Heavy Metals Adsorption by Nanosheet: Mechanism and Effective Parameters

Nowadays, scientists are working on removing heavy metals from the environment. Among the methods for heavy metals removal such as precipitation, evaporation, electroplating and ion exchange, which have many disadvantages, adsorption is the cost effective and environmental friendly technique. Using nanosheets as the base materials for the adsorption because of their large surface area and high adsorption capacity is broadened. Carbon products (Graphene), boron nitride materials (BNM), transition metal dichalcogenides (TMDs), layered double hydroxiades (LDHs) and MXene are most well-known nanosheets, which have used for heavy metal ions removal from aqueous solutions. In this review, experimental and simulation studies on nanosheet adsorbents are presented to pinpoint the importance of this group of nano-materials on water/wastewater treatment technology. Molecular dynamics (MD) and density functional theory (DFT) are the most common simulation methods for demonstration of adsorption mechanism of nanosheets. In addition, synthesis methods, adsorption mechanism, adsorption performance, and effective parameters of nanosheets and novel techniques to improve the adsorption capability and regeneration of adsorbents are introducing. This study indicate that nanosheets can regenerate over a number of adsorption/desorption cycles. With all the advantages of nanosheets, it should be noted that their use in larger industrial scales should be further investigated.