The influence of natural sorbents on the trace metals stabilization in contaminated bottom sediments of freshwater reservoirs

Project title: The influence of natural sorbents on the trace metals stabilization in contaminated bottom sediments of freshwater reservoirs
Project Manager:  dr hab. Małgorzata Wojtkowska, prof. uczelni
Source of funding: BEYOND POB II

The project deals with the problem of contaminated bottom sediments of freshwater reservoirs in terms of the use of sorbents stabilizing heavy metals polluting the sediments. The research will be carried out on a surface water reservoir located in a urban agglomeration. The aim of the work will be to investigate the effectiveness and determine the optimal conditions for the stabilization of metals in contaminated sediments in the presence of natural sorbents. The research will use substances of natural origin with sorption properties. Parallel experiments will be carried out on: raw sludge and sludge mixed with sorbents and will be repeated four times in an annual cycle. The experimental systems will be moistened with lake water. This will allow the determination of the mobility of heavy metals. The method will make it possible to learn about the properties of sorbents in the immobilization of toxic metal forms in bottom sediments. The research will determine the most favorable reaction conditions for the sorption mechanisms in the water-sediment system. The criteria for the selection of the most appropriate conditions for the stabilization of metals in the sediment will be determined in experimental systems based on the measurements of selected parameters. During the experiments, the variability of the content of organic substances and electrolytic conductivity in the supernatant water will be controlled. The assumptions in the research will allow for the selection of a more effective sorbent in the effective stabilization of metals in the sediment. The project will describe the process of immobilization of metals in relation to their bioavailable forms with the use of selected sorbents. Speciation methods based on sequential speciation extraction proposed by the Community Bureau of Reference and modeling with the PHREEQC program will be used to describe the impact of independent variables (water and sediment quality) on the value of metals and to evaluate mobile forms of metals. Pollutant sorption isotherms will be determined in accordance with the proposed model equations. The obtained results will broaden the knowledge of methods of metal stabilization in contaminated bottom sediments. Equations describing the equilibrium of metals sorption in bottom sediments will be proposed. Descriptions of the kinetics of the metal sorption process for both sorbents and a model for the description of metals adsorption on sorbents will be presented.