Kailash C. Dash

Bio: Kailash C. Dash is an academic researcher from Utkal University. The author has contributed to research in topics: Imidazole & Schiff base. The author has an hindex of 14, co-authored 69 publications receiving 601 citations.

Synergistic extraction of uranium(vi) by mixtures of beta -diketones and structurally related crown ethers

Abstract: Uranium(VI) was extracted from nitrate aqueous medium by mixtures of /?-diketones (HX), thenoyltrifluoroacetone (ΗΤΤΑ)/ dibenzoylmethane (DBzM) and crown ethers (CE) such as dicyclo-hexano-18-crown-6 (DC18C6)/dibenzo-18-crown6 (DB18C6)/monobenzo-15-crown-5 (B15C5) in chloroform. The extraction constants of the chelate and of mixed species, the synergistic factor and the formation constant of the extracted species were evaluated. The adduct stoichiometry was found to have the general formula U02X2 · CE, irrespective of the crown ether used. It was found that no specific cavity size is required for the adduct formation. The order of synergism was found as DC18C6 > B15C5 > DB18C6, which could be explained in terms of the crown ether basicity rather than the correspondence between the cavity size of the crown ether and the uranium(VI) crystal radii. Solid complexes of these metals with /?-diketones and crown ether have been isolated and characterized by using elemental analysis, IR and NMR spectroscopic techniques.

Extraction of zirconium(IV) from HCl solutions by mixtures of Aliquat-336 and Alamine-336 with TBP

Abstract: Synergism has been observed in the extraction of zirconium(IV) by mixtures of Aliquat 336 or Alamine 336 with a neutral donor TBP from aq. HCl solutions. Although the extractant dependency for Zr(IV) is found to be nearly second power with respect to TBP alone, monosolvate is found to be formed for extraction by its mixture with Aliquat 336 or Almine 336. Quantitative extraction is observed with mixtures at a lower acidity than that with individual extractants. The species formed is tentatively assigned to be Q2ZrCl6. TBP, where\(Q{\mathbf{ }} = {\mathbf{ }}R_3 {\mathbf{ }}\mathop N\limits^ + (CH_3 )\) for Aliquat 336 and\(R_3 {\mathbf{ }}\mathop N\limits^ + H\) for Alamine 336.

A Cobalt-Iron Double-Atom Catalyst for the Oxygen Evolution Reaction.

Abstract: Single-atom catalysts exhibit well-defined active sites and potentially maximum atomic efficiency. However, they are unsuitable for reactions that benefit from bimetallic promotion such as the oxygen evolution reaction (OER) in an alkaline medium. Here we show that a single-atom Co precatalyst can be in situ transformed into a Co-Fe double-atom catalyst for the OER. This catalyst exhibits one of the highest turnover frequencies among metal oxides. Electrochemical, microscopic, and spectroscopic data, including those from operando X-ray absorption spectroscopy, reveal a dimeric Co-Fe moiety as the active site of the catalyst. This work demonstrates double-atom catalysis as a promising approach for the development of defined and highly active OER catalysts.

Interfacial growth of a metal–organic framework (UiO-66) on functionalized graphene oxide (GO) as a suitable seawater adsorbent for extraction of uranium(VI)

Abstract: Extraction of radioactive uranium (U(VI)) from seawater has recently received extensive attention in the nuclear energy field. In this study, to acquire more void space of an MOF as active points for improving adsorption capacity, GO–COOH/UiO-66 composites were designed via coordination of the carboxyl groups of GO with zirconium ion of UiO-66; this was included as a part of the rapid and effective two-step method. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) were used to determine the effectiveness of the synthesis of GO–COOH/UiO-66 composites. The GO–COOH/UiO-66 composites were investigated for adsorption of U(VI) from an aqueous solution and artificial seawater. The results showed that the GO–COOH/UiO-66 composites had a high adsorption capacity at a suitable seawater pH with a high removal rate of U(VI) at the ppb and ppm levels. The adsorption process closely fitted the Langmuir isotherm model and pseudo-second-order rate equation. Based on the FTIR spectroscopy, the change in pH before and after the adsorption of U(VI), and X-ray photoelectron spectroscopy (XPS), a possible sorption mechanism of U(VI) onto GO–COOH/UiO-66 composites was revealed. In addition, the adsorbent showed good chemical stability under the operating conditions for the adsorption–desorption of U(VI) from an aqueous solution, which indicated a promising potential for applications in the extraction of U(VI) in seawater.