Heterogeneous Amidoximization Of Polyacrylonitrile And Its Uranyl Ionadsorption Behavior

In the development of the nuclear industry,radioactive uranium-containing waste liquids are produced.It is of great significance to deal with uranium-containing waste liquid reasonably and effectively and reduce the emission of harmful substances.In this paper,polyacrylonitrile was modified by heterogeneous method,and polyacrylonitrile and hydroxylamine hydrochloride were reacted under certain experimental conditions.Design-Expert experimental software was used to design the experimental scheme,considering the reaction temperature,time,pH,the volume ratio of methanol to water,and the molar ratio of hydroxylamine hydrochloride to polyacrylonitrile on the preparation results of amidoxime-based adsorbent.The prepared amidoxime-based adsorbent materials were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy.Infrared spectroscopy indicated that the strength of the nitrile absorption peak in the modified material was significantly reduced,and the intensity of the absorption peak of the amidoxime group(-C(=NOH)NH2)was significantly increased,indicating that the target functional group had been formed.The modified sample has a certain morphology,appears as a microsphere,and has some micropores on the surface,which is beneficial to subsequent adsorption experiments.The adsorption performance of amidoxime-based adsorbent on uranyl ions was investigated by formulating different concentrations of uranyl nitrate solution.The effects of adsorption time,adsorption temperature,initial solution uranium concentration and other factors on the experimental results were investigated.Dynamic adsorption experiments were carried out on the basis of static adsorption experiments,and the effects of bed height,initial solution concentration and flow rate on the breakthrough curve were investigated.The static adsorption experiments carried out under the adsorption conditions of temperature 298 K,adsorbent mass 0.05 g,initial solution uranium concentration 100mg/L,pH=2.5,solution volume 100 mL,adsorption time 48 h showed that there are several groups of samples adsorbed in many materials.The capacity is relatively large,and the maximum adsorption capacity reaches 124.24 mg/g.The adsorption amount of amidoxime polyacrylonitrile on U(VI)in aqueous solution increased with the increase of adsorption temperature,time and initial solution U(VI)concentration.The results of adsorption temperature analysis showed that the adsorption of U(VI)in aqueous solution by amidoxime polyacrylonitrile accorded with the Langmuir isotherm adsorption model equation.The results of adsorption thermodynamic analysis show that the adsorption of U(VI)in aqueous solution by amidoxime polyacrylonitrile is a spontaneous process of increasing endothermic entropy.The mechanism of adsorption rate control showed that amidoxime polyacrylonitrile played a leading role in the intraparticle diffusion process during the adsorption of U(VI)in aqueous solution.The results of dynamic adsorption experiments show that the adsorption process can meet the material balance well.The adsorption capacity of the adsorption column under different conditions is about the same.Different dynamic models can analyze the breakthrough curve to some extent.In the actual process,The parameters of the adsorption process are calculated using different dynamic adsorption models in combination with specific conditions.