Mohammad Mehdi Sadeghi - Department of Chemical Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran.

Water pollution is one of the important issues attracting researchers over the years. Heavy metals such as mercury, cobalt, lead, chromium and nickel are the main groups of pollutants in these waters that have harmful effects on health. Various methods have been used to remove various water contaminants. Conventional techniques for the disposal of heavy metal ions, include ion exchange, surface adsorption, membrane filtration, electrochemical methods, cloud point extraction, etc. In most of these methods, there are disadvantages such as the need for complex devices, lack of solvent, secondary wastewater, pre-filtering problems, time consumption, etc. that create limitations in using these methods. But there are new and alternative methods using nano-based strong adsorbent that have more benefits than conventional ones, as they provide more surfaces for absorptionthat enhance their ability to extract and improve performance. They are also economically low cost and easy to use. In this paper, an overview of the common and new methods for the removal of heavy ions from industrial wastewater, as well as their advantages and disadvantages is done and types of adsorbents are studied, focusing on the removal of heavy ions in the industrial wastewater by modified nano composite adsorbent.

Heavy metals, Waste water, Adsorbent, Nano composite.