Investigation on Strontium Adsorption Selectivity of Hydrothermally Synthesized Layered Sodium Titanates

2020 ◽  
Vol 12 (2) ◽  
pp. 186-190 ◽  
Author(s):  
Hiroto Kunishi ◽  
Takeshi Hagio ◽  
Yuki Kamimoto ◽  
Ryoichi Ichino

Two layered sodium titanate phases, sodium nonatitanate (Na4Ti9O20) and sodium trititanate (Na2Ti3O7), have been hydrothermally synthesized and their Sr2+ adsorption selectivity was investigated in the coexistence of Cs+ with ionic equivalent concentration. Although both phases exhibit Sr2+ selective adsorption, Na4Ti9O20 adsorbed both Sr2+ and Cs+, while the adsorption of Cs+ was not detected on Na2Ti3O7, despite its higher adsorption capacity. To investigate the causes for the high Sr2+ selectivity of Na2Ti3O7, additional adsorption tests were carried out in different pH, which can be interpreted as the Sr2+ –H+ binary system, and in single and ternary systems of Al3+, Sr2+ and K+ with ionic equivalent concentrations. When changing the pH, the adsorption amount of Sr2+ showed a high and nearly constant value at pH above 4 and drastically decreased at pH below 3, reaching nearly zero at pH 2. In the Al3+–Sr2+ –K+ ternary system, the adsorption amount decreased in the order of Sr2+, Al3+ and K+. The adsorption amount of K+ was low compared to that of Sr2+ and Al3+ in both the single and ternary systems. Meanwhile, the adsorption amount of Sr2+ significantly decreased compared to that in the single system, unlike in the Sr2+–Cs+ binary system where the adsorption of Sr2+ was almost the same. From these results, the high Sr2+ selectivity of Na2Ti3O7 in the Sr2+–Cs+ binary system was anticipated to be due to the size effect. The smaller interlayer spacing of Na2Ti3O7 compared to that of Na4Ti9O20 appears to inhibit the intercalation of Cs+ due to its large ionic radius.

2019 ◽  
Vol 25 (34) ◽  
pp. 3633-3644
Author(s):  
Nasrullah Shah ◽  
Saba Gul ◽  
Mazhar Ul-Islam

: Core-shell polymers represent a class of composite particles comprising of minimum two dissimilar constituents, one at the center known as a core which is occupied by the other called shell. Core-shell molecularly imprinting polymers (CSMIPs) are composites prepared via printing a template molecule (analyte) in the coreshell assembly followed by their elimination to provide the everlasting cavities specific to the template molecules. Various other types of CSMIPs with a partial shell, hollow-core and empty-shell are also prepared. Numerous methods have been reported for synthesizing the CSMIPs. CSMIPs composites could develop the ability to identify template molecules, increase the relative adsorption selectivity and offer higher adsorption capacity. Keen features are measured that permits these polymers to be utilized in numerous applications. It has been developed as a modern technique with the probability for an extensive range of uses in selective adsorption, biomedical fields, food processing, environmental applications, in utilizing the plant's extracts for further applications, and sensors. This review covers the approaches of developing the CSMIPs synthetic schemes, and their application with special emphasis on uses in the biomedical field, food care subjects, plant extracts analysis and in environmental studies.


Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1437
Author(s):  
Chih Ming Ma ◽  
Bo-Yuan Yang ◽  
Gui-Bing Hong

Hydrogel beads based on the husk of agarwood fruit (HAF)/sodium alginate (SA), and based on the HAF/chitosan (CS) were developed for the removal of the dyes, crystal violet (CV) and reactive blue 4 (RB4), in aqueous solutions, respectively. The effects of the initial pH (2–10) of the dye solution, the adsorbent dosage (0.5–3.5 g/L), and contact time (0–540 min) were investigated in a batch system. The dynamic adsorption behavior of CV and RB4 can be represented well by the pseudo-second-order model and pseudo-first-order model, respectively. In addition, the adsorption isotherm data can be explained by the Langmuir isotherm model. Both hydrogel beads have acceptable adsorption selectivity and reusability for the study of selective adsorption and regeneration. Based on the effectiveness, selectivity, and reusability of these hydrogel beads, they can be treated as potential adsorbents for the removal of dyes in aqueous solutions.


2014 ◽  
Vol 809-810 ◽  
pp. 297-301
Author(s):  
Ping Rui Meng ◽  
Liang Bo Li

In order to selectively separate luteolin from its crude solution, we synthesized luteolin molecular imprinted polymers (LMIP) with high recognition specificity for luteolin, using an imprinting technique. Luteolin was used as template, methanol as solvent, and N,N’-methylenebisacrylamide (MBAA) as the cross-linking. Then prepared LMIP were characterized and evaluated by scanning electron microscope (SEM) and equilibrium absorption experiments. The results showed that the cavities matching with the template molecules in size and structure were present in the LMIP. Adsorption dynamics analysis suggested that, when the adsorption time reached 4 h, the adsorption process had reached balance and the adsorption capacity was at steady state. The selective adsorption amount reached at 35.65 umol/g for the LMIP, while a lower value of 11.68 umol/g for the blank polymer (i.e. nontemplated). Relative to the corresponding blank polymer, LMIP had an excellent recognition to luteolin in methanol solution. Keywords: Molecular imprinting, Molecular recognition, Adsorbent, Luteolin


2021 ◽  
Author(s):  
Hanbang Liu ◽  
Danhua Yuan ◽  
Liping Yang ◽  
Jiacheng Xing ◽  
Shu Zeng ◽  
...  

The traditional zeolites used in air separation are generally N2-selective adsorbents. It was found for the first time that the O2/N2 adsorption selectivity can be reversed by directly decorating the...


2018 ◽  
Vol 19 (9) ◽  
pp. 2797 ◽  
Author(s):  
Heleen Van Den Noortgate ◽  
Bert Lagrain ◽  
Tom Wenseleers ◽  
Johan Martens

The pharaoh ant is a notorious and hard to eradicate pest, which poses a threat in hospitals, spreading pathogens and contaminating sterile equipment. When applied on ants, zeolites adsorb part of their epicuticular wax layer. The ants are then vulnerable to desiccation, since this layer regulates water exchange. We analyzed the chemical composition of this wax layer using GC-MS (Gas Chromatography-Mass Spectrometry). A hexane wash of M. pharaonis foragers resulted in the identification of 53 components, four of which were not previously defined in Monomorium species. Selective adsorption of specific compounds on zeolites assisted in the identification of compounds which could not be separated on the GC column and allowed for the identification of three additional compounds. Zeolites show different affinities for the wax compounds depending on pore structure and chemical composition. Selective adsorption of alkanes on zeolites is also investigated in the fields of refinery processes and catalysis. Pore mouth and key lock adsorption mechanisms and selectivity according to molecular weight and branching, investigated in these fields, are also involved in adsorption processes of epicuticular waxes. The insecticidal activity of a zeolite is related to adsorption selectivity rather than capacity. One of the best adsorbing zeolites showed limited insecticidal activity and can be considered as a non-lethal alternative for epicuticular wax sampling.


2020 ◽  
Vol 22 (11) ◽  
pp. 6441-6448 ◽  
Author(s):  
Jongwoo Park ◽  
Mayank Agrawal ◽  
Dorina F. Sava Gallis ◽  
Jacob A. Harvey ◽  
Jeffery A. Greathouse ◽  
...  

We assess the nontrivial deviation in predicting the adsorption selectivity from bulk mixtures of complex molecules using nanoporous adsorbents approximated as rigid and intrinsically flexible.


Chemosensors ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 31
Author(s):  
Nada Abdulrazzaq ◽  
Baseem Al-Sabbagh ◽  
Julia Rees ◽  
William Zimmerman

A cost effective, fast, and accurate technique was needed to measure the vapor composition of a binary system (ethanol-water) and also that of a liquid composition in a ternary system (acetic acid-acetol–water) in a microbubble distillation unit. Cheap TGS-series gas sensors were used for this purpose with both calibrations and measurements carried out in a specially designed chamber. A single parameter polynomial regression was fitted to the binary system, and a two parameter polynomial with an interaction term was fitted to the ternary system. The correlation coefficient, R-squared, was found to be greater than 0.99 for both systems, thus validating the implementation of this novel sensor.


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