Efficient adsorption of tartrazine from an aqueous solution using a low-cost orange peel powder

Orange peel powder was activated using different methods and was used to remove tartrazine (E102) from an aqueous solution. The following three adsorbents were synthethized: orange peel powder activated thermally (POAT), orange peel powder activated with sulfuric acid (POAA), orange peel powder activated with soda (POAS). These adsorbents were then characterized by Fourier Transform Infra-Red Spectrometry (FTIR), Raman spectroscopy, powder X-Ray Diffraction (XRD), and point-of-zero charge. The experimental parameters such as contact time, dose of adsorbent, initial concentration of tartrazine, pH, and temperature were studied. The adsorption capacities of tartrazine for the optimal POAT, POAA, and POAS were found to be 121.74, 122.25, and 116.35 mg/g, respectively. The experimental data were analyzed by Freundlich and Temkin isotherm models, as well as the pseudo-second-order kinetic model.