Kinetics and equilibrium modeling of lead(II) and chromium(III) ions'' adsorption onto clay from Kono-bowe, Nigeria

Abstract

Abstract:Clay from Kono-bowe, Nigeria, was activated thermally and chemically and used to remove lead(II) and chromium(III) ions from aqueous solution. The effects of adsorption process variables were studied as well as the kinetics and equilibrium of the process. Analysis of the activated samples showed that the surface area, cation exchange capacity, and adsorption performance were positively favored by both activation processes. It was observed that the adsorption rate increased with an increase in temperature, contact time, adsorbent dosage, initial ion concentration, and solution pH values. The pH P ZC of the adsorbents was determined to be 6.5, 7.4, and 7.2, for KBR, KBTA, and KBAA, respectively.It was observed that sample KBAA yielded maximum adsorption efficiency of 99.9% for the removal of chromium(III), and gave maximum adsorption efficiency of 98.7% for lead(II) removal. The results of the kinetics analysis of the adsorption data revealed that adsorption follows pseudo-second-order kinetics. Analysis of the equilibrium data showed that the Langmuir isotherm provided a better fit to the experimental data for KBR, while the Freundlich isotherm fitted the experimental data of KBTA and KBAA. Evaluation of the thermodynamic parameters revealed that the adsorption process is spontaneous and endothermic.

Chemically Modified CaO/Fe3O4 Nanocomposite by Sodium Dodecyl Sulfate for Cr(III) Removal from Water

“…where C i and C 0 are the initial and equilibrium concentrations of Cr(III), respectively. V is the volume of the solution, M is the mass of adsorbent, R is the adsorption percentage of Cr(III), and q e is adsorption capacity [22,23]. average pore width of 135.745 Å, and total pore volume of 0.123 cm 3 g -1 .…”

“…where D is the average crystal size in the same unit as that of l (Å or nm), l is the wavelength of X-ray radiation 1.54056 Å (0.154056 nm), K is the shape factor (here assumed as 0.90), b is the full width at half maximum (FWHM; in radians), and q is the diffraction angle [23].…”

“…The two peaks observed at 590.14 and 630.63 cm -1 were attributed to Fe-O bond stretching vibrations, indicating the magnetic nature of the CaO/Fe 3 O 4 /SDS nanocomposite. Moreover, the two peaks observed at 1072.28 and 1249.70 cm -1 were related to the O-C-O functional group and stretching adsorption of S=O on SDS; both of the peaks overlap within this region[23,24].Additionally, BET analysis showed an adsorbent specific surface area of 36.47 m 2 g -1 , average pore diameter of 141.551 Å,Chem. Eng.…”

Leaching of Potentially Toxic Metals (PTMs) from Two Nigerian Clays and Related Clay Pottery Used Locally as Foodwares

“…The results from this study indicate that Cd, Cr, Cu and Pb were not in leachable forms in the Ara-Ekiti and Kono-Boue Clay Pots and the poor leachability of certain metals from foodwares has previously been reported by Anderson and Aderemi [13,14]. The non leachability of Cd, Cr, Cu, and Pb from the clays even at increased temperatures and pH conditions has previously been highlighted in adsorptions employing the Kono-Boue Clays for removal of Cr and Pb from water by Ajemba [15].…”

Sorption mechanisms of Chromium(III), Copper(II) and Lead(II) on two natural mixed clays from Burkina Faso as determined by extended X-ray absorption fine structure (EXAFS) spectroscopy

“…Cr 3+ was found to: coordinate with phosphate ions and substitute calcium ions on bone char surfaces in aqueous solution (Jose et al, 2016); be physically adsorbed on the surface of chorfa silt material (Ouadjenia-Marouf et al, 2013); be uptake on micaceous polymineral from Kenya (Attahirua et al, 2012); be adsorbed following pseudo-second-order kinetics on natural clay from Kono-Bowe in Nigeria (Ajemba, 2014). Pb 2+ was adsorbed as an acetylacetonate complex by hydrophobic interaction on mesoporous silicate surface (Oshima et al, 2005) and with electrochemical ionexchange between Pb 2+ and clays surfaces (smectite and kaolin), and complexation reaction (Etoh et al, 2016).…”