Study On Electrochemical Technology For Efficient Phosphorus Removal And Recycling Of Chemical Polishing Wastewater

Chemical polishing wastewater has complex components and high concentration of pollutants.If discharged directly,it will cause incalculable harm to water bodies and human health.China has abundant phosphate ore resources,but there are many poor and few rich mines.The resource recovery and utilization of phosphorus containing wastewater is urgent,Based on the high phosphorus content of this type of wastewater and the concept of“energy saving and emission reduction”,this paper proposes three treatment methods to achieve efficient phosphorus removal and phosphorus resource recovery of wastewater.The main conclusions obtained include:（2）Dilute the viscous chemical polishing wastewater 50 times and treat it using the two-chamber fuel cell.The power generation efficiency of the wastewater is 7.31k W·h/t,and the phosphorus removal rate can reach 99.95%.The yield of the phosphorus recovery product blue iron ore is 5.68kg/t of wastewater;During continuous multi cycle operation,the recommended replacement frequency for iron anodes is once every 3 cycles.The intensity of factors affecting battery performance is in the order of air cathode>proton membrane>iron anode.（3）Dilute the viscous chemical polishing wastewater by 50 times and use a single one-chamber fuel cell to treat it.The power generation efficiency is 2.26k W·h/t of wastewater,and the phosphorus removal rate can reach 89.23%.The yield of phosphorus recovery product blue iron ore is 2.73kg/t of wastewater;The main reason why the performance of a single cell battery is lower than that of a dual cell battery is that the pH rises slowly during operation and Fe²⁺accumulation is insufficient;During continuous multi cycle operation,the replacement frequency of the iron anode is once in three cycles,and the effect of the iron anode and the air cathode on battery performance is not significantly different.（3）Dilute the viscous chemical polishing wastewater for 5 times and treat it with electrodialysis+iron-contactor process.The concentration of acid recovered by electrodialysis method is 1.6mol/L;The phosphorus removal rate of iron Contact process is 99.91%,and the yield of phosphorus recovery product blue iron ore is 3.95kg/t wastewater.The iron Contact process can operate stably for 4 cycles,and the phosphorus removal rate is above 99%.After the fourth cycle,the iron sheet is completely corroded;In the optimization experiment of phosphorus removal and ore production,it was found that the main reason for improving phosphorus removal rate and blue iron ore production was the Fe（II）/P molar ratio in the wastewater during pH adjustment,with the optimal Fe（II）/P molar ratio of 1.36±0.08.（4）Through the above three conclusions,it can be found that“electrodialysis+iron-contactor process”and“the two-chamber fuel cell”have the best treatment effect on phosphorus containing chemical polishing wastewater,but the phosphorus removal rate of electrodialysis+iron-contactor process(0.0457 mg·L^-1·h^-1)is far greater than that of the two-chamber fuel cell(0.0070 mg·L^-1·h^-1),and its stability and technical feasibility are also greater than that of double chamber battery.Therefore,electrodialysis+iron-contactor process is the best method to treat phosphorus containing chemical polishing wastewater.