Immobilization of pollutants on clay surface

Abstract

Title: IMMOBILIZATION OF POLLUTANTS ON CLAY SURFACE The thesis consists of eight chapters and a bibliography. The first chapter introduces clays and clay minerals with respect to their occurrence, structural features, classification and utilization. This chapter gives particular emphasis on the structure of kaolinite and its important characteristics. The important role played by the clays in the environment has been described with respect to some existing literature and also with special emphasis on removal of organic pollutants. The second chapter gives a brief description of the objectives of the work undertaken and the experimental methodology used to arrive at the results. The techniques for purification of clays and their characterization with respect to chemical composition, moisture content, loss on ignition, XRD, XRF and IR spectroscopic data, have been described giving the experimental parameters. The methodology for the adsorption experiments and the calculation procedures are also described. The third chapter covers the results obtained from characterization studies. The clay samples were shown to have a moisture content of 1.60 to 2.14% and LOI value of 11.75 to 13.60%. The composition analysis showed the raw clays to have a SiO2/Al2O3 ratio between 5.7 and 10.8 which improved to around 1.3 after purification. The purified clays had 43.7 - 54.9% SiO2 and 33.3 - 40.1% Al2O3. The clays were shown to have 0.7 - 0.9% Fe2O3 with appreciable amount of CaO, K2O, TiO2P2O5, Na2O and MgO. The clay samples were also rich in several trace elements and rare carths. The XRD data of the pure clay samples indicated that the predominant clay mineral present in them was kaolinite with some amount of quartz impurities. The IR measurements yielded appropriate frequencies expected for the OH and SiO stretching regions, and OH and SiO bending regions in kaolinite, and the data complemented the conclusions drawn from XRD analysis. The fourth chapter of the thesis deals with the adsorption of phenol on six kaolinite samples