Elahe Ahmadi Kamarposhti; Nader Bahramifar; Salma Ehsani Tilami
Abstract
Water pollution caused by heavy metals due to the increasing growth of industries is very worrying. Among heavy metals, evaluating the effect of silver (Ag) toxicity and its challenges on human and environmental health is very important and fundamental. This paper, for the first time, assessed the ability ...
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Water pollution caused by heavy metals due to the increasing growth of industries is very worrying. Among heavy metals, evaluating the effect of silver (Ag) toxicity and its challenges on human and environmental health is very important and fundamental. This paper, for the first time, assessed the ability of palm leaf ash (PLA) as a biosorbent to reduce the amount of water-soluble Ag cations from water. To do so, the effect of adsorbent amount, contact time, initial concentration of Ag ions, pH of the solution, and the temperature was evaluated on the adsorption process. The adsorption process was more consistent with the Freundlich isothermal model and the pseudo-second-order model was in better agreement with experimental data. The results of the experiments showed that the removal percentage of Ag ions and adsorption capacity was accrued from 91.84 to 99.94% and from 25.89 to 52.771 mg/g with increasing pH from 3 to 8 respectively and the enthalpy of the adsorption process (ΔH) was 6996.36 j/mol. Furthermore the removal efficiency of Ag at the initial concentration was obtained at 99.7%, Therefore, it can be concluded that cheapness, and abundance and high sorption capacity are the main advantages of this adsorbent.
Masoud Shariati-Rad; Mohsen Irandoust; Somayyeh Amri; Mostafa Feyzi; Fattaneh Ja’fari
Volume 1, Issue 1 , March 2014, , Pages 6-12
Abstract
A method was developed for removal, preconcentration and spectrophotometric determination of trace amounts of methyl red based on SiO2-coated Fe3O4magnetic nanoparticles. The influence of pH, dosage of adsorbent and contact time on the adsorption of dye was explored by central composite design. The kinetic ...
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A method was developed for removal, preconcentration and spectrophotometric determination of trace amounts of methyl red based on SiO2-coated Fe3O4magnetic nanoparticles. The influence of pH, dosage of adsorbent and contact time on the adsorption of dye was explored by central composite design. The kinetic data were analyzed based on the Langmuir and Freundlich adsorption isotherms. The Langmuir model was fitted well to data and the maximum monolayer capacity q max of 49.50 mg g−1 was calculated. The results showed that desorption efficiencies of higher than 99% can be achieved in a short contact time of 3 min and in one step elution using 2.0 mL of 0.1 mol L−1 NaOH. The magnetic nanoparticles were washed with deionized water and reused for two successive removal processes with removal efficiencies more than 90%. Then desorbed dye was determined spectrophotometrically. The calibration curve was linear in the range of 0.025–0.250 mg L−1 of dye with a correlation coefficient of 0.9922. The relative standard deviations obtained upon application of the method to the real samples were lower than 0.7%. A preconcentration factor of the method was 50.
