Abstract

CARLOS, Medina, et al. Chromic Oxide Recovery from Tannery Wastewater and Application as Dye. Rev Politéc. (Quito) [online]. 2025, vol.55, n.1, pp.41-50. ISSN 2477-8990.  https://doi.org/10.33333/rp.vol55n1.04.

The leather tanning industry utilizes large amounts of chromium in its processes, resulting in substantial volumes of wastewater that contain high concentrations of chromium. This wastewater could serve as a source for recovering this metal after disposal. This study aims to exploit this wastewater to extract chromium oxide (Cr2O3), a material with a wide range of useful properties suitable for various applications. In this study, the effluent was used as a chromium (III) source, and ammonium hydroxide (NH4OH) was employed as a precipitant, adjusting the pH to 10. The resulting precipitate was filtered, dried at 70°C, and then calcined at 400, 600, and 700°C for 5 hours. After calcination, the material was ground for a further analysis. Characterization of the material was performed using Fourier Transform Infrared (FT-IR) spectroscopy, X-ray Diffraction (XRD), and Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDX). FT-IR analysis revealed characteristic peaks corresponding to chromium oxide (III). XRD studies confirmed the formation of Cr2O3 with a hexagonal structure. SEM images indicated that the particles lacked a defined shape, with crystal sizes varying between 25 and 97 μm and an average crystal size of 78 nm. The presence of chromium oxide was further confirmed through EDS compositional analysis.

Keywords : chromic oxide; dye; wastewater; precipitating agent.

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