scholarly journals Ammonium-to-sodium ion-exchange process at the interlayer of octacalcium phosphate

RSC Advances ◽  
2021 ◽  
Vol 11 (62) ◽  
pp. 39503-39507
Author(s):  
Yuki Sugiura ◽  
Yoji Makita ◽  
Masanori Horie
Keyword(s):  
Calcium Phosphate ◽  
Ion Exchange ◽  
Exchange Process ◽  
Octacalcium Phosphate ◽  
Sodium Ion ◽  
Ionic Exchange ◽  
Ion Exchange Process

Octacalcium phosphate (OCP) has been considered as the layer component of calcium phosphate, but whether it achieves the ionic-exchange ability of conventional layer components is unclear. In this study, we demonstrated the evidence of ionic exchange process at the interlayer of OCP.

scholarly journals IR GRIN lenses prepared by ionic exchange in chalcohalide glasses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Claire Fourmentin ◽  
Xiang-Hua Zhang ◽  
Enora Lavanant ◽  
Thierry Pain ◽  
Mathieu Rozé ◽  
...  
Keyword(s):  
Refractive Index ◽  
Ion Exchange ◽  
Thermal Imaging ◽  
Chalcogenide Glasses ◽  
Exchange Process ◽  
Optical Design ◽  
Ionic Exchange ◽  
Ion Exchange Process ◽  
Chalcohalide Glasses ◽  
Atmospheric Windows

AbstractIn order to decrease the number of lenses and the weight of thermal imaging devices, specific optical design are required by using gradient refractive index (GRIN) elements transparent in the infrared waveband. While widely used for making visible GRIN lenses with silicate glasses, the ion exchange process is very limited when applied to chalcogenide glasses due to their low Tg and relatively weak mechanical properties. In this paper, we develop chalco-halide glasses based on alkali halide (NaI) addition in a highly covalent GeSe2–Ga2Se3 matrix, efficient for tailoring a significant and permanent change of refractive by ion exchange process between K+ and Na+. Optical and structural properties of the glass samples were measured showing a diffusion length reaching more than 2 mm and a Gaussian gradient of refractive index Δn of 4.5.10–2. The obtained GRIN lenses maintain an excellent transmission in the second (3–5 µm) and third (8–12 µm) atmospheric windows.

Removal of Toxic Dyestuffs from Aqueous Solution by Amphoteric Bioadsorbent

2020 ◽  
Vol 16 ◽  
Author(s):  
Reda M. El-Shishtawy ◽  
Abdullah M. Asiri ◽  
Nahed S. E. Ahmed
Keyword(s):  
Aqueous Solution ◽  
Ion Exchange ◽  
Dye Removal ◽  
Exchange Process ◽  
Cationic Dyes ◽  
Carboxyl Groups ◽  
Maximum Adsorption Capacity ◽  
Equilibrium Isotherm ◽  
Ion Exchange Process ◽  
Dyes And Pigments

Background: Color effluents generated from the production industry of dyes and pigments and their use in different applications such as textile, paper, leather tanning, and food industries, are high in color and contaminants that damage the aquatic life. It is estimated that about 105 of various commercial dyes and pigments amounted to 7×105 tons are produced annually worldwide. Ultimately, about 10–15% is wasted into the effluents of the textile industry. Chitin is abundant in nature, and it is a linear biopolymer containing acetamido and hydroxyl groups amenable to render it atmospheric by introducing amino and carboxyl groups, hence able to remove different classes of toxic organic dyes from colored effluents. Methods: Chitin was chemically modified to render it amphoteric via the introduction of carboxyl and amino groups. The amphoteric chitin has been fully characterized by FTIR, TGA-DTG, elemental analysis, SEM, and point of zero charge. Adsorption optimization for both anionic and cationic dyes was made by batch adsorption method, and the conditions obtained were used for studying the kinetics and thermodynamics of adsorption. Results: The results of dye removal proved that the adsorbent was proven effective in removing both anionic and cationic dyes (Acid Red 1 and methylene blue (MB)), at their respective optimum pHs (2 for acid and 8 for cationic dye). The equilibrium isotherm at room temperature fitted the Freundlich model for MB, and the maximum adsorption capacity was 98.2 mg/g using 50 mg/l of MB, whereas the equilibrium isotherm fitted the Freundlich and Langmuir model for AR1 and the maximum adsorption capacity was 128.2 mg/g. Kinetic results indicate that the adsorption is a two-step diffusion process for both dyes as indicated by the values of the initial adsorption factor (Ri) and follows the pseudo-second-order kinetics. Also, thermodynamic calculations suggest that the adsorption of AR1 on the amphoteric chitin is an endothermic process from 294 to 303 K. The result indicated that the mechanism of adsorption is chemisorption via an ion-exchange process. Also, recycling of the adsorbent was easy, and its reuse for dye removal was effective. Conclusion: New amphoteric chitin has been successfully synthesized and characterized. This resin material, which contains amino and carboxyl groups, is novel as such chemical modification of chitin hasn’t been reported. The amphoteric chitin has proven effective in decolorizing aqueous solution from anionic and cationic dyes. The adsorption behavior of amphoteric chitin is believed to follow chemical adsorption with an ion-exchange process. The recycling process for few cycles indicated that the loaded adsorbent could be regenerated by simple treatment and retested for removing anionic and cationic dyes without any loss in the adsorbability. Therefore, the study introduces a new and easy approach for the development of amphoteric adsorbent for application in the removal of different dyes from aqueous solutions.

Chromate ion-exchange process at alkaline pH

1986 ◽  
Vol 20 (9) ◽  
pp. 1177-1184 ◽  
Author(s):  
Arup K. Sengupta ◽  
Dennis Clifford ◽  
Suresh Subramonian
Keyword(s):  
Ion Exchange ◽  
Exchange Process ◽  
Alkaline Ph ◽  
Ion Exchange Process ◽  
Chromate Ion

The Application of ß“-Alumina As A Solid State Laser Host

1985 ◽  
Vol 60 ◽  
Author(s):  
J. D. Barrie ◽  
D. L. Yang ◽  
B. Dunn ◽  
O. M. Stafsudd
Keyword(s):  
Optical Properties ◽  
Solid State ◽  
Ion Exchange ◽  
Exchange Process ◽  
Laser Action ◽  
Solid State Laser ◽  
Host Crystal ◽  
State Laser ◽  
Ion Exchange Process ◽  
Single Host

AbstractIon exchanged ß“-aluminas display a number of interesting optical properties which suggest that the material is well suited for application as a solid state laser host. Small platelets of Nd3+ Ion exchanged β“-alumina exhibit laser action with gain coefficients many times greater than YAG. The versatility of the ion exchange process enables one to form a wide variety of compounds with different active ions and concentrations, thereby allowing the study of many different effects within a single host crystal.

Removal of Se(VI) from Raw Water by Ion Exchange Process

2012 ◽  
Vol 430-432 ◽  
pp. 941-948 ◽  
Author(s):  
Yong Sheng Shi ◽  
Yu Zhen Shi ◽  
Lin Wang
Keyword(s):  
Ion Exchange ◽  
Removal Rate ◽  
Exchange Process ◽  
Selenium Concentration ◽  
Quality Standard ◽  
Raw Water ◽  
Strong Base ◽  
Ion Exchange Process ◽  
Efficiency Cost ◽  
Easy Operation

Studies have been carried out on removal of Se(Ⅵ) from raw water by ion exchange process. The experiment results indicate that employment of strong-base anion exchange resin of 201×7 can receive a desirable result for Se removal. It is particularly true that the removal rate of Se(Ⅵ) can achieve more than 96% when the Se(Ⅵ) concentration in raw water is 100μg/L. This allows selenium concentration of the supply water in full conformity to the quality standard currently available for drinking water. Ion exchange process for Se removal has been proved to be competent for its efficiency, cost effectiveness and easy operation.

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