Recovery and recycle of wastewater contaminated with heavy metals using adsorbents incorporated from waste resources and nanomaterials-A review

Recovery and recycle of wastewater are essential because of the need of huge quantities of water everywhere in this world. Presence of heavy metals in wastewater such as iron (Fe), molybdenum (Mo), manganese (Mn), zinc (Zn), nickel (Ni), copper (Cu), vanadium (V), cobalt (Co), tungsten (W), chromium (Cr), arsenic (As), silver (Ag), antimony (Sb), cadmium (Cd), mercury (Hg), lead (Pd), uranium (U), etc is the serious environmental issues and risk for human and animal health. Adsorbents are simple and low-cost methods to treat the pollutants and heavy metals of wastewater. The adsorbents are capable to treat the wastewater prepared from different wastes such as domestic, agricultural, industrial, animal and marine waste etc. In recent years, novel nanomaterials are also used as adsorbents which enhance the treatment efficiency of wastewater. Adsorption is a mass transfer phenomenon revolving shift of elements from a fluid to a solid phase based on the concentration gradient. The mechanism which helps in separation of contaminants from the effluent and the factors governing the efficiency of adsorption are discussed elaborately. (C) 2021 Elsevier Ltd. All rights reserved.