Organosulphur-modified biochar: An effective green adsorbent for removing metal species in aquatic systems

Author(s)

Macedo, Carlos Alves ^[1] ; Gontijo, Erik Sartori Jeunon ^[2] ; Herrera, Santiago Gomez ^[2] ; Rangel, Elidiane Cipriano ^[2] ; Komatsu, Daniel ^[3] ; Landers, Richard ^[4] ; Rosa, Andre Henrique ^[2]

Affiliation

^[1] Sao Paulo State Univ UNESP, Inst Chem, Rua Prof Francisco Degni, 55, BR-14800060 Araraquara, SP - Brazil

^[2] Sao Paulo State Univ UNESP, Inst Sci & Technol, Ave Tres Marco, 511, BR-18087180 Sorocaba, SP - Brazil

^[3] Pontifical Catholic Univ Sao Paulo PUC SP, Campus Sorocaba, R Joubert Wey, 290, BR-18030070 Sorocaba, SP - Brazil

^[4] Univ Estadual Campinas, Gleb Wataghin Inst Phys, Dept Appl Phys, Surface Phys Lab, BR-13083859 Campinas, SP - Brazil

• Document type: Journal article
• Source: SURFACES AND INTERFACES; v. 22, FEB 2021.
• Web of Science Citations: 0

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+ > Cr3+ > Cd2+ similar or equal to Ni2+ and Cd2+ > Pb2+ > 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. (AU)

• FAPESP's process: 18/20326-1 - Dissolution and toxicity of silver nanoparticles in the presence of aquatic humic substances and extracellular polymeric substances
• Grantee: André Henrique Rosa
• Support Opportunities: Regular Research Grants