Author(s): Alves Macedo, João Carlos [UNESP] ; Sartori Jeunon Gontijo, Erik [UNESP] ; Gómez Herrera, Santiago [UNESP] ; Rangel, Elidiane Cipriano [UNESP] ; Komatsu, Daniel ; Landers, Richard ; Rosa, André Henrique [UNESP]
Date: 2021
Persistent ID: http://hdl.handle.net/11449/208225
Origin: Oasisbr
Subject(s): adsorption; biochar; green adsorbent; heavy metals; water treatment
Made available in DSpace on 2021-06-25T11:08:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-02-01
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°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°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+> Cr3+> Cd2+ ≅ Ni2+ and Cd2+> Pb2+> Ni2+≅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.
São Paulo State University (UNESP) Institute of Chemistry Rua Prof. Francisco Degni, 55, Quitandinha - CEP 14800-060
São Paulo State University (UNESP) Institute of Science and Technology, Av. Três de Março, 511, Alto da Boa Vista – CEP: 18087-180
Pontifical Catholic University of São Paulo (PUC SP) Campus Sorocaba, R. Joubert Wey, 290, Vila Boa Vista – CEP: 18030-070
Laboratory of Surface Physics Department of Applied Physics “Gleb Wataghin” Institute of Physics University of Campinas, CEP 13083-859
São Paulo State University (UNESP) Institute of Chemistry Rua Prof. Francisco Degni, 55, Quitandinha - CEP 14800-060
São Paulo State University (UNESP) Institute of Science and Technology, Av. Três de Março, 511, Alto da Boa Vista – CEP: 18087-180
