Chemical and physical characterization of a natural clay and its use as photocatalyst for the degradation of the methabenzthiazuron herbicide in water

An Algerian, natural clay was investigated and used as a catalyst for the degradation of an aquatic harmful pollutant: Methabenzthiazuron (MBTU) herbicide. The clay was brought from a location near Tamanrasset city in southern Algeria. The natural clay was characterised by XRF and XRD analyses, SEM-EDS and UVvis absorption spectroscopy. This characterisation revealed that the clay contains mainly SiO2, Al2O3 and Fe2O3. Moreover, density functional theory (DFT) reactivity parameters have been calculated and rationalised for the MBTU. The effect on the MBTU photodegradation was studied in function of various parameters including: the carboxylic acid nature, oxalic acid concentration, pH, pollutant concentration, clay concentration and methanol presence. The results showed that the MBTU photodegradation by MBTU/Clay/OA/UV365 nm system was significant in the experimental optimal conditions: [clay] = 1 g/L, [MBTU] = 5 mg/L, pH = 1.5 in the presence of oxalic acid.