Monitoring of copper phytofiltration performance by x-ray analytical techniques

SBARATO, V.; LEANI, J.J.; RIEGO, D.; BENCHARSKI, C.; MÜLLER, E. ; PÉREZ R.D.

Campinas

Conferencia; 2nd Groundwater Remediation using Nano/Biotechnology with focus on the Contaminated Resources on Brazil (GRUN II); 2021

CNPEM

In this work, micro-XRF was considered as apossible technique for monitoring the rate of incorporation of Cuinto aquatic plants of a laboratory-scale phytofiltration system.This system employed Salvinia biloba Raddi under controlledconditions of light and nutrients. This aquatic plant is beingconsidered as an efficient hiperaccumulator of Cu and is widelyspread in South America lakes and rivers. A set of 30 plants wasexposed at 40 ppm w/w of Cu along 6 days. The analytical procedurewas based on the periodic in vivo quantitative analysis of Cu atselected points in the plants using micro-XRF. For the measurements,a dedicated spectrometer for micro-XRF analysis that focalize MoX-ray tube emission with a capillary optic was employed. The accuracyin elemental quantification was effectively improved with theassistance of the Monte Carlo XMI-MSIM simulation code [1]. Theprecise results demonstrated that the proposed methodology is able toprovide an efficient indicator of the moment since the plants becomesaturated. This indicator is essential for deciding when plantsshould be harvested and replaced to improve the metal removalcapacity of the phytofiltration system. The knowledge of the chemical state of copper ishighly valuable to decide the final destiny of harvested plants. Thiswork presents an application of Energy-Dispersive Inelastic X-rayScattering (EDIXS) using a conventional x-ray tube as source, forchemical state discrimination of copper in the harvested plants [2].Several EDIXS spectra of five samples were acquired using an incidentbeam with energy below the Cu-K edge. EDIXS peaks were then studiedby principal component analysis in order to properly discriminate thefine structure of each spectrum. The results showed that copper inroots and leaves had different chemical valence supporting that EDIXScould be a way to differentiate between bioadsorption andbioaccumulation.[1]Sbarato V. et al., Analytical Methods, doi: 10.1039/D1AY00360G (2021)[2]Perez, R.D. et al., Rev. Sci. Instr., 92: 13102-8, doi:10.1063/5.0026061 (2021)