Research On The Removal Of Mercury Pollutants From Water Bodies By Aluminum-Based Alloys

Mercury pollution in water does harm to the environment and human health.Zero-valent metal is widely used to remove Hg(II)in water,but it has the disadvantages of passivation,inactivation and secondary pollution.Researches found that adding Al to make bimetal can improve the reaction activity,and prolong the service life by means of the galvanic effect.But the metal distribution of the bimetal prepared by the deposition method is uneven,and it is easy to fall off during application and affect the metal performance.It is particularly important to research and develop a material with high reactivity and stability to achieve high-efficiency removal of mercury in water.In this study,aluminum-based alloys(Al-Fe,Al-Zn alloys)were prepared by the melting method.Utilize the reduction activity of Fe and Zn and the galvanic reaction with Al to delay metal corrosion and maintain high activity.The effect of Al-Fe and Al-Zn alloys on mercury removal in water was explored,including different metal content,initial pH(2-11),initial mercury concentration(10-1300mg/L),repeatability and the impact of mine wastewater coexisting ions on mercury removal.XRD,SEM,XPS and other characterization methods were used to analyze the mechanism of Al-Fe and AlZn alloys for removing mercury from water.The results showed that Al-Fe50 and Al-Zn50(the number at the end of the metal element indicates the mass percentage of the metal)has good reactivity and stability.At a pH of 2,the reduction activity of Fe in the Al-Fe50 alloy played a major role;and Al was the main electron donor when the pH rose to alkaline,achieving a removal rate of over 80%.The removal rate of 500 mg/L Hg(II)was maintained at 98%in 5 cycles of Al-Fe50,and the removal rate decreased in the early stage of the reaction.Al-Zn50 was suitable for the removal of Hg(Ⅱ)in the range of pH 2-11,and the removal rate of 98%was achieved after 3 minutes of reaction.The variaiton of Hg(Ⅱ)concentration between 10-1300 mg/L had no significant effect on the removal effect,and the removal capacity of 1221 mg/L Hg(Ⅱ)by Al-Zn50 was 4985 mg/g.Al-Zn50 had the potential for reuse and showed good selectivity in the application of actual mine wastewater.The aluminum-based alloys,Al-Fe50 and Al-Zn50 took advantage of the reduction properties of metals to reduce Hg(Ⅱ)to Hg(0).The negative charge on the surface of the material adsorbed Hg(Ⅱ)through electrostatic interaction.What’s more,precipitation during the reaction because of pH variation and the complexation of hydroxyl groups on the surface further accelerated the removal of Hg(Ⅱ).Al-Fe and Al-Zn alloys show great reactivity and practical application potential in the removal of Hg(Ⅱ)pollutant in water bodies,providing a new idea for the application of aluminum-based alloy materials to heavy metal remediation in water.