Application in chromium (VI) removal of natural and dried cactus

This research presents two type of cactus (Opuntia ficus-indica) (natural cactus (NC) and dried cactus (DC)) as a biological adsorbent, evaluated for the effectiveness of hexavalent chromium Cr(VI) removal from artificially contaminated aqueous solutions. The characterization of the biosorbents were made using different techniques such as X-ray Fluorescence (XRF), Fourier transform infrared (FTIR) and Scanning Electron Microscope (SEM) to better understand the adsorption mechanism-property relationship. Adsorption kinetics showed that the adsorption behavior followed the pseudo-second-order kinetic model. The adsorption isotherms fitted by the Langmuir model showed that the highest Cr(VI) adsorption capacities using natural cactus and dried cactus are 21.19 and 2.63 mg/g respectively. Additionally, various physiochemical parameters such as contact time, adsorbent dosage, pH and temperature were investigated in a batch-adsorption technique. The results illustrated that the cactus have significant potential as economic, safe and effective adsorbent materials for the Cr(VI) adsorption from the aqueous solution.