Adsorption Characteristics of Activated Carbon for the Reclamation of Eosin Y and Indigo Carmine Colored Effluents and New Isotherm Model

The adsorption response of eosin Y and indigo carmine acid dyes on activated carbon as a function of system temperature for a fixed concentration was investigated at various temperatures via adsorption isotherms and their thermodynamic quantities such as enthalpy, entropy, and Gibbs free energy changes. The adsorption data were exploited to develop a new adsorption isotherm. The new isotherm was developed with the spirit of solid–liquid phase equilibrium and regular solution theory. The proposed model has four adjustable constants and correlates adsorption isotherm in terms of the system temperature and melting temperature of the dye. The effect of pH on the removal of acid dyes was reported. The pH variation was observed to affect the adsorption efficiency. The removal of eosin Y and indigo carmine decreased from 99.4% to 82.6% and 92.38% to 79.48%, respectively, when the pH of the solution varied from 2 to 12. The thermodynamic analysis of the process reveals that the process of the removal of acid dyes is exothermic and spontaneous. Moreover, the kinetics parameters of the batch process are reported.     

Solvent extracted and extraction chromatographically adsorbed complexes of bifunctional extractants with f-elements

The IR spectra of the solvent extracted and extraction chromatographically adsorbed complexes of HNO₃, Nd(III), Th(IV) and U(VI) with bifunctional extractants dihexyl N,N-diethylcarbamoylmethylophosphonate (CMP) and octyl (phenyl)-N,N-diisobutylcarbamoyl-methylphosphine oxide (CMPO) have been recorded. The shifts in the P=0 and C=0 streching frequencies have been interpreted. The nitrate ions bound with metal ions were found to be bidentate. The nature of binding of the extractant to the metal ions in the solvent extracted and extraction chromatographically adsorbed complexes were found to be similar.     

Low energy position-hydrogen scattering

The positron-hydrogen scattering problem has been investigated using an integral approach at low incident positron energies. The effects of adiabatic and non-adiabatic potentials in both the direct and the rearrangement channels have been considered. The present values of the elastic S-wave phase shifts are found to be in reasonable agreement with the exact results.     

Cauchy problem for perfectly conducting viscous magnetofluid in general relativity

In recent years evidence has been accumulating that shows that in the early universe matter was in the dense plasma state, possibly associated with a strong primordial magnetic field. It has also been shown that the effect of particle creation at this epoch is equivalent in macroscopic theory to the effect of viscosity, of which shear viscosity was much more important and which may have removed some anisotropy present initially. The aim of this paper is to study the Cauchy problem for a perfectly conducting viscous magnetofluid assuming the pressure and coefficients of viscosity to be functions of the density alone. We also study the consistency conditions satisfied by four unknown quantities on the initial Cauchy hypersurface and show that hydrodynamic and Alfvén waves cannot be differentiated, unlike what occurs in a perfect magnetofluid.     

“Pauli effect” in relativity

Abraham's electromagnetic energy-momentum tensor predicts a force term additional to that given by Minkowski. We show that a symmetric energy-momentum tensor derived by Taub from a general variational principle also predicts this “Pauli effect”.     

Intramolecular charge-transfer dynamics in covalently linked perylene-dimethylaniline and cyanoperylene-dimethylaniline

The excited-state dynamics of covalently linked electron donor-acceptor systems consisting of N, N-dimethylaniline (DMA) as electron donor and either perylene (Pe) or cyanoperylene (CNPe) as acceptor has been investigated in a large variety of solvents, including a room-temperature ionic liquid, by using femtosecond time-resolved fluorescence and absorption spectroscopy. The negligibly small solvent dependence of the absorption spectrum of both compounds and the strong solvatochromism of the fluorescence are interpreted by a model where optical excitation results in the population of a locally excited state (LES) and emission takes place from a charge-separated state (CSS). This interpretation is supported by the fluorescence up-conversion and the transient absorption measurements that reveal substantial spectral dynamics in polar solvents only, occurring on time scales going from a few hundreds of femtoseconds in acetonitrile to several tens of picoseconds in the ionic liquid. The early transient absorption spectra are similar to those found in nonpolar solvents and are ascribed to the LES absorption. The late spectra due to CSS absorption show bands that are red-shifted relative to those of the radical anion of the acceptor moiety by an amount that depends on solvent polarity, pointing to partial charge separation. Global analysis of the time-resolved data indicates that the charge separation dynamics in PeDMA is essentially solvent controlled, whereas that in CNPeDMA is faster than diffusive solvation, this difference being accounted for by a larger driving force for charge separation in the latter. On the other hand, the CSS lifetime of PeDMA is of the order of a few nanoseconds independently of the solvent, whereas that of CNPeDMA decreases with increasing solvent polarity from a few nanoseconds to a few hundreds of picoseconds. Comparison of these results with previously published data on the fluorescence quenching of Pe and CNPe in pure DMA shows that the charge separation and the ensuing charge recombination occur on similar time scales independently of whether these processes are intra- or intermolecular.     

A Concise Synthesis of the DNA‐Intercalating and Antimalarial Alkaloid Cryptolepine and Its Fluorescence Behaviour in Solvents of Different Polarities

A microwave‐induced rapid and facile synthesis of the DNA‐intercalating and antimalarial drug cryptolepine is described. The key step in this synthesis involves the aqueous‐phase base‐catalyzed condensation of isatin and 1‐acetyl‐1H‐indol‐3‐yl acetate which has been simplified and expedited by dielectric heating, employing an ordinary domestic microwave oven. The method transforms the synthesis of an important drug molecule from a prohibitively lengthy process to a matter of a few minutes with a much improved yield. Dual absorption and fluorescence is observed from the molecular system in solvents of different polarity thus providing valuable insight into its binding modes toward protein or DNA.     

Regioselective Synthesis of Quinazolinone‐/Phenanthridine‐Fused Heteropolycycles by Pd‐Catalyzed Direct Intramolecular Aerobic Oxidative C−H Amination from Aromatic Strained Amides

A new route for the expedient synthesis of specific regioisomer of quinazolinone‐ and phenanthridine‐fused heterocycles through a palladium‐catalyzed regioselective intramolecular oxidative C?H amination from cyclic strained amides of aromatic amido–amidine systems (quinazolinones) has been developed. The amine functionalization of an aromatic C?H bond from a strained amide nitrogen involved in aromaticity has been a challenging work so far. The fusion of two heterocyclic cores, quinazolinone and phenanthridine, can occur in two different ways (linear and angular), but under the conditions reported here, only linear type isomer is exclusively produced. This approach provides a variety of substituted quinazolinone‐ and phenanthridine‐fused derivatives in moderate to excellent yields. Moreover, such fused molecules show excellent fluorescent properties and have great potential to be a new type of fluorophores for the use in medicinal and material science.