Review on the Combined Effect of Cold Plasma Treatment Technology and Cyanobacteria in Heavy Metal Removal such as Zinc, Calcium, and Magnesium

The presence of heavy metal ions dissolved in tap water poses serious problems for human health. With the rapid growth of the world's population, the need to improve current technology for water purification and in order to provide safe drinking water is constantly increasing. Compared to various conventional heavy metal removal methods, cyanobacteria-mediated heavy metal removal is a more advantageous method, because of the cost-effective, on-site, and green chemistry approach. Cyanobacteria are a very suitable tool for the sequestration of metals because they can simultaneously divide the metal through biosorption and bioaccumulation. Bioabsorption is a cell surface occurrence, while bioaccumulation occurs inside the cell. In addition, the use of plasma technology as a driving force increases the percentage of metal removal in different periods. To write this article, a detailed search was carried out from the authors' experiences and articles and the latest articles available in PubMed, Web of Science, Google Scholar, ScienceDirect, Scopus, Medline, and Scientific Information Database databases. A review of the available articles showed that although there are many studies on the use of cyanobacteria in the removal of heavy metals, their combined use with plasma technology in biological treatment has been less studied. As a result, the purpose of this article is to review the separation of cyanobacteria in heavy metal ions from wastewater and the defense mechanism of cyanobacteria against metal-induced toxicity. In addition, we attempt to compare the ability of different species of cyanobacteria to separate heavy metals from water under different environmental conditions by producing exopolysaccharides and biosynthetic pathways. The results of this study can provide a complete picture of the identification and implementation of an applied bioremediation technique on an industrial scale that is cost-effective and environmentally sustainable.