Study On The Sorption Of Radiounclides (Eu³⁺,Th⁴⁺) And Cations (Ni²⁺,Pb²⁺) To Attapulgite

In this paper, the batch adsorption experiment and combining with micro-characterizing (such as Fourier Transform infrared sorption (FTIR), X-ray photoelectron spectroscopy(XPS), and XRD so on) were used to study the adsorption of Ni(II), Pb(II), Eu(III) and Th(IV) on attapulgite. The dissertation was divided into ten chapters.In the first chapter, the study background, basic content and sketch of experimental scheme were introduced in brief.In the second and third chapter, some basic concepts and principles related to adsorption on solid-liquid surface were described, and the methods, which were used in this paper, were introduced in detail.In the fourth chapter, the structure, elements of composition, function groups, and the adsorption sites of attapulgite was characterized by XPS, XRD, FTIR and Acid-Base titration, respectively; the relative parameters of acid constants, sites density and so on were calculated.In the fifth and sixth chapter, the adsorption of Ni(II) on Na-attapulgite and ACT-attapulgite were investigated, respectively; it indicated that the adsorption of Ni(II) was influenced strongly by pH and ionic strength. Compared with Na-attapulgite, the adsorption capacity of ACT-attapulgite to Ni(II) was improved significantly.In the seventh and eighth chapter, the adsorption of Pb(II) onto activated attapulgite and Eu(III) onto Na-attapulgite were studied respectively, and the FITEQL code and Surface Complexation Model(SCM) were used to simulated the adsorption data of Pb(II) and Eu(III) onto attapulgite; and found the main adsorption species of Pb(II) and Eu(III) onto attapulgite was weak sites(=WOH) at low pH values, however, was strong sites(=SO~-) at higher pH values. In addition, the adsorption species was influenced by ionic strength weakly.In the ninth chapter, the adsorption of Th(IV) on activated attapulgite was investigated. In the tenth chapter, the results were summarized and future study proposals were put forward.The results of this paper show that attapulgite has good adsorption ability to heavy metal ions and radionuclides, and its organic modified sample, i.e., ACT-attapulgite, has advantage in treating high concentration of heavy metal ions than attapulgite. The adsorption of Ni(II), Pb(II), Eu(III) and Th(IV) increased with increasing pH and decreasing ionic strength. The influence of soil HA/FA on adsorption of heavy metal ion and radiounclides varied with different typical of cations, and different effects of HA/FA on cations adsorption were also found at different pH values. The thermodynamic parameters (i.e.;â–³H~0,â–³S~0, andâ–³G~0) of the heavy metals and radionuclides adsorption onto attapulgite were calculated from the temperature dependence, and the results suggested that the adsorption reaction was spontaneous and exothermic with a high affinity. The adsorption mechanism was interpreted from the batch and spectroscopic results, and indicated that surface complexation model and cation competition exchange were considered as the main mechanism...