Synthesized and characterized brownmillerite type Ca₂Fe₂O₅ nanoparticles degrade Alizarin Red S (ARS) quinone dye in the darkness, making it a promising material for the degradation of not only ARS but of other persistent dyes, too.

Abstract

Evaluation of effective and low-cost materials as catalysts to combat the threat of pollution is a significant and growing trend. With this aim, we have synthesized calcium ferrite brownmillerite by wet preparation approach as a catalyst for pollution. The structural analysis is established by the X-ray diffraction of Ca₂Fe₂O₅, whereas the tetrahedral and octahedral sites band stretching for ferrite specimen has been deduced using FTIR. The bandgap energy has been estimated by the Tauc relation (2.17 eV). Ca₂Fe₂O₅ brownmillerite exhibits a BET surface area of 10 m²/g and a BJH pore volume of 0.121 cm³/g with the average particle size of 70 nm. Importantly, the alizarin Red S dye degradation has been studied using the prepared ferrite catalyst, under dark ambient conditions and without the presence of any acidic or basic additives. Degradation is also supported by both FTIR and TOC analysis. Surface properties of brownmillerite Ca₂Fe₂O₅ have been characterized using electronic spectroscopy and CO₂ temperature programmed desorption (TPD) analysis and revealed that the basic surface of brownmillerite Ca₂Fe₂O₅ offers active sites that are suitable for degradation processes. All results show that the preparation of brownmillerite Ca₂Fe₂O₅ via the Pechini method is suitable to produce fine surfaces and pores with nanosized particles.