Phytoremediation using algae and macrophytes: I

Abstract

Heavy metals are the global environmental contaminants. Their toxicity of various heavy metals to living systems is well established. The most common treatment processes used include chemical precipitation, oxidation/reduction, ion exchange, reverse osmosis, and solvent extraction. Biological methods of metal removal employ various microbes or plant species and are cost-effective as compared to physicochemical methods. Biosorption has become known as a potential and cost-effective alternative for heavy metal exclusion from aqueous solution. Agricultural by-products have also offered a potential alternative as biosorbents for heavy metals among the existing techniques and are yet a subject of broad studies. Agricultural biosorbents including soybean hulls, peanut hulls, almond hulls, cottonseed hulls, and corncobs have also been proven to take out heavy metal ions. The inspiration of using plants for environmental remediation is very ancient and cannot be traced to any meticulous source. In the course of progressively mesmerizing scientific innovations, pooled with interdisciplinary explorations, phytoremediation is considered to be environmentally friendly technology. Various plant species have shown variable potential for metal uptake. As a plant-based technology, the success of phytoextraction is inherently dependent on several plant characteristics, the two most important being the ability to accumulate large quantities of biomass rapidly and the capacity to accumulate large quantities of environmentally important metals in the shoot tissue. The mechanism of metal uptake, translocation, role of rhizosphere in metal uptake, and possibility of using algae in phytoremediation were reviewed.