Nano α-Fe₂O₃ As Adsorbent For The Removal Of Congo Red In Aqueous Solutions

This work will be in two types of moderate system synthesis ofα-Fe₂O₃ as adsorbent,the adsorption performance of Congo red in the simulated dye wastewater was carried out systematic study,at the same time,the dynamics,thermodynamics and adsorption mechanism of the adsorption process are evaluate using different models.The effects of synthetic parameters on the morphology and adsorption properties ofα-Fe₂O₃ were also compered.The results show that the adsorption capacity ofα-Fe₂O₃ adsorbent in wastewater is better than that of most similar materials,and its mild preparation method has a potential application prospect in the treatment of industrial wastewater.The main research results are as follows:In ferric chloride-epoxy propane synthesized at 100℃in the water system synthesis ofα-Fe₂O₃ adsorption results show that the maximum adsorption capacity of up to 107 mg/g,the removal rate of Congo red can reach 56%and 95%in the solution within 2 and 60 min,respectively.The adsorption kinetics studies show that the adsorption process is in line with secondary adsorption model,which means that the adsorption process is controlled by electron sharing or exchange.The results of adsorption thermodynamics experiment and calculation show that the adsorption process is a spontaneous exothermic entropy reduction process.The fitting results of adsorption isotherm show that the adsorption process is more consistant with the Langmuir adsorption model,indicating that the adsorption process is a single molecular layer adsorption dominated by physical adsorption.Synthetic parameters to adjust the adsorption results show that the solvent properties of parameter change on the influence of the adsorption quantity is unclear or shows some rules.However,when adding water solvent（water and molysite mole ratio:26/1,53/1 and 79/1）,may be due to the decreasing concentration of ferric chloride,formed by theα-Fe₂O₃ with smaller size and larger specific surface area and its adsorption of Congo red to217 mg/g.2.The results of the study on the adsorption performance of theα-Fe₂O₃material system synthesized at 80℃in the ferric chlorine-primary amine-epoxy propane-water system show that the adsorption model and mechanism satisfied by the kinetics,thermodynamics and isotherms of theα-Fe₂O₃ material system did not change substantially.The results show that the longer reaction time increases the crystallinity of the product and the adsorption capacity of the material.Interestingly,when continuous adjusting primary amine alkyl chain length,the shape changes of material didn’t seem to be obvious or show some regularity of change.However,the maximum adsorption amount for Congo red by using cetylamine significantly increased to 357 mg/g,its removal rate of Congo red can reach 80%and 100%within 2 min and 30 min,respectively.The results indicate that adsorption capacity and adsorption rate of our material were far higher than the commercialization ofα-Fe₂O₃（maximum adsorption capacity for 58 mg/g,the removal rate of 85%after 120 min）.These results provide impetus for the development of new adsorbents with high efficiency.At the same time,the reasons for some of the obtained adsorption results cannot be well explained,which needs further in-depth analysis and research in the future.