Study of the effect of an acid treatment of a natural Moroccan bentonite on its physicochemical and adsorption properties

2016 ◽  
Vol 75 (5) ◽  
pp. 1098-1117 ◽  
Author(s):  
Ikram Daou ◽  
Omar Zegaoui ◽  
Ali Amachrouq
Keyword(s):  
Acid Treatment ◽  
Physicochemical Characterization ◽  
Weight Ratio ◽  
Exchange Capacity ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
The Impact

In this study, a natural bentonite taken from a deposit in the Northeast of Morocco has been purified (PB) and treated with various HCl molarities (xHPB) in order to obtain an HCl/Bentonite weight ratio equal to 0.2, 0.4 and 0.6. The obtained physicochemical characterization results indicated that the PB sample is composed mainly of the montmorillonite phase. The impact of acid treatment was investigated by identifying changes in the chemical composition, cation exchange capacity, infrared absorption bands, crystalline structure, morphology of the particles and specific surface area. The adsorption behavior of methylene blue (MB) and methyl orange (MO) in aqueous solution onto PB and xHPB samples was investigated by varying the initial concentration of dyes, the contact time and the temperature. The obtained results showed that the experimental data best fit the Langmuir model and the pseudo-second-order kinetic model. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) studies carried out after MB and MO adsorption onto PB samples indicated that MB cations were intercalated, in the form of monomers and dimers, with a large amount of monomers, slightly tilted against the plane of the clay surface. While MO molecules adsorb, with a near perpendicular alignment, with their SO3− group and O− atoms facing the mineral surface plane.

Adsorption of Pb(II) on raw and organically modified Jordanian bentonite

Clay Minerals ◽  
2015 ◽  
Vol 50 (4) ◽  
pp. 485-496 ◽  
Author(s):  
I. Hamadneh ◽  
R. Abu-Zurayk ◽  
B. Abu-Irmaileh ◽  
A. Bozeya ◽  
A. H. Al-Dujaili
Keyword(s):  
Exchange Capacity ◽  
Second Order ◽  
Area Measurement ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Modified Bentonite ◽  
X Ray ◽  
Order Kinetic Model ◽  
Pseudo Second Order

AbstractA comparative study using bentonite (BT), hexadecyltrimethylammonium-modified bentonite (BT-HDTMA) and phenyl fatty hydroxamic acid-modified bentonite (BT-PFHA) as adsorbents for the removal of Pb(II) has been proposed. These adsorbents were characterized by X-ray diffraction, X-ray fluorescence, Fourier-transform infrared spectroscopy and surface area measurement. Cation exchange capacity was also determined in this study. The adsorbent capabilities for Pb(II) from aqueous solution were investigated, and the optimal experimental conditions including adsorption time, adsorbent dosage, the initial concentration of Pb(II), pH and temperature that might influence the adsorption performance were also investigated. The experimental equilibrium adsorption data were tested by four widely used two-parameter equations, the Langmuir, Freundlich, Dubinin- Radushkevich (D-R) and Temkin isotherms. The monolayer adsorption capacities of BT, BT-HDTMA and BT-PFHA for Pb(II) were 149.3, 227.3 and 256.4 mg/g, respectively. The experimental kinetic data were analysed by pseudo-first order, pseudo-second order and intraparticle diffusion kinetics models. The experimental data fitted very well with the pseudo-second order kinetic model. Determination of the thermodynamic parameters, ΔG, ΔH and ΔS showed the adsorption to be feasible, spontaneous and exothermic.

scholarly journals Insights into Starch Coated Nanozero Valent Iron-Graphene Composite for Cr(VI) Removal from Aqueous Medium

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Prasanna Kumarathilaka ◽  
Vimukthi Jayaweera ◽  
Hasintha Wijesekara ◽  
I. R. M. Kottegoda ◽  
S. R. D. Rosa ◽  
...  
Keyword(s):  
Point Of Zero Charge ◽  
Inert Material ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Graphene Composite ◽  
Removal Capacity ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
First Time

Embedding nanoparticles into an inert material like graphene is a viable option since hybrid materials are more capable than those based on pure nanoparticulates for the removal of toxic pollutants. This study reports for the first time on Cr(VI) removal capacity of novel starch stabilized nanozero valent iron-graphene composite (NZVI-Gn) under different pHs, contact time, and initial concentrations. Starch coated NZVI-Gn composite was developed through borohydrate reduction method. The structure and surface of the composite were characterized by scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), and point of zero charge (pHpzc). The surface area and pHpzc of NZVI-Gn composite were reported as 525 m2 g−1 and 8.5, respectively. Highest Cr(VI) removal was achieved at pH 3, whereas 67.3% was removed within first few minutes and reached its equilibrium within 20 min obeying pseudo-second-order kinetic model, suggesting chemisorption as the rate limiting process. The partitioning of Cr(VI) at equilibrium is perfectly matched with Langmuir isotherm and maximum adsorption capacity of the NZVI-Gn composite is 143.28 mg g−1. Overall, these findings indicated that NZVI-Gn composite could be utilized as an efficient and magnetically separable adsorbent for removal of Cr(VI).

scholarly journals The Removal of Uranium and Thorium from Their Aqueous Solutions by 8-Hydroxyquinoline Immobilized Bentonite

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 626 ◽  
Author(s):  
Salah ◽  
Gaber ◽  
Kandil
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Langmuir Isotherm ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
X Ray ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The sorption of uranium and thorium from their aqueous solutions by using 8-hydroxyquinoline modified Na-bentonite (HQ-bentonite) was investigated by the batch technique. Na-bentonite and HQ-bentonite were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier Transform Infrared (FTIR) spectroscopy. Factors that influence the sorption of uranium and thorium onto HQ-bentonite such as solution pH, contact time, initial metal ions concentration, HQ-bentonite mass, and temperature were tested. Sorption experiments were expressed by Freundlich and Langmuir isotherms and the sorption results demonstrated that the sorption of uranium and thorium onto HQ-bentonite correlated better with the Langmuir isotherm than the Freundlich isotherm. Kinetics studies showed that the sorption followed the pseudo-second-order kinetic model. Thermodynamic parameters such as ΔH°, ΔS°, and ΔG° indicated that the sorption of uranium and thorium onto HQ-bentonite was endothermic, feasible, spontaneous, and physical in nature. The maximum adsorption capacities of HQ-bentonite were calculated from the Langmuir isotherm at 303 K and were found to be 63.90 and 65.44 for U(VI) and Th(IV) metal ions, respectively.

scholarly journals Preparation of chitosan/MCM-41-PAA nanocomposites and the adsorption behaviour of Hg(II) ions

2018 ◽  
Vol 5 (3) ◽  
pp. 171927 ◽  
Author(s):  
Yong Fu ◽  
Yue Huang ◽  
Jianshe Hu
Keyword(s):  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Adsorption Behaviour ◽  
X Ray Diffraction ◽  
Mesoporous Composite ◽  
Adsorption Temperature ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Enthalpy And Entropy ◽  
Mcm 41

A novel functional hybrid mesoporous composite material (CMP) based on chitosan and MCM-41-PAA was reported and its application as an excellent adsorbent for Hg(II) ions was also investigated. Innovatively, MCM-41-PAA was prepared by using diatomite and polyacrylic acid (PAA) with integrated polymer–silica hybrid frameworks, and then CMP was fabricated by introducing MCM-41-PAA to chitosan using glutaraldehyde as a cross-linking agent. The structure and morphology of CMP were characterized by X-ray diffraction, Fourier transform infrared spectra, thermogravimetric analysis, scanning electron microscopy and Brunauer–Emmett–Teller measurements. The results showed that the CMP possessed multifunctional groups such as –OH, –COOH and –NH 2 with large specific surface area. Adsorption behaviour of Hg(II) ions onto CMP was fitted better by the pseudo-second-order kinetic model and the Langmuir model when the initial Hg(II) concentration, pH, adsorption temperature and time were 200 mg l −1 , 4, 298 K and 120 min, respectively, as the optimum conditions. The corresponding maximum adsorption capacity could reach 164 mg g −1 . According to the thermodynamic parameters determined such as free energy, enthalpy and entropy, the adsorption process of Hg(II) ions was spontaneous endothermic adsorption.

scholarly journals Preparation and Characterization of a Novel Amidoxime-Modified Polyacrylonitrile/Fly Ash Composite Adsorbent and Its Application to Metal Wastewater Treatment

2022 ◽  
Vol 19 (2) ◽  
pp. 856
Author(s):  
Yan Sun ◽  
Xiaojun Song ◽  
Jing Ma ◽  
Haochen Yu ◽  
Gangjun Liu ◽  
...  
Keyword(s):  
Fly Ash ◽  
Adsorption Process ◽  
Single Layer ◽  
Nitrogen Adsorption ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
High Degree

The polyacrylonitrile/fly ash composite was synthesized through solution polymerization and was modified with NH2OH·HCl. The amidoxime-modified polyacrylonitrile/fly ash composite demonstrated excellent adsorption capacity for Zn2+ in an aqueous medium. Fourier transform-Infrared spectroscopy, thermogravimetric analysis, nitrogen adsorption, X-ray diffraction, and scanning electron microscopy were used to characterize the prepared materials. The results showed that the resulting amidoxime-modified polyacrylonitrile/fly ash composite was able to effectively remove Zn2+ at pH 4–6. Adsorption of Zn2+ was hindered by the coexisting cations. The adsorption kinetics of Zn2+ by Zn2+ followed the pseudo-second order kinetic model. The adsorption process also satisfactorily fit the Langmuir model, and the adsorption process was mainly single layer. The Gibbs free energy ΔG0, ΔH0, and ΔS0 were negative, indicating the adsorption was a spontaneous, exothermic, and high degree of order in solution system.

scholarly journals Synthesis of Reusable Cyclodextrin Polymers for Removal of Naphthol and Naphthylamine from Water

2021 ◽  
Author(s):  
Weifeng Xu ◽  
Xiang Liu ◽  
Jianzhe Cai ◽  
Tiemeng Xue ◽  
Kewen Tang
Keyword(s):  
Adsorption Equilibrium ◽  
Order Kinetic ◽  
Naphthalene Derivatives ◽  
Initial Concentration ◽  
Low Concentration ◽  
Adsorption Temperature ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Cyclodextrin Polymers ◽  
The Impact

Abstract As one group of important naphthalene derivatives, naphthol and naphthylamine, are diffusely employed as dye intermediates. The presence of naphthol and naphthylamine in water systems may pose risks to the environment and public health due to their carcinogenicity. In this study, four mesoporous polymers prepared by β-cyclodextrin derivatives and tetrafluoroterephthalonitrile were obtained, and applied to deal with 1-naphthylamine, 2-naphthylamine, 1-naphthol, and 2-naphthol from water. The impact of adsorption time, initial concentration of naphthol and naphthylamine, and temperature on the adsorption efficiency of the four polymers were explored separately. The four polymers present fast adsorption kinetics towards naphthol and naphthylamine, attaining 93%~100% of adsorption equilibrium uptake for 1-naphthol, 1-naphthylamine, 2-naphthylamine in 15 min, and 87%~90% of equilibrium uptake for 2-naphthol in 15 min. The kinetics could be depicted well by the pseudo-second-order kinetic model. The adsorption isotherms of the four polymers towards naphthol and naphthylamine accord with Redlich-Peterson or Sips model. The adsorption ratio increases fast with reducing the initial concentration of naphthol and naphthylamine, which suggest that these polymers are applicable to removing low concentration of naphthol and naphthylamine from water. The adsorption ratio of naphthol and naphthylamine in 5 mg/L, can achieve over 95% in 25 oC. In addition, the four polymers can be effortlessly recovered by a gentle and simple washing procedure with little reduction in performance. The adsorption performance of the four polymers towards the four naphthalene derivatives can be improved by increasing the adsorption temperature. In conclusion, the prepared β-cyclodextrin polymers exhibit rapid water treatment in removing the four low-concentration naphthalene derivatives with convenient regeneration and good reusability.

scholarly journals Physicochemical Characterization of Moroccan Natural Clays and the Study of their Adsorption Capacity for the Methyl Orange and Methylene

2020 ◽  
Vol 8 (4) ◽  
pp. 1258-1267
Keyword(s):  
Methyl Orange ◽  
Physicochemical Characterization ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Calcined Clay ◽  
X Ray ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Natural Clays

The objective of this work was the physicochemical characterization of a Moroccan natural clay from the Jorf Arfoud region (Lampert Coodinates: x = 595610, y = 101578) and its valorization in the elimination of organic pollutants (methyl orange MO and methylene blue MB) from aqueous solutions, with the adsorption technique on raw and calcined clay at 500°C. The clay was characterized by chemical analysis such as X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning electron microscopy (SEM). Crude and purified clays, consisting essentially of silica and alumina, are a characteristic property of phyllosilicates and also contain amounts of quartz, kaolinite and calcite as associated minerals. The experiments were performed after optimization of the parameters influencing the system, such as pH, adsorbent mass, initial dye concentration and temperature. The clays used absorb better the MB than MO, for an initial concentration of 10 mg/L and 20 mg/L respectively. Langmuir and Freundlich models of adsorption isotherms were applied to fit experimental equilibrium data. Results have showed that the adsorption of MB and MO followed very well the second order kinetic model on raw clay. The adsorption process was found to be exothermic in the case of MB. However, the adsorption of MO was endothermic.

scholarly journals Formation of porous wollastonite-based ceramics after sintering with yeast as the pore-forming agent

2017 ◽  
Vol 49 (3) ◽  
pp. 235-246 ◽  
Author(s):  
Nina Obradovic ◽  
Suzana Filipovic ◽  
Jelena Rusmirovic ◽  
Georgeta Postole ◽  
Aleksandar Marinkovic ◽  
...  
Keyword(s):  
Diffraction Method ◽  
Ion Concentration ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Phosphate Ions ◽  
Intra Particle Diffusion ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Set Up ◽  
Influence Of Ph

In this paper, synthesis of porous wollastonite-based ceramics was reported. Ceramic precursor, methylhydrocyclosiloxane, together with micro-sized CaCO3, was used as starting material. After 20 min of ultrasound treatment, and calcination at 250 oC for 30 min, yeast as a pore-forming agent was added to the as-obtained powders. Sintering regime was set up based on the results obtained by differential thermal analysis. Prepared mixture was pressed into pallets and sintered at 900 oC for 1 h. After the sintering regime, porous wollastonite-based ceramics was obtained. The phase composition of the sintered samples as well as microstructures was analyzed by X-ray diffraction method and SEM. In a batch test, the influence of pH, contact time and initial ion concentration on adsorption efficiency of As+5, Cr+6, and phosphate ions on synthesized wollastonite-based ceramics were studied. Time-dependent adsorption was best described by pseudo-second-order kinetic model and Weber-Morris model that predicted intra-particle diffusion as a rate-controlling step of overall process. High adsorption capacities 39.97, 21.87, and 15.29 mgg-1 were obtained for As+5, Cr+6, and phosphate ions, respectively.

scholarly journals Fabrication of Porous Hydroxyapatite Granules as an Effective Adsorbent for the Removal of Aqueous Pb(II) Ions

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Duyen Thi Le ◽  
Thao Phuong Thi Le ◽  
Hai Thi Do ◽  
Hanh Thi Vo ◽  
Nam Thi Pham ◽  
...  
Keyword(s):  
Industrial Wastewater ◽  
Sintering Temperature ◽  
Order Kinetic ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Porous Hydroxyapatite ◽  
X Ray ◽  
Langmuir Adsorption ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Porous hydroxyapatite (HAp) granules have been successfully fabricated from a HAp powder precursor and polyvinyl alcohol (PVA) additive by a simple sintering process. The composition and microstructures of the HAp were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with an energy dispersive X-ray (EDX) spectrometer. The effects of sintering temperature and PVA/HAp mass ratios on color, water stability, morphology, and chemical composition of HAp are discussed. Optimum conditions for the fabrication of HAp granules were found to be a PVA/HAp mass ratio of 3/20 and a sintering temperature of 600°C for 4 h. Accordingly, the obtained HAp is white in color, is in the granular form with a size of about 2 × 10 mm, and has a specific surface area of 70.6 m2/g. The adsorption of Pb2+ onto the as-prepared HAp granules was carried out in aqueous solution by varying the pH, the adsorbent dose, the initial concentration of Pb2+, and the contact time. The results of adsorption stoichiometry of Pb2+ on the HAp granule adsorbent were fitted to the Langmuir adsorption isotherm model (R2 = 0.99). The adsorption capacity and removal efficiency of the HAp granule adsorbent for Pb2+ under optimal conditions were found to be 7.99 mg/g and 95.92%, respectively. The adsorption process obeyed a pseudo-second-order kinetic model with R2∼1. The porous HAp granules studied in this work showed potential for the removal of Pb2+ from industrial wastewater.

scholarly journals In situ synthesis of layered double hydroxides on γ-Al2O3 and its application in chromium(VI) removal

2017 ◽  
Vol 75 (6) ◽  
pp. 1466-1473 ◽  
Author(s):  
Shifeng Li ◽  
Fang Qi ◽  
Min Xiao ◽  
Hongtao Fan ◽  
Yanming Shen ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Layered Double Hydroxides ◽  
Adsorptive Capacity ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Chromium Vi ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Double Hydroxides

Mg-Al layered double hydroxides (LDHs) adsorbent was synthesized in situ on γ-Al2O3 for the removal of Cr(VI) from aqueous solution. The material was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electronic microscopy and thermogravimetry and differential thermal analysis. Compared to the LDHs powder, the calcined LDHs sorbent prepared in situ on γ-Al2O3 had higher specific surface area and was easy to recover and reuse. The adsorptive capacity for removing Cr(VI) from aqueous solution was resulting from the memory effect of LDHs based on the XRD results. Both the pseudo-second-order kinetic model and the Langmuir model fit the experimental data well. Furthermore, the adsorbent exhibits excellent sorption–regeneration performances.

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