A Study On Electrochemical Degradation Of Ammonia Nitrogen By Modified Zeolite Three-Dimensional Electrode

Ammonia nitrogen is one of the most common pollutants in water.With the development of human socialization,excessive ammonia nitrogen discharged into water,which not only affects human health,but also damages the balance of ecological environment.Therefore,development an economical and effective treatment technology of ammonia nitrogen has become a problem that needs solve urgently.Electrochemical oxidation technology is an"environmentally friendly"technology,which has the advantages of high efficiency and no secondary pollution in the treatment of ammonia nitrogen wastewater.In this paper,electrochemical oxidation technology used to treat simulated ammonia nitrogen wastewater,and the influence of anode materials and filler particles on the degradation of ammonia nitrogen was studied.The energy consumption of ammonia nitrogen removal by two-dimensional and three-dimensional electrodes was compared.Na Cl modified zeolite was selected as the particle electrode of three-dimensional electrochemical reaction.On this basis,the influences of various factors on the electrochemical degradation of ammonia nitrogen in the modified zeolite three-dimensional reactor were investigated.Finally,the electrochemical degradation mechanism of the ammonia nitrogen by modified zeolite three-dimensional electrode was discussed.Among the electrochemical reactors with titanium-based ruthenium iridium rhodium coated sheet(DSA),iron plate,stainless steel plate,graphite plate as anode,stainless steel plate as cathode,filled with activated carbon,natural zeolite,Na Cl modified zeolite and unfilled particles,The best degradation effect is the titanium-base ruthenium iridium rhodium coated sheet(DSA)as the anode,the stainless steel plate as the cathode,and the three-dimensional electrochemical reactor filled with Na Cl modified zeolite.Compared with the two-dimensional electrochemical reactor without filled particles.The degradation effect of ammonia nitrogen by three-dimensional is increased by about 35%.Using NaCl modified zeolite to adsorb ammonia nitrogen,under the conditions of zeolite particle size 35 mesh,dosage 10g/L,reaction time 90min,and p H value 7,the modified zeolite adsorption capacity for ammonia nitrogen reached 1.21mg/g,Compared with natural zeolite,the adsorption capacity of modified zeolite for ammonia nitrogen is increased by about 29%.Electrochemical regeneration of adsorption saturated modified zeolite.The regeneration rate of the modified zeolite maintained at about 84%after six regenerations.As a three-dimensional electrochemical particle electrode,the modified zeolite not only has the adsorption effect on ammonia nitrogen,but also has the good electrochemical regeneration.Modified zeolite is the ideal material as a three-dimensional electrochemical particle electrode.The best experimental conditions for the electrochemical degradation of ammonia nitrogen by modified zeolite three-dimensional electrode were:current density 10m A/cm~2,chloride ion concentration 300mg/L,p H value 9,reaction time 90min,and 30mg/L ammonia nitrogen can be degraded by more than 98%.The modified zeolite three-dimensional electrochemical reaction removes ammonia nitrogen mainly through direct oxidation,indirect oxidation,and adsorption of particle electrodes.Ammonia nitrogen directly converted to nitrogen through lost electrons on the anode,or indirectly oxidized by strong oxides produced by electrolysis.The adsorption of modified zeolite also played a role in the degradation of ammonia nitrogen.After the reaction,the concentration of nitrous nitrogen was lower than the detection limit,and the concentration of nitrate nitrogen is 1.1 mg/L.The ammonia nitrogen in the solution was main converted into nitrogen.