NOPR Collection:

Adsorptive removal of Fe(III) using gallic acid anchored iron magnetic nano-adsorbents synthesized via two different routes under microwave irradiation

2020-06-04T20:42:27Z

Title: Adsorptive removal of Fe(III) using gallic acid anchored iron magnetic nano-adsorbents synthesized via two different routes under microwave irradiation Authors: Rahim, Asmaa M Abdel; Ahmed, Salwa A; Soliman, Ezzat M Abstract: Under microwave solvent free conditions, bare iron magnetic nanoparticles (Fe₃O₄-MNPs) have been silica coated, amine functionalized and gallic acid grafted, in presence and absence of tetraethylorthosilicate (TEOS). The synthesized adsorbents in both cases have been followed up by Fourier transform infrared, scan electron microscopy and transmission electron microscopy analyses to verify and compare the progress of surface modification. The effects of various parameters on the adsorption efficiency of Fe(III) such as pH of solution, amount of adsorbent and contact time have been studied and optimized. The adsorbents Fe₃O₄-MNPs-SiO₂-CPTMS-1,2-EDA-GA and MNPs-CPTMS-1,2-EDA-GA exhibit higher Fe(III) capacities (4.980 and 4.700 mmol/g) than their analogous Fe₃O₄-MNPs-SiO₂-APTMS-GA and Fe₃O₄-MNPs-APTMS-GA (4.324 and 4.230 mmol/g). The studies of sorption kinetics showed rapid sorption dynamics by a second-order kinetic model, suggesting chemisorption mechanism. Fe(III) adsorption equilibrium data have been fitted well to the Langmuir isotherm. The results of medium stability as criteria for potential coating and values of metal uptake capacity support the possibility of the direct use of alkoxysilanes as an alternative to TEOS not only for coating but also for amine functionalization. This is strengthened by almost equal capability of gallic acid anchored adsorbents for extraction of trace concentrations of Fe(III) spiked natural water samples. Page(s): 9-20

A novel conductometric titration approach for rapid determination of boron

2020-01-22T05:41:49Z

Title: A novel conductometric titration approach for rapid determination of boron Authors: Ananthanarayanan, R; Rajiniganth, M P; Sivaramakrishna, M; Panigrahi, B S; Panigrahi, B K Abstract: In laboratories dealing with radioactive samples it is important to minimize both the sample size and also the associated waste generated in an analysis. To meet this objective a rapid conductometric titration technique is developed to determine boron in the moderators of Pressurized Heavy Water Reactors (PHWR’s). Using this novel PC interfaced titration facility a minimum tenfold reduction in sample size is achieved compared to conventional conductometric titration. Determination of boron is based on the conversion of extremely weak boric acid to better conducting boron mannitol complex and titrating the complex against NaOH. Various parameters affecting the analysis, when moving from large to small sample size, are analyzed and optimized. The technique is primarily proposed for the assay of boron (≥0.5 ppm) during reactor startup. Each analysis requires less than 10 min. The detection limit is 0.5 ppm and the precision obtained at this level is 4.6% RSD. The technique is a good alternative to less sensitive carminic acid based spectrophotometric method. Page(s): 21-30

Densimetric, acoustic and viscometric behaviour of sucrose solutions in aqueous 1-butyl-3-methylimidazolium hexafluorophosphate at different temperatures and ambient pressure

2020-01-22T05:39:10Z

Title: Densimetric, acoustic and viscometric behaviour of sucrose solutions in aqueous 1-butyl-3-methylimidazolium hexafluorophosphate at different temperatures and ambient pressure Authors: Sharma, Tanu; Sharma, Taniya; Kumar, Ashwani; Bamezai, Rajinder K Abstract: The thermophysical properties like density, speed of sound and viscosity have been measured for different molalities of sucrose in aqueous and different concentrations of aqueous solutions of an ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate, at different temperatures and atmospheric pressure. The results are explained in terms of acoustic parameters like apparent molar volume, apparent molar isentropic compressibility, limiting apparent molar volume, limiting apparent molar isentropic compressibility, limiting apparent molar transfer volume, limiting apparent molar transfer compressibility, hydration number, etc. Further, pair and triplet interaction coefficients, solvation number, viscosity B-coefficients and activation parameters have also been evaluated. The results demonstrate that solute-solvent interactions exist in the ternary system which increases with an increase in ionic liquid concentration. Page(s): 31-42

Selenium-capped cyclic peptide nanoparticles for penicillamine drug delivery: A DFT Study

2020-01-22T05:37:11Z

Title: Selenium-capped cyclic peptide nanoparticles for penicillamine drug delivery: A DFT Study Authors: Moghimi, Sara; Morsali, Ali; Heravi, Mohammad M Abstract: Using a model for performance of penicillamine (PCA) anti-cancer drug on selenium-cyclic peptide nanoparticle (CPSeNP), 11 noncovalent configurations have been investigated. Se8 ring model and cyclooctaglycine have been used for selenium nanoparticle (SeNP) and cyclic peptide (CP), respectively. Binding energies, quantum molecular descriptors and solvation energies have been studied in gas phase and water at M06-2X /6-31G** level of theory. The calculated energies represent the high-energy stability of CPSeNP/PCA 1-11 configurations. Solvation energies showed that drug solubility increases, which is a major factor for their use in drug delivery. Regarding to quantum molecular descriptors such as hardness and electrophilic power, the drug reactivity increases in the vicinity of SeNP. The QTAIM analysis revealed that intramolecular interaction Se-L (L =O, H , S, C , N) plays an important role in the system. Se-L interaction in all configurations is relevant to weak interactions. The configurations that PCA drug is located in parallel with the carrier (CPSeNP) are more stable than penicillamine-CP or penicillamine-SeNP systems. Page(s): 43-50