Abstract:In the present study, the adsorption behaviors of mordenite (a common zeolite) with respect to Cu 2+ and Ni 2+ from aqueous solutions were investigated. The sorption data followed the Freundlich and Langmuir isotherms. The maximum sorption capacities were found to be 9.778 and 5.371 mg/g at pH 6, initial concentration of 40 mg/L and temperature of 30 for Cu 2+ and Ni 2+ , respectively. The kinetic experimental data fitted the pseudo-second order equation very well and the values of rate constant of adsorption … Show more
“…This is in agreement with the findings of Al-Muhtaseb et al [14]. This maximum sorption capacity may be attributed to having a complete monolayer coverage [40]. As well, the affinity constant (b) values obtained herewith, which is related to adsorption energy, was comparable for both materials indicating that probably not all binding sites on the surface of CDP were available for Ni binding due to its relative hydration energy.…”
<p>The adsorption of nickel from liquid solutions onto carbonized date pits (CDP) and rice husks (CRH) has been investigated in the current study. The process was studied in a batch system with respect to the initial pH, contact time, temperature, adsorbent dose and nickel initial concentration. The results showed that the experimental data was well represented by first order model for CDP and second order model for CRH. Based on the kinetic modeling, the apparent activation energies calculated were 7.84 kJ and 18.502 kJ/mol for CDP and CRH, respectively. The results also indicated that process of nickel uptake by CDP and CRH was physical adsorption process. The equilibrium data for CDP indicated that it fitted both Freundlich and Langmuir models. However, adsorption onto CRH fitted Freundlich model better based upon the higher value of R<sup>2</sup> obtained. The thermodynamic parameters (ΔH°, ΔS° and ΔG°) calculated from the experimental data indicated that the process was endothermic and spontaneous.</p>
“…This is in agreement with the findings of Al-Muhtaseb et al [14]. This maximum sorption capacity may be attributed to having a complete monolayer coverage [40]. As well, the affinity constant (b) values obtained herewith, which is related to adsorption energy, was comparable for both materials indicating that probably not all binding sites on the surface of CDP were available for Ni binding due to its relative hydration energy.…”
<p>The adsorption of nickel from liquid solutions onto carbonized date pits (CDP) and rice husks (CRH) has been investigated in the current study. The process was studied in a batch system with respect to the initial pH, contact time, temperature, adsorbent dose and nickel initial concentration. The results showed that the experimental data was well represented by first order model for CDP and second order model for CRH. Based on the kinetic modeling, the apparent activation energies calculated were 7.84 kJ and 18.502 kJ/mol for CDP and CRH, respectively. The results also indicated that process of nickel uptake by CDP and CRH was physical adsorption process. The equilibrium data for CDP indicated that it fitted both Freundlich and Langmuir models. However, adsorption onto CRH fitted Freundlich model better based upon the higher value of R<sup>2</sup> obtained. The thermodynamic parameters (ΔH°, ΔS° and ΔG°) calculated from the experimental data indicated that the process was endothermic and spontaneous.</p>
“…The Langmuir isotherm, the monolayer model, was developed to represent chemisorption (Wang 2009). The Langmuir model is based on assumptions that the binding sites are homogeneously distributed over the adsorbent surface, no interaction between adsorbed molecules, and all the binding sites have the same affinity for adsorption of a single molecular layer.…”
Section: Equilibrium Adsorption Isotherms Of Monosolute Systemsmentioning
The present work reports the synergistic and inhibitory adsorption effects involved in the multicomponent adsorption of heavy metal ions (Cu(II), Ni(II), and Cd(II)) from binary systems using chemically olive stone activated carbon (COSAC) as adsorbent. In order to evaluate the adsorption capacity of COSAC to remove studied heavy metals, adsorption of metal ions in single and binary systems were conducted. Kinetics adsorption rates in binary systems are very fast as compared to that in single ones and well represented by the pseudo second-order. Langmuir and Sips model fit mono-solute adsorption isotherms and the maximum adsorption capacity of COSAC decreased in the following order: Cd(II) [ Ni(II) [ Cu(II). In binary equilibrium systems, the effect of initial concentration of interfering metal ions on the removal of target ones was studied. Different mutual interactions between metal ions dealing with the decrease and the enhancement of inhibitory and synergetic effects were detected. Results showed that the effects on the adsorption of the metal ions in binary mixture strongly depend on the initial concentration of both metal ions in the solution. In most of the scenarios studied, the total amount of metal ions adsorbed was higher than the sum of the ones obtained in single solutions, suggesting synergetic interactions between the two metal ions. This study proves that COSAC is an effective adsorbent for the removal of heavy metals from multicomponent solutions.
“…3). Overall, dachiardite, clinoptiloite, and mordenite can be considered major minerals involved in adsorption for heavy metal control 45–48 .Figure 2XRD peaks of the composite mineral adsorbents CMA1 and CMA2. Albite (Alb), Calcite (Cal), Dachiardite (Dac), Clinoptiloite (Cli), and Mordenite (Mor) have been identified.Figure 3SEM images of the composite mineral adsorbents CMA1 (left) and CMA2 (right).…”
This study evaluated the efficiency of the removal of heavy metals from contaminated water via adsorption isotherm and kinetic experiments on two composite mineral adsorbents, CMA1 and CMA2. The developed CMA1 (zeolite with clinoptilolite of over 20 weight percent and feldspar of ~10 percent, with Portland cement) and CMA2 (zeolite with feldspar of over 15 weight percent and ~9 percent clinoptilolite, with Portland cement) were applied to remove Cu, Cd, and Pb ions. Based on the adsorption isotherm and kinetic experiments, the adsorbents CMA1 and CMA2 exhibited high removal efficiency for Cu, Cd, and Pb ions in solution compared to other adsorbents. In the adsorption kinetic experiment, CMA2 demonstrated better adsorption than CMA1 with the same initial concentration and reaction time, and Cu, Cd, and Pb ions almost reached equilibrium within 180 min for both CMA1 and CMA2. The results of the adsorption kinetic experiments with pseudo-first-order (PFO) and pseudo-second-order (PSO) models indicated that the PSO model was more suitable than the PFO model. Comparing the Langmuir and Freundlich adsorption isotherm models, the former showed a very slightly higher correlation coefficient (r2) than the latter, indicating that the two models can both be applied to heavy metal solutions on a spherical monolayer surface with a weak heterogeneity of the surface. Additionally, the adsorbents CMA1 and CMA2 demonstrated different removal abilities depending on which heavy metals were used.
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