Research On The Adsorption Performance Of U(Ⅵ),Sr(Ⅱ)and Co(Ⅱ) Onto Metallic Oxides

To alleviate the energy crisis and reduce environment pollution,nuclear power has attracted the nation’s attention and underwent rapid development due to its cleaness,which also arouse the public’s concern of threat to human due to the possible release of harmful nuclides to the environment.Therefore,the safe disposition of radioactive effluent becomes a critical problem needed to be solved.Adsorption,as an easy-handling technique,was generally adopted in water decontamination.And the key to improve the adsorption performance is the properties of the selected adsorbent.Herein,three adsorptive materials namely graphene oxide(GO),Ni0.6Fe2.4O4and W18O49/C were synthesized and their adsorption towards U(Ⅵ),Sr(Ⅱ)and Co(Ⅱ)in aqueous solutions was investigated.Main results are presented below:(1)The existing of HA can stimulate the U(Ⅵ)’s immobilization on GO surface,and basically the stimulation effect is positively proportional to HA concentration.Besides,the adding order of the ingredients also makes a difference on the adsorption performance,which can be attributed to the abundant amphiprotic functional groups on HA’s surface and HA can alter GO’s dispersity in aqueous solutions when coexisting with it.(2)Porous magnetic Ni0.6Fe2.4O4 micro-particles(PMNM)prepared from microemulsion method exhibited a typical porous nature with uniform pore size distribution.The pre-concentration of U(Ⅵ)from aqueous solution reaches equilibrium in 2 hours with a maximum adsorption capacity of 189.04 mg·g-1 at 318.15 K.Besides,experimental analysis revealed that the U(Ⅵ)ions’ immobilization onto PMNM’s surface was a multilayer inner sphere complexation process.(3)The WOx/C(mesoporous tungsten oxide and carbon nanowire network),synthesized by a solvothermal method,has abundant oxygen vacancies and carbonaceous functional groups as well as strong acid-resisting property.Adsorption experiments demonstrated that WOx/C’s adsorption towards Sr(Ⅱ)and Co(Ⅱ)was strongly pH-dependent and the Qmax calculated from Langmuir model was 175.0 and 326.0 mg·g-1(308 K)for Sr(Ⅱ)and Co(Ⅱ),respectively.Adsorption mechanism study revealed that oxygen vacancies and C-O on WOx/C are the predominant binding sites.In summary,this study systematically investigated the adsorption performance of three prepared oxides and discovered that WOx/C possesses the advantages of simple synthetic method,strong acid resistance,fast adsorption kinetics and high adsorptioncapacity,thereby it has the potential to be adopted as adsorbent for nuclides,elimination from aquatic environment.