Research On Hydrothermal Controllable Preparation Of Iron Oxides Composite At Different Ph And Their Application

Dye wastewater treatment technology has been a research hot spot,and has a wide range of treatment methods.The adsorption method is one of the important research directions.The method has such characteristics as simple operation,low cost and remarkable effect.Iron oxides are a kind of green materials with stable physical and chemical properties,widely available sources and varied topographies.Therefore,in this paper,5-SSIPA-supported iron oxide and peanut-like?-Fe₂O₃ were prepared,and its adsorption performance was also investigated.Firstly,a composite material,in which 5-SSIPA was successfully supported on iron oxide by the combination of ionic bonds,was successfully prepared by the one-step hydrothermal method.The properties of the material were characterized by SEM,TEM,EDS,XRD,EA,FT-IR,TGA,NH₃-TPD and other characterization and the adsorption over Rose Bengal was systematically studied.The results show that 5-SSIPA has been successfully loaded on the iron oxide,and the material has good thermal stability and showed good adsorption properties over Rose Bengal.Its maximum adsorption capacity is 287.36 mg/g,which is much bigger than activated carbon of 40.03 mg/g.Adsorption kinetics studies show that the adsorption process meet the pseudo-second-order kinetic equation and the isothermal adsorption process in line with the Langmuir equation.Secondly,we prepared?-Fe₂O₃ by a one-pot process and controlled the morphologies,size and other characteristics of the resulting samples by changing the reaction conditions,such as the content of ligand 5-SSIPA,reaction temperature,concentration,and reaction time.The obtained samples were characterized by SEM,TEM,XRD,FT-IR and other means to clarify the characteristics of the resulting samples.At the same time,its adsorption over Rose Bengal bears a simple comparison with the iron oxide composite loaded with 5-SSIPA.The results showed that the maximum adsorption amount of?-Fe₂O₃ over Rose Bengal was 50.6 mg/g,which was less than 287.36 mg/g of iron oxide composite.Finally,the formation mechanism of peanut-like?-Fe₂O₃ is described.Experiments show that it undergoes five consecutive stages of nucleation,reunion,transformation,growth and maturation in the process of formation and is closely related to each other.The first is the formation of Fe?OH?₃,FeOOH,and?-FeO?OH?particles.These particles continue to agglomerate and grow,and then undergo a phase transition process to obtain?-Fe₂O₃,which is further grown and matured.Finally,?-Fe₂O₃ with peanut morphology is obtained.On this basis,the five-step mechanism of formation of peanut-like?-Fe₂O₃ was pointed out.