In this paper,rhamnolipid modified nanoscale zero-valent iron(RL@nZVI)was prepared by liquid phase reduction method and characterized by X-ray diffraction,transmission electron microscopy,and Fourier infrared spectroscopy.The effects of pH,reaction time,interfering ions and other factors on uranium removal were studied.The adsorption kinetic model and characterization results were used to ex-plain the uranium removal mechanism.The results showed that the successful loading of rhamnolipid on the Fe0 surface could effectively improve the oxidation resistance and dispersion of nanomaterials,and the specific surface area was increased by about 2.5 times,reaching 12.30 m2/g.When the pH value was 5 and the reaction time was 30 min,the uranium concentration in the RL0.1@nZVI and RL0.2@nZ-VI experimental groups was reduced to 33.8 μg/L and 24.4 μg/L,respectively,which reached the na-tional emission standard.Different concentrations of metal ions had different degrees of influence on the uranium removal,and the equilibrium uranium removal rates of Cu2+,Mg2+,Mn2+and Zn2+experimental groups were 28.26％,95.82％,93.39％and 96.28％,respectively.The adsorption kinetic results showed that the quasi-second-order kinetic equation was more suitable for describing the adsorption processes of nZVI(R2=0.999)and RL0.1@nZVI(R2=0.998).The RL0.1@nZVI after uranium ad-sorption was characterized,and the results showed that the ratio of U(Ⅳ)to U(Ⅵ)in the RL0.1@nZVI was 7∶1,and the ratio of Fe2+to Fe3+was about 2∶1,indicating that redox,adsorption and co-precipita-tion reactions occurred during the remediation of uranium-contaminated groundwater by RL0.1@nZVI.RL@nZVI is an ideal material for treating uranium-contaminated groundwater.
维普
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