TITLE:
Adsorption of Chromium (VI) Using Nano-ZnO Doped Scrap Tire-Derived Activated Carbon
AUTHORS:
Jean Tsitsi Chigova, Stanford Mudono
KEYWORDS:
Adsorption, Zinc Oxide Nanoparticles, Tire Granules, Hexavalent Chromium, Tannery Effluent
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.10 No.9,
September
27,
2022
ABSTRACT: Nowadays, nano mineral modified biochars show a
promising adsorption capacity for
pollutants removals by combining the advantages of porous structure of biochar and unique property of nano minerals. In this work, nano-zinc oxide doped scrap
tire derived activated carbon (nZnO-STAC) was synthesized 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,
intraparticle diffusion and Elovich kinetic models. Characterization of the
activated 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 dosage, contact time and adsorbent particle size
on the Cr (VI) removal efficiency. The results showed optimum Cr (VI) removal at pH 3, 10 mg/L concentration, 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 predominantly 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 R2 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 chromium (VI) polluted
industrial wastewaters.