The synergistic potential of biochar and nanoparticles in phytoremediation and enhancing cadmium tolerance in plants

Cadmium (Cd) is classified as a heavy metal (HM) and is found into the environment through both natural processes and intensified anthropogenic activities such as industrial operations, mining, disposal of metal-laden waste like batteries, as well as sludge disposal, excessive fertilizer application, and Cd-related product usage. This rising Cd disposal into the environment carries substantial risks to the food chain and human well-being. Inadequate regulatory measures have led to Cd bio-accumulation in plants, which is increasing in an alarming rate and further jeopardizing higher trophic organisms, including humans. In response, an effective Cd decontamination strategy such as phytoremediation emerges as a potent solution, with innovations in nanotechnology like biochar (BC) and nanoparticles (NPs) further augmenting its effectiveness for Cd phytoremediation. BC, derived from biomass pyrolysis, and a variety of NPs, both natural and less toxic, actively engage in Cd removal during phytoremediation, mitigating plant toxicity and associated hazards. This review scrutinizes the application of BC and NPs in Cd phytoremediation, assessing their synergistic mechanism in influencing plant growth, genetic regulations, structural transformations, and phytohormone dynamics. Additionally, the review also underscores the adoption of this sustainable and environmentally friendly strategies for future research in employing BC-NP microaggregates to ameliorate Cd phytoremediation from soil, thereby curbing ecological damage due to Cd toxicity.