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.
Elham Chiani; Seyed Naser Azizi; Shahram Ghasemi; Salma Ehsani Tilami
Abstract
Today, many efforts have been made to use agricultural waste as a cheap and abundant resource for providing suitable adsorbents to remove pollutants such as industrial dyes. The aim of this study was to remove dye from water under different conditions using SBA-15 nano particles as adsorbents their silica ...
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Today, many efforts have been made to use agricultural waste as a cheap and abundant resource for providing suitable adsorbents to remove pollutants such as industrial dyes. The aim of this study was to remove dye from water under different conditions using SBA-15 nano particles as adsorbents their silica was prepared from stem sweep ash (SSA). Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and N2 adsorption experiments were applied to evaluate the structural characteristics of obtained adsorbent. In addition, to remove Azure B dye by SBA-15, the optimal values were obtained as the parameters of contact time = 30 min, pH = 8, temperature = 65 °C, adsorbent amount = 0.01 g, stirring rate = 90 rpm and initial dye concentration = 100 mg/L. The kinetic and thermodynamic experiments were conducted on the adsorption process as well. The results of the experiments demonstrated that the total surface area and total pore volume of the adsorbent were 780 m2/g and 0.8483 cm3/g, respectively. Moreover, the surface adsorption process of Azure B followed the Langmuir's isothermal model, and kinetic data followed the surface adsorption of pseudo-second-order kinetic model. Besides, the values of ΔH° and ΔS° were 5409.32 j/mol and 37.28 j/mol K, respectively, and the maximum adsorption capacity of adsorbent was 166.66 mg/g.
