Facile Synthesis of Magnetic -Coffee Ground-Biochar Composite as an Efficient Heterogeneous Catalyst for Degradation of Methylene Blue in Fenton-Like System.

Abstract

Water pollution is a major environmental concern, with organic pollutants like methyl blue (MB) posing significant risks to aquatic ecosystems and human health. Advanced oxidation processes (AOPs), particularly the Fenton reaction, have shown great potential for the degradation of organic pollutants in water. However, traditional Fenton systems based on the Fe2+- H2O2 system have limitations, including rapid H2O2 consumption and iron sludge generation. This study investigates the synthesis and application of magnetic coffee ground biochar (Fe₃O₄/CGBC) as a heterogeneous catalyst for the degradation of MB. Coffee ground-biochar was produce by pyrolysis at optimized condition, Followed by magnetic modification to enhance its separation properties and catalytic activity. The physiochemical parameters of CGBC and Fe3O4/CGBC were characterized by FTIR, SEM and XRD techniques. The Fenton oxidation process was optimized by varying parameters such as PH, adsorbent dosage (Fe3O4/CGBC), and dosage of hydrogen peroxide (H2O2). The catalytic oxidation of MB were monitored by UV-Vis spectrophotometry. The results demonstrated that Fe₃O₄/CGBC achieved a maximum degradation efficiency of 94.42% under optimal conditions (pH 2, 14.69 mmol/L H₂O₂, 4 g/L catalyst, 120 min). Proximate analysis revealed the biochar's high fixed carbon content (38.2%), low ash content (10.62%), and moderate volatile matter (15.28%), contributing to its stability and catalytic activity. Additionally, reusability studies confirmed the catalyst's efficiency over multiple cycles, while interference studies highlighted its robustness in the presence of hydroxyl radical scavengers. This study demonstrates that Fe₃O₄/CGBC is a sustainable, cost-effective, and efficient catalyst for heterogeneous Fenton oxidation, offering a promising solution for wastewater treatment applications.