The reutilization of domestic bio-wastes for thallium remediation

PAMELA Y. QUINTAS; GUILHERME L. DOTTO; LETICIA B. ESCUDERO

Mendoza

Simposio; 15th Rio Symposium on Atomic Spectrometry; 2019

Universidad Nacional de Cuyo

The present work is based on a biosorption study using wastes generated from the consumption of mate, a traditional South American infused drink that is prepared by steeping dried leaves of yerba mate (Ilex paraguariensis) in hot water, for the removal of thallium from environmental samples. Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Electrothermal Atomic Absorption Spectrometry (ETAAS) were used as characterization and detection analytical techniques. For biosorption experiments, 25 mL of 25 mg/L Tl(I) solutions were prepared in Erlenmeyer flasks and the pH of each solution was adjusted to pH 4, 6 and 8. Then, different amounts of the biosorbent were added to the previous solutions. The flasks were stirred at 250 rpm during 300 min at room temperature and the solid phase was separated by centrifugation at 510 x g for 5 min. The effect of pH and biosorbent concentration on the biosorption capacity was studied using an experimental design. Under the optimal experimental conditions, a maximum biosorption capacity of 46.4 mg Tl/g of dried yerba mate and about 50% removal of the contaminant from aqueous solutions was obtained. Kinetic studies yielded data that were in accordance with pseudo−second order model. Equilibrium studies were also developed and indicated that Sips was the most appropriate model, with a maximum capacity of biosorption at 328 K of 333.4 mg g−1. The thermodynamic evaluation exhibited an endothermic, spontaneous and favorable biosorption. The biosorbent that have been previously used for drinking mate could be re-used as an efficient alternative for the biosorption and removal of Tl(I) from environmental water samples, promoting a sustainable decontamination process.