Magnetic cork as adsorbent to remove hexavalent chromium from aqueous solution

J. Abenojar, S. López de Armentia, J.C. del Real-Romero, M.A. Martínez

Applied Water Science Vol. 14, pp. 267-1 - 267-17

Summary:

Chromium contamination of water is a severe environmental problem due to the potential carcinogenicity of Cr(VI). In this work, magnetic cork powder was used as a porous material, and its removal efficiency for Cr(VI) was compared to that of natural cork powder through two mechanisms: adsorption and reduction. Adsorption isotherms and adsorption kinetics were utilized to calculate the reaction rate using a pseudo-first-order model, pseudo-second-order model, and intraparticle diffusion. After adsorption, the powder was characterized by scanning electronic microscopy with energy-dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy (XPS). EDAX allowed to see a mapping distribution of Fe and Cr, and XPS revealed the presence of Cr₂O₃ and Cr(OH)₃, confirming the reduction of Cr(VI) to Cr(III). All the Cr was efficiently reduced and adsorbed onto the surface of the magnetic cork at 20 °C, 27 °C, and 50 °C within 120 min with stirring. The relative efficiencies to the total milligrams of added adsorbent were 98, 98.6, and 99.7 mg, respectively. This is comparable to the adsorption on the natural cork surface at the same temperatures, which measured 97.8, 98.5, and 99.6 mg, respectively, of 100 mg/L Cr(VI) solution. Furthermore, the magnetic cork offers the advantage of being removable by applying a magnetic field.

Spanish layman's summary:

La contaminación por cromo en el agua es un problema grave debido a la carcinogenicidad del Cr(VI). Este estudio utilizó polvo de corcho magnético para eliminar Cr(VI) mediante adsorción y reducción, superando al corcho natural. Las técnicas de caracterización confirmaron la reducción de Cr(VI) a Cr(III). A 20–50 °C, las eficiencias alcanzaron ~99%. El corcho magnético es fácil de retirar con un campo magnético, siendo muy eficaz para tratar agua.

English layman's summary:

Chromium contamination in water is a major issue due to Cr(VI)’s carcinogenicity. This study used magnetic cork powder to remove Cr(VI) via adsorption and reduction, outperforming natural cork. Characterization techniques confirmed Cr(VI) reduction to Cr(III). At 20–50 °C, efficiencies reached ~99%. Magnetic cork’s added advantage is easy removal using a magnetic field, making it highly effective for water treatment.

Keywords: Magnetic cork · Industrial waste reuse · Hexavalent chromium adsorption · Ultraviolet–visible spectroscopy

JCR Impact Factor and WoS quartile: 5,700 - Q1 (2023)

DOI reference: https://doi.org/10.1007/s13201-024-02322-z

Published on paper: 2024.

Published on-line: November 2024.

Citation:
J. Abenojar, S. López de Armentia, J.C. del Real-Romero, M.A. Martínez, Magnetic cork as adsorbent to remove hexavalent chromium from aqueous solution. Applied Water Science. Vol. 14, pp. 267-1 - 267-17, 2024. [Online: November 2024]