Kinetic modeling and toxicological assessment of Eriochrome Black T dye: enhanced adsorptive approach using novel ZrO2/Pisum Sativum nanocomposites

The presence of synthetic dyes in wastewater, particularly Eriochrome Black T (EBT), poses a significant environmental challenge due to their toxic and persistent nature in water. This study investigates the use of biomass from Pisum sativum (garden pea), biochar, ZrO₂ nanoparticles (ZrO₂ NPs), and a composite of ZrO₂ and Pisum sativum (ZrO₂ NCs) for effectively removing EBT dye from aqueous solutions. The novel ZrO₂ NCs were synthesized and characterized using analytical techniques like scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) to study the morphology and functional group elucidation, respectively. The dye removal efficiency was tested under various experimental conditions, including different initial dye concentrations, pH levels, catalyst dosages, and contact times. Results showed that ZrO₂ NCs performed exceptionally well, demonstrating a synergistic effect and outperforming the individual materials. Under optimal conditions—pH 5, a 10 mg/L dye solution, 0.25 g adsorbent dosage, and a contact time of 720 min—92.65% of the dye was removed. To ensure that the treated wastewater was safer, toxicity assessments were conducted. The brine shrimp lethality test and hemolytic assay revealed significant reductions in toxicity, with 75.28 and 85.56% reductions, respectively. Additionally, the Ames test showed a reduction in mutagenicity, with 70.43 and 73.31% reductions for the TA98 and TA100 bacterial strains, respectively, after the treatment with ZrO₂ NCs. Kinetic studies indicated that the process followed the pseudo-second-order kinetics. This research underscores the potential of combining nanotechnology with biomass-derived materials to create sustainable and efficient solutions for dye removal, providing a promising method for wastewater treatment applications.