Removel Of U(?) From Aqueous Solution Using Green Synthesized Iron Nanoparticales Supported On Bentonited

The rapid development of nuclear power industry results in sustainable development of uranium mining and metallurgy industry,which produces large quantities of radioactive materials entering the groundwater environment through leakage,precipitation and leaching,causes serious environmental and social problems,and poses a great threat to human health.Therefore,the efficient treatment of uranium-containing wastewater lies in an urgent situation.In this study,the sunflower extract was used as a reducing agent,and the iron nanoparticles material?SF-FeNPs?was prepared by liquid phase reduction.The bentonite-loaded iron nanoparticles composite?SF-FeNPs/BT?was prepared by using Bentonite as carrier and in situ reduction of iron salt was embedded into Bentonite using sunflower extract.Then Bentonite,SF-FeNPs and SF-FeNPs/BT materials were used separately in the laboratory to simulate the treatment of uranium-containing wastewater.The effects of different factors on U?VI?removal in water were investigated,and the best removal conditions were determined.Scanning electron microscopy,X-ray powder diffractometry,and X-ray energy dispersive spectroscopy were used to characterize the samples before and after the reaction.Kinetic model and adsorption isotherm models were used to fit the experimental data,and U?VI?in water was removed from the material.The experimental results are as follows.The experiment results of removal U?VI?by SF-FeNPs showed that the green synthesized nano-iron material is a spherical particle with a particle size of 30⁶0nm,and the sample part is oxidized.The contact removal rate reached 92.95%at 30°C,pH=6 and initial uranium concentration of 10mg·L^-1,SF-FeNPs dosage of 0.1g under the conditions of 90 min contact shock.The kinetic and adsorption isotherm studies indicated that the removal of U?VI?in water by SF-FeNPs was more consistent with the pseudo-second-order kinetic equation and the Langmuir adsorption isotherm model;The removal of U?VI?in water by SF-FeNPs may be achieved by the synergistic effect of redox and coprecipitation.The experiment results of removal U?VI?by Bentonite showed that the maximum adsorption occured at 30?,pH=7,initial uranium concentration of 10mg·L^-1,bentonite dosage of 0.1g,and contact shaking for 90 min.The removal rate reached 63.42%,higher temperature favors the adsorption;the characterization analysis showed that the U?VI?in water removed from bentonite was mainly physical adsorption.The experiment results of removal U?VI?by SF-FeNPs/BT showed that zero-valent nano-iron was successfully loaded on bentonite and owns good stability and dispersibility in bentonite materials proved by Characterization;Under the same experimental conditions,the removal efficiency and reaction rate of composites was significantly better than those of single bentonite and SF-FeNPs materials,and remove U?VI?in water in a wider range of solution pH.The removal efficiency reached98.67%at 30°C,pH=5,initial uranium concentration of 10mg·L^-1,SF-FeNPs/BT dosage of 0.075 g,contact shaking for 90 min.Coexisting ions such as F^-?SiO₃^2-?CO₃^2-?HCO₃^-?Cu ²⁺?Ca ²⁺?Mn²⁺had certain inhibitory effects on U?VI?removal from water by SF-FeNPs/BT,Inhibition increased with the increase of ion concentration;Kinetic studies showed that the adsorption behavior of U?VI?in SF-FeNPs/BT removal water can be described by pseudo-second-order equations;the isotherm adsorption model study showed that the Langmuir and Freundlich adsorption isotherm models can describe the entire adsorption process better,and theoretical adsorption at 30?was 10.6mg·g^-1;the characterization analysis indicated that the removal of U?VI?in water by SF-FeNPs/BT may be achieved by the synergistic effect of reduction precipitation and physical adsorption.