Impact of Phytoremediation on rehabilitation of soils contamined by heavy metals
Exchange scientist
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Redouane Tarik, PhD student
Supervisor at Swiss institution
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Paul Scherrer Institut: Christian Ludwig
Supervisor at MENA institution
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Moulay Ismail University, Meknes, Morocco: Noureddine El Moualij
Presentation of the projet
A detailed description of the plant and soil samples and the areas investigated in this work can be found in the project report of the vising student (see the annex). Based on the target metals of the mining activities As, Cd, Cu, Pb and Zn were the main heavy metals investigated in the mobility exchange project. The work of the visiting student focused on the characterization of these metals in four soils and six local plants. Additionally, the matrix content was also determined. Firstly, the visiting scientist was trained on a daily basis on good laboratory practice and the use of different equipment and the related software needed for the analysis.
The analytical activities made by him are summarized here:
- For the chemical characterization and the determination of the heavy metal content in the soil and the plant samples, appropriate sample preparation procedure, including acidic digestion, and quantified analysis using ICP-OES (Inductively Coupled Plasma - Optical Emission Spectroscopy) and subsequent data analysis were conducted. Four soil samples and six plants were taken from four different areas close to a mine near Tighza. The plant samples were first dried, ground, weighted, then digested using a high-pressure microwave digestion unit. The digested samples were diluted and adequate standard solutions of the different elements of interest were prepared. The samples and the standard solutions were then analyzed using ICP-OES, the data was treated in Excel and the heavy metals of interest and other matrix elements (34 elements in total) were quantified in the soils and the plants.
- The soil and plant samples were further characterized by using a thermogravimetric analyzer (TGA). For all samples, incineration experiments were carried out under oxidizing conditions (a mixture of O2/Ar with a flow ratio of 1/4). The water, organic and inorganic content was determined. The volatilization of the heavy metals can be quantified using the TG and ICP-OES data of the fresh plant samples and their solid residues after the thermal treatment. To gain a deeper insight, the analysis of the residues will be made by CPM group and shared in the near future with the PhD. student.
- The data treatment of the elemental and thermogravimetric analyses and a report summarizing the analytical procedure and the results were made by the visiting student (see the annex). The report will be used for his PhD thesis and for a joint manuscript of the two involved institutes upon adding additional data from the ongoing Ph.D. research.
- The visiting scientist attended several meetings at the group, laboratory anddepartment levels.
- An additional molecular analysis using HPLC-MS (not planned in the proposal) of water and ethanol extracts of two plants were performed with the help of CPE group (PSI). The data will further help to characterize the plants studied in the PhD thesis of the visiting student.