| Water resource pollution and shortage have driven the rapid development of membrane filtration technology in the field of wastewater treatment.Membrane treatment technology has become a common method for treating leachate in most landfills,but it produces a concentrated liquid with high organic concentrations and poor biodegradability.With the increasingly strict national policies and water quality standards,the reasonable treatment of nanofiltration concentrates has become a technical challenge in practical engineering applications.Among various organic wastewater treatments,the three-dimensional particle electrode electrochemical technology has been widely applied,mainly using activated carbon,chalcopyrite,and composite self-made materials as particle electrodes.However,activated carbon has limited adsorption capacity,and the process of making self-made particle electrode materials is tedious.Moreover,it can cause saturation and blockage problems when the pollutant concentration is high.Aluminum particle materials are inexpensive and easy to obtain and can be replaced with materials from common household aluminum cans.Therefore,metal materials such as aluminum particles have significant advantages as particle electrodes,and currently,here is little research on the treatment of nanofiltration concentrates using three-dimensional electrode systems with aluminum particles as particle electrodes both domestically and internationally.This article first conducted research on the three-dimensional particle electrode electrochemical process for treating nanofiltration concentrate using a static experimental device.The experimental parameters such as electrode plate and particle electrode material,current density,etc.were optimized and selected.On this basis,the treatment efficiency and stability of the three-dimensional electrode system during continuous operation were explored,and the combined process was compared and optimized.In addition,the contribution of free radical removal during the removal of nanofiltration concentrate by the three-dimensional electrode was studied,and the organic matter in the water before and after treatment was analyzed.The main research results are as follows:（1）In the static experiments,compared with other electrode combinations（Ti/Ru O2-Ti/Ru O2-Ti/Ru O2-Ti/Ru O2,Ti/Ru O2-graphite-Ti/Ru O2-graphite,graphite-copper-graphite-copper）,using graphite-graphite-graphite-graphite as the plate combination can effectively reduce the energy consumption and residual chlorine concentration in the reaction system.With a current intensity of 4 A,a plate spacing of 2.5cm,a volume of 378 cm3 of aluminum particles,and a pump circulation flow rate of 2 L/h,after a treatment time of 120 min,the color removal rate of the nanofiltration concentrate can reach 98.94%,UV254 with 74.85%,TOC with 67.46%,COD for 51.93%,with an energy consumption cost of only 10.75 RMB/m3.（2）Under the optimal experimental conditions mentioned above,the study of continuous operation and combined processes of the three-dimensional system shows that the effluent quality of the three-dimensional system is stable during continuous operation.By comparing and optimizing combined processes（iron electrocoagulation-three-dimensional electrode electrochemistry,three-dimensional electrode electrochemistry-alkaline neutralization,three-dimensional electrode electrochemistry-iron electrocoagulation）,the research shows that the three-dimensional electrode electrochemistry-iron electrocoagulation process can effectively solve the problem of low p H of the effluent from the three-dimensional system and further improve the treatment effect of the three-dimensional system on nanofiltration concentrate.（3）Compared to traditional electrochemical systems,the three-dimensional system with aluminum particles as the particle electrode can improve the removal efficiency of organic pollutants in nanofiltration concentrate by nearly twice.GC/MS analysis indicated the composition and removal of organic compounds in the nanofiltration concentrate,and the results showed that the three-dimensional electrode system can remove most of the organic compounds,and decompose them into small molecules. |
PDF Full Text Request