Hydroxyapatite Supported Cu-Ni Metal Catalyst For Simulated Oxalic Acid Wastewater By Heterogeneous Catalytic Ozonation

With the rapid development of society,metallurgical industry,pharmaceutical industry,chemical engineering and other departments have accumulated a large number of toxic oxalic acid wastewater to be discharged.Once a person accidentally comes into contact with untreated oxalic acid wastewater,it forms calcium oxalate and zinc oxalate with calcium and zinc,which is not easily absorbed and discharged from the body.If the amount of exposure is large,the calcium ion content in the blood of the human body will be sustained through the action of oxalic acid.And then to the critical level,the absorption of calcium will be adversely affected by the human body,and when serious,it will also threaten human life.Therefore,the effective treatment o f oxalic acid wastewater has also attracted human attention.In this experiment,the heterogeneous catalytic ozonation of simulated oxalic acid wastewater over hydroxyapatite supported Cu-N i metal catalyst was studied.Firstly,Ni-HAP and Cu-HAP,Cu-Ni-HAP catalysts were developed by ion exchange reaction between nitrate(copper,nickel)and hydroxyapatite.The catalysts were characterized by BET,SEM,TEM,XRD and XPS.The results showed that the whole catalyst showed the morphology of cloth,and the active components were successfully loaded on the support in the form of Cu O,Ni O.Hydroxyapatite loaded with two active components could further promote the increase of the loading of active components,which was helpful to the better loading of active compone nts on hydroxyapatite carrier.Then the preparation conditions of the catalyst were further studied.Different preparation conditions will have corresponding effects on the activity of the catalyst,including the content of active components of the catalyst,calcination temperature and calcination time.(1)With the increase of the loading of the active components of the catalyst,the activity of the catalyst increases at first and then decreases,and the decrease is faster than the increase;(2)With the increase of calcination temperature,the activity of the catalyst also increased at first and then decreased,but the increase was faster than that of the decrease;(3)With the increase of calcination time,the activity of the catalyst continued to increase,but the subsequent increase was a little slower,with little difference.The optimum technological parameters for the preparation of the catalyst were as follows: the loading of active component Cu,N i was 0.5%,0.1%,the calcination temperature was 700 °C,and the calcination time was 5 h.Finally the influencing factors of heterogeneous catalytic ozonation technology were studied.Different reaction conditions would affect the treatment of simulated oxalic acid wastewater by heterogeneous catalytic ozo nation,including the dosage of catalyst,ozone concentration and temperature.(1)The more the amount of catalyst,the more the effect of treating simulated oxalic acid wastewater,but the later trend slowed down;(2)The higher the ozone concentration,the higher the effect of treating simulated oxalic acid wastewater,but the trend slows down from the middle stage;(3)The higher the temperature,the effect of treating simulated oxalic acid wastewater increases at first and then decreases,and the amplitude of increase is faster than that of decrease.The optimum reaction conditions for heterogeneous catalytic ozonation of simulated oxalic acid wastewater were as follows: catalytic dose 2g,ozone concentration 5mg/L,temperature 25 °C.