Showing papers by "Kamalika Sen published in 2017"

Biogenic Nano-CuO-Catalyzed Facile C–N Cross-Coupling Reactions: Scope and Mechanism

Abstract: We demonstrate here a green and efficient biogenic synthesis of copper(II) oxide nanoparticles using easily available Ocimum Sanctum leaf extract at room temperature. The biogenic copper oxide nanoparticles have shown excellent activity on N-arylation of cyclic and acyclic amides with aryl and styryl halides. Broad substrate scope, excellent functional group tolerance, and high yields were observed. This protocol is also extended for the N-arylation of substituted aryl amines and nitrogen heterocycles including pyrole, indole, imidazole, benzimidazole, and carbazole. The catalyst was characterized by EPR, UV, FT-IR, BET, AAS, TGA analysis, XPS, XRD, and HR-TEM.

Separation of long-lived 152Eu radioisotopes from a binary mixture of 152Eu and 134Cs by calcium alginate: a green technique

Abstract: Calcium alginate (CA) hydrogel beads were prepared and used for the separation of 152Eu from trace and macro amounts of cesium. Best separation was achieved from 10−2 M HNO3, upon shaking 30 CA beads with the solution containing 152Eu and Cs for 20 min and then allowing a settle for further 10 min. Back extraction of europium without any contamination of Cs was successfully obtained after treating the 152Eu adsorbed CA beads with 0.1 M HNO3 and 1 M HNO3 solutions.

On the kinetics of block copolymer mediated palladium quantum dot synthesis: Application in reduction of Cr(VI) to Cr(III)

Abstract: In this work we have designed a simple, eco-friendly, one-pot method for the synthesis of palladium nanoparticles of quantum dot dimension (PdQDs) using a non-toxic, biocompatible block co polymer which functions as a reducing and stabilizing agent during the synthesis. The entire synthesis is free from any especial experimental set up and reaction conditions. These QDs were characterized by several well know characterization techniques such as UV–vis spectroscopy (UV–vis), transmission electron microscopy (TEM), Fourier transform infra-red spectroscopy (FTIR), dynamic light scattering (DLS), and ξ potential measurements. The transformation of a yellow solution into dark brown solution was indicative of the formation of the PdQDs. The kinetics of this reaction was monitored using a time scan absorption measurement which reveals a sigmoidal curve, a signature of noble metal nanoparticles. The rate of nucleation and growth were calculated using Finke and Watzky model. The synthesized colloidal PdQDs were employed for the reduction of environmentally toxic Cr(VI) to safer Cr(III). The reaction was catalyzed by the PdQDs in presence of acetic acid and was dependent on the concentration of both. The order and rate constant of the reduction reaction was calculated. A comparatively faster and complete reduction of Cr(VI) to Cr(III) using this catalysis was achieved at room temperature in presence γ irradiation, thus making the method more effective in its approach for bulk remediation of Cr(VI).

Radiometric analysis of isotherms and thermodynamic parameters for cadmium(II) adsorption from aqueous medium by calcium alginate beads

Abstract: Studies on the extraction behavior and immobilization of cadmium by greener reagents have important bearings in today’s science. No-carrier-added (NCA), 109Cd radionuclide is a potential candidate towards radiopharmaceutical studies for both in vivo and in vitro applications and is also used in industrial and environmental studies. Herein, we have studied the adsorption and desorption characteristics of cadmium in both NCA and bulk concentrations into calcium alginate using radiochemical method. Various isotherms like Langmuir, Freundlich, Temkin and Dubinin–Radushkevich have been studied and compared to match the adsorption phenomenon. A spontaneous endothermic physisorption process is expected from thermodynamic parameters.

Production, separation and embedment of no-carrier added 93mMo in iron-doped calcium alginate beads from 7Li irradiated yttrium target

Abstract: No-carrier-added 93mMo radionuclide is a promising candidate in the field of radiopharmaceuticals. In the present investigation 93mMo was produced by 7Li irradiation of natural Y-foil target following the reaction natY(7Li,3n)93mMo and was separated from the bulk Y target using iron-doped calcium alginate (Fe-CA) hydrogel beads. High separation factor (S Mo/Y = 4.38 × 102) was obtained. The isotopically pure 93mMo could also be embedded in Fe-CA beads, which might act as smart material for administration to human body.

Separation of no-carrier-added 97 Ru from 11 B-induced Y target by encapsulation of 97 Ru into calcium alginate hydrogel beads

Abstract: 97Ru radioisotope, a promising candidate for radiopharmaceutical applications was produced by natY(11B,3n) 97Ru reaction with 40 MeV projectile energy. Calcium alginate (CA) hydrogel beads, an environmentally benign matrix, were used for separation of no-carrier-added (NCA) 97Ru from the bulk yttrium target through adsorption–desorption experiments with a high separation factor (S Ru/Y = 2.6 × 104). It was also possible to encapsulate high purity 97Ru in CA hydrogel beads.