| Abstract:Uranium is not only the main components of the nuclear power, but also the necessary strategic material of the national defense construction. In order to meet the nuclear power development and the national defense construction demand (the nuclear war industry), it is still necessary to intensify of the intergrowth of Uranium mining and mineral smelting. However, lots of wastewater containing Uranium produced in the process of the Uranium mining and mineral smelting, will change the Uranium mines surrounding environment background radiation and the species genetic distortion. It would be a potential threat to human survival and social development, and also cause people’s health and the national economic development. Therefore, seeking a variety of novel functional adsorbents with high adsorption efficiency, good regeneration performance and low cost, is becoming more and more important.First, we have summarizesd the main pollution characteristics of the wastewater containing Uranium during the Uranium mining and metallurgy, harm and its processing method. At the same time, we have constructed a series of novel functional adsorbent materials with friend environment, good adsorption and regeneration performance, based on the complexing space structure of Uranyl ion. With the help of Fourier Transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray powder diffraction (XRD) and N2adsorption/stripping experiment, we have characterized all the various adsorbent. Using the simulation wastewater containing Uranium during Uranium mining and metallurgy as the research object, the method of static adsorption experiment was carried out a series of adsorption experiment, inspected the various influence factors on the properties of adsorbent, with a variety of adsorption dynamics/thermodynamic and isotherm models fitting of experimental data. The main research contents and results are as follows:(1) A new method was proposed-cystine chemical modification Saccharomyces Cerevisiae (SC) and a novel biological adsorbent was obtained——Modification Saccharomyces Cerevisiae (MSC).The adsorption characteristics of SC and MSC for Uranium were studied with the static adsorption experiment method, respectively. The results showed that the maximum Uranium adsorption quantities of SC and MSC were all in pH of6.0, and the maximum adsorption quantity of MSC q∞is6.5times this of SC. By the adsorption Uranium dynamics research of SC and MSC, we found the adsorption Uranium of SC and MSC had completed80%of the adsorption amount in1.0h, and the adsorption equilibrium have be achieved at about1.5h. And the secondary reaction kinetics model can better describe the adsorption process of SC and MSC for Uranium. Isotherm model research results show that the adsorption Uranium process of SC and MSC could all meet the Langmuir and Freundlich isotherm models.This showed that the control of Uranium adsorption rate may be a chemical adsorption process. Through the desorption experiment of SC and MSC, we found SC and MSC had a good regeneration performance, and the adsorption ability had not declined significantly after8times adsorption-desorption experiment.And it showed SC and MSC could be reused many times.(2) A new type of environmental protection and economy preparation method of Fe3O4nanoparticle was studied and we put forward a new method of surface functionalization modification of Fe3O4nanoparticle.The adsorption characteristics of Fe3O4nanoparticle and surface amine-functionalization of magnetic adsorbent Fe3O4-NH2for Uranium were studied with the static adsorption experiment method, respectively. The results showed that the best adsorption conditions of Fe3O4nanoparticle and Fe3O4-NH2nanoparticle is:pH value is5.0,6.0respectively; the initial concentration of Uranium are all5.0mg/L;the adsorption time are all1.0h; reaction temperature are all under the condition of normal temperature (25℃).By the adsorption Uranium dynamics research of Fe3O4nanoparticle and Fe3O4-NH2nanoparticle, we found that the secondary reaction kinetics model could better describe the adsorption process of Fe3O4nanoparticle and Fe3O4-NH2nanoparticle for Uranium. Thermodynamics research results show that the adsorption processes of Fe3O4nanoparticle and Fe3O4-NH2nanoparticle are spontaneous, endothermic. And the adsorption Uranium capacity of Fe3O4-NH2nanoparticle is bigger than this of Fe3O4nanoparticle.Through the desorption experiment of Fe3O4nanoparticle and Fe3O4-NH2nanoparticle, we found Fe3O4nanoparticle and Fe3O4-NH2nanoparticle had a good regeneration performance, and the adsorption Uranium rate could be still more than80%after6times adsorption-desorption experiment. (3) The "graft loading"was completed between the Fe3O4nanoparticle with a large number of amino, hydroxyl and carboxyl functional groups on the surface, and Saccharomyces Cerevisiae with carboxyl and hydroxyl groups on the surface, throughing the O-acylation reaction or N-acylation reaction. And a novel functional adsorbent was obtained—Nano-Fe3O4loading Saccharomyces Cerevisiae (NFSC). We have studied the adsorption Uranium performance and mechanism from the aspects of factors which influence the adsorption performance.The experimental results showed that the best adsorption Uranium conditions of the adsorben NFSC is: the pH value is7.0;the initial concentration of Uranium is5.0mg/L;the addition amount is20mg and the optimum size of NFSC is12nm. By the adsorption Uranium dynamics research of NFSC, we found that the secondary reaction kinetics model could better describe the adsorption Uranium, process of NFSC than the first order reaction kinetics model.Isotherm model research results show that the adsorption Uranium process of NFSC could all meet the Langmuir and Freundlich isotherm models. And the adsorption model is the combination of the monolayer coverage and the multilayer adsorption. Through the desorption experiment of NFSC, we found NFSC had a good repeated use performance, and the adsorption Uranium rate could be still more than90%after8times adsorption-desorption experiment.(4)A new functionalization modification method of the mesoporous silica SBA-15was proposed, with FeCl3.6H2O as source of iron, and diethyl phosphoryl ethyl triethoxy silane (PTS)and ammonia propyl triethoxy silane (APS)as the organic modification group.And a new type of functional magnetic mesoporous silica G-PA-SBA-15was obtained. We have studied the solution pH value, the reaction time, the initial concentration of Uranium and the influence of temperature on the adsorption of Uranium. The results showed that the G-PA-SBA-15would be the maximum adsorption quantity:pH value is6.0;the reaction time is1.0h; the initial concentration of Uranium is20mg/L;the adsorption temperature is25℃.By the adsorption Uranium dynamics research of G-PA-SBA-15,we found that the secondary reaction kinetics model could better describe the adsorption Uranium process of G-PA-SBA-15.Isotherm model research results show that the adsorption Uranium process of G-PA-SBA-15could meet the Langmuir model.The result shows that the adsorption sites on the surface of G-PA-SBA-15are evenly distributed, which have the same affinity of uranyl ion. And the adsorption model belongs to the monolayer adsorption model. Thermodynamics research results show that the adsorption processes of G-PA-SBA-15is spontaneous, endothermic. The temperature increase would improve the adsorption Uranium capacity of G-PA-SBA-15in a small range.Through the desorption experiment of G-PA-SBA-15,we found G-PA-SBA-15could be reused many times because the adsorption ability had not declined significantly, and the adsorption Uranium rate could be still more than80%after8times adsorption-desorption experiment Using0.1mol/L HC1, NaOH and EDTA. |
PDF Full Text Request