Preparation Of Graphene Oxide Based Composites And Application In Eutrophication Of Water System

Graphene oxide?GO?has been widely used for the removal of pollutants in wastewater due to its advantages,such as large specific surface area,abundant surface active groups.However,GO tends to agglomerate leading to reduce the adsorption capacity during usage.Studies indicate the agglomeration can be inhibited effectively by loading nanomaterials on the surface of GO.Therefore,screening materials that can selectively adsorb phosphate is of great importance for the formation of GO based composites.In this dissertation,GO was used as the marix and then the GO-based composites can be obtained by precipitation method using zirconium oxychloride,lanthanum nitrate,yttrium nitrate and ammonium hydroxide as raw materials.Finally the removal of phosphate in simulated wastewater was studied,including the following research content.?1?GO was synthesized by the Hummer method and then characterized by XRD,SEM.IR.BET,Zeta potential and so on.The results show that the synthesized GO has a lamellar structure with a large amount of negative charges on its surf'ace and an isoelectric point is about 2.?2?Zirconia,lanthanum hydroxide and basic yttrium oxide were respectively supported on graphene oxide by a chemical precipitation method,forming GO@ZrO₂.GO@La?OH?3 and GO@YOOH composites.Then XRD,SEM,Zeta potentials,IR and BET were used to characterize the composites.XRD and SEM show that the granular Zr02,spindle-shaped La?OH?3 and granular YOOH distributed on the surface of GO.BET show that the loading of inorganic materials greatly increased the specific surface area of GO.The isoelectric point of GOCd@ZrO₂,GO@La?OH?3 and GO@YOOH was pH?3,pH?7 and pH=9,respectively.?3?The adsorption experiments show that the adsorption of phosphate radical for GO@ZrOz composites reached the equilibrium within 60 min.The maximum adsorption capacity was 61.35 mg/g?element P?and the optimum pH value was 2.The competitive adsorption indicated the inorganic ions,such as Cl-,NO3-,and 5O42-,hardly affected the adsorption capacity of GO@ZrO₂ composites.After three cycles of adsorption-desorption,the adsorption capacity of GO@ZrO₂ composite can still reach 49.81 mg/g?element P?.?4?The adsorption experiments show that the adsorption of phosphate radical on GO@La?OH?3 composite reached adsorption equilibrium within 180 min.The maximum adsorption was 54.61 mg/g?element P?and the optimal pH range was 4-10.The Cl?NO-3,SO42-and humic acid have little effect on the adsorption of GO@La?OH?3.The adsorption capacity can still reach more than 40.01 mg/g?element P?after three rounds of adsorption-desorption.?5?The adsorption experiments show that the adsorption equilibrium of phosphate radical can reach within 45 min for GO@YOOH composite with the maximum adsorption of 136.73 mg/g?element P?.