scholarly journals Effect of structural differences of pumice on synthesis of pumice-supported nFe0: removal of Cr (VI) from water

2021 ◽  
Vol 11 (7) ◽  
Author(s):  
Bilsen Tural ◽  
Erdal Ertaş ◽  
Mehmet Güzel ◽  
Servet Tural
Keyword(s):  
Iron Content ◽  
Second Order ◽  
Zero Valent Iron ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Support Material ◽  
Solution Ph ◽  
Nanoscale Zero Valent Iron ◽  
Pseudo Second Order

AbstractIn this study, pumice from different regions of Turkey (Diyarbakir, Southeast Turkey and Bitlis, East Turkey) has been supplied and used as supporting material for nanoscale zero-valent iron (nFe0). Native Bitlis pumice (NBP)-supported nanoscale zero-valent iron (BP-nFe0) and native Diyarbakir pumice (NDP)-supported nanoscale zero-value iron (DP-nFe0) were synthesized under the same conditions. Native pumice (NDP, NBP) and pumice-supported nFe0 (DP-nFe0 and BP-nFe0) adsorbents were morphologically and structurally characterized by SEM, EDX, XRF and BET. When using NBP as support material, the iron content of the BP-nFe0 increased 1.9-fold from 1.99 to 3.83%. However, iron content of NDP (2.08%) increased approximately 29 times after it is used as a support material in synthesis of DP-nFe0 (60%). The removal potential of native pumice (NBP and NDP) and iron-modified pumice (BP-nFe0 and DP-nFe0) samples was investigated to remove Cr(VI) ions. The parameters of solution pH, initial metal concentration, contact time and the amount of adsorbent in the removal of chromium (VI) ions were investigated. Langmuir, Freundlich, Temkin, Dubinin–Radushkevich and Jovanovic isotherm models were used to evaluate the adsorption equilibrium data. The equilibrium adsorption was found so as to be well described by the Langmuir isotherm model for all the adsorbents studied. The maximum adsorption capacity of Cr(VI) ions for NDP, NBP, DP-nFe0 and BP-nFe0 was 10.82, 14.30, 161.29 and 17.39 mg/g, respectively. The rate of Cr(VI) removal was subjected to kinetic analysis using pseudo-first-order, pseudo-second-order, intraparticle diffusion and Elovich models. Kinetic studies suggest that adsorption of NDP, NBP, DP-nFe0 and BP-nFe0 described more favorably by the pseudo-second-order kinetic model. The results showed that NDP is a much better support material for nFe0 when compared to NBP.

Adsorption of heavy metals from aqueous solutions by Mg–Al–Zn mingled oxides adsorbent

2016 ◽  
Vol 74 (7) ◽  
pp. 1644-1657 ◽  
Author(s):  
Mona El-Sayed ◽  
Gh. Eshaq ◽  
A. E. ElMetwally
Keyword(s):  
Heavy Metals ◽  
Metal Ion ◽  
Second Order ◽  
Ion Concentration ◽  
Precipitation Method ◽  
Isotherm Models ◽  
Infrared Spectrometry ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Pseudo Second Order

In our study, Mg–Al–Zn mingled oxides were prepared by the co-precipitation method. The structure, composition, morphology and thermal stability of the synthesized Mg–Al–Zn mingled oxides were analyzed by powder X-ray diffraction, Fourier transform infrared spectrometry, N2 physisorption, scanning electron microscopy, differential scanning calorimetry and thermogravimetry. Batch experiments were performed to study the adsorption behavior of cobalt(II) and nickel(II) as a function of pH, contact time, initial metal ion concentration, and adsorbent dose. The maximum adsorption capacity of Mg–Al–Zn mingled oxides for cobalt and nickel metal ions was 116.7 mg g−1, and 70.4 mg g−1, respectively. The experimental data were analyzed using pseudo-first- and pseudo-second-order kinetic models in linear and nonlinear regression analysis. The kinetic studies showed that the adsorption process could be described by the pseudo-second-order kinetic model. Experimental equilibrium data were well represented by Langmuir and Freundlich isotherm models. Also, the maximum monolayer capacity, qmax, obtained was 113.8 mg g−1, and 79.4 mg g−1 for Co(II), and Ni(II), respectively. Our results showed that Mg–Al–Zn mingled oxides can be used as an efficient adsorbent material for removal of heavy metals from industrial wastewater samples.

scholarly journals A Study of The Equilibrium, Kinetics, and Thermodynamics of Malachite Green Dye Adsorption Onto Lignin

2021 ◽  
Author(s):  
Vani Gandham ◽  
UMA Addepally ◽  
Bala Narsaiah T
Keyword(s):  
Malachite Green ◽  
Group Analysis ◽  
Dye Adsorption ◽  
Second Order ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Adequate Treatment ◽  
Pseudo Second Order ◽  
Kinetics And Isotherms

Abstract Malachite Green (MG), a cationic synthetic dye is considered hazardous when discharged into the water bodies without any adequate treatment. It can affect the multiple segments of the environment leading to irreversible persistent changes. So, there is a need for remediation with cost-effective method to remove dyes from effluents. Adsorption is one such technique to remove dyes from wastewater and is effective and economical. The present study describes the removal of MG cationic dye from wastewater using eco-friendly and biodegradable lignin extracted from hydrothermally treated rice straw by adsorption process. Functional group analysis and morphological characterisation was done to the extracted lignin after quantification. The maximum percent removal of MG 92 ± 0.2 % was observed from a series of batch experiments at optimum process parameters of: contact time 80 min, initial dye concentration 50 ppm, lignin dosage 0.25g, pH 7, temperature 300c and with 100 rpm agitation speed. The adsorption kinetics and isotherms were determined for the experimental data using four kinetic models (pseudo-first-order, second order, pseudo-second-order and intra-particle diffusion model) and two isotherm models (Langmuir and Freundlich). The results suggested that the kinetics data fit to the pseudo-second-order kinetic model with the maximum adsorption capacity 36.7 mg/g and the two isotherm models were applicable for the adsorption of MG onto the lignin. Additionally, the thermodynamic parameters ΔSo, ΔHo and ΔGo were evaluated. Therefore, lignin which is an environmental friendly and low cost carbon material that can be used as an adsorbent for dye removal.

Comparative studies on adsorptive removal of heavy metal ions by biosorbent, bio-char and activated carbon obtained from low cost agro-residue

2015 ◽  
Vol 73 (2) ◽  
pp. 423-436 ◽  
Author(s):  
Çisem Kırbıyık ◽  
Ayşe Eren Pütün ◽  
Ersan Pütün
Keyword(s):  
Activated Carbon ◽  
Metal Ion ◽  
Low Cost ◽  
Chemical Activation ◽  
Second Order ◽  
Isotherm Models ◽  
Standard Entropy ◽  
Order Kinetic ◽  
Solution Ph ◽  
Pseudo Second Order

In this study, Fe(III) and Cr(III) metal ion adsorption processes were carried out with three adsorbents in batch experiments and their adsorption performance was compared. These adsorbents were sesame stalk without pretreatment, bio-char derived from thermal decomposition of biomass, and activated carbon which was obtained from chemical activation of biomass. Scanning electron microscopy and Fourier transform–infrared techniques were used for characterization of adsorbents. The optimum conditions for the adsorption process were obtained by observing the influences of solution pH, adsorbent dosage, initial solution concentration, contact time and temperature. The optimum adsorption efficiencies were determined at pH 2.8 and pH 4.0 for Fe(III) and Cr(III) metal ion solutions, respectively. The experimental data were modelled by different isotherm models and the equilibriums were well described by the Langmuir adsorption isotherm model. The pseudo-first-order, pseudo-second-order kinetic, intra-particle diffusion and Elovich models were applied to analyze the kinetic data and to evaluate rate constants. The pseudo-second-order kinetic model gave a better fit than the others. The thermodynamic parameters, such as Gibbs free energy change ΔG°, standard enthalpy change ΔH° and standard entropy change ΔS° were evaluated. The thermodynamic study showed the adsorption was a spontaneous endothermic process.

scholarly journals LDH Nanocubes Synthesized with Zeolite Templates and Their High Performance as Adsorbents

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3315
Author(s):  
Moftah Essa Elkartehi ◽  
Rehab Mahmoud ◽  
Nabila Shehata ◽  
Ahmed Farghali ◽  
Shimaa Gamil ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Average Pore Size ◽  
Second Order ◽  
Polluted Water ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Average Pore ◽  
X Ray ◽  
Pseudo Second Order

In this work, the efficiency of the adsorptive removal of the organic cationic dye methylene blue (MB) from polluted water was examined using three materials: natural clay (zeolite), Zn-Fe layered double hydroxide (LDH), and zeolite/LDH composite. These materials were characterized via X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) diffraction (XRF), low-temperature N2 adsorption, pore volume and average pore size distribution and field emission scanning electron microscopy (FE-SEM). The properties of the applied nanomaterials regarding the adsorption of MB were investigated by determining various experimental parameters, such as the contact time, initial dye concentration, and solution pH. In addition, the adsorption isotherm model was estimated using the Langmuir, Freundlich, and Langmuir–Freundlich isotherm models. The Langmuir model was the best-fitting for all applied nanomaterials. In addition, the kinetics were analyzed by using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models, and the pseudo-second-order model was an apparent fit for all three applied nanomaterials. The maximum Adsorption capacity toward MB obtained from the materials was in the order zeolite/LDH composite > zeolites > Zn-Fe LDH. Thus, the zeolite/LDH composite is an excellent adsorbent for the removal of MB from polluted water.

Improvement of As(III) removal with diatomite overlay nanoscale zero-valent iron (nZVI-D): adsorption isotherm and adsorption kinetic studies

2016 ◽  
Vol 17 (1) ◽  
pp. 212-220 ◽  
Author(s):  
Nusavadee Pojananukij ◽  
Kitirote Wantala ◽  
Sutasinee Neramittagapong ◽  
Chitsan Lin ◽  
Duangkanok Tanangteerpong ◽  
...  
Keyword(s):  
Adsorption Isotherm ◽  
Kinetic Studies ◽  
Second Order ◽  
Zero Valent Iron ◽  
Order Kinetic ◽  
Kinetic Adsorption ◽  
Nanoscale Zero Valent Iron ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Nanoscale zero-valent iron coated on diatomite (nZVI-D) was successfully synthesized as a composite material. It is the combination of nZVI and diatomite which has been proved to be a promising material in arsenite or As(III) removal. The result showed that 25.5% of As(III) was removed using diatomite only but more than 95% of As(III) was removed using nZVI-D, at the same contact time of 60 min and pH 6. The experimental isotherm data for As(III) adsorption at different initial concentrations were analyzed using the Langmuir, Freundlich, and Dubinin–Radushkevich equations. Among these three, the equilibrium data fitted well with the Langmuir isotherm. The kinetic adsorption was also studied using the pseudo-first, second-order, and intraparticle diffusion equations. The data were well explained by the pseudo-second-order kinetic model. From the results of kinetic adsorption and the adsorption isotherm, it can be concluded that arsenite adsorption was controlled by the mass transfer and adsorption process.

scholarly journals Treatment of textile effluents by chloride-intercalated Zn-, Mg- and Ni-Al layered double hydroxides

2016 ◽  
Vol 7 (3) ◽  
pp. 307-318 ◽  
Author(s):  
F. Z. Mahjoubi ◽  
A. Khalidi ◽  
O. Cherkaoui ◽  
R. Elmoubarki ◽  
M. Abdennouri ◽  
...  
Keyword(s):  
Oxygen Demand ◽  
Freundlich Isotherm ◽  
Chloride Ions ◽  
Second Order ◽  
Cod Removal ◽  
Precipitation Method ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Solution Ph ◽  
Pseudo Second Order

This work involved the preparation, characterization and dyes removal ability of Zn-Al, Mg-Al and Ni-Al layered double hydroxide (LDH) minerals intercalated by chloride ions. The materials were synthetized by the co-precipitation method. X-ray diffraction, Fourier transform infrared, thermogravimetric-differential thermal analysis and transmission electron microscopy characterization exhibited a typical hydrotalcite structure for all the samples. Adsorption experiments for methyl orange were performed in terms of solution pH, contact time and initial dye concentration. Experimental results indicate that the capacity of dye uptake augmented rapidly within the first 60 min and then stayed practically the same regardless of the concentration. Maximum adsorption occurred with acidic pH medium. Kinetic data were studied using pseudo-first-order and pseudo-second-order kinetic models. Suitable correlation was acquired with the pseudo-second-order kinetic model. Equilibrium data were fitted to Langmuir and Freundlich isotherm models. The maximum Langmuir monolayer adsorption capacities were 2,758, 1,622 and 800 mg/g, respectively, for Zn-Al-Cl, Mg-Al-Cl and Ni-Al-Cl. The materials were later examined for the elimination of color and chemical oxygen demand (COD) from a real textile effluent wastewater. The results indicated that the suitable conditions for color and COD removal were acquired at pH of 5. The maximum COD removal efficiency from the effluent was noted as 92.84% for Zn-Al-Cl LDH.

scholarly journals ADSORPTION CHARACTERISTICS OF ZIZYPHUS JUJUBA SEED SHELL ACTIVATED NANO POROUS CARBON FOR REMOVING COPPER (II) IONS FROM WASTEWATER

2016 ◽  
Vol 4 (12) ◽  
pp. 226-241
Author(s):  
K Veeravelan ◽  
S Arivoli ◽  
V Marimuthu
Keyword(s):  
Aqueous Solution ◽  
Adsorption Process ◽  
Second Order ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Solution Ph ◽  
Batch Mode ◽  
Zizyphus Jujuba ◽  
Pseudo Second Order ◽  
Nano Carbon

In the present study, adsorption of copper (II) ions from aqueous solution by Activated Zizyphus Jujuba shell Nano Carbon was investigated under batch mode. The influence of solution pH, sorbent dose, copper concentration, contact time and temperature was studied. The copper adsorption was favored with maximum adsorption at pH 6.5. Sorption equilibrium time was observed in 60 min. The equilibrium adsorption data were correlated with Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Hurkins-Jura, Halsay, Radlich-Peterson, Jovanovic and BET isotherm models. The kinetics of the adsorption process was tested by pseudo-first-order, pseudo-second order, Elovich and Intra-particle diffusion models. It was shown that adsorption of copper could be described by the pseudo-second order kinetic model. Thermodynamic parameters such as Gibbs free energy (ΔG0), the enthalpy (ΔH0) and the entropy change of sorption (ΔS0) have also been evaluated and it has been found that the adsorption process was spontaneous, feasible and endothermic in nature. The results indicated that Activated Zizyphus Jujuba shell Nano Carbon can be used as an effective and low-cost adsorbent to remove copper (II) from aqueous solution.

scholarly journals Adsorption of Chromium Ions on Activated Carbon Produced from Cow Bones

2019 ◽  
Vol 20 (2) ◽  
pp. 23-32
Author(s):  
Marah Waleed Khalid ◽  
Sami D. Salman
Keyword(s):  
Surface Area ◽  
Kinetic Equations ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Raw Material ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Solution Ph ◽  
Chromium Ions ◽  
Pseudo Second Order

Due to the broad range uses of chromium for industrial purposes, besides its carcinogenic effect, an efficient, cost effective removal method should be obtained. In this study, cow bones as a cheap raw material were utilized to produce active carbon (CBAC) by physiochemical activation, which was characterized using: SEM to investigate surface morphology and BET to estimate the specific surface area. The best surface area of CBAC was 595.9 m2/gm which was prepared at 600 ᵒC activation temperature and impregnation ratio of 1:1.5. CBAC was used in aqueous chromium ions adsorption. The investigated factors and their ranges are: initial concentration (10-50 mg/L), adsorption time (30-300 min), temperature (20-50 ᵒC) and solution pH (2-11). Isotherm of adsorption and its kinetics were studied. The adsorption process was modeled statistically and was represented by an empirical model. Equilibrium data were fitted to the Langmuir and Freundlich isotherm models and the data best represented by Freundlich isotherm. Pseudo- first order and pseudo- second order kinetic equations were utilized to study adsorption kinetics, where chromium adsorption on CBAC fitted pseudo- second order fitted the data more adequately. The best removal efficiency was found to be 94.32%.

scholarly journals Adsorption of Phenol on Commercial Activated Carbons: Modelling and Interpretation

2020 ◽  
Vol 17 (3) ◽  
pp. 789 ◽  
Author(s):  
Bingxin Xie ◽  
Jihong Qin ◽  
Shu Wang ◽  
Xin Li ◽  
Hui Sun ◽  
...  
Keyword(s):  
Experimental Data ◽  
Activated Carbons ◽  
Freundlich Isotherm ◽  
Mesoporous Structure ◽  
Second Order ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Phenol Removal ◽  
Order Kinetic ◽  
Pseudo Second Order

Adsorption by activated carbons (AC) is an effective option for phenolic wastewater treatment. Three commercial AC, including coal-derived granular activated carbons (GAC950), coal-derived powdered activated carbons (PAC800), and coconut shell-derived powdered activated carbons (PAC1000), were utilized as adsorbent to study its viability and efficiency for phenol removal from wastewater. Pseudo-first order, pseudo-second order, and the Weber–Morris kinetic models were used to find out the kinetic parameters and mechanism of adsorption process. Further, to describe the equilibrium isotherms, the experimental data were analyzed by the Langmuir and Freundlich isotherm models. According to the experimental results, AC presented a micro/mesoporous structure, and the removal of phenol by AC was affected by initial phenol concentration, contact time, pH, temperature, and humic acid (HA) concentration. The pseudo-second order kinetic and Langmuir models were found to fit the experimental data very well, and the maximum adsorption capacity was 169.91, 176.58, and 212.96 mg/g for GAC950, PAC800, and PAC1000, respectively, which was attributed to differences in their precursors and physical appearance. Finally, it was hard for phenol to be desorbed in a natural environment, which confirmed that commercial AC are effective adsorbents for phenol removal from effluent wastewater.

scholarly journals Cr6+ adsorption by modified vermiculite

2020 ◽  
Author(s):  
Valeria Medoro ◽  
Celia Marcos Pascual ◽  
Giacomo Ferretti ◽  
Giulio Galamini ◽  
Massimo Coltorti
Keyword(s):  
Earth Sciences ◽  
Inductively Coupled Plasma ◽  
Contact Time ◽  
Second Order ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Experimental Conditions ◽  
X Ray ◽  
Pseudo Second Order

<p><strong>Abstract</strong>: <strong>Cr<sup>6+</sup> adsorption by modified vermiculite</strong></p><p><strong> </strong></p><p>Valeria Medoro- University of Ferrara , Department of Physics and Earth Sciences, Italy</p><p>Celia Marcos Pascual-University of Oviedo, Department of Geology, Spain</p><p>Giacomo Ferretti- University of Ferrara , Department of Physics and Earth Sciences, Italy</p><p>Giulio Galamini- University of Ferrara , Department of Physics and Earth Sciences, Italy</p><p>Massimo Coltorti- University of Ferrara , Department of Physics and Earth Sciences, Italy</p><p> </p><p>This work aimed at investigating the adsorption of Cr<sup>6+</sup> in water by exfoliated vermiculite. The adsorbant tested in this experiment was a vermiculite (from China) which has been subjected to heating at 1000 °C for 1 minute, resulting in an exfoliated vermiculite.</p><p>Three effects were studied: 1) contact time; 2) initial concentracion of Cr<sup>6+</sup>; 3) adsorbent mass. Samples were analysed by X Ray Fluorescence (XRF), X Ray Diffraction (XRD) and the solutions with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to quantify the adsorbed Cr<sup>6+</sup> by the vermiculite.</p><p>Results from XRD diffraction showed a conversion of vermiculite into flogopite  after heating at 1000°C for 1 minute because of: 1) high content of potassium, 2) dehydration and 3) structural re-ordering; after the contact of vermiculite with Cr<sup>6+</sup>, the mineral structure did not change. The adsorption of Cr<sup>6+</sup> was studied by Langmuir, Freundlich and Dubinin-Kaganer-Radushkevich (DKR) isotherm models. DKR model, indicative of a cooperative process, described adsorption equilibrium better than the other two models and the maximum adsorption capacity obtained was of 2.81 mol/g. Kinetic was studied using pseudo-first and pseudo-second order kinetic models, with a better description of the process by pseudo-second order model with correlation coefficient almost unitary (R<sup>2</sup>=0.9984; other kinetic parameters were k<sub>2</sub>=0.0015 and the absorption initial rate of 0.2x10<sup>-8</sup> mg g<sup>-1</sup> h<sup>-1</sup>). </p><p>The present study demonstrates the effectiveness of modified vermiculite adsorbents for the treatment of hexavalent chromium-contaminated waters and that its adsorption depends on the experimental conditions (such as contact time, initial concentracion of Cr<sup>6+</sup> and adsorbent mass).</p>

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