Research On Synthesis Of Nano-Fe₃O₄ By One-pot Method Assisted With Microwave From Pickling Waste Liquid And Its Adsorption Application

As a kind of hazardous industrial waste liquid,steel pickling waste liquor contains a large amount of acid,iron and a little heavy metal ion,which will result in water pollution,soil calcification,wasting of iron resource by being directly discharged.The technique of microwave has the advantage of effective,requires less time,convenient manipulation and safety,thus it was used in this study to treat the steel pickling waste liquor.In this study,carbide slag was used to treat the steel pickling waste liquor,and nano-Fe₃O₄ was produced by microwave to promote one-pot method.The details of exploration are as follows:Firstly,Design microwave to promote one-pot method to processing the steel pickling waste liquor.The production conditions were explored and optimized by single factor experiment and orthogonal experiment,hydrated lime as neutralizer and precipitator,and produced Fe₃O₄ at the same time.The iron content of the product was 64.4%.The new technique simplifies the process of oxide co-precipitation,reduces the reaction time to 30min,and the technological process is short and effective.XRD and magnetic analysis of the product showed that the product have more complete crystal growth,stronger magnetism compared with product prepared by oxide coprecipitation process.Secondly,carbide slag as neutralizer and precipitator,the steel pickling waste liquor was treated by microwave to promote one-pot method.Nano-Fe₃O₄ was prepared at the condition as follow:the concentration of carbide slag turbid liquid was 10 wt%,microwave pulse radiation power was 255 W.The product iron content was 58%,and the grain size was 35nm,which was nano-scale magnetic mesoporous material.Besides,material balance and economic feasibility analysis were also conducted,and the economic benefit of this process was remarkable.Finally,Nano-Fe₃O₄ was used as adsorbent in the adorption study process of adsorption methyl orange in water.The removal rate of 96.3%was obtained under the following adsorption conditions:the dosage of adsorbent was 15 g/L,the adsorption time was 100 min,the pH was 3.0,the initial concentration of the methyl orange was 100 mg/L.Besides,this process conforms to the second order kinetics model and the adsorption isotherm conforms to the Freundlich model.