Comparative Studies Of The Aniline Adsorption On Modified Bentonites

This thesis has chosen aniline as a subject to study its adsorption effects on modified bentonites in water media. Research results derived from SEM, XRD, TGA, and IR analysis have indicated that bentonites modified with different methods not only lost their original appearance characteristics but also have their interlayer spacings and surface polarity more or less changed. Taking the adsorption of aniline as a parameter, it has been proven experimentally that all the bentonites modified with the modification methods used in this thesis research were able to show enhanced adsorption of aniline. Among them, bentonies modified with chemical methods had higher adsorption effect than the physical ones;cationic modifications had higher adsorption than their anionic counterparts, and cationic suractant, hexadecyl trimethyl ammonium bromide proved to be especially the most effective. This thesis research has also systematically studied and summarized the impact of a number of factors on the adsorption of aniline on the modified bentonites, including baking temperature, ultrsonic frequency, concentration of non-ionic surfactants, initial pH of the solution, concentration of the co-existing cations, and temperature. The kinetic comparation of aniline adsorption on original and modified bentonites has been illustrated in a graph, indicating that the kenetics here is in accordance with the Langmuir law. The curves of aniline adsorption were able to be expressed with Freundlich isotherm equations. The thermodynamic model of the aniline adsorption has been established. Calculation indicates that the adsorption processes of both the original and the modified bentonites are spontaneous and exothermic. According to the heat released,it was inferred that this adsorption process would be a surface adsorption and partition.In addition, some complexes were synthesized and utilized to modify bentonites and increase their adsorption over aniline, bringing a new idea on bentonites modification. With the development of technologies, bentonite modifications with complexes may find wide applications based on their excel features.