TY - JOUR ID - 1667 TI - Comparative and Competitive Study of LDH/Diatomite and Chitosan/Diatomite for Adsorptive Removal of Chloride Ion from Aqueous Solution JO - Journal of Mining and Environment JA - JME LA - en SN - 2251-8592 AU - Sadough Abbasian, F. AU - Rezai, B. AU - Azadmehr, A. R. AU - Hamidian, H. AD - Department of Mining Engineering ,Science And Research Branch,Islamic Azad University,Tehran,Iran AD - Department of Mining and Metallurgical Eng. Amirkabir University of Technology, Tehran, Iran AD - Department of Mining Engineering, Qaem Shahr Branch Islamic Azad University, Qaem Shahr, Iran Y1 - 2020 PY - 2020 VL - 11 IS - 1 SP - 261 EP - 279 KW - Adsorption KW - Wastewater KW - Chloride KW - Anion exchange KW - Diatomite DO - 10.22044/jme.2020.9023.1789 N2 - In this work, two clay-based composites are prepared for the adsorptive removal of the chloride ions from aqueous solutions. These composites are characterized through Fourier transform-infrared spectroscopy, scanning electron microscopy, X-ray fluorescence spectroscopy, and X-ray diffraction analysis. The effects of different parameters such as the contact time, amount of adsorbent, chloride concentration, temperature, and pH are studied by batch experiments. Also the isotherm, kinetic, and thermodynamic of the adsorptive removal of the chloride ions from these two composites are investigated. According to the results obtained, the adsorptive removal of chloride ions is initially rapid, and the equilibrium time is reached after 30 min. The optimal pH value is 7.0 for a better adsorption, and the maximum capacity can be achieved, which is 60.2 mg/g with 1000 mg/L of the initial chloride concentration. The Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich adsorption models are applied to describe the equilibrium isotherms at different chloride concentrations. According to the equilibrium isotherms and the correlation coefficients (R2CDC: 0.9424, R2LDC: 0.996), the process can be described by the Langmuir model, and exhibits the highest removal rate of 97.24% (24.31 mg/g) with 250 mg/L of the initial chloride concentration. The pseudo-first-order and pseudo-second-order, intra-particle diffusion, and mass transfer kinetics models are used to identify the mechanism of the adsorptive removal of the chloride ions. The pseudo-second order model due the correlation coefficients (R2CDC: 0.9217-0.9852, R2LDC: 0.9227-0.9926) can be fitted to the kinetic calculations, and it is applicable for the adsorptive removal of chloride ions by the adsorbents. The thermodynamic calculations show that in a low chloride concentration, the sorption is spontaneous, associative, and endothermic; and in a high concentration, it is unspontaneous, dissociative, and endothermic. The calculated value of free energy (E) for adsorption onto the adsorbents suggests that the reaction rate controls the adsorptive removal of the chloride process rather than diffusion. It can be concluded that these two composites can be used as effective and applicable adsorbents for the adsorptive removal of chloride ions. UR - https://jme.shahroodut.ac.ir/article_1667.html L1 - https://jme.shahroodut.ac.ir/article_1667_746043776caf4accffd64609e40dc970.pdf ER -