Kinetics and Thermodynamics of β-Carotene Adsorption onto Acid-Activated Clays Modified by Zero Valent Iron

Abstract

The adsorption of β-carotene from crude palm oil onto acid-activated clay and clay modified by zero valent iron (ZVI) was investigated in this work. Spectroscopic studies including FTIR, XRD, and SEM were used for its characterization. The adsorption characteristics such as kinetics, mechanism, isotherms, and thermodynamics of β-carotene were studied. The kinetic data were analyzed using the pseudo-first-order kinetic equation, pseudo-second-order kinetic equation, and intraparticle diffusion model. The pseudo-second-order kinetic model is the only one that describes the experimental data well (R2 ≥ 0.969). The chemical analysis of bulk clay showed that the predominant oxides are Al2O3 (57.91 wt%), Fe2O3 (32.54 wt%), SiO2 (3.09 wt%), K2O (2.37 wt%), and CaO2 (1.73 wt%). The adsorption capacity increases with an increase in temperature. The equilibrium data were described better by the Freundlich model for all clays. To determine the best fit kinetic model for each system, three error analysis methods, namely, chi-square (χ2), residual mean squared error (RMSE), and mean percent error (%APE) were used to evaluate the data. A thermodynamic study demonstrated that β-carotene adsorption is spontaneous, endothermic, and an entropy driven process for both forms of clay.

Physico-Chemical Study of the Adsorption of Carotenoids from Carrots on Raw and Modified Kaolinites

“…The analysis of the adsorbents showed that these materials are heterogeneous. We can however admit a homogeneous distribution of the adsorption sites, as justification for the conformity of the experimental results with the Langmuir model, similar observation was done by [37].…”

“…Among the different models developed to describe the kinetics of adsorption in solution, three are used in most work. These are the pseudo first order models, the pseudo second order model, and the intraparticle diffusion model [37]- [42]. These three models were therefore used here to model the kinetics of carotene adsorption by raw or modified kaolinites.…”

Mathematical Modelling using Full Factorial Design in Response Surface Methodology Applied in the Adsorptive Removal of Dye Basic Blue 9 From Synthetic Aqueous Solutions Onto Oryza Sativa Husk-derived Nano-silica Doped Smectic Clay

“…The kinetics and equilibrium modeling and calculations are done using models and techniques commonly described such as Langmuir, Freundlich, and Redlich-Paterson for isotherms models and pseudo-first-order, pseudo-second-order and Weber Morris or intra-particle diffusion for kinetic models [15,[24][25][26][27][28][29].…”

Theoretical and Experimental Study of the Adsorption of Natural Red 4 Dye from Synthetic Aqueous Media Using a Low-cost Silica-smectite Composite

“…In order to elucidate the mechanism of adsorption of NR4 onto SSC, the experimental data have been compared to the theoretical models of pseudo-first order, pseudo-second order, and intraparticle diffusion which are commonly used in the adsorption of dyes [27][28][29][30][31]…”