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Adsorption of silver, thorium and nickel ions from aqueous solution onto rice husk
(2021-10-01)
Zafar, Shagufta
;
Khan, Muhammad Imran
;
Shanableh, Abdallah
;
Ahmad, Saleem
;
Manzoor, Suryyia
In this article, adsorption of metal ions such as silver (Ag(I)), thorium (Th(IV)) and nickel (Ni(II)) from aqueous solution onto rice husk (RH) was performed at room temperature. Adsorption of these metal ions (silver, thorium, and nickel) onto RH was demonstrated by using Fourier trans-form infrared spectroscopy and energy-dispersive X-ray. Morphology of RH was investigated before and after adsorption of these metal ions onto it by using scanning electron microscopy. The effect of different operational parameters (contact time, initial concentration of metal ion solution, weight of RH, pH, and temperature) on the percentage removal of these metal ions was explored in detail and compared. Experimental data for adsorption of these metal ions onto RH was sub-jected to Langmuir and Freundlich isotherm models. Results showed that adsorption of silver and thorium fitted well to Langmuir isotherm model (R<sup>2</sup> > 0.99) whereas adsorption of Ni(II) fitted well to Freundlich isotherm model (R<sup>2</sup> > 0.99). Adsorption kinetics study demonstrated that adsorp-tion of these metal ions onto RH from aqueous solution fitted well to pseudo-second-order model. Adsorption thermodynamics investigation represented that adsorption of these metal ions onto RH was endothermic process. The values of Gibb’s free energy were –6.53 to –9.17 kJ/mol for Ag(I), –1.11 to –3.57 kJ/mol for Th(IV) and –0.89 to –1.40 kJ/mol for Ni(II). The negative values of Gibb’s free energy for these metal ions suggested that the adsorption process was spontaneous in nature. The regeneration of RH and recovery of these metal ions were also studied.
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Kinetic, equilibrium, and thermodynamic studies for adsorptive removal of cobalt ions by rice husk from aqueous solution
(2020-11-01)
Zafar, Shagufta
;
Khan, Muhammad Imran
;
Rehman, Hafeez Ur
;
Fernandez-Garcia, Javier
;
Shahida, Shabnam
Herein, batch adsorptive removal of cobalt ions (Co(II)) from aqueous solution was studied at room temperature. Adsorption of cobalt ions onto rice husk (RH) was confirmed by utilizing Fourier transform infrared, scanning electron microscopy, and energy diffraction energy-dispersive X-ray analysis. The effect of contact time, mass of RH, initial concentration of cobalt ion solution, tem-perature, and pH on the percentage discharge of Co(II) was revealed. The nonlinear models such as pseudo-first-order model, pseudo-second-order model, intraparticle diffusion model, and Elovich model were utilized to study kinetics for adsorptive removal of cobalt ions (Co(II)) from aqueous solution. Results showed that experimental data fitted well to nonlinear pseudo-second-order kinetic model. Nonlinear isotherms such as Langmuir, Freundlich, and Dubinin–Radushkevivh (D–R) were used to reveal experimental data of cobalt ion adsorption onto RH. Results represented that experimental data fitted well to nonlinear isotherms. Adsorption thermodynamic study showed that adsorption of Co(II) onto RH was an endothermic and spontaneous process. Moreover, desorp-tion of cobalt ions was also revealed. Therefore, RH could be utilized as a good adsorbent for the removal of Co(II) from aqueous solution at room temperature.
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Kinetic, equilibrium and thermodynamic studies for adsorption of nickel ions onto husk of oryza sativa
(2019-11-01)
Zafar, Shagufta
;
Khan, Muhammad Imran
;
Khraisheh, Majeda
;
Lashari, Mushtaq Hussain
;
Shahida, Shabnam
This research focus onto batch adsorption of nickel ions (Ni(II)) onto husk of Oryza sativa (HOS) from aqueous solution at room temperature. Several techniques such as Fourier transform infrared, scanning electron microscopy and energy dispersive X-ray were employed to confirm adsorption of Ni(II) onto HOS. The effect of operational parameters such as contact time, amount of adsorbent, initial concentration of metal ions, temperature and pH on the percentage removal of Ni(II) was evaluated. The removal of Ni(II) was 62.32% under optimum amount of adsorbent (0.3 g) at room temperature. Adsorption kinetics study has exhibited that experimental data fitted-well to pseudo-second-order kinetic model. Linear and nonlinear forms of Langmuir, Freundlich and Dubinin-Radushkevivh isotherms were used to analyse experimental data and results showed that adsorption data fitted well to nonlinear and linear form of adsorption isotherms. Adsorption thermodynamic study has indicated that adsorption of Ni(II) onto HOS was an endothermic and spontaneous process.
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Adsorption kinetic, equilibrium and thermodynamic study for the removal of Congo Red from aqueous solution
(2017-12-01)
Khan, Muhammad Imran
;
Zafar, Shagufta
;
Khan, Muhammad Ali
;
Buzdar, Abdul Rehman
;
Prapamonthon, Prasert
In this study, the adsorption of Congo red (CR) dye from aqueous solution onto cationic polymeric film (BIII) was investigated at ambient temperature. The effect of operational parameters such as contact time, membrane dosage, initial dye concentration and temperature on the adsorption of CR from aqueous solution was studied. Adsorption kinetics has been studied by employing several kinetic models and attained results showed that the adsorption data fitted-well to the pseudo-second-order kinetic model. Nonlinear forms of two parameters and three parameters isotherms were applied on experimental data and the results indicated that the adsorption data fitted well to the various two and three parameters isotherms. Thermodynamic study showed that the adsorption of CR onto cationic polymeric film (BIII) was an exothermic process.

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