Adsorption Performance Of Zinc Oxide With Different Morphology For The Recovery Of Uranium(?)

As a kind of natural radioactive element,uranium will greatly affect the life and health of creatures on earth if it enters into the biological body.While at present,as the depleting of traditional energy resources,the proportion of nuclear power generation is ever greater,and the amount of uranium-bearing radioactive wastewater is keeping increasing,which seriously endangers nature and human health.So,the wastewater should be properly treated to meet the sewage discharge standard before discharging.The adsorption method,based on the metallic oxide,hydrous oxide and its hydroxide,is the common method used for the extraction of uranium ions from seawater and the treatment of uranium-bearing industrial wastewater.In terms of adsorption,ZnO has been attracting the extensive attention.Especially in 2014,H.Kaynar reported the excellent effect of porous nano-ZnO treating on Uranium(VI),maximum adsorption capacity is up to 111 mg g-1,which has attracted the attention of many scholars both at home and abroad.But so far,there are no relevant reports which study the adsorption properties of ZnO concerning the morphology effects.The main purposes of the present study is as follows:1.Using hydrothermal method to prepare the flower-like nano ZnO which mainly consist of nanosheets with {001} facets exposed.Carrying out SEM and XRD characterizations on flower-like ZnO and commercial ZnO,and the results show that there are large differences on main facets exposed within the two crystals.2.Investigating the impacts of morphology on ZnO absorbing uranium(VI).Taking the irregular shape commercial ZnO and flower-like nano-ZnO as adsorbents,and carrying out adsorption experiments under the same condition to compare the differences between the two adsorbents.The experimental results show that the flower-like nano-ZnO containing more {001} facet has better adsorption ability,which reaches up to2439.02 mg g-1,is double the adsorption ability of nano-ZnO.3.Carrying out the experiment of the flower-like ZnO adsorbing uranium(VI)under suitable conditions,and through investigating the impacts of parameters in the reaction system such as p H,dosage,initial concentration and temperature on adsorption effectiveness,to determine the optimum condition of adsorbing uranium(VI).On the surface of single factor experiment results,the adsorption effect was best when p H=5,C0=700mg/L,m=10mg,T=298k,t=180min?The dynamic experiment results show that the reaction of ZnO adsorbing uranium is consistent with the quasi-dynamic equations.The thermodynamic analysis shows that the enthalpy of the adsorption reaction is 33.78 k J mol-1,and the Gibbs free energy can change from-24.13 k J mol-1 at 298 K to-28.67 k J mol-1 at 318 K,which indicate that the adsorption process is endothermic and spontaneous.