Algae-based green AgNPs, AuNPs, and FeNPs as potential nanoremediators

This review addresses green algae-based gold (Au), iron (Fe), and silver (Ag) nanoparticles (NPs) as eco-friendly nanomaterials to deal with biological, organic, and inorganic environmental contaminants. Among nanotechnological tools that can fully degrade, adsorb, and/or convert pollutants into less harmful structures, AgNPs, AuNPs, and FeNPs deserve highlight for their efficiency and low cost. However, green protocols are preferable to produce them in an eco-friendly manner. Although phycosynthesis is still in its infancy, algae present various advantages as green raw materials to NPs’ synthesis; fast growth rate, low-energy input requirement, low costs, easy and eco-friendly cultivation, and high tolerance to metals are examples. To allow their large-scale application, however, challenges regarding obtaining sufficient biomaterial with good reproducibility, designing protocols to achieve desirable features on NPs, and recovering the biocompatible nanomaterial after use still need attention. Perspectives for the field involve surpassing these limitations, broadening knowledge on synthesis mechanisms, protocols, and new species useful to offer, in the future, commercial eco-friendly, and low-cost phycosynthesized AuNPs, AgNPs, and FeNPs to nanoremediation. The potential of these NPs to deal with environmental contaminants, their advantageous characteristics and biocompatibility, the main limitations associated with their large-scale application, and future prospects for the field will receive attention.