Water pollution from industrial dyes is increasingly recognized as a pressing challenge for ecosystems, significantly impacting both environmental and human health. Among these dyes, Congo Red (CR), widely employed across textile and food industries, poses severe risks due to its carcinogenic properties. Addressing this pollution, researchers have synthesized dysprosium-doped barium hexaferrite nanoparticles, denoted as BaDyxFe12−xO19, using the sol-gel auto-ignition (SGA) technique, to effectively degrade CR under natural sunlight.
Published on March 15, 2025, the study showcases the development of these innovative photocatalysts, which exhibited remarkable efficacy, achieving degradation efficiencies of 89.29% within just 90 minutes of sunlight exposure. The results underline the potential of photocatalytic processes as viable solutions for improving wastewater treatment methodologies, particularly for toxic dye contaminants.
The harmful effects of synthetic dyes like CR are exacerbated by their persistent nature and toxicity; studies have linked CR exposure to genotoxic and carcinogenic effects, particularly concerning bladder cancer due to its metabolite, benzidine. Therefore, tackling such pollutants is imperative, aligning with the Sustainable Development Goal 6, which calls for clean water access and sanitation.
Through rigorous characterization, the synthesized nanoparticles were subjected to structural analysis via X-ray diffraction (XRD) and examined under field emission scanning electron microscopy (FESEM). The analysis confirmed their hexagonal crystal structure, exhibiting the advantageous properties necessary for efficient photocatalytic activity.
Utilizing the SGA technique, BaDyxFe12−xO19 nanoparticles were fabricated with varying dysprosium concentrations (x = 0.02, 0.04, and 0.06). The process begins by mixing and stirring precursors, including barium and dysprosium nitrates and citric acid, to promote homogeneity. Upon neutralization, the mixture transforms to gel and is calcined at high temperatures, producing the final nanoparticle product.
The research revealed substantial variations in photocatalytic performance based on the dysprosium content. The degradation efficiencies achieved were 84.36% for BDF1, 86.47% for BDF2, and 89.29% for BDF3, with the latter demonstrating the highest efficacy. This performance highlights the impact of surface area commonly associated with the amount of dysprosium doping, with specific surface areas of 1.069 m2/g for BDF1 and 1.466 m2/g for BDF3.
Characterization of their photocatalytic properties showcased the preferred alkaline conditions for maximizing dye degradation through enhanced interaction between CR molecules and catalysts. The research established optimal operational parameters, demonstrating how increasing iron oxide nanoparticles' concentration improves the degradation process until reaching saturation, where excess material obstructs light penetration.
During the experiments, researchers implemented UV-VIS spectrophotometric methods to detect concentration changes of CR before and after treatment, confirming the successful breakdown of the dye within specified conditions. The comparative analysis consistently shows enhanced rates of degradation across varying concentrations and conditions.
Significantly, the study highlights the operational longevity of these nanoparticles, indicating minor declines (around 5% to 6%) over five reuse cycles, reinforcing their economic viability and sustainable application potential. The findings suggest promising pathways for broader adoption of dysprosium-doped barium hexaferrites not only as efficient photocatalysts but as integral components of pollutant remediation strategies.
Conclusively, the synthesis and application of BaDyxFe12−xO19 nanoparticles indicate significant advancements in addressing water pollution. This approach not only paves the way for effective remediation of toxic dyes like Congo Red but also aligns with global efforts toward achieving sustainable environmental health.