Photocatalytic degradation of phenol under visible light irradiation by using ferrous oxalate synthesized from iron-rich mineral sands via a green hydrothermal route

The development of efficient green-photocatalysts represents a promising alternative for eliminating organic contaminants found in water. In this work, the photocatalyst & alpha;ferrous oxalate dihydrate (& alpha;-FOD) was synthesized using Ecuadorian black sands as an iron-rich precursor and was further used for phenol degradation for the first time. The synthesis was performed under hydrothermal conditions using aqueous oxalic acid at 135 degrees C and reaction times of 4 and 12 h. Also, ethanol and ethylene glycol were evaluated as co-solvents in the synthesis reaction. The characterization performed showed that synthesized photocatalysts were mainly composed of monoclinic FOD (crystallinity indexes between 75 and 87%) in the form of mesoporous particles with specific surface areas between 19.6 and 46.1 m2/g. The optical band gap energy was estimated in the range of 2.31-2.49 eV, which demonstrated visible light response. Indeed, under visible light irradiation, the photocatalytic activity of synthesized materials showed over 92% phenol removal within a short time (6 h) with a photocatalyst dose of 0.5 g/L. Also, stability and reusability of photocatalyst upon visible light was demonstrated. These results suggest that the photoactive green materials synthesized herein from a lowcost precursor can be used for degradation of organic contaminants under solar light irradiation. & COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).