Author(s): Landers, Richard, 1946-
Date: 2021
Persistent ID: https://hdl.handle.net/20.500.12733/1666580
Origin: Oasisbr
Subject(s): Adsorção; Metais pesados; Biomassa; Adsorption; Heavy metals; Biomass; Green adsorbent; Water treatment; Biochar; Artigo original
Abstract: Organosulphur-modified biochar (BC) can be used as a green adsorbent for removing potentially toxic metal ions from aqueous solutions. In this study, sugarcane bagasse BCs (produced at pyrolysis temperatures from 300 to 700 degrees C) were modified in a single-step reaction with isothiocyanate. The performance and selectivity of raw and modified BCs for removing Cd2+, Ni2+, Pb2+ and Cr3+ from mono- and multi-element aqueous solutions were investigated. The characterisation of the BCs was performed by proximate analysis, Fourier transformed infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS) and pyrolysis coupled to gas chromatography-mass spectrometry (Py-GC-MS). The results showed that the organosulphur modification increased S and N contents on the surface of the BCs, particularly isothiocyanate groups. The maximal adsorptions were observed for raw and modified BCs produced at 700 degrees C and pH 6. The adsorption kinetics of Cd2+, Ni2+, Pb2+ and Cr3+ before and after BC modification was best described by the pseudo-second order kinetic model. The results indicated that the removal of metal ions by modified-biochars follows the order Pb2+ gt; Cr3+ gt; Cd2+ similar or equal to Ni2+ and Cd2+ gt; Pb2+ gt; Ni2+ similar or equal to Cr3+ for mono-element and multi-element systems, respectively. The mechanisms involved in the adsorption were physisorption, chemisorption, complexation, precipitation, and ion exchange. The presence of other metal ions in the multi-element system caused a synergistic effect on adsorption of Cr3+, Cd2+ and Ni2+ and an antagonistic effect on adsorption of Pb2+. Organosulphur-modified BC can be an effective andselective adsorbent for removing Cd2+, Ni2+, Pb2+ and Cr3+ from aqueous solutions
FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ
COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES
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