Development and characterization of MWCNTs from activated carbon as adsorbent for metronidazole and levofloxacin sorption from pharmaceutical wastewater: Kinetics, isotherms and thermodynamic studies

Abstract

Population growth coupled with wide spread of illness in both man and other animals have extensively increased the production and use of pharmaceutical products with various antibiotics discharged into the surrounding ecosystem. Such antibiotics when consumed by man and other living organisms cause serious health issues and therefore, there is need for urgent attention to treat such wastewater before been discharged. The application of synthesized multi-walled carbon nanotubes, MWCNTs as a novel adsorbent for the removal of metronidazole and levofloxacin in a batch adsorption process was investigated. Nickel-ferrites dope Activated carbon was produced via impregnation process and applied for the synthesis of MWCNTs in a CVD reactor. The produced nickel-ferrites doped activated carbon was characterized for thermal stability, surface area and surface morphology using TGA, BET and SEM respectively. The TGA result indicates high thermal stability of the catalyst with peak degradation temperature of 360.21 °C and slate-like nature morphology. The Brunette-Emmett-Teller result shows the surface area of pure activated carbon and Fe-Ni supported on activated carbon to be 840.38 and 650.45 m2/g respectively. The surface morphology of the produced carbon nanotubes depicts the presence of long-strand tubes of carbon nanotubes. The results of the adsorption process revealed that the adsorption parameters were fitted to the pseudo-second order model. The kinetics model of the adsorption of metronidazole and levofloxacin on the de adsorbent is fitted to pseudo-first order kinetic while Freundlich isotherm described the sorption of metronidazole and levofloxacin with a strong bonding between the molecules of the sorbate and the surfaces of the adsorbent. The results of the study indicate the possible development of low-cost and high purity MWCNTs adsorbent for the sorption of metronidazole and levofloxacin from pharmaceutical wastewater using activated carbon derived from wood sawdust.