Uranium removal from aqueous solution using macauba endocarp-derived biochar: Effect of physical activation

Sabine N Guilhen; Suzimara Rovani; Leandro G de Araujo; Jorge A S Tenório; Ondřej Mašek

doi:10.1016/j.envpol.2020.116022

Uranium removal from aqueous solution using macauba endocarp-derived biochar: Effect of physical activation

Environ Pollut. 2021 Mar 1:272:116022. doi: 10.1016/j.envpol.2020.116022. Epub 2020 Nov 10.

Authors

Sabine N Guilhen¹, Suzimara Rovani², Leandro G de Araujo³, Jorge A S Tenório⁴, Ondřej Mašek⁵

Affiliations

¹ Instituto de Pesquisas Energéticas e Nucleares, Comissão Nacional de Energia Nuclear, Av. Professor Lineu Prestes, 2242 - 05508-000, São Paulo, Brazil. Electronic address: snguilhen@ipen.br.
² Instituto de Pesquisas Energéticas e Nucleares, Comissão Nacional de Energia Nuclear, Av. Professor Lineu Prestes, 2242 - 05508-000, São Paulo, Brazil. Electronic address: suzirovani@gmail.com.
³ Instituto de Pesquisas Energéticas e Nucleares, Comissão Nacional de Energia Nuclear, Av. Professor Lineu Prestes, 2242 - 05508-000, São Paulo, Brazil. Electronic address: lgoulart@alumni.usp.br.
⁴ Depto. de Engenharia Química da Escola Politécnica, Universidade de São Paulo, Rua do Lago, 250 - 05508-080, São Paulo, Brazil. Electronic address: jtenorio@usp.br.
⁵ UK Biochar Research Centre, School of Geosciences, University of Edinburgh, Alexander Crum Brown Road, Crew Building, EH9 3LA, Edinburgh, UK. Electronic address: ondrej.masek@ed.ac.uk.

PMID: 33221084
DOI: 10.1016/j.envpol.2020.116022

Abstract

The main aim of this study was to evaluate options for addressing two pressing challenges related to environmental quality and circular economy stemming from wastage or underutilization of abundant biomass residue resources and contamination of water by industrial effluents. In this study we focused on residues (endocarp) from Macaúba palm (Acrocomia aculeata) used for oil production, its conversion to activated biochar, and its potential use in uranium (U) removal from aqueous solutions. Batch adsorption experiments showed a much higher uranyl ions (U(VI)) removal efficiency of activated biochar compared to untreated biochar. As a result of activation, an increase in removal efficiency from 80.5% (untreated biochar) to 99.2% (after activation) was observed for a 5 mg L^-1 initial U(VI) concentration solution adjusted to pH 3 using a 10 g L^-1 adsorbent dosage. The BET surface area increased from 0.83 to 643 m² g^-1 with activation. Surface topography of the activated biochar showed a very characteristic morphology with high porosity. Activation significantly affected chemical surface of the biochar. FTIR analysis indicated that U(VI) was removed by physisorption from the aqueous solution. The adsorbed U(VI) was detected by micro X-ray fluorescence technique. Adsorption isotherms were employed to represent the results of the U adsorption onto the activated biochar. An estimation of the best fit was performed by calculating different deviation equations, also called error functions. The Redlich-Peterson isotherm model was the most appropriate for fitting the experimental data, suggesting heterogeneity of adsorption sites with different affinities for uranium setting up as a hybrid adsorption. These results demonstrated that physical activation significantly increases the adsorption capacity of macauba endocarp-derived biochar for uranium in aqueous solutions, and therefore open up a potential new application for this type of waste-derived biochar.

Keywords: Activation; Biochar; Endocarp; Macauba; Uranium.

MeSH terms

Adsorption
Charcoal
Hydrogen-Ion Concentration
Kinetics
Uranium* / analysis
Water
Water Pollutants, Chemical*

Substances

Water Pollutants, Chemical
biochar
Water
Charcoal
Uranium