Treated Kaolin Clay Incorporated with Nickel Nanoparticles for Enhanced Removal of Crystal Violet and Methyl Orange from Textile Wastewater

Abstract

In this study, a novel biobased treated kaolin clay incorporated with zerovalent nickel (TKC-Ni 0 NPs) was fabricated and employed as an efficient functionalized adsorbent for the elimination of crystal violet (CV) and methyl orange (MO) from textile wastewater. The adsorption capacity of TKC-Ni 0 NPs was improved by incorporating the functional moieties of nickel nanoparticles on the treated kaolin clay structure using the experimental data from the kinetics, isotherm, thermodynamics, and reusability study. The crystalline structures, functional groups, and morphological characteristics of TKC, Ni 0 NPs, and TKC-Ni 0 NPs were analyzed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and high-resolution scanning electron microscopy (HRSEM). The point of zero charge pH on the surface of the TKC-Ni 0 NPs was evaluated as 4.5. The adsorptive removal of CV and MO was explored at solution pH, contact time, adsorbent dosage, initial CV/MO concentration, and temperature. Maximum adsorption capacities of 802.56 and 812.28 mg/g were reported for both CV and MO using TKC-Ni 0 NPs at the optimal solution pH of 6 for CV and 4 for MO, contact time of 60 min, adsorbent dosage of 25 mg/L, initial CV/MO concentration of 100 mg/L, and temperature of 313 K. Remarkably, TKC-Ni 0 NPs exhibited favorable behavior for the adsorption of MO and CV in the presence of both cationic and anionic coexisting ions. The reusability study showed over 92.00 and 94.00% effectiveness for CV and MO even after 10 cycles, respectively, which holds great promise for industrial use. A pseudo-second-order kinetic model effectively suited the adsorption kinetics, implying that the adsorption process is chemisorption controlled. Among the explored isotherm models, the Langmuir isotherm model exhibited the best fit for the experimental data. Thermodynamic analysis indicated that the adsorption is endothermic and spontaneous on the adsorbent surface. Consequently, a cost-effective, versatile, and stable biobased composite with significant potential for industrial wastewater treatment was successfully developed.