abstract
The use of banana peels as biosorbent for mercury sorption fromdifferent aqueous solutions was investigated in this work. The impact of the operating conditions, such as biosorbent dosage, contact time and ionic strength was evaluated for realistic initial Hg(II) concentrations of 50 mu g dm(-3). Biosorbent dosage and contact time showed more influence on Hg(II) removal than ionic strength, and their increase led to improve Hg(II) uptake achieving final concentrations with drinking water quality. The kinetic behaviour of the sorption process was assessed through the reaction-based models of pseudo-first order, pseudo-second order and Elovich, being the last two more appropriated to describe the process. The equilibrium study showed that Freundlich isotherm provided the best fit to the experimental results (R-2 = 0.991), which may suggest a multilayer mechanism at biosorbent surface, and the sorption capacity of banana peels obtained from Langmuir isotherm was 0.75 mg g(-1). The ability of banana peels to sorb Hg(II) was also examined under real waters, like seawater and a wastewater, which confirmed the feasibility of the biosorbent. Additionally, a counter-current two-stages unit has been proposed for the application of banana peels as biosorbent in water treatments for mercury removal. (C) 2019 Elsevier B.V. All rights reserved.
keywords
HEXAVALENT CHROMIUM BIOSORPTION; AQUEOUS-SOLUTIONS; TOXIC METALS; ADSORPTION; KINETICS; SORPTION; WASTE; EQUILIBRIUM; ORDER; IONS
subject category
Environmental Sciences & Ecology
authors
Fabre, E; Lopes, CB; Vale, C; Pereira, E; Silva, CM
our authors
Carlos Manuel Silva
Associate Professor
Cláudia Batista Lopes
Assistant Researcher
Elaine Fabre
PhD Studentacknowledgements
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, FCT Ref. UID/CTM/50011/2019, financed by national funds through the FCT/MCTES. E. Fabre acknowledges the financial support of CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico), Brazil. C.B. Lopes acknowledges the national funds (OE), through FCT, I.P., in the scope of the framework contract foreseen in the UID/CTM/50011/2019 numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19.