Preparation of cationic surfactant-modified kaolin for enhanced adsorption of hexavalent chromium from aqueous solution

Abstract

In the current work, we have reported a cationic surfactant-modified Ethiopian kaolin for improved adsorption of Cr(VI) from aqueous solution. The raw kaolin was modified by treating with CTAB to enhance the adsorption properties. The crystal structure and vibrational analysis of CTAB-kaolin were investigated by Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction (p-XRD) techniques. The successful modification of kaolin by CTAB through intercalation and coating was investigated by XRD and FTIR. p-XRD confirms the raw kaolin obtained from Belesa, Tigo kebele is kaolinite mineral. The study has also focused on the application of kaolin-CTAB for adsorption of hexavalent chromium. The percent removal of Cr(VI) was investigated at different parameters such as pH, contact time, concentration of Cr(VI) and adsorbent dosage. CTAB-kaolin shows 99% removal of Cr(VI) at the adsorption equilibrium (time = 180 min, 100 mg CTAB-kaolin, 10 ppm/100 ml). The Langmuir and Freundlich isotherm models were used to investigate the adsorption process of chromium onto kaolin-CTAB composites. The equilibrium data obeyed Langmuir model than Freundlich, which shows that the adsorption process proceeds through monolayer adsorption and maximum adsorption capacity was found to be Q o = 22.72 mg/g. The pseudo-second-order kinetics model is found to be well fitted than Pseudo-first-order kinetics, which implies that the adsorption mechanism more favors electrostatic interaction between chromium and kaolin-CTAB composites. In conclusion, CTAB-kaolin was found to be a promising adsorbent for the efficient removal of Cr(VI) from the aqueous solution.

Functionalized MWCNTs-quartzite nanocomposite coated with Dacryodes edulis stem bark extract for the attenuation of hexavalent chromium

“…This study was examined over a concentration range of 10–100 mg g −1 with a fixed adsorbent dose of 0.25 g. As shown in Fig. 11 , the result revealed that the uptake capacities of PQ and Q increased from 2.5 to 24.3 mg g −1 and 5.1 to 44.0 mg g −1 respectively as the initial Cr(VI) concentration increased from 10 to 100 mg dm −3 at 298 K. It indicated that the adsorptive removal of Cr(VI) onto PQ and Q was strappingly dependent on the initial hexavalent chromium concentration 68 . The phenomenon could be associated with enhanced collisions frequency between the Cr(VI) ions and the adsorption sites on the surface PQ and Q, resulting in higher surface coverage at high initial Cr(VI) concentrations, and thus high uptake capacities.…”

Hydrothermal green synthesis of MoS2 nanosheets for pollution abatement and antifungal applications

“…The spectrum of MoS 2 NSs shows the broad bands between 3748 and 3400 cm −1 attribute to the characteristics of O–H stretching of the intermolecular and intramolecular hydrogen bonds. 44,45 The characteristic vibrational bands at 3300–2800 cm −1 and 1488 cm −1 can be assigned to the stretching of the C–H alkyl stretching band in l -cysteine. 46 Thus, the FTIR results further affirmed the presence of residual amino acid on the surface of MoS 2 .…”

“…The spectrum of MoS 2 NSs shows the broad bands between 3748 and 3400 cm À1 attribute to the characteristics of O-H stretching of the intermolecular and intramolecular hydrogen bonds. 44,45 The characteristic vibrational Fig. 2 The UV-Vis absorption spectrum of MoS 2 NSs.…”

RSM-BBD Optimization of Fenton-Like Degradation of 4-Nitrophenol Using Magnetite Impregnated Kaolin

“…Kaolin was activated by H 2 SO 4 based on a protocol reported in previous work. 34,35 Particularly, the raw kaolin sample was purified by washing with distilled water 3 times followed by drying in an oven at 105°C for 3 hours. The dried sample was crushed to obtain a fine powder that was able to pass through a 63-μm mesh size sieve.…”