in the reaction process,but also can be used as the basis for the selection of degradation equipment.Meanwhile,different forms of mechanical energy in the ambient environment are collected and utilized,which promotes the self-powered degradation of organic pollutants.