Catalytic Oxidation of Phenol Using Iron-Supported Illite: Optimization of Parameters for Efficient Wastewater Treatment

This study investigates the catalytic oxidation of phenol using an iron-supported natural illite clay catalyst, focusing on optimizing degradation efficiency and minimizing environmental impact. Phenol, a hazardous industrial pollutant, poses risks to ecosystems, particularly affecting plant germination and fish survival in contaminated waters. To address these concerns, an iron-impregnated natural illite clay catalyst was developed to enhance the stability and reactivity of iron sites, promoting effective phenol degradation in wastewater.

The optimal degradation conditions were achieved at pH 3 and 50°C, facilitating hydroxyl radical formation and accelerating the reaction kinetics. Under these conditions, the catalyst achieved a 99% degradation rate for phenol and an 83% reduction in chemical oxygen demand (COD), indicating significant pollutant mineralization. Minimal iron leaching was observed, ensuring catalyst stability. Additionally, the H₂O₂ concentration was optimized at 0.5 mM, balancing efficient degradation with reduced chemical use.

To understand the degradation mechanism, scavenger tests confirmed hydroxyl radicals (•OH) as the primary reactive species. The identification of intermediate by-products was performed using high-performance liquid chromatography (HPLC), revealing a stepwise oxidation pathway that demonstrated the effective breakdown of phenolic compounds into less harmful substances. The catalyst also showed excellent reusability over five cycles with minimal activity loss, highlighting its potential for sustainable application. This study demonstrates the potential of iron-supported natural clay catalysts as a cost-effective, environmentally friendly solution for treating phenolic pollutants, reducing toxicity and supporting healthier ecosystems in aquatic environments.