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.

废水的回收和再循环至关重要，因为世界各地都需要大量的水。废水中存在重金属，例如铁（Fe），钼（Mo），锰（Mn），锌（Zn），镍（Ni），铜（Cu），钒（V），钴（Co），钨（ W），铬（Cr），砷（As），银（Ag），锑（Sb），镉（Cd），汞（Hg），铅（Pd），铀（U）等是严重的环境问题，人类和动物健康的风险。吸附剂是处理废水中的污染物和重金属的简单且低成本的方法。该吸附剂能够处理由不同废物（例如家庭，农业，工业，动物和海洋废物等）制备的废水。近年来，新型纳米材料也被用作吸附剂，以提高废水的处理效率。吸附是一种传质现象，它基于浓度梯度使元素从流体旋转到固相。详细讨论了有助于从废水中分离出污染物的机理以及控制吸附效率的因素。