Exploration of Eco-Friendly Hydrochar’s Potential in Advanced Oxidative Processes for Dicamba Degradation within a Circular Bio-Economy Framework

Abstract

Dicamba, renowned for its limited sorption capacity, presents a substantial risk of contaminating surface and groundwater if the disposal of spray tank effluent is not adequately controlled. In this work, a dicamba effluent underwent treatment through a Fenton-like process employing an iron/hydrochar (Hy-Fe) composite, synthesized via hydrothermal methods using coffee husk as the precursor. The Hy-Fe displayed carbon, hydrogen, and nitrogen levels of 52.30%, 5.21%, and 1.49%, respectively. Additionally, the material exhibited a specific surface area measuring 9.00 m2 g−1. The presence of the γ-Fe2O3 phase within the composite was confirmed through X-ray diffraction analysis. The Fenton-like process employing Hy-Fe demonstrated approximately 100% degradation of dicamba within 5 h. The treated effluent underwent toxicity evaluation via biological assays using beans (Phaseolus vulgaris) as indicator plants, revealing no observable signs of intoxication. These findings were corroborated by High-Performance Liquid Chromatography, providing additional confirmation of the degradation results. Additionally, decontamination of personal protective equipment potentially contaminated with dicamba was also assessed. The Hy-Fe composite demonstrated reusability across three degradation cycles, achieving degradation percentages of 100%, 70%, and 60%, respectively. The Hy-Fe composite demonstrates substantial potential for use in a Fenton-like process. This process is characterized by its simplicity, speed, and sustainability. The notable effectiveness, evidenced by high degradation rates and minimal toxicity, underscores its suitability as a practical solution for addressing dicamba contamination.