Study On Enhanced Electrolysis Of Swine Wastewater With Rare Earth Mg Alloy And Activated Carbon Electrode

Due to the problem of the waste of magnesium plate materials and the lack of precipitate recovery method when sacrificing magnesium anode electrolysis swine wastewater.In this paper,the performance of different magnesium alloy anodic electrolytic systems for the treatment of nitrogen and phosphorus wastewater was studied.Sacrificial anodes of magnesium alloys were selected by investigating the indicators of phosphorus and magnesium as well as the electrochemical performance,surface microstructure and operating cost of magnesium alloys.Discussed under the condition of different activated carbon content WE43-Activated carbon-SS304 three-dimensional electrode new electrolytic system for three consecutive batches electrochemical performance of nitrogen and phosphorus wastewater,by investigating the phosphorus,magnesium,and other indicators,as well as before and after electrolytic pyrolysis characteristics of activated carbon,pore distribution,surface elements characteristic,in the new type of three dimensional electrode electrochemical system of activated carbon best content.Under the condition of the optimal amount of activated carbon,the effect of continuous electrolysis of 10 batches of actual swine wastewater by WE43-Activated carbon-SS304 new electrolysis system was studied.The main conclusions are as follows:（1）Compared with AZ91D,AGS and AZ31 magnesium alloy anodic electrolytic systems,the phosphorus removal rate of WE43 rare earth magnesium alloy electrolytic system reaches 90.2%at 30 min,the phosphorus removal rate is 1.82 mg L^-1 min^-1,and the residual magnesium concentration is about 50 mg L^-1.The phosphorus removal rate and residual magnesium concentration showed a cubic function relationship with the electrolytic time.The results of LSV,Tafel and EIS showed that the electrochemical performance of WE43 was better.SEM-EDS detection showed that WE43 contained fine and granularγalloy phase.The total operating cost of recovery of ammonium magnesium phosphate from nitrogen and phosphorus wastewater by WE43 electrolysis is 60%of AZ91D magnesium alloy（commonly used）.WE43 can be used to recover nitrogen and phosphorus from wastewater by sacrificial anode electrolysis.（2）The phosphorus removal rate of each batch of wastewater is more than 90.1%in the 40th minute,and the phosphorus concentration after electrolysis is lower than 8mg L^-1.The phosphorus removal rate was 1.54 mg L^-1 min^-1,and the residual magnesium concentration in the solution was the lowest,which was lower than other systems with10～30 mg L^-1.The results of SEM-EDS and TG-DTG showed that the activated carbon adsorbed magnesium ammonium phosphate during electrolysis.BET structural characterization showed that the main pore type of activated carbon was mesoporous,and magnesium ammonium phosphate precipitation was adsorbed in the activated carbon pores of 20～50 nm during electrolysis.（3）Under the electrolysis condition of 30 g activated carbon,10 batches of actual swine wastewater were treated by continuous electrolysis with WE43-Activated carbon-SS304 electrolysis system.The removal rates of phosphorus,COD and ammonia nitrogen in the electrolytic system were 78.1%±5.1%,61.4%±2.6%and 55.1%±5.5%,respectively.The results of 10 batches of continuous treatment with three-dimensional electrode electrolysis system are relatively stable,which provides a reference for long-term operation of magnesium anode electrolysis technology for swine wastewater treatment.After electrolysis,the adsorbed substance of activated carbon causes the peak weight loss rate to increase after pyrolysis.FTIR analysis showed that activated carbon adsorbed inorganic and organic matter containing carbon,nitrogen and phosphorus after electrolysis.SEM-EDS analysis of activated carbon shows that when the actual swine wastewater is electrolyzed by The WE43-Activated carbon-SS304 three-dimensional electrode system,Mg ions will be adsorbed on the surface of activated carbon,magnesium ammonium phosphate precipitation generated by the reaction,organic matter in swine wastewater,etc.