scholarly journals Thorium(IV) adsorption onto multilayered Ti3C2Tx MXene: a batch, X-ray diffraction and EXAFS combined study

2021 ◽  
Vol 28 (6) ◽  
Author(s):  
Lin Wang ◽  
Wuqing Tao ◽  
Enzhao Ma ◽  
Zijie Li ◽  
Peng Ren ◽  
...  
Keyword(s):  
Electrostatic Interaction ◽  
Active Sites ◽  
Adsorption Mechanism ◽  
Adsorption Process ◽  
Exchange Process ◽  
Outer Sphere ◽  
Strong Acid ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Sites

The interlayer regulation of layered environmental adsorption materials such as two-dimensional early transition metal carbides and carbonitrides (MXenes) plays an important role in their purification performance for specific pollutants. Here the enhanced uptake of ThIV by multilayered titanium carbides (Ti3C2Tx) through a hydrated intercalation strategy is reported. ThIV adsorption behaviors of three Ti3C2Tx samples with different c lattice parameters were studied as a function of contact time, pH, initial concentration, temperature and ion strength in batch experiments. The results indicated that the ThIV uptake was pH and ionic strength dependent, and the adsorption process followed the pseudo-second-order kinetics and the heterogeneous isotherm (Freundlich) model. Thermodynamic data suggested that the adsorption process of all MXene samples was a spontaneous endothermic reaction. The dimethyl sulfoxide intercalated hydrated Ti3C2Tx featured the largest interlayer space and exhibited the highest ThIV adsorption capacity (162 mg g−1 at pH 3.4 or 112 mg g−1 at pH 3.0), reflecting the significant increase in available adsorption sites from Ti3C2Tx interlayers. The adsorption mechanism has been clarified based on adsorption experiments and spectroscopic characterizations. An ion exchange process was proposed for the interaction between hydrated MXenes and ThIV, where H+ from surface [Ti−O]−H+ groups were the primary active sites on Ti3C2Tx. Extended X-ray absorption fine structure (EXAFS) fitting results, in combination with X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses, clearly indicated that ThIV mainly formed the outer-sphere complexes on Ti3C2Tx surface through electrostatic interaction under strong acid conditions, while at pH > 3.0 the adsorption mechanism was determined by inner-sphere coordination and electrostatic interaction together.

scholarly journals Application of Modified Bentonites for Arsenite (III) Removal from Drinking Water

2018 ◽  
Vol 63 (1) ◽  
pp. 113-121 ◽  
Author(s):  
Dóra Buzetzky ◽  
Noémi Csilla Tóth ◽  
Noémi M. Nagy ◽  
József Kónya
Keyword(s):  
Active Sites ◽  
Ammonium Acetate ◽  
Exchange Process ◽  
Sorption Isotherms ◽  
Basal Spacing ◽  
Similar Amount ◽  
X Ray Diffraction ◽  
Ion Content ◽  
X Ray ◽  
Ion Exchange Process

Four modified bentonites (La(III), Ce(III), Y(III), Fe(III)) were prepared by ion exchange process to remove arsenite (III) ions from water. The modified bentonites were examined with X-ray fluorescence spectroscopy (XRF) and X-ray diffraction (XRD). The rare earth (REE) and Fe(III) ion content in bentonite was higher than the CEC values obtained by ammonium acetate method related to trivalent ions (2.7 x 10-4 mol g-1). The kinetics, equilibrium time, sorption isotherms and desorption experiments were examined. Lanthanum, yttrium and cerium bentonite can bind similar amount of arsenite(III) ions. Iron-bentonite cannot bind significant amounts of arsenite ions. The active sites and the solubilities of the sorption complex were determined. Arsenite (III) ions sorb in the interlayer space as REEAsO3. The solubility of the arsenite complex was two orders of magnitude smaller than that of the phosphate complex. After desorption the eluted amount of arsenite (III) was 55 % related to the sorbed amount of arsenite. The d(001) basal spacing of modified bentonites and that of after sorption and desorption was measured. After the sorption of arsenite ion on lanthanum bentonite, the d(001) basal spacing of montmorillonite was decreased and after desorption an increase in d(001) basal spacing was observed again. Modified bentonites can be used for removing arsenic ions from water.

scholarly journals Adsorption of p-Nitrophenol onto PDMDAAC-Modified Bentonites

2005 ◽  
Vol 23 (5) ◽  
pp. 407-416 ◽  
Author(s):  
Xianjia Peng ◽  
Zhaokun Luan ◽  
Hongmei Zhang ◽  
Binghui Tian ◽  
Bin Fan
Keyword(s):  
Adsorption Mechanism ◽  
Adsorption Process ◽  
Interlayer Space ◽  
Removal Rate ◽  
Cost Effective ◽  
Dual Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Capacities ◽  
Ph Dependent

A novel organobentonite was prepared by modifying bentonite with poly(dimethyldiallylammonium chloride) (PDMDAAC), a harmless and cost-effective type of polycation. Zeta potential and X-ray diffraction measurements suggest that PDMDAAC was intercalated into the bentonite interlayer space. PDMDAAC—bentonite has been found to be effective for the removal of p-nitrophenol with a removal rate of 81.4% being achieved. The adsorption process was pH-dependent and was slightly decreased by the Ca2+ and Mg2+ ions co-existing in the solution. A dual-phase adsorption mechanism was suggested for the process. The adsorbents obtained from the regeneration of PDMDAAC—bentonite still exhibit good adsorption capacities.

Research on Lead (II) Adsorption Mechanism from Aqueous Solution by Calcium Carbonate Modified Diatomite Absorbent

2018 ◽  
Vol 921 ◽  
pp. 21-28 ◽  
Author(s):  
Li Li Ma ◽  
Qing Lin Xie ◽  
Nan Chun Chen ◽  
Hui Xu ◽  
Hai Miao Zhou ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Calcium Carbonate ◽  
Adsorption Isotherms ◽  
Adsorption Mechanism ◽  
Adsorption Process ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pseudo Second Order ◽  
Modified Diatomite

In this study, calcium carbonate was used to coat and link the surface of diatomite for the formation of a novel modified adsorbent (referred to as Ca–diatomite). Various analytical techniques were used to characterize structure and mechanisms of modification and adsorption process, like Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD). Results showed that that Calcium carbonate had been successful grafted onto the surface of diatomite after modification, and Calcium carbonate modification improved the adsorption performance of diatomite for the removal of lead (II) ions from aqueous solution. Ca–diatomite adsorption isotherms and adsorption kinetics were also been studied. The adsorption isotherms and the kinetic data were best fitted with the Langmuir model and pseudo-second-order kinetics, respectively.

Adsorption Mechanism and Electrochemical Performance of Congo Red onto Magnetic CuFe2O4 Nanoparticles

2020 ◽  
Vol 12 (5) ◽  
pp. 643-651
Author(s):  
Ao-Lin He ◽  
Yu-Wei Huang ◽  
Lei Fang ◽  
Jing Xu
Keyword(s):  
Electron Microscopy ◽  
Congo Red ◽  
Adsorption Mechanism ◽  
Adsorption Process ◽  
Ph Value ◽  
Electrochemical Performances ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
X Ray ◽  
Transmission Electron

Magnetic CuFe2O4 nanoparticles were synthesized by the facile alcohol-solution combustion approach, and they were characterized by transmission electron microscopy (TEM), energy dispersive X-ray Spectroscopy (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The magnetic CuFe2O4 nanoparticles were employed to adsorb Congo red (CR) from aqueous medium. The study of magnetic CuFe2O4 nanoparticles for CR adsorption at room temperature was performed, and the Langmuir isotherm and pseudo-second kinetics model matched well with the adsorption process, those suggested that the mechanism of CuFe2O4 nanoparticles for CR adsorption followed the adsorption behavior of monolayer. The adsorbance descended with the increase of pH value, especially the pH value exceeded 7, and the adsorbance amounted to 77% of the initial one via 10 recycles. While, the electrochemical performances of bare magnetic glassy carbon electrode (MGCE), MGCE/CuFe2O4 nanoparticles, and MGCE/nanoparticles adsorbed CR were measured by EIS and CV.

Adsorption Characteristics of Reactive Red 2BF onto MnFe2O4 Nanorods Fabricated by the Facile Alcohol-Solution Combustion–Calcination Technique

2020 ◽  
Vol 12 (6) ◽  
pp. 744-749
Author(s):  
Dawei He ◽  
Shasha Li
Keyword(s):  
Adsorption Mechanism ◽  
Adsorption Process ◽  
Alcohol Solution ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
X Ray ◽  
Transmission Electron ◽  
Monolayer Adsorption ◽  
Pseudo Second Order

Magnetic MnFe2O4 nanorods were fabricated by the alcohol-solution combustion–calcination technique. The morphology, microstructure, and composition of as-prepared MnFe2O4 nanorods were characterized using the transmission electron microscopy (TEM), the X-ray diffraction (XRD), the energy dispersive spectroscopy (EDS), and the vibrating sample magnetometer (VSM). Moreover, the magnetic MnFe2O4 nanorods were employed to remove reactive red 2BF (RR-2BF), the experimental results showed the pseudo-second-order kinetics model could be applied to describe the adsorption process of RR-2BF onto MnFe2O4 nanorods in the initial RR-2BF concentrations of 100–400 mg/L, while, the isotherm data of RR-2BF onto MnFe2O4 nanorods could conform to Langmuir model owing to the value of the square deviations, which revealed that, the adsorption of RR-2BF onto MnFe2O4 nanorods was the monolayer adsorption mechanism.

Role of the Structure and Electronic Properties of Fe2O3-MoO3 Catalyst on the Dehydration of Isopropyl Alcohol

1993 ◽  
Vol 58 (7) ◽  
pp. 1591-1599 ◽  
Author(s):  
Abd El-Aziz A. Said
Keyword(s):  
Active Sites ◽  
Isopropyl Alcohol ◽  
Oxide Catalyst ◽  
Flow System ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalyst Composition ◽  
Surface Active

Molybdenum oxide catalyst doped or mixed with (1 - 50) mole % Fe3+ ions were prepared. The structure of the original samples and the samples calcined at 400 °C were characterized using DTA, X-ray diffraction and IR spectra. Measurements of the electrical conductivity of calcined samples with and without isopropyl alcohol revealed that the conductance increases on increasing the content of Fe3+ ions up to 50 mole %. The activation energies of charge carriers were determined in presence and absence of the alcohol. The catalytic dehydration of isopropyl alcohol was carried out at 250 °C using a flow system. The results obtained showed that the doped or mixed catalysts are active and selective towards propene formation. However, the catalyst containing 40 mole % Fe3+ ions exhibited the highest activity and selectivity. Correlations were attempted to the catalyst composition with their electronic and catalytic properties. Probable mechanism for the dehydration process is proposed in terms of surface active sites.

Physicochemical and Catalytic Properties of Spinels Formed by Solid-Solid Interaction Between Fe2O3and V2O5

1996 ◽  
Vol 61 (8) ◽  
pp. 1131-1140 ◽  
Author(s):  
Abd El-Aziz Ahmed Said
Keyword(s):  
Vanadium Oxide ◽  
Active Sites ◽  
Catalyst Surface ◽  
Catalytic Properties ◽  
Flow System ◽  
Oxide Catalysts ◽  
X Ray Diffraction ◽  
Selective Catalyst ◽  
X Ray ◽  
Solid Catalysts

Vanadium oxide catalysts doped or mixed with 1-50 mole % Fe3+ ions were prepared. The structure of the original samples and those calcined from 200 up to 500 °C were characterized by TG, DTA, IR and X-ray diffraction. The SBET values and texture of the solid catalysts were investigated. The catalytic dehydration-dehydrogenation of isopropanol was carried out at 200 °C using a flow system. The results obtained showed an observable decrease in the activity of V2O5 on the addition of Fe3+ ions. Moreover, Fe2V4O13 is the more active and selective catalyst than FeVO4 spinels. The results were correlated with the active sites created on the catalyst surface.

Preparation of xanthated bentonite and its removal behavior for Pb(II) ions

2010 ◽  
Vol 61 (5) ◽  
pp. 1235-1243 ◽  
Author(s):  
Y. F. He ◽  
F. R. Li ◽  
R. M. Wang ◽  
F. Y. Li ◽  
Y. Wang ◽  
...  
Keyword(s):  
Adsorption Mechanism ◽  
Removal Rate ◽  
Freundlich Isotherm ◽  
Particle Size Analysis ◽  
Lead Ions ◽  
Size Analysis ◽  
Optimum Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir

Xanthate was successfully grafted onto bentonite by a relatively simple solution reaction. The obtained xanthated bentonite (XBent) was characterized by FT-IR spectrophotometer, thermogravimetric analysis (TG), particle size analysis, x-ray diffraction (XRD) and scanning electron microscopy (SEM). XBent acting as a type of environmentally friendly adsorbent was applied to remove lead ions from aqueous solutions. The optimum conditions were as follows: [Pb2 + ] = 500 mg L−1, [XBent] = 2 g L−1, pH = 5.0; oscillating 60 min under 200 rpm at 25°C. The removal rate of lead was up to 99.9%. It was found that the lead(II) ions—XBent adsorption isotherm model fitted well to the Freundlich isotherm. The adsorption mechanism was also investigated by SEM and XRD, which concluded that lead ions were complexed or chelated with XBent. XBent appears to have potential to be used later in water treatment as a type of inorganic polymer reagent.

Molecular tapes in the structure of isoguaninium chloride

2017 ◽  
Vol 74 (1) ◽  
pp. 108-112 ◽  
Author(s):  
Urszula Anna Budniak ◽  
Paulina Maria Dominiak
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Charge Density ◽  
Interaction Energy ◽  
Electrostatic Interaction ◽  
Electrostatic Interactions ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Structure

Isoguanine, an analogue of guanine, is of intrinsic interest as a noncanonical nucleobase. The crystal structure of isoguaninium chloride (systematic name: 6-amino-2-oxo-1H,7H-purin-3-ium chloride), C5H6N5O+·Cl−, has been determined by single-crystal X-ray diffraction. Structure analysis was supported by electrostatic interaction energy (E es) calculations based on charge density reconstructed with the UBDB databank. In the structure, two kinds of molecular tapes are observed, one parallel to (010) and the other parallel to (50\overline{4}). The tapes are formed by dimers of isoguaninium cations interacting with chloride anions. E es analysis indicates that cations in one kind of tape are oriented so as to minimize repulsive electrostatic interactions.

Preparation and Properties of Nano-Crystalline Cellulose Electro-Rheological Fluid

2015 ◽  
Vol 815 ◽  
pp. 217-221
Author(s):  
Ling Li Xu ◽  
Xing Ling Shi ◽  
Qing Liang Wang
Keyword(s):  
Room Temperature ◽  
Silicone Oil ◽  
Strong Acid ◽  
Crystalline Cellulose ◽  
Methyl Silicone ◽  
Shearing Stress ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nano Crystalline ◽  
Transmission Electron

nanocrystalline cellulose (NCC) was prepared from micro-crystalline cellulose (MCC) by strong acid hydrolysis. The characteristics of such particle were studied by transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. Electro-rheological fluids (ERF) were prepared by dispersing NCC and MCC in methyl-silicone oil, and their ER effects were measured. Experimental results indicated that NCC ERF exhibited a remarkable ER effect. The highest static shearing stress of NCC ERF (3.5 g/ml) was 5.1 kPa at the room temperature under a 4 .2 kV/mm electric field, increased about 5.5 times compared to MCC ERF, and sedimentation of NCC ERF was not observed even after 60 days.

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