Review on advancing heavy metals removal: The use of iron oxide nanoparticles and microalgae-based adsorbents

Industrial effluent comprises several highly toxic substances that have polluted water and harmed natural resources. The existence of heavy metals in wastewater, on the other hand, limits the biodegradability of major organic pollutants, transforming them into long-term ecosystem components. Membrane separation, advanced oxidation, and adsorption have all been used to treat wastewater, but adsorption has proven to be preferable due to its low technical skill demand and relatively high pollutant removal efficiency while employing a low adsorbent dose. As a result, one of the approaches that has yielded promising results and sparked widespread attention is the synthesis of novel adsorbents. Recently, there has been a lot of interest in immobilizing microbial cells on biosorbents to reduce contaminants. Compared to other biological treatment technologies, biosorbent immobilized microorganisms can increase microbial abundance, repeated utilization ratio, microbial metabolic capability, and so on. However, the study on this approach is still in its early stages. The interaction between biosorbent and microbes has received little attention, with many research projects limited to laboratory settings. Further explanation is needed to address issues such as challenging recovery and secondary contamination from remaining contaminants following biosorbent adsorption. This article provides a detailed overview of biosorbent-based wastewater treatment technologies. It investigated the mechanics of immobilized microorganisms and assessed their applicability in wastewater treatment using biosorbents.