Zahra Mirkazehi; Mohammad Reza Rezaei; Mohammad Sayadi
Abstract
Landfill leachate is the fluid percolating through the landfill and is one of the most important environmental challenges that lead to the contamination of water and soil resources. In this study, magnetic graphene oxide nanoparticles with WO3 (GO-Fe3O4/WO3) were synthesized through the hydrothermal ...
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Landfill leachate is the fluid percolating through the landfill and is one of the most important environmental challenges that lead to the contamination of water and soil resources. In this study, magnetic graphene oxide nanoparticles with WO3 (GO-Fe3O4/WO3) were synthesized through the hydrothermal method to eliminate chemical oxygen demand (COD) from leachate. The obtained products were characterized using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Thermogravimetric analysis (TGA), and Vibrating sample magnetometer (VSM) analysis. The influence of various operating parameters, such as initial solution pH, adsorbent dosage, contact time, and temperature, on COD removal was studied. Additionally, kinetic, isotherm, and thermodynamic studies were conducted to evaluate the adsorption capacity of the adsorbent. The results revealed that the maximum adsorption capacity of GO-Fe3O4/WO3 was 2500 mg/g adsorbent at pH 4, a contact time of 90 minutes, an adsorbent dosage of 25 mg g-1, and a temperature below 298 K, respectively. According to the adsorption kinetic fitting results, the experimental adsorption data were well described by the pseudo-second order kinetic with an R2 value of 0.97, and the Freundlich isotherm equation with an R2 value of 0.99. The thermodynamic results indicated that the adsorption was spontaneous and exothermic for COD adsorption. In general, the adsorption process of the synthesized GO-Fe3O4/WO3 nanocomposite revealed that it is highly effective for landfill leachate treatment and has great practical value in leachate treatment.
Sadegh Roushenas; Maryam Female Nikzad; Ali Asghar Ghoreyshi; mohsen ghorbani
Abstract
In this study, pectin/γ-Fe2O3/gl nanocomposite was synthesized using a single-step chemical precipitation method and used as an eco-friendly adsorbent to remove Cd2+ and Pb2+ from aqueous solution. The nanocomposite was characterized by FE-SEM, EDX, FTIR, XRD, VSM, and TEM analyses. The effect ...
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In this study, pectin/γ-Fe2O3/gl nanocomposite was synthesized using a single-step chemical precipitation method and used as an eco-friendly adsorbent to remove Cd2+ and Pb2+ from aqueous solution. The nanocomposite was characterized by FE-SEM, EDX, FTIR, XRD, VSM, and TEM analyses. The effect of various parameters such as solution pH (2 to 5), contact time (0 to 60 min), initial ion concentration (10 to 200 mg. L-1), and adsorbent dosage (0.1 to 0.4 g.L-1) on the removal efficiency was investigated. The maximum adsorption capacity of Cd (II) in the conditions (pH: 5, dose of adsorbent: 0.2 g.L-1, and contact time:40 min, initial concentration: 50 mg.L-1 ) and Pb (II) in the conditions (pH: 4.5, dose of adsorbent: 0.1g.L-1, and contact time:30min, initial concentration: 50 mg.L-1 ) was 470 and 325 mg. g-1, respectively. The adsorption kinetics was studied using several kinetic models including Langmuir isotherm, Freundlich isotherm, Sips isotherm, and Temkin isotherm. Results indicated that the adsorption mechanism could be well represented by the pseudo-second-order model. The equilibrium data of Cd (II) and Pb (II) adsorption were reasonably described by the Sips and Langmuir isothermal models. The positive value of delta H and negative values of delta G exhibit the endothermic and spontaneous nature of the adsorption process.
Soodabeh Khalili; Ali Asghar Ghoreyshi; Mohsen Jahanshahi; Behnam khoshandam
Abstract
Multiwalled carbon nanotubes (MWCNT) were found to be an effective separation media for purifing CO2 from O2. Significant uptakes of CO2 and O2 were measured at 288 K, 298K and 308 K over the pressure range of 1 to 40 bar using volumetric method in dual sorption vessels. The same shape of isotherms ...
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Multiwalled carbon nanotubes (MWCNT) were found to be an effective separation media for purifing CO2 from O2. Significant uptakes of CO2 and O2 were measured at 288 K, 298K and 308 K over the pressure range of 1 to 40 bar using volumetric method in dual sorption vessels. The same shape of isotherms introduced a common mechanism of adsorption but the amount of CO2 adsorbed on MWCNT is 2 times higher than O2 adsorption. The mass uptake of CO2 and O2 by MWCNT was found to increase with increasing pressure and decreasing temperature. The experimental data was well fitted by the Langmuir and Freundlich model isotherms considering the values of regression correlation coefficients. Following a simple acidic treatment procedure, CO2 and O2 adsorption was increased over range of pressure. The adsorbents was characterized by N2 adsorption isotherm at 77 K, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The effect of temperature and pressure on selectivity obtained from IAST demonstrated that maximum selectivity over the pressure and temperature ranges p = 0.5-5 bar and T = 298–308 K was achieved at 308 K and 5 bar.
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