Biosorption and bioremediation of heavy metal ions from wastewater using algae: A comprehensive review

Algal-based bioremediation has emerged as a promising, environmentally sustainable, and economically feasible method for the removal of heavy metal ions from contaminated wastewater. This review offers a comprehensive examination of the potential of both microalgae and macroalgae in biosorption and bioremediation processes. It investigates the physicochemical mechanisms involved, including surface adsorption, ion exchange, complexation, bioaccumulation, bioprecipitation, and enzymatic reduction. The efficiency of metal removal is influenced by various factors such as algal species, metal type, pH, and temperature. Case studies underscore the successful application of algae in removing metals such as lead, cadmium, arsenic, and chromium. The advantages of using algae include high metal-binding capacity, rapid growth rates, biomass regeneration potential, and minimal sludge generation. However, challenges persist in biomass harvesting, reusability, and scaling up for real-world applications. Future advancements may focus on the genetic engineering of algal strains and integration with other treatment technologies to enhance performance and feasibility in industrial settings.