Study On Corrosion Process Of Nano Zero-valent Iron In Undisturbed Anaerobic Water Environment

With the progress of the times,the world economy has developed rapidly,and the industrial level and people’s living standards have been continuously improved.Humankind’s demand for various types of resources such as water resources has continued to increase.While continuously satisfying human needs for various types of resources,the pollution caused by human production activities to the ecological environment cannot be underestimated.At present,the use of surface water in China and the development and utilization of groundwater have gradually become saturated,and the problem of environmental pollution that China faces,especially water pollution,is not optimistic.It seriously threatens the sustainable development of mankind,and water pollution control is facing more and more severe challenges.At present,there are more than a dozen kinds of typical groundwater remediation technologies.The in-situ remediation technology of groundwater can minimize the disturbance of pollution remediation to the environment,and it can save funds to a certain extent.In the in-situ remediation technology,the infiltration reaction wall is a typical representative method,and the filling medium is most commonly zero-valent iron.Nano zero-valent iron is widely used by many scholars for removing groundwater contaminants due to its large surface area,good adsorption performance,strong reduction ability,rapid removal rate,abundant material sources,and injection into deeper aquifers.The advantages of nano zero-valent iron n can also be used to limit the disadvantages of its application: a strong reduction ability makes it more susceptible to oxidation by water,oxygen,or other substances,and reduces the amount of nano zero-valent iron and the reaction of pollutants.This paper simulates the anaerobic state of groundwater,studies the corrosion of nano zero-valent iron in the water environment,explores the corrosion effects of common anions in water and groundwater on nano zero-valent iron,and uses Laser Raman spectroscopy(RS),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS)to determine the corrosion products.Through preliminary research,the following understanding has been obtained:(1)The corrosion of nano zero-valent iron in the undisturbed anaerobic water condition is very weak,and the proportion of corrosion products is less.(2)In the undisturbed anaerobic ultra-pure water and anaerobic groundwater,the corrosion products of nano zero-valent iron are mainly magnetite and lepidocrocite and are mixed with a small amount of maghemite,among which the groundwater corrosion products contains trace amounts of siderite;(3)The corrosion products of nano zero-valent iron in anaerobic sodium chloride solution,anaerobic sodium bicarbonate solution and anaerobic sodium sulfate,mainly consisting of magnetite and lepidocrocite and mixed with a small amount of maghemite.And siderite was also produced in the sodium bicarbonate solution.The relative content of lepidocrocite in the solution product was increased compared to the water.(4)In the presence of bicarbonate ions,siderite formation occurs in the corrosion products of nano zero-valent iron,and bicarbonate ions affect the relative content of lepidocrocite in the product to some extent.