Biosorpce iontů chromu Cr (III) a zinku Zn (II) z vodných roztoků pomocí rostlinné biomasy

Abstract

This thesis submitted examines the ability of biomass of cultivated algae species Chlorella vulgaris and natural algae species Spirogyra sp. to adsorb Cr (III) and Zn (II) ions, respectively the use of biomass of roots, stems and leaves of an invasive plant species Reynoutria japonica to adsorb Zn (II) ions, all of them from aqueous solutions in a discontinuous biosorption process. The thesis is divided into five main parts: The theoretical background research part presents the state of current knowledge. In the beginning there is a simplified concept definition of heavy metals, as well as a list of heavy metal species, important from the viewpoint of their negative environmental impact. It is followed by brief description of advantages and disadvantages of biosorptions – one of several new environmental biotechnologies which are currently extensively investigated. In this part also a detailed description of biosorption mechanisms; as well as main physico-chemical parameters influencing the processes are presented. The mechanism of biosorption of various biosorbent species is discussed, including their taxonomically based review. In the next part, the aim of the thesis, as well as the process for its acomplishment, is stated. In methodical part of this thesis, the biosorbents used in the experiments and methods of their treatment and alteration are described. Principles of kinetic and sorption isotherms setting are also presented. In the part of results and discussion all experiments are described, including cultivation of Chlorella vulgaris, biosorption processes time courses determination, and modelling of their kinetics. The effect of solution pH, biomass dosing, and initial concentration of metal ions on biosorption process is evaluated. Specific sorption capacities of individual biosorbents are identified, sorption isotherms are plotted, and zeta potentials are stated. In addition to these results, for all Reynoutra japonica biomass types, EDS, FTIR and SEM analyses are presented. In the end, possibility of desorption of Cr (III) ions from Chlorella vulgaris biomass and Zn (II) ions from biomass of Reynoutria japonica leaves with the use of 0,2 M H2SO4 is discussed. In the final part of thesis there is an assessment of experimental results, and of future possible use of studied biosorbents in practise. Next steps in research of studied biosorbents are proposed.