Journal of Geoscience and Environment Protection, 2022, 10, 121-135 https://www.scirp.org/journal/gep ISSN Online: 2327-4344 ISSN Print: 2327-4336 DOI: 10.4236/gep.2022.109008 Sep. 27, 2022 121 Journal of Geoscience and Environment Protection Adsorption of Chromium (VI) Using Nano-ZnO Doped Scrap Tire-Derived Activated Carbon Jean Tsitsi Chigova, Stanford Mudono Department of Chemical Engineering, Faculty of Engineering, National University of Science and Technology (NUST), Bulawayo, Zimbabwe Abstract Nowadays, nano mineral modified biochars show a promising adsorption capacity for pollutants removals by combining the advantages of porous struc- ture of biochar and unique property of nano minerals. In this work, nano- zinc oxide doped scrap tire derived activated carbon (nZnO-STAC) was syn- thesized by wetness impregnation method. Equilibrium data were analyzed using Langmuir and Freundlich isotherm models while the kinetics of the process were examined using Lagergren Pseudo-first and second order, intra- particle diffusion and Elovich kinetic models. Characterization of the acti- vated carbon by Powder X-ray Diffraction (PXRD). The surface groups present on the activated carbon surface were determined using the Fourier Transform Infra-Red Spectroscopy (FTIR) analysis. Optimization studies were carried out to determine the effects of pH, initial metal concentration, adsorbent do- sage, contact time and adsorbent particle size on the Cr (VI) removal effi- ciency. The results showed optimum Cr (VI) removal at pH 3, 10 mg/L con- centration, 120 minutes of contact using 1000 - 1400 µm adsorbent particle size at a dosage of 2.5 g/L. The adsorbent structure was found to be predomi- nantly amorphous. The chromium removal efficiency of the adsorbent was around 81.6%. Of the tested kinetic models, the pseudo-second order model exhibited the best fit with the experimental data with an R 2 value of 0.9744. This study clearly demonstrates the feasibility of using the nano-ZnO doped scrap tyre derived activated carbon adsorbent for the remediation of chro- mium (VI) polluted industrial wastewaters. Keywords Adsorption, Zinc Oxide Nanoparticles, Tire Granules, Hexavalent Chromium, Tannery Effluent How to cite this paper: Chigova, J. T., & Mudono, S. (2022). Adsorption of Chro- mium (VI) Using Nano-ZnO Doped Scrap Tire-Derived Activated Carbon. Journal of Geoscience and Environment Protection, 10, 121-135. https://doi.org/10.4236/gep.2022.109008 Received: June 13, 2022 Accepted: September 24, 2022 Published: September 27, 2022 Copyright © 2022 by author(s) and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution-NonCommercial International License (CC BY-NC 4.0). http://creativecommons.org/licenses/by-nc/4.0/ Open Access