Iron-Zinc Impregnated Biochar Composite as a Promising Adsorbent for Toxic Hexavalent Chromium Remediation: Kinetics, Isotherms and Thermodynamics

Autor: Vusumzi E. Pakade, Mpho Cynthia Qhubu, Banele Methula, Thokozani Xaba, Malvin Moyo
Rok vydání: 2021
Předmět:
Zdroj: Chemistry Africa. 5:1797-1807
ISSN: 2522-5766
2522-5758
DOI: 10.1007/s42250-021-00273-5
Popis: Owing to the high toxicity of chromium(VI) and the considerable lower toxicity of chromium(III), the removal of chromium(VI) based on reduction to chromium(III) is drawing more and more attraction. In this study, a biochar-zerovalent iron-zinc ferrite composite was developed and its efficacy in the reduction-assisted removal of chromium(VI) was investigated under various experimental conditions of initial solution pH, initial chromium(VI) concentration and contact time. The composite was derived by the pyrolysis of bleached Macadamia nutshell biomass impregnated with 1-[(cyclohexylamino)methyl]-2-naphtholate-zinc(II) complex and iron(II) chloride at 800 °C. Scanning electron microscopic images of the composite showed the porous texture of the composite while X-ray diffraction patterns of the composite suggested the presence of zerovalent iron and zinc ferrite. Maximum chromium removal equaling 89.7% was observed at initial solution pH of 3.0. The Freundlich isotherm model, a modified Van‘t Hoff thermodynamic model, and the pseudo second-order kinetic model were most appropriate in describing the observed effects of Cr(VI) concentration, temperature and contact time on the quantity of Cr(VI) ions adsorbed on the composite, respectively. In conclusion, the biochar-zerovalent iron-zinc ferrite composite showed great potential in the removal of Cr(VI) from aqueous solutions.
Databáze: OpenAIRE
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