Maya Chatterjee

A New Granular Composite with High Selectivity for Cesium Ion Prepared from Phosphomolybdic Acid Hydrate and Inorganic Porous Material

Ammonium molybdophosphate (AMP) was incorporated in the porous alumina matrix (JA) by successive impregnation with H3Mo12O40P and NH4NO3. The loading percentage of AMP crystals on JA increased with the repetition times of impregnation. The distribution coefficients of Cs+ on AMP-loaded granular composite (JAAMP) was above 104 cm3/g in the presence of 1 mol/dm3 while those of other nuclides were less than 10, indicating high selectivity of JAAMP to Cs+. The separation factor of 137Cs to other nuclides 85Sr,60Co, 152Eu,241Am,22Na) (αCs/Sr;Co;Eu;Am;Na =K d,Cs/K d,Sr;Co;Eu;Am;Na) was estimated to be above 103. The breakthrough curve for Cs+ through the column packed with JAAMP exhibited a symmetrical S-shaped profile, and this exchanger proved to be effective for the selective isolation of radiocesium from a simulated high-level liquid waste.

Molecular dynamics simulation of metal porphyrin complex encapsulated in zeolite

Molecular dynamics (MD) simulation was applied to study the configuration of metal (Mg, Co, Fe) porphyrin complexes encapsulated in Y-type (USY, NaY) zeolites. In absence of exchanged cations the metal center interacts with framework oxygen atoms and a low catalytic activity of the porphyrin-zeolite system is expected. However, in presence of exchanged cations, which interact with framework oxygen atoms, the metal center is available to interact with reactants and a good catalytic activity of the porphyrin-zeolite system is expected.

Chapter 7:Efficient Transformation of Biomass-derived Compounds into Different Valuable Products: A “Green” Approach

In this work, supercritical carbon dioxide (scCO2), and scCO2/H2O were investigated for the processing of biomass-derived compounds such as 5-hydroxymethylfurfural (5-HMF), furfural and tetrahydrofurfuryl alcohol (THFA) into a vast array of fuel and non-fuel related chemicals. Higher solubility of reactant gasses in scCO2 results in an acceleration of the reaction rate and enhancement of the product selectivity. As a reaction medium, scCO2 offers promise to play a role in the conversion of 5-HMF to linear alkane, which relies heavily on hydrogen concentration. Furthermore, 5-HMF can be successfully converted to 2,5-dimethylfuran (a fuel additive) with the highest selectivity (100%) in ascCO2/H2O mixture. In the presence of H2O, scCO2 creates an acidic environment and contributes to improving the selectivity of 2,5-dimethylfuran. Similarly, furfural also produces 2-methylfuran through the hydrogenation/hydrogenolysis of the C–O bond. 1,5-pentanediol, which is used as a monomer in the polyester industry, could be conveniently obtained with 91% selectivity from THFA in scCO2 under the homogeneous conditions of a CO2–H2-substrate. Hence, the remarkable advantage of the present catalytic system has confirmed the potential utilisation of alternative “green” solvents in the conversion of different biomass based compounds.