Study On Adsorption Mechanism Of Molybdenum And Uranium By Oxidizing And Reducing Iron Ore

Iron is one of the heavy metals in the earth's crust,as REDOX elements,mainly goethite in oxidation environment,such as oxidation iron content,the main form of pyrite reduction environment,find out the iron in the oxidizing and reducing conditions in water-iron ore between adsorption and reduction mechanism,to understand the delay element migration transformation has important scientific significance.Relying on the national natural fund and project,this paper USES the synthetic goethite and pyrite,through different p H,initial concentration,adsorption time and so on under the condition of adsorption experiments,discusses uranium and molybdenum in water-goethite/pyrite interface adsorption mechanism,combined with Fourier transform infrared spectroscopy?FTIR?before and after adsorption of pyrite.Research shows that:?1?Goethite is an oxidizing iron ore,and its adsorption effect on molybdenum and uranium is better than pyrite.?2?The adsorption effect of goethite and pyrite on molybdenum and uranium is related to p H value.In the more acidic environment,molybdenum is more favorable to be adsorbed on goethite,and the adsorption effect of goethite on uranium is the strongest in the neutral and alkaline environment,and the p H value is the strongest at7.5.The adsorption effect of pyrite molybdenum was the best under alkaline condition.The adsorption effect of uranium is obvious under acidic conditions.?3?The equilibrium time of adsorption of molybdenum by gothenite was 16h,while the equilibrium time of adsorption of uranium by gothenite was 4h,and the adsorption rate reached 97.82%.However,the adsorption time of molybdenum and uranium in pyrite is very long,and the equilibrium time is 96 hours.?4?The data of molybdenum adsorption by goethite can be simulated by Freundlich isothermal,and the adsorption process is mainly physical adsorption and multi-layer adsorption.The adsorption process of uranium is more in line with Freundlich isothermal adsorption and quasi-second-order kinetic equation.However,the kinetic model correlation coefficient of pyrite adsorption molybdenum is small and the kinetic characteristics are not obvious.The process of uranium adsorption is more in line with the quasi-second-order kinetic equation,which indicates that the adsorption of uranium is mainly dominated by ion exchange or Shared chemisorption.?5?PHREEQC simulation shows that when the p H is around 3,the occurrence forms of molybdenum are H2Mo4 and Mo S2.At a p H of about 7.5,uranium mainly occurs in?UO₂?₃?OH?⁵⁺and UO₂?CO₃?₂^2-.When the p H is around 9,the occurrence forms of molybdenum are Mo O₄^2-and Mo S₂.At p H around 5,the main forms of uranium are UO₂OH⁺,UO₂SO₄ and UO₂²⁺.?6?Fourier transform infrared spectroscopy?FTIR?analysis shows that in the process of adsorption of molybdenum and uranium by pyrite,the transmittance of pyrite decreases,and there may be a process of adsorption and reduction.