Biosorption of Heavy Metals by Algae: Recent Advances, Mechanisms, and Applications in Wastewater Treatment-A review

The global concern surrounding heavy metal contamination has intensified due to their elevated toxicities, non-biodegradable nature, the propensity to bioaccumulate within the human body and food chain, and their potential to induce cancer in humans. Various remediation techniques have been employed to isolate hazardous materials (HMs), with a focus on traditional methodologies. However, these methodologies often prove cost-prohibitive for large-scale projects, requiring meticulous oversight and continuous supervision. Additionally, their low efficiency compromises their effectiveness in removing hazardous materials. Multiple studies have provided compelling evidence supporting the potential of biosorption as a highly effective technique for eliminating heavy metals from aqueous solutions. Algae, due to their widespread presence in both seawater and freshwater environments, cost-effectiveness, reusability, and efficient metal sorption capabilities, are considered valuable biosorbents. This review presents a comprehensive analysis of recent research findings on various algae types' performance, applications, and chemistry for removing heavy metals from wastewater. The intricate mechanisms involved in the bioaccumulation and detoxification of heavy metals in algae are explored in this article. This review discussed the impact of various parameters, such as pH, temperature, initial metal concentration, biomass loading, and contact time, on the observed outcomes. Also, this article delves into the chemistry of metal biosorption by algal species, which possess numerous metal binding groups on their cell surfaces, including carboxylate, amine, imidazole, phosphate, sulfhydryl, sulfate, and hydroxyl groups. Algae, abundantly present in both marine and freshwater environments, have emerged as fundamental components in the recently developed metal biosorption process. This process has proven highly effective for detoxifying industrial effluents containing metals, showcasing its competitiveness in this domain.