A critical review on the interaction of iron-based nanoparticles with blue-green algae and their metabolites: From mechanisms to applications

The rapid increase in application of iron-based nanoparticles (IBNPs) based on their outstanding characteristics has raised global attention. Understanding the environmental fates or the potential ecological effects of IBNPs is essential to develop reasonable guidelines for the application of IBNPs at a practical range. As the primary producers, cyanobacteria and green algae in the aquatic system play a fundamental role both in the whole food chain and future biomass energy development. This review summarizes the present state of knowledge regarding environmental behavior of IBNPs and their ecological effects on blue-green algae, as well as blue-green algae biomass harvesting and metabolites removal. Various environmental factors and concomitant algal metabolites show great impacts not only on aggregation, sedimentation, dissolution and aging of IBNPs, but also on latish interactions like toxicity and adsorption processes of IBNPs to blue-green algae biomass. The presence of algal organic matter (AOM) plays a two-side role in participating in the interactions between IBNPs and algal cells, which has not been emphasized in previous researches. The application of magnetic IBNPs for algae harvesting is a fast and efficient technology, and surface modified IBNPs always exert superior biomass harvesting efficiency than bare IBNPs because of their more functional groups and higher positively charged zeta potential. Synchronously, the removal of algal metabolites such as extracellular organic matter and microcystins will also help to enhance aquatic quality and safety. This review will enrich our understanding of the usage, discharge, and potential ecological effects of IBNPs and the proper utilization of sustainable green nanotechnology in algal harvesting.