Exhausted Yerba Mate Leaves (Ilex paraguariensis) as Biosorbent for the Removal of Metals from Aqueous Solutions

Abstract

Erva mate é a bebida do tipo chá mais popular na América do Sul. Consequentemente, uma grande quatidade de resíduos da erva já usada é gerada, podendo ser usada na remoção de metais. Neste estudo, foi avaliada a capacidade das folhas de erva-mate esgotadas na remoção de metais. A maior adsorção foi observada em pHs abaixo de 5. A capacidade de adsorção das folhas de erva-mate foi de 12,28, 11,77 e 8,80 mg g -1 para Pb(II), Cr(III) e Cr(VI), respectivamente.Yerba mate is the most popular tea-like beverage of South America. Consequently, there is a huge generation of residues of exhausted yerba mate and these may be used for removal of metals. The capability of exhausted yerba mate leaves in the removal of metals was evaluated in this study. The greatest adsorption was found to be at pHs below 5 and the adsorption capacity was 12.28, 11.77 and 8.80 mg g -1 for Pb(II), Cr(III) and Cr(VI), respectively.

Polyphenol–SiO2 hybrid biosorbent for heavy metal removal. Yerba mate waste (Ilex paraguariensis) as polyphenol source: Kinetics and isotherm studies

“…In an adsorption process where charge associated interaction prevails, the magnitude of E DR is in the range of 8-16 kJ/mol [51]. This was the case of Pb(II), Cr(III) and Cr(VI) calculated mean free energy of adsorption, which is consistent with a previous work where metal adsorption was studied over exhausted Yerba mate leaves [28]. This type of interaction is explained by the presence of o-dihydroxyphenyl metal chelating groups in polyphenolic structures of the Si-Pol matrices [52].…”

“…This is probably due to a decrease in polyphenol related adsorption and an increase in SiO 2 network related adsorption [14]. In a previous study, it was demonstrated that polyphenol related adsorption on Yerba mate leaves is higher at low pHs where cations form insoluble complexes with polyphenol's o-dihydroxyphenyl groups [28]. In all cases the higher adsorption of the Si-Pol matrices was observed at pH 3 (significantly different, p < 0.05), except for the case of Cr(III) adsorption where the adsorption related to the SiO 2 network is added to polyphenols quelating activity.…”

Leaves, Infusion, and Grounds—A Three–Stage Assessment of Element Content in Yerba Mate (Ilex paraguariensis) Based on the Dynamic Extraction and Mineralization of Residues

“…Therefore, these residues are a potential material for further usage. The use of yerba mate grounds was reported as cost-effective and an efficient adsorbent in the removal of metal ions, Pb(II), Cr(III), and Cr(VI), from aqueous solutions [13]. Similar studies were also reported for other materials, e.g., exhausted tea waste as an adsorbent for the removal of Cu and Pb from wastewater [14].…”

“…Co was only found below the quantification limit (BQL) in Sample no. 15, which was Brazilian-origin despalada with additives, while Se was found BQL in three samples (10,11,13). In turn, As and Pb were found BQL in 14 and 15 samples, respectively.…”