Developing a Framework for Optimal Performance of Activated Carbon/ Graphene Oxide/Activated Carbon-Graphene Oxide Nano Adsorbent for the Removal of Antibiotics from Wastewater

Abstract

Antibiotics are important drugs for treating infectious diseases and they have undoubtedly saved the lives of millions of people. A growing global problem is the emergence of antibiotic resistance, which means that the antibiotic does not work on the bacteria that cause the disease. Likely, many of the resistance genes we find in pathogenic bacteria today have their origin in the environment where, for example, they may have been part of the bacteria's defence mechanism. Adsorption is a physiochemical method widely used in wastewater treatment, is a fast, competent, and economical technology. Nowadays, a carbon-based material, graphene-based material has been extensively utilized because of its properties like high surface area, porosity, and reaction rate. This study emphases the removal of major antibiotics, namely Tetracycline and Doxycycline from wastewater. To achieve the objective of this study, nano adsorbent like activated carbon (AC), graphene oxide (GO) and composite nano adsorbent AC-GO (Activated carbon -graphene oxide) had been synthesized, characterized, and utilized for studies of adsorption equilibrium and kinetics for the elimination of antibiotics. Langmuir isotherm model was the best fit for equilibrium data obtained for Tetracycline and Doxycycline. For kinetic adsorption, pseudo-second-order was fitting best with experimental data. Physical and chemical adsorption plays a vital role in adsorption onto nano adsorbent AC, GO, and AC-GO. The adsorption of Tetracycline and Doxycycline on nano adsorbent was owing not only to the larger surface area but also due to -EDA (electron donor-acceptor interactions), hydrogen bonding, and electrostatic attraction-repulsion theory. After 3 regeneration cycles, the AC GO still demonstrated a high adsorption capacity and reusability