A comprehensive review on the removal of antibiotics from water and wastewater using carbon nanotubes: synthesis, performance, and future challenges

Abstract

Recently, various emerging pollutants have been detected in water and wastewater, among which antibiotics can be considered a real threat to human life and environment because of their unique properties (bio-accumulation, bio-magnification, resistance, and bio-transformation). Therefore, it is urgent to apply methods for the detection and removal of these pollutants. Given that antibiotics cannot be completely removed by conventional methods, developing alternative methods to enhance their removal efficiency should be the focus of researchers. Over the past decades, carbon nanotubes (CNTs) have gained considerable attention owing to their remarkable merits (high surface area, low density and high thermal conductivity). However, despite the numerous advantages of CNTs, they suffer from some limitations, which can be solved by surface modification. Hence, this comprehensive review aims to help readers to improve their fundamental knowledge regarding the main characteristics of common antibiotics and their environmental and health effects, their fate in the environment, common methods for their removal, physicochemical methods for the modification of CNTs, identifying the effects of various parameters (pH, dosage, initial concentration, and time) on the removal process, and the reusability and major mechanism for the adsorption of antibiotics by CNTs. Finally, we summarize the isotherm and kinetic models for the removal of antibiotics. Our results exhibit that all the data fitted the Langmuir isotherm model, which reveals that the adsorption process on modified-CNTs is homogenous and monolayer. Furthermore, herein, the adsorption kinetics is well described by the pseudo-second-order model. Overall, this review provides useful insight for young researchers to understand the adsorption of antibiotics and achieve the future goal of using CNTs as promising adsorbents.