Nano-adsorbents for Wastewater Treatment: A Review

The concern over increasing awareness for development of systems to improve water quality for effluents from wastewater treatment and industrial facilities has provided incentives to develop new technologies and improve performance, of existing technologies. Various methods exist fir the removal of toxic metal ions from aqueous solutions, but adsorption is by far the most versatile and widely used process. In recent years, a great deal of attentions has been focused onto the application of nanostructured materials as adsorbents or catalysts to remove toxic and harmful substances from wastewater and air. This study mainly focused on those nano-adsorbents which are used for wastewater treatment. The nano adsorbents which were studied are classified into two classes namely carbon derived (in form of tubes, wires and particles) and non carbon derived (metals, metal oxides, etc.) nano-adsorbents. A detailed study on each nano-adsorbent is done through studying their synthesis, characterization, adsorption characteristics and their uses and application in the real world. The synthesis of nano-adsorbents was studied using different methods such as arc discharge method, laser ablation and chemical vapour deposition. The characterization of nano-adsorbents was carried out using Raman spectroscopy. The experimental characteristics of adsorption at different pH, temperature are studied and their results are discussed. The applications of nunomaterials may yield benefits to the environment through the development of new technologies and the widespread uses of nanomaterials will also likely result in their introduction to our environment. It is therefore critical that the researchers in the area of nanotechnology should address important aspects related to the development of nano-materials. The present study also deals with the future developments of nano-materials and challenges in this field of environmental engineering.