The High Efficiency of Anionic Dye Removal Using Ce-Al13/Pillared Clay from Darbandikhan Natural Clay

Abstract

Natural clay from Darbandikhan (DC) was evaluated in its natural form, after acid activation (ADC), and after pillaring (PILDC) as a potential adsorbent for the adsorption of methyl orange (MO) as a model anionic dye adsorbate. The effect of different clay treatments was investigated using X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Scanning Electron Microscope (SEM) and Fourier-Transform Infrared Spectroscopy (FT-IR), and N2 physisorption analysis. Both acid activation and pillaring resulted in a significant increase in adsorption affinity, respectively. The adsorption favored acidic pH for the anionic dye (MO). The adsorption process was found to follow pseudo-second-order kinetics with activation energies of 5.9 and 40.1 kJ·mol−1 for the adsorption of MO on ADC and PILDC, respectively, which are characteristic of physical adsorption. The adsorption isotherms (Langmuir, Redlich-Peterson and Freundlich) were fitted well to the experimental data. The specific surface area of the natural clay was very low (22.4 m2·g−1) compared to high-class adsorbent materials. This value was increased to 53.2 m2·g−1 by the pillaring process. Nevertheless, because of its local availability, the activated materials may be useful for the cleaning of local industrial wastewaters.

A novel functionalized chitosan nanoadsorbent for efficient elimination of malachite green from aqueous media

“…At pH = 8, about 80% of the dye was removed at 5 min with 3 mg of the adsorbent. As the MNCTS dose was increased, the MG removal percentage enhanced because of the increase in the total number of the adsorption sites 27 …”

“…As can be observed in Figure 11, the MG removal percentage raised steadily with increasing temperature, reaching the highest removal rate at 45°C and then reached to equilibrium. The increase in the dye removal efficiency is because of the increase in the rate of MG molecules diffusion from the bulk solution to the MNCTS surface at higher temperatures 27 . In addition, the increase in the mobility of the MG molecules can generate enough energy to interact with the active sites at the adsorbent surface 51 .…”

“…As the MNCTS dose was increased, the MG removal percentage enhanced because of the increase in the total number of the adsorption sites. 27 The influence of initial MG concentration on the removal efficiency and adsorption capacity of the synthesized nanoadsorbent was As can be seen in Figure 8, when the adsorbent content is kept constant, the percentage of the dye absorbed on the adsorbent decreases with increase in the MG concentration, which is due to the saturation of the adsorbent. In addition, as the MG initial concentration increased, the adsorption capacity of the MNCTS increased.…”

“…The increase in the dye removal efficiency is because of the increase in the rate of MG molecules diffusion from the bulk solution to the MNCTS surface at higher temperatures. 27 In addition, the increase in the mobility of the MG molecules can generate enough energy to interact with the active sites at the adsorbent surface. 51 Although some authors have reported that adsorption on CTS is exothermic, 35,52 the results of this study show that adsorption of the MG on the nanochitosan modified by triazinetrione is an endothermic process.…”

“…Some chemical methods for modification of chitosan include cross-linking, impregnation, and grafting. 27 Chemical cross-linking of the chitosan has been found to enhance its mechanical strength, stability, and resistance against acid, alkali, and chemicals. 28 The aim of this work was to modify the chitosan molecule and create an efficient chitosan-based adsorbent for the removal of MG from aqueous media.…”