Microalgae-mediated biosorption is a promising approach for the effective removal of heavy metals from wastewater. This review highlights the potential of microalgae in addressing heavy metal pollution, emphasizing their ability to remove contaminants from diverse wastewater sources. Microalgae offer advantages such as energy efficiency, cost-effectiveness, nutrient recycling, minimal sludge formation, and greenhouse gas reduction. They are particularly effective in treating industrial, agronomic, and mining discharges, demonstrating versatility and efficiency in wastewater purification. The review also explores the synthesis of biochar from microalgae for wastewater treatment, addressing gaps in previous research and considering innovative applications like biochar generation. Biochar provides efficient adsorption and environmental sustainability. The review delves into the properties, operational strategies, and applications of microalgae-based treatment in heavy metal remediation from wastewater. Microalgae are diverse photosynthetic organisms with high biomass productivity and carbon fixation rates. They are classified into prokaryotic cyanobacteria and eukaryotic protists, thriving in various aquatic environments. Their ability to harness solar radiation for photosynthesis and their ecological significance make them valuable for bioremediation. Cultivation techniques include photobioreactors and open ponds, with factors such as light intensity, temperature, pH, and nutrient availability influencing growth. Strain selection is crucial for maximizing biomass productivity and quality, with species like Chlorella vulgaris and Spirulina platensis being particularly effective. Biosorption is a key mechanism for heavy metal removal, involving the passive, non-metabolic interaction between contaminants and cell surfaces. Microalgae's cell walls, rich in polysaccharides and functional groups, facilitate the adsorption of heavy metal ions. Bioaccumulation, a metabolic process, involves the active transport of metal ions into living cells, with intracellular binding proteins like metallothioneins and phytochelatins playing a crucial role. Microalgae-based biosorption is cost-effective, efficient, and environmentally friendly, offering a viable alternative to conventional methods. The review also discusses the application of microalgae in decentralized water treatment systems, where they provide a localized solution for heavy metal removal, particularly in areas with limited infrastructure. Overall, microalgae offer a sustainable and effective approach for heavy metal remediation from wastewater.Microalgae-mediated biosorption is a promising approach for the effective removal of heavy metals from wastewater. This review highlights the potential of microalgae in addressing heavy metal pollution, emphasizing their ability to remove contaminants from diverse wastewater sources. Microalgae offer advantages such as energy efficiency, cost-effectiveness, nutrient recycling, minimal sludge formation, and greenhouse gas reduction. They are particularly effective in treating industrial, agronomic, and mining discharges, demonstrating versatility and efficiency in wastewater purification. The review also explores the synthesis of biochar from microalgae for wastewater treatment, addressing gaps in previous research and considering innovative applications like biochar generation. Biochar provides efficient adsorption and environmental sustainability. The review delves into the properties, operational strategies, and applications of microalgae-based treatment in heavy metal remediation from wastewater. Microalgae are diverse photosynthetic organisms with high biomass productivity and carbon fixation rates. They are classified into prokaryotic cyanobacteria and eukaryotic protists, thriving in various aquatic environments. Their ability to harness solar radiation for photosynthesis and their ecological significance make them valuable for bioremediation. Cultivation techniques include photobioreactors and open ponds, with factors such as light intensity, temperature, pH, and nutrient availability influencing growth. Strain selection is crucial for maximizing biomass productivity and quality, with species like Chlorella vulgaris and Spirulina platensis being particularly effective. Biosorption is a key mechanism for heavy metal removal, involving the passive, non-metabolic interaction between contaminants and cell surfaces. Microalgae's cell walls, rich in polysaccharides and functional groups, facilitate the adsorption of heavy metal ions. Bioaccumulation, a metabolic process, involves the active transport of metal ions into living cells, with intracellular binding proteins like metallothioneins and phytochelatins playing a crucial role. Microalgae-based biosorption is cost-effective, efficient, and environmentally friendly, offering a viable alternative to conventional methods. The review also discusses the application of microalgae in decentralized water treatment systems, where they provide a localized solution for heavy metal removal, particularly in areas with limited infrastructure. Overall, microalgae offer a sustainable and effective approach for heavy metal remediation from wastewater.