Experimental study and parameters optimization of heavy metals phytoremediation removal process by Azolla pinnata using response surface methodology

Abstract

Heavy metals contamination of industrial wastewater is a significant environmental concern due to the toxicity, persistence, and bio accumulative nature of metals such as cadmium (Cd), nickel (Ni), and lead (Pb). Phytoremediation is efficient, eco-friendly and economic selected for the treatment using Azolla pinnata as quantic plant. The physical characterization of Azolla pinnata shows structural characteristic contributed significantly to the high removal efficiency. This study investigated the potential of the aquatic Azolla pinnata as a low cost and environmentally sustainable phytoremediation agent for the removal of Cd, Ni, and Pb from contaminated water. Synthetic wastewater containing different initial metals concentrations (0.5, 1, 3, and 5 mg/L) was treated with A. pinnata, and changes in metal concentrations were monitored throughout the treatment period. Metals removal efficiency was evaluated based on the reduction in dissolved metal concentrations. Response surface methodology (RSM) was applied to optimize the effects of biomass dosage, treatment time, and initial metal concentration for the high removal of these meals. Analysis of variance (ANOVA) was used to determine the significance of the experimental factors and their interactions. The results demonstrated that Azolla pinnata effectively removed the investigated heavy metals, with particularly high removal performance observed for Pb and Cd. The optimization analysis indicated that a treatment time of approximately 18.4 days and an A. pinnata biomass of 49.4 g provided the optimized conditions for achieving maximum simultaneous removal of Cd, Ni, and Pb. These findings demonstrate the potential of Azolla pinnata as an effective, economical, and environmentally friendly phytoremediation material for heavy metals contaminated wastewater. The use of plant biomass also offers potential for sustainable treatment systems by reducing dependence on conventional chemical-based remediation methods.