Surface Modification of Carbon Nanotubes-Based (CNTs) Nano Adsorbent for Removing Dyes from Aqueous Media

Due to the rapid growth of industries, and population the water shortage has become a global problem. The most hazardous organic contaminants found in textile wastewater are dyes. There are several techniques for removing dyes from wastewater, but the majority of them are costly and time-consuming. The most practiced technique for removing dyes is adsorption. Carbon nanotubes (CNTs) are employed extensively in the water treatment industry because of their superior mechanical strength, high aspect ratio, toughness, and defined cylindrical hollow structure. The hydrophobic wall and cost of CNTs restrict their usage on a commercial scale, however, this problem has been partially alleviated by altering their surfaces or doping with other metal oxides. The effect of surface alteration, on the adsorption potential, characterization, and removal effectiveness of CNTs are discussed in detail. The market value and overall demand for CNTs are thoroughly explored. The process variables influencing the sorption mechanism and removal efficiencies such as adsorbent dose, pH, contact time, and temperature are discussed in detail. The economic viability of CNTs is checked by the desorption and reusability of adsorbents. The literature supports the claim that surface modification significantly increased adsorption capacity and removal efficiency. However, more research should be needed to explore non-toxic modifiers for improved surface activation.