Study On The Construction Of Iron-containing Waste Residue-electric Field Coupling System And Its Performance In Treating Pesticide Wastewater

At present,the removal of refractory pollutants in water is a research hotspot in the field of water treatment.Electrochemical process has the characteristics of high efficiency,environmental protection and versatility.In recent years,it has been increasingly used in wastewater treatment,especially the removal of refractory biodegradable substances.The iron-containing waste slag-electric field coupling process can overcome the problems of high energy consumption,low current efficiency and short electrode material life in traditional electrochemical technology.In this process,the choice of particle electrode is one of the most important factors affecting the catalytic effect.Therefore,it is of great significance to develop and improve a low-cost,good-performance particle electrode for the iron-containing waste slag-electric field coupling process.Based on the concept of “use waste to treat waste and turn waste into treasure”,industrial solid wastes such as fly ash,steel slag,and red mud are used as raw materials to prepare particle electrodes,and an iron-containing waste slag-electric field coupling system is constructed to remove pollutants in the water.Its effectiveness is explored in order to provide new ideas for resource utilization of industrial waste residues and provide reference for more economical sewage treatment.The research results of this paper mainly include the following three aspects:(1)Construction of iron-containing waste slag-electric field coupling system.This article first explores the feasibility of using fly ash and steel slag as raw materials to prepare particle electrodes and use them in the iron-containing waste slag-electric field coupling system to treat water pollutants.The results showed that the particle electrode prepared with fly ash as a raw material was coupled with an electric field,and85.60% of methylene blue was removed within 56 minutes.The prepared steel slag particle electrode is coupled with an electric field.Under the conditions of pH 3,voltage 12 V,initial methylene blue solution concentration 15 mg/L,and electrolyte concentration 0.3 mol/L,the methylene blue removal rate reaches91.41%,which is higher than the two-dimensional electrochemical system.23.48%,36.2% lower energy consumption.(2)The mechanism of the iron-containing waste slag-electric field coupling system to remove methylene blue.In order to further understand the removal mechanism of the iron-containing waste slag-electric field coupling system on the removal of pollutants,it is compared with the electro-Fenton(EF)and electro-flocculation(EC)processes.The results show that compared with the EC and EF processes that are affected by a specific pH value,the iron-containing waste slag-electric field coupling system has better performance and the lowest energy consumption in the range of pH 3.0-11.0.Through the comparison of the three systems,the analysis of flocs and solutions by FTIR and GC-MS,and the characterization of the particle electrode before and after use,it is inferred that the fly ash-red mud particle electrode-electric field coupling system combines the electric Fenton ·OH Oxidation,the removal of pollutants by flocculation in electro-flocculation and the oxidation of target pollutants by the particle electrode.The flocs and solution in the system were analyzed and tested,and the degradation pathway of methylene blue by the coupled system was inferred.The heavy metal dissolution test of the particle electrode shows that the prepared fly ash-red mud particle electrode can be used for wastewater treatment without causing secondary pollution.In actual surface water experiments,the fly ash-red mud particle electrode-electric field coupling process still shows great potential.(3)Study on the performance of iron-containing waste slag-electric field coupling system to remove pesticides in water.Fly ash and red mud are prepared with different proportions of fly ash-red mud particle electrodes,their physical and chemical properties are characterized,and they are coupled with an electric field for pesticide wastewater treatment.The results show that under the conditions of fly ash: red mud =3:4,particle electrode dosage 100 g/L,cell voltage 5V,and initial pH 6.8 for 30 minutes,the removal rate of atrazine(ATZ)in the solution It can reach 90.1%.In addition,the fly ash-red mud particle electrode still maintains high catalytic performance after seven cycles of use,indicating that the particle electrode has good stability and recyclability.Through the control experiment,free radical suppression experiment and the characterization of the solution,the reaction mechanism of the iron-containing waste slag-electric field coupling system and the degradation pathway of ATZ are proposed.The results show that ·OH is the main active free radical that degrades ATZ,and ATZ is mainly degraded on the surface of the particle electrode.