M. Massoud; M. Erhayem; F. Al-Tohami
Abstract
In the present study, batch adsorption experiments of hazardous cadmium ions, Cd(II), onto low-cost Dodonaeae Viscose Legs (DVLs) surface were conducted with respect to contact time, solution pH, adsorbent dosage, initial Cd concentration and temperature. Sorption isotherm, kinetic and thermodynamic ...
Read More
In the present study, batch adsorption experiments of hazardous cadmium ions, Cd(II), onto low-cost Dodonaeae Viscose Legs (DVLs) surface were conducted with respect to contact time, solution pH, adsorbent dosage, initial Cd concentration and temperature. Sorption isotherm, kinetic and thermodynamic models were used to describe the equilibrium stage and their constants were determined. The DVLs were used without chemical or physical activation processes. The results showed that the optimum adsorption capacity of DVLs for Cd(II) ions was found to be 25.29 mg/g at solution pH 5.26, 50 min and 303K. DVL adsorption data was fitted well with Langmuir isotherm. The mean free energy was found to be 1.82E-02 using Dubinin-Radushkevich (DRK) isotherm, which indicates that the adsorption of Cd(II) ions onto DVL surface is physical adsorption. The activation energy (Ea) was 3.06 kJ/mol, which confirms that Cd(II)-DVL adsorption process is physical sorption. Pseudo-first-order, pseudo-second-order, Elovich, intra-particle and extra-particle diffusion models were used to describe the adsorption kinetics. The results show strong correspondence to a pseudo-second-order kinetics. Thermodynamic parameters suggested that the adsorption of Cd(II) ions onto DVL surface is an exothermic process.
D. Basrur; J. Ishwara Bhat
Abstract
In this study the preparation of activated carbon from agricultural product were reported. The fenugreek seeds were activated by chemical and microwave activation methods. The characterization of carbon materials were carried out using different techniques like Fourier Transform Infrared Spectroscopy ...
Read More
In this study the preparation of activated carbon from agricultural product were reported. The fenugreek seeds were activated by chemical and microwave activation methods. The characterization of carbon materials were carried out using different techniques like Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Thermo Gravimetric Analysis (TGA), X-Ray Diffraction (XRD). Adsorption experiment was carried out for the adsorption of two different basic dyes, Methylene Blue (MB) and Crystal Violet (CV) under varying conditions such as concentration of dye, mixing time and adsorption temperature. The data acquired from concentration variation were found to fit well with Langmuir and also Freundlich isotherms. Kinetic studies revealed the fact that the system follows second order. Thermodynamic parameters like ΔH≠, ΔS≠ and ΔG≠ were calculated from the study on adsorption at different temperature. The adsorbent preparation via microwave technology is a desired methods which is resulted in conservation of energy for an efficient production of activated carbon.
