Efficient Phenol Degradation by a Natural Illite-Based Catalyst via Integrated Advanced Oxidation Processes

Phenol is a hazardous aromatic compound frequently detected in industrial effluents, posing serious risks to aquatic ecosystems and human health. In this study, a natural illite-based catalyst impregnated with 2% iron (Fe@SCRT) was synthesized and evaluated for phenol degradation via various advanced oxidation processes (AOPs), including Fenton, Sono-Fenton, Photo-Fenton, and their combined forms.

The catalyst was characterized using XRD, FTIR, and SEM-EDX, confirming successful iron incorporation and structural modification. Among the tested processes, the combined Sono-Photo-Fenton system achieved the highest degradation efficiency, exceeding 95% phenol removal within 60 minutes. Operational parameters such as pH, H₂O₂ concentration, and catalyst dosage were optimized to enhance performance. Statistical analyses, including standard deviation and ANOVA, revealed significant differences among individual and combined processes.

Scavenger studies identified hydroxyl radicals as the primary oxidative species, with contributions from superoxide radicals and metal ions. The catalyst showed good stability across multiple reuse cycles with minimal iron leaching.

Preliminary eco-toxicological tests, including seed germination and fish survival assays, demonstrated a clear reduction in effluent toxicity after treatment, supporting the environmental viability of the approach.

This study introduces a novel integration of multiple AOPs using a low-cost, natural clay-based catalyst, with both performance and toxicity assessments. The synergistic effect of the Sono-Photo-Fenton process using Fe@SCRT is reported here for the first time. These findings highlight the potential of Fe@SCRT as a sustainable and efficient catalyst for wastewater treatment applications.