Mehdi Sedighi; Majid Mohammadi
Abstract
Consistent with the US Environmental Protection Agency, heavy metals are classified as carcinogenic to humans. Their numerous agricultural, industrial, domestic, medical, and technical requirements have resulted in their widespread dissemination in the environment. This article examines a new green adsorbent ...
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Consistent with the US Environmental Protection Agency, heavy metals are classified as carcinogenic to humans. Their numerous agricultural, industrial, domestic, medical, and technical requirements have resulted in their widespread dissemination in the environment. This article examines a new green adsorbent for the removal of two hazardous heavy metals, lead and mercury. The impact of contact time, pH, initial concentration, and temperature on the adsorption capacity of Pb2+ and Hg2+ were evaluated. Experimental data were analyzed by adsorption models. The equilibrium data were well adapted to the Langmuir adsorption model. The results show that the adsorption is homogeneous and localized in a monolayer. In addition, the maximum adsorption capacity was 277.78 mg/g for Pb2+ and 64.52 mg/g for Hg2+ from Langmuir isotherm. Thermodynamic data, including free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) variations were also considered. The important point is that the negative value of ΔG° signifies the spontaneity of the adsorption process of the heavy metals−NiO/ZSM-5 system.
Lida Rahmanzadeh; Mohsen Ghorbani; Mohsen Jahanshahi
Abstract
Mercury is one of the most toxic metals present in the environment. Adsorption has been proposed among the technologies for mercury adsorbent. The kinetics of adsorption depends on the adsorbent concentration, and the physical and chemical characteristics of adsorbent. In this study we were used a novel ...
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Mercury is one of the most toxic metals present in the environment. Adsorption has been proposed among the technologies for mercury adsorbent. The kinetics of adsorption depends on the adsorbent concentration, and the physical and chemical characteristics of adsorbent. In this study we were used a novel adsorbent, magnetite-polyrhodanine core- shell nanoparticles, for removing Hg(II) from aqueous solution. The effect of pH, initial Hg(II) concentration, initial adsorbent concentration and contact time on the efficiency of Hg(II) removal were investigated systematically by batch experiments. The maximum adsorption capacity was obtained 29.14 mg g-1 at PH=6.5 and 25°C with 10 g L-1 nano adsorbent. The kinetic data of adsorption of Hg(II) ion on the synthesized adsorbent were best described by a pseudo- second- order equation, indicating their chemical adsorption. The Freundlich, Langmuir and Temkin isotherms were used to modeling of mercury adsorption on Hg(II) in aqueous medium which modeled best by the Freundlich isotherm is whole concentration rage.