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 Cyprinus carpio (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.

This study explores the adsorption and catalytic degradation of 2,4,6-trinitrotoluene (TNT) from aqueous solutions, using montmorillonite-based catalysts. Commercially, montmorillonite K10 was modified through aluminum pillaring (K10-Al-PILC), followed by vanadium intercalation (K10-Al-PILC-V) and ozone activation. A novel aspect of this work is the use of naturally contaminated water as the TNT source. The selected sample, collected from the Plaiul Arșiței–Cireșu–Leșunț region (Oituz, Bacau, Romania), originated from an area historically exposed to explosive residues, where TNT traces were previously identified. The adsorption performance of the materials was evaluated by varying adsorbent dosage, contact time, and solution pH. Catalytic ozonation experiments were conducted under different catalyst masses, ozone concentrations, and reaction times to assess degradation efficiency. The results demonstrated that aluminum pillaring significantly enhanced the adsorption capacity of the clay, while vanadium incorporation further improved both adsorption and catalytic activity. The vanadium-modified material exhibited superior performance in TNT removal, both through adsorption and oxidative degradation. Additionally, the catalytic ozonation process led to the formation of degradation products with reduced toxicity, confirming the potential of these materials for environmental remediation of nitroaromatic pollutants in real water systems.