Nanotechnology-Assisted Phytoremediation of Heavy Metal Contaminated Soils: A State-of-the-Art Review on Recent Progress, Challenges, and Future Directions

Soil contamination by heavy metals (HMs) poses significant environmental and public health challenges, necessitating the pressing need for efficient and sustainable remediation strategies. Traditional phytoremediation technology, while cost-effective, less toxic, and eco-friendly, faces limitations such as low efficiency, prolonged duration, and partial HMs removal. This review critically explored the integration of nanotechnology with traditional phytoremediation (nanophytoremediation) as an innovative solution for addressing the limitations of traditional phytoremediation. The paper systematically explores synthesis methods, key factors influencing nanophytoremediation efficacy, and the mechanisms governing nanoparticle (NP)-plant-soil-microbe interactions. Moreover, the synergistic role of rhizosphere microbes in improving HM solubility and plant tolerance is highlighted. Comparative case studies demonstrate the superior performance of nanophytoremediation over traditional phytoremediation methods in improving HM bioavailability, reducing phytotoxicity, stimulating plant growth, and enhancing rhizosphere microbial activity. Despite the effectiveness of the nanophytoremediation, challenges such as NP ecotoxicity, long-term environmental persistence, and regulatory gaps necessitate careful consideration. Future directions advocate for green synthesis, AI-driven optimization, large-scale field trials, and robust policy frameworks to ensure safe implementation. This review offers a roadmap for designing and developing nanotechnology-assisted phytoremediation strategies for the researchers and policymakers, aligning with global ecosystem restoration and sustainability goals.