| Abstract [eng] |
The rising demand for food requires production and implementation of new, more efficient fertilizers which would maximize the yield. This should be achieved while minimizing the costs of production as well as the potential negative impact of fertilizers on the environment and humans. The aim of this work is to determine the immobilization mechanisms of Cu, Co and Zn ions on the surface of zeolites (NaX, NaA, CaX) and to investigate the influence of Fe and K ions on their desorption. Adsorption parameters of Cu, Co, Zn ions are determined in this study. Pseudo-first, pseudo-second, Vermuelen and Elovich kinetic models were applied in order to describe adsorption kinetics. It was found that CaX zeolite has the greatest adsorpotion capacity for Cu, Co and Zn ions. By using kinetic modelling, it was concluded that adsorption of ions on the surface of zeolites is similar to chemisorption in nature. At first adsorption process is fast and then slows down, because the limiting step of the process becomes diffusion of Cu, Co, Zn ions into the deeper layers of the zeolite. Xray diffraction analysis was performed which confirms the hypothesis of ion-exchange mechanism on the surface of zeolite since its structure remains unchanged. The paper also presents the principal technological scheme for production of slowrelease fertilizers. Calculations for production of 1 ton of product are presented. The results are summarized in 5 conclusions. Thesis consists of 69 pages and includes lists of figures and tables, introduction, literature survey, experimental part, results and discussion, technological recommendations, conclusions, references and CV of the author. The work contains 22 tables and 22 figures. |
