02601nas a2200241   4500008004100000022001400041245018300055210006900238260000800307300001100315490000800326520170900334653002002043653002502063653002702088653002102115653001302136100002002149700001602169700001802185700002602203856013002229       2023                        eng d  a1387-181100aInsights into adsorption of various gases on extra-framework cations of zeolite: a dispersion corrected DFT study on zeolite cluster models with Li plus , Na plus and K plus ions0 aInsights into adsorption of various gases on extraframework cati  cNov  a1127390 v3613 a<p>
	Design of an economical and sustainable gas separation material is relevant in several industrial processes. Zeolites with tunable pore sizes are ideal molecular sieves of many gases. The adsorption centers of these molecular sieves are extra-framework Lewis acid centers. In this study, we attempt to delineate the electronic properties of such centers (Li+, Na+ and K+) and their sorption properties towards N2, O2, CO, CO2 and H2. Negative framework of zeolites are modeled using different cluster models that present distinct electronic environment and role of this environment on the Lewis acidity of the cation. The sorption property towards different gases is evaluated using dispersion corrected DFT studies. The results obtained are benchmarked for one of the studied model using CCSD calculations. The results indicate that while the local environment modulates the adsorption properties, the relative adsorption properties between different ions follow the same order irrespective of the type of negative framework modeled. This reveals that intrinsic atomic properties of the charge compensating cations drive the sorption properties of the zeolites. Adsorption energies compounded with the analysis of IR stretching frequencies of the adsorbed gases reveals that Li centers shows molecular adsorption (charge donation to the cationic centers) towards N2 as compared to O2 and towards CO2/CO as compared to H2, demonstrating the applicability of Li-Zeolites as ideal membranes for oxygen concentrators and syngas separation. These adsorption studies are ratified by the BOMD simulations at 300 K, where H2 and O2 desorbs while N2, CO and CO2 remains adsorbed to the cationic site.</p>
10aBOMD simulation10aCO/CO2/H2 separation10aExtra-framework cation10aN2/O2 separation10azeolites1 aDevasia, George1 aKumar, Ravi1 aVaval, Nayana1 aKrishnamurty, Sailaja  uhttps://library.ncl.res.in/content/insights-adsorption-various-gases-extra-framework-cations-zeolite-dispersion-corrected-dft01871nas a2200241   4500008004100000022001400041245012500055210006900180260000800249300001400257490000800271520104600279100001801325700002901343700001701372700001901389700001601408700002101424700001801445700001601463700002301479856012701502       2025                        eng d  a1520-610600aInsights into the Chemical Durability and Structure of ZnO-Incorporated Sodium Borosilicate Glasses from Solid-State NMR0 aInsights into the Chemical Durability and Structure of ZnOIncorp  cJUL  a7349-73600 v1293 a<p>
	ZnO-incorporated NBS glasses have been studied for their application as a matrix for nuclear waste immobilization. However, structural factors affecting chemical durability have not been established. In this study, the structural changes in NBSZn glasses across various Na2O/(B2O3 + ZnO) ratios are explored using multinuclear MAS, MQMAS NMR, and EXAFS techniques. The Na MAS and MQMAS studies reveal remarkable changes in the Na environment after ZnO incorporation, which leads to an increase in chemical durability. Based on the results from NMR and EXAFS, we rationalized the structure of this glass in terms of the modified random network (MRN) model. The glass network comprises a highly polymerized region and alkali percolation channels bordered by nonbridging oxygens from the depolymerized regions. The constriction of these percolation channels increases the chemical durability of the glass. Our findings will help in the advancement of Zn-containing NBS glasses as a promising matrix for nuclear waste immobilization.</p>
1 aIllath, Kavya1 aAnanthanarayanan, Arvind1 aBanerjee, D.1 aMishra, R., K.1 aKumar, Ravi1 aBhattacharya, D.1 aKumar, Sanjay1 aManohar, S.1 aAjithkumar, T., G.  uhttps://library.ncl.res.in/content/insights-chemical-durability-and-structure-zno-incorporated-sodium-borosilicate-glasses