3D Porous Graphene/Polyvinyl Alcohol Composites: The Effect of Modification on the Adsorption Properties

Polyvinyl alcohol (PVA) was grafted on graphene nanosheets (GN) in the reduction of graphene oxide with hydrazine hydrate. The obtained GN-PVA (GP) suspension was treated with the freezing–thawing cycle to fabricate 3D porous monolithic GP materials, which were modified with carbon disulfide to introduce xanthan groups on the wall of porous materials, marked as GPCs. The characterization of GPCs confirmed that PVA was attached on the surface of GNs, and xanthan groups were effectively functionalized on the porous structures, which were composed of randomly oriented GNs. The Pb[Formula: see text] adsorption pattern for GPC materials was investigated. The kinetic adsorption and isotherm data fit the pseudo second-order kinetic and the Langmuir isotherm models, respectively. The maximum adsorption capacity of Pb[Formula: see text] reached 242.7[Formula: see text]mg/g. And GPCs for Pb[Formula: see text] adsorption could be regenerated with ethylenediamine tetracetic acid (EDTA) solution for repetitious adsorption.

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Carbon Nanofibers: A New Adsorbent for Copper Removal from Wastewater

Metals ◽

10.3390/met8110914 ◽

2018 ◽

Vol 8 (11) ◽

pp. 914 ◽

Cited By ~ 8

Author(s):

Irene García-Díaz ◽

Felix López ◽

Francisco Alguacil

Keyword(s):

Adsorption Capacity ◽

Carbon Nanofiber ◽

Great Influence ◽

Isotherm Models ◽

Particle Diffusion ◽

Maximum Adsorption Capacity ◽

Order Kinetic ◽

Helical Ribbon ◽

Pseudo Second Order

This research describes the adsorption of Cu2+ onto a helical ribbon carbon nanofiber. The characterization of carbon nanofiber by zeta potential showed an isoelectronic pH of 1.9. The influence of different adsorption factors, such as stirring speed, temperature, pH, adsorbent concentration, etc., on the Cu2+ adsorption capacity have been evaluated. The pH has a great influence on Cu2+ adsorption, with the maximum adsorption capacity reached at a pH of 10. The experimental data fit well to pseudo-second order kinetic and Langmuir isotherm models (qm = 8.80 mg·g−1) at T = 298 K and pH = 4. The Cu2+ adsorption could be explained by the particle diffusion model. Results showed that carbon nanofiber could be successfully used for the elimination of Cu2+ from wastewater.

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Preparation and characterization of Ca(II) cross-linking modified pectin microspheres for Pb(II) adsorption

Water Science & Technology ◽

10.2166/wst.2019.151 ◽

2019 ◽

Vol 79 (8) ◽

pp. 1484-1493

Author(s):

Fen Li ◽

Zhao Xu ◽

Xiaoyan Wen ◽

Xiaoyong Li ◽

Yanhong Bai ◽

...

Keyword(s):

Adsorption Mechanism ◽

Isotherm Models ◽

Cross Linking ◽

Maximum Adsorption Capacity ◽

Order Kinetic ◽

Wastewater Purification ◽

Adsorption Ability ◽

Pectic Acid ◽

Pseudo Second Order

Abstract A novel adsorbent, composed of cross-linked de-esterified pectin microspheres, was prepared via cross-linking with Ca(II) and modification by de-esterified pectin, low-methoxyl pectin (LMP) and pectic acid (PA). Fourier transform infrared (FTIR), energy dispersive spectrometry (EDS), scanning electron microscopy (SEM) and atomic absorption spectroscopy (AAS) were applied too, exhibiting a successful fabrication, good adsorption ability, and well-defined surface microstructure beneficial to Pb(II) adsorption. The adsorption ability of pectin microspheres (PMs), low-methoxyl pectin microspheres (LMPMs) and pectic acid microspheres (PAMs) for Pb(II) in aqueous solution were explored. The maximum adsorption capacity of PMs, LMPMs and PAMs was 127 mg·g−1, 292 mg·g−1 and 325 mg·g−1 at pH 5.0 respectively, indicating a great improvement of LMPMs and PAMs in the adsorption ability for Pb(II) compared with PMs. Furthermore, the adsorption mechanism was proposed. The experimental data were well fitted with pseudo-second-order kinetic and Langmuir isotherm models. Five-cycle reusability tests demonstrated that microspheres could be used repeatedly. All the results confirmed that LMPMs and PAMs, which presented outstanding adsorption capability and reusability, could be a good candidate for wastewater purification.

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Preparation of chitosan/amine modified diatomite composites and adsorption properties of Hg(II) ions

Water Science & Technology ◽

10.2166/wst.2018.018 ◽

2018 ◽

Vol 77 (5) ◽

pp. 1363-1371 ◽

Cited By ~ 2

Author(s):

Yong Fu ◽

Yue Huang ◽

Jianshe Hu ◽

Zhengjie Zhang

Keyword(s):

Schiff Base ◽

Contact Time ◽

Ph Value ◽

Adsorption Properties ◽

Maximum Adsorption Capacity ◽

Order Kinetic ◽

Adsorption Effect ◽

Order Kinetic Model ◽

Pseudo Second Order ◽

Modified Diatomite

Abstract A green functional adsorbent (CAD) was prepared by Schiff base reaction of chitosan and amino-modified diatomite. The morphology, structure and adsorption properties of the CAD were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and Brunauer Emmett Teller measurements. The effect of pH value, contact time and temperature on the adsorption of Hg(II) ions for the CAD is discussed in detail. The experimental results showed that the CAD had a large specific surface area and multifunctional groups such as amino, hydroxyl and Schiff base. The optimum adsorption effect was obtained when the pH value, temperature and contact time were 4, 25 °C and 120 min, respectively, and the corresponding maximum adsorption capacity of Hg(II) ions reached 102 mg/g. Moreover, the adsorption behavior of Hg(II) ions for the CAD followed the pseudo-second-order kinetic model and Langmuir model. The negative ΔG0 and ΔH0 suggested that the adsorption was a spontaneous exothermic process.

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

Water Science & Technology ◽

10.2166/wst.2016.329 ◽

2016 ◽

Vol 74 (7) ◽

pp. 1644-1657 ◽

Cited By ~ 8

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.

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Characterization of natural- and organobentonite by XRD, SEM, FT-IR and thermal analysis techniques and its adsorption behaviour in aqueous solutions

Clay Minerals ◽

10.1180/claymin.2012.047.1.31 ◽

2012 ◽

Vol 47 (1) ◽

pp. 31-44 ◽

Cited By ~ 45

Author(s):

G. A. Ikhtiyarova ◽

A. S. Özcan ◽

Ö. Gök ◽

A. Özcan

Keyword(s):

Surface Area ◽

Bet Surface Area ◽

Maximum Adsorption Capacity ◽

Textile Dye ◽

Order Kinetic ◽

Order Kinetic Model ◽

Pseudo Second Order ◽

Ft Ir ◽

Thermal Analysis Techniques

AbstractIn this study, natural bentonite was modified with hexadecyltrimethylammonium (HDTMA) bromide to obtain organobentonite (HDTMA-bentonite). Bentonite and HDTMA-bentonite were then characterized using XRD, XRF, SEM, FT-IR, thermogravimetric (TG) analysis, elemental analysis and Brunauer-Emmett-Teller (BET) surface area techniques. The HDTMA+ cation was found to be located on the surface and enters the interlayer spaces of smectite according to the XRD and SEM results. FT-IR spectra indicated the existence of HDTMA functional groups on the bentonite surface. The BET surface area significantly decreased after the modification due to the coverage of the pores of natural bentonite. After the characterization, the adsorption of a textile dye, Reactive Blue 19 (RB19), onto bentonite and HDTMA-bentonite was investigated. The maximum adsorption capacity of HDTMA-bentonite for RB19 was 502 mg g-1 at 20°C. The adsorption process followed a pseudo-second-order kinetic model and it was exothermic and physical in nature.

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

10.21203/rs.3.rs-1009760/v1 ◽

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.

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

Applied Water Science ◽

10.1007/s13201-021-01458-6 ◽

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.

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Preparation of novel porous Al2O3-SiO2 nanocomposites via solution-freeze-drying-calcination method for the efficient removal of uranium in solution

Nanotechnology ◽

10.1088/1361-6528/ac3c7a ◽

2021 ◽

Author(s):

Maoling Wu ◽

Ling Ding ◽

Jun Liao ◽

Yong Zhang ◽

Wenkun Zhu

Keyword(s):

Adsorption Process ◽

Interaction Mechanism ◽

Isotherm Models ◽

Maximum Adsorption Capacity ◽

Order Kinetic ◽

Order Kinetic Model ◽

Langmuir Isotherm Model ◽

Pseudo Second Order ◽

Calcination Method ◽

Adsorption Desorption

Abstract In this work, the efficient extraction of uranium in solution using Al2O3-SiO2-T was reported. Kinetics and isotherm models indicated that the removal process of uranium onAl2O3-SiO2-T accorded with pseudo-second-order kinetic model and Langmuir isotherm model, which showed that the adsorption process was a uniform mono-layer chemical behavior. The maximum adsorption capacity of Al2O3-SiO2-T reached 738.7 mg g-1, which was higher than AlNaO6Si2 (349.8 mg g-1) and Al2O3-SiO2-NT (453.1 mg g-1), indicating that the addition of template could effectively improve the adsorption performance of Al2O3-SiO2 to uranium. Even after five cycles of adsorption-desorption, the removal percentage of uranium on Al2O3-SiO2-T remained 96%. Besides, the extraction efficiency of uranium on Al2O3-SiO2-T was 72.5% in simulated seawater, which suggested that the Al2O3-SiO2-T was expected to be used for uranium extraction from seawater. Further, the interaction mechanism between Al2O3-SiO2-T and uranium species was studied. The results showed that the electrostatic interaction and complexation played key roles in the adsorption process of Al2O3-SiO2-T to uranium.

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Adsorption of Phenol on Commercial Activated Carbons: Modelling and Interpretation

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17030789 ◽

2020 ◽

Vol 17 (3) ◽

pp. 789 ◽

Cited By ~ 2

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.

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Cr6+ adsorption by modified vermiculite

10.5194/egusphere-egu2020-1394 ◽

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

Abstract: Cr6+ adsorption by modified vermiculite&#160;Valeria Medoro- University of Ferrara , Department of Physics and Earth Sciences, ItalyCelia Marcos Pascual-University of Oviedo, Department of Geology, SpainGiacomo Ferretti- University of Ferrara , Department of Physics and Earth Sciences, ItalyGiulio Galamini- University of Ferrara , Department of Physics and Earth Sciences, ItalyMassimo Coltorti- University of Ferrara , Department of Physics and Earth Sciences, Italy&#160;This work aimed at investigating the adsorption of Cr6+&#160;in water by exfoliated vermiculite. The adsorbant tested in this experiment was a vermiculite (from China) which has been subjected to heating at 1000 &#176;C for 1 minute, resulting in an exfoliated vermiculite.Three effects were studied: 1) contact time; 2) initial concentracion of Cr6+; 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 Cr6+ by the vermiculite.Results from XRD diffraction showed a conversion of vermiculite into flogopite&#160; after heating at 1000&#176;C for 1 minute because of: 1) high content of potassium, 2) dehydration and 3) structural re-ordering; after the contact of vermiculite with Cr6+, the mineral structure did not change. The adsorption of Cr6+&#160;was studied by Langmuir, Freundlich and&#160;Dubinin-Kaganer-Radushkevich&#160;(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 (R2=0.9984; other kinetic parameters were k2=0.0015 and the absorption initial rate of 0.2x10-8 mg g-1 h-1).&#160;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 Cr6+ and adsorbent mass).

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