From Nature to Remediation: Biomaterials for Malachite Green Retention and Degradation

The increasing presence of synthetic dyes in aquatic environments presents a serious threat to ecosystems and human health. This study investigates the potential of natural biomaterials, specifically fish-derived components extracted from <i>Cyprinus carpio</i> (fish bladder and fish scales), for the simultaneous retention and degradation of a potentially toxic dye: Malachite Green (MG). The biomaterials were characterized using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, thermogravimetric analysis (TGA), and high-performance liquid chromatography with mass spectrometry detection (HPLC-MS) for degradation monitoring. Batch adsorption experiments were conducted under varying biomaterial dosage, contact time and pH. Results demonstrated that all tested biomaterials exhibited significant adsorption capacities, with fish scales (FS) achieving a maximum removal efficiency of 91.2%, and fish bladder (FB) reaching 82% under optimal conditions. In catalytic ozonation tests, the fish scales impregnated with vanadium (FS-V) catalyst demonstrated significantly higher degradation efficiency, reaching 63.84% at an ozone flow rate of 0.5 g O₃·h^-1. The comparative analysis highlights the multifunctionality of these eco-friendly biomaterials, offering both pollutant capture and partial degradation. These findings suggest that low-cost, naturally derived biomaterials can serve as effective alternatives to synthetic adsorbents in water treatment applications, contributing to sustainable environmental remediation strategies.