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.

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.

Adsorption of the harmful hormone ethinyl estradiol inside hydrophobic cavities of CTA+ intercalated montmorillonite

2016 ◽  
Vol 74 (3) ◽  
pp. 663-671 ◽  
Author(s):  
A. E. Burgos ◽  
Tatiana A. Ribeiro-Santos ◽  
Rochel M. Lago
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
High Efficiency ◽  
Interlayer Space ◽  
Ethinyl Estradiol ◽  
Significant Loss ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrophobic Cavity ◽  
Adsorption Capacities ◽  
Derivative Thermogravimetry

Hydrophobic cavities produced by cetyltrimethylammonium cation (CTA+) exchanged and trapped in the interlayer space of montmorillonite were used to remove the harmful hormone contaminant ethinyl estradiol (EE2) from water. X-ray diffraction, thermogravimetry/derivative thermogravimetry, elemental analysis (carbon, hydrogen, nitrogen), Fourier transform infrared, scanning electron microscopy/energy dispersive spectroscopy, Brunauer–Emmett–Teller and contact angle analyses showed that the intercalation of 9, 16 and 34 wt% CTA+ in the montmorillonite resulted in the d001 expansion from 1.37 to 1.58, 2.09 and 2.18 nm, respectively. EE2 adsorption experiments showed that the original clay montmorillonite does not remove EE2 from water whereas the intercalated composites showed high efficiency with adsorption capacities of 4.3, 8.8 and 7.3 mg g−1 for M9CTA+, M16CTA+ and M34CTA+, respectively. Moreover, experiments with montmorillonite simply impregnated with cetyltrimethylammonium bromide showed that the intercalation of CTA+ to form the hydrophobic cavity is very important for the adsorption properties. Simple solvent extraction can be used to remove the adsorbed EE2 without significant loss of CTA+, which allows the recovery and reuse of the adsorbent for at least five times.

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.

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.

Synthesis of carboxyl-introduced chitosan with C2 amine groups protected and its use in copper (II) removal

2017 ◽  
Vol 76 (8) ◽  
pp. 2095-2105 ◽  
Author(s):  
Liu Dong ◽  
Cheng Wen ◽  
Yu Junxia ◽  
Ding Yigang
Keyword(s):  
Schiff Base ◽  
Adsorption Mechanism ◽  
Cross Linking ◽  
Hydroxyl Groups ◽  
Mechanism Study ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Capacities ◽  
Amine Groups ◽  
Hydrochloride Solution

A route for the formation of carboxyl-introduced chitosan (CI-CS) with C2 amine groups protected (CIAP-CS) was investigated to improve copper (II) adsorption. First, the C2 amine groups of the chitosan (CS) were protected via a Schiff-base reaction by benzaldehyde. Then the product was obtained by the introduction of pyromellitic dianhydride to the C6 hydroxyl groups on CS via epichlorohydrin. The last product was obtained by removing the Schiff base with dilute hydrochloride solution. CI-CS without C2 amine groups protected was directly synthesized as well. The adsorbents were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectrometer (XPS). The adsorption properties for copper (II) were investigated. FTIR spectroscopy and XPS clearly showed that most of the amine groups in CS were converted to –N = CH2 groups after the benzaldehyde treatment and that no cross-linking reactions with CS were involved; the HCl treatment after the cross-linking reaction effectively released nitrogen atoms protected into the form of the primary amine again. The results confirm that the CIAP-CS cross-linked with the new method had significantly greater adsorption capacities than the CI-CS cross-linked directly with CS. Mechanism study revealed that the increased adsorption performance is attributed to the large number of primary carboxyl and amine groups available on the surfaces of the CIAP-CS. The adsorption mechanism is based on ion exchange and chelating action, and the adsorption process is mainly chemisorption.

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.

scholarly journals Ti/RuO2-IrO2-SnO2 Anode for Electrochemical Degradation of Pollutants in Pharmaceutical Wastewater: Optimization and Degradation Performances

2020 ◽  
Vol 13 (1) ◽  
pp. 126
Author(s):  
Guozhen Zhang ◽  
Xingxing Huang ◽  
Jinye Ma ◽  
Fuping Wu ◽  
Tianhong Zhou
Keyword(s):  
Removal Rate ◽  
Inorganic Compounds ◽  
Oxide Coating ◽  
X Ray Diffraction ◽  
Pharmaceutical Wastewater ◽  
High Concentration ◽  
Dimensionally Stable Anodes ◽  
X Ray ◽  
Initial Ph ◽  
Cod Removal Rate

Electrochemical oxidation technology is an effective technique to treat high-concentration wastewater, which can directly oxidize refractory pollutants into simple inorganic compounds such as H2O and CO2. In this work, two-dimensionally stable anodes, Ti/RuO2-IrO2-SnO2, have been developed in order to degrade organic pollutants from pharmaceutical wastewater. Characterization by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) showed that the oxide coating was successfully fabricated on the Ti plate surface. Electrocatalytic oxidation conditions of high concentration pharmaceutical wastewater was discussed and optimized, and the best results showed that the COD removal rate was 95.92% with the energy consumption was 58.09 kW·h/kgCOD under the electrode distance of 3 cm, current density of 8 mA/cm2, initial pH of 2, and air flow of 18 L/min.

A Sulfide Ion Sensor from Commercial Bentonite

2014 ◽  
Vol 894 ◽  
pp. 412-415
Author(s):  
Duangsamorn Morawong ◽  
Atchana Wongchaisuwat ◽  
Ladda Meesuk
Keyword(s):  
Interlayer Space ◽  
Intercalation Compound ◽  
X Ray Diffraction ◽  
Solid Reaction ◽  
X Ray ◽  
Sulfide Ion ◽  
Best Response ◽  
Percent Recovery ◽  
Synonymous Term ◽  
Nernstian Slope

Bentonite is a synonymous term of montmorillonite which is a clay mineral consisting of 2 : 1 aluminosilicate layered structure. In this work, a commercial bentonite was used to prepare an intercalation compound [Ca (2,2-bipyridine)3]2+in the interlayer space, by solid-solid reaction, which formation was confirmed by the expansion of the interlayer space of bentonite from 1.5 to 1.8 nm, by powder X-Ray Diffraction technique. The intercalation compound [Ca (2,2-bipyridine)3]2+-bentonite was then used as a sensor to assemble a potentiometric electrode. The electrode gave best response to sulfide ion in terms of Nernstian slope. Precision of measurement, reproducibility and percent recovery were also studied. The electrode could be used to measure sulfide ion in real water samples and gave satisfactory results.

scholarly journals Intercalation of oxalate ions in the interlayer space of a layered double hydroxide for nickel ions adsorption

2016 ◽  
Vol 5 (2) ◽  
pp. 144
Author(s):  
Doungmo Giscard ◽  
Théophile Kamgaing ◽  
Ranil Clément Tonleu Temgoua ◽  
Ervice Ymele ◽  
Francis Merlin Melataguia Tchieno ◽  
...  
Keyword(s):  
Interlayer Space ◽  
X Ray Diffraction ◽  
Batch Mode ◽  
Nickel Ions ◽  
X Ray ◽  
Modified Clay ◽  
Pseudo Second Order ◽  
Oxalate Ions ◽  
Double Hydroxide ◽  
Clay Materials

In this study, sorption properties of a synthesized anionic clay were enhanced by the intercalation of oxalate ions in its interlayer space. The pristine and modified clay materials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and thermal analysis. These techniques confirmed the presence of oxalate ions in the interlayer space of the clay. The intercalated clay was then used as a matrix for the sorption in batch mode of nickel ions in aqueous solution. The influence of a number of parameters such as contact time, pH, initial concentration of the analyte and adsorbent dosage were studied. The maximum adsorption of nickel was obtained at pH 6, that is, about 90% Ni2+ removal. The adsorbent/adsorbate equilibrium follows a pseudo-second order kinetics and best matches the Langmuir model. The modified clay was shown to be efficient matrix for the sorption of nickel ions.

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