A comprehensive review of recent advances in phytoremediation of wastewaters using Azolla species

This review article examines recent advances in the use of Azolla species for the phytoremediation of wastewater. Azolla is an aquatic macrophyte fern with rapid growth and high nutrient uptake capabilities and has the potential for removing pollutants, including heavy metals, nutrients, and organic contaminants from wastewater. We explore various studies that highlight the efficiency of different Azolla species, the mechanisms underlying their phytoremediation potential, and the factors influencing their effectiveness, including environmental conditions and genetic variations. Reported removal efficiencies by Azolla species vary widely, with heavy metal removal often exceeding 90% for Fe, Cr, and Pb, and nutrient removal rates reaching up to 78% for COD and 66% for total nitrogen. Such high remediation potentials highlight Azolla's applicability in diverse wastewater contexts. In particular, advances in genetic engineering and biotechnology focused on enhancing phytoremediation capacity are also discussed. Also, the review presented challenges and limitations in applying Azolla-based phytoremediation at a larger scale, suggesting potential strategies for overcoming these issues. Unlike previous reviews that provided generalized overviews, this article emphasizes recent genetic and biotechnological advancements, comparative species performance, and integration strategies for large-scale applications. Therefore, this aims to provide a clear understanding of Azolla's role in sustainable wastewater management and guide future research directions in this field.