Removal Of P-chlorophenol And Nitrate In Aqueous Solution By Al-Mg-Ni And A-Ni Alloys

P-chlorophenol(4-CP)is a kind of organic pollutant with trivalent effect which can be produced in the process of pesticide production,chlorination and bleaching of paper making,chlorination and disinfection of drinking water,etc.Once exposed to human beings,it will have a strong stimulation effect on respiratory tract and skin.The problem of nitrate(NO3-)pollution in water is very prominent in China and even the world.If long-term drinking by NO3-contaminated groundwater will easily lead to gastric cancer,esophageal cancer,blue baby disease and other diseases.In this paper,the chemical degradation effect and mechanism of 4-CP and NO3-in water by Al-Mg25-Ni50(Mg mass fraction 25%)and Al-Ni50 alloys were studied.The removal effects of the above two alloys on 4-CP and NO3-were investigated under different conditions(initial pH,Cu ion load,EDTA addition),and the effects of different Al-Mg-Ni alloy materials on the removal effects of 4-CP were also investigated.Finally,according to the distribution of liquid phase products,the XRD and SEM diagrams before and after the alloy reaction and the dissolution of metal ion concentration in the solution,the mechanism of removing 4-CP and NO3-from the alloy was proposed.The results showed that under the condition of 10 g/L Al-Mg25-Ni50 alloy and initial pH=2.0,the complete removal of 4-CP at 25 mg/L(0.195mM)and NO3-at 25 mg-N/L could be achieved within 15 min and 30 min respectively.Under the condition of 3%copper ion loading,the same removal effect of pollutants can be achieved,but the dissolution of magnesium ion exceeds the water quality standard limit.Under the condition of adding EDTA of 5 mM,the removal effect of pollutants is not as good as adjusting the initial pH=2.0 or adding 3%copper ion loading.After the addition of 10 mM EDTA and the adjustment to the initial pH=11.0,the reduction performance of Al-Ni50 alloy was reflected,but the concentration of aluminum and nickel ions far exceeded the groundwater quality standard.Al-Mg60-Ni20 and Al-Mg40-Ni20 alloys formed by different proportions of Al-Mg-Ni alloy materials are not as effective as Al-Mg25-Ni50 alloys in removing 4-CP.The removal of pollutants by Al-Mg25-Ni50 alloy mainly relies on the reaction of Mg elements in the alloy to provide electrons,and the reduction degradation of pollutants is carried out after the formation of hydrogen atoms on the surface of Al-Mg25-Ni50 alloy.The Al,Mg and Ni in the alloy form galvanic cells mutually,inhibiting the dissolution of aluminum and nickel ions and accelerating the reaction at the same time.The degradation mechanism of 4-CP is reduction dechlorination,and the product is phenol.The reduction products of NO3-are mainly N2 and NH4+.However,the removal mechanism of 4-CP by Al-Ni50 alloy without pretreatment is adsorption,with no removal effect on NO3-.Al-Mg25-Ni50 alloy with good reduction performance by adding 25%Mg is superior to Al-Ni50 alloy in the removal effect of 4-CP and NO3-as well as the dissolving effect of metal ion concentration.This study provides an insight into the development of new catalysts for chemical degradation of pollutants in aqueous environment.And lay a foundation for the follow-up research.