NOPR Collection:

Influence of organic solvents, head-groups and temperature on the micellization behavior of some cationic surfactants

2016-07-20T06:23:29Z

Title: Influence of organic solvents, head-groups and temperature on the micellization behavior of some cationic surfactants Authors: Sood, A K; Kaur, Rupinderjit; Banipal, T S Abstract: The effect of organic solvents, viz., dioxane, dimethylformamide and ethylene glycol on the micellization behavior of cationic surfactants, i.e., tetradecyltrimethyl ammonium bromide (TTAB), tetradecyldimethylbenzyl ammonium chloride (C14BCl) and their dimeric homologue, dimethylene-1,2-bis(tetradecyldimethyl ammonium bromide) (14-2-14) is studied in aqueous solutions using conductometric and viscometric techniques at different temperatures (288.15–318.15 K). It is observed that the critical micelle concentration and degree of counterion dissociation values increase with the increase in volume percentage and the temperature. Studies on the the temperature dependence of the CMC values show that the standard Gibbs free energy of micellization values increase with the concentration of organic solvents and temperature whereas the opposite trend is observed forenthalpy. The randomness of the system decreases in presence of solvents. The relative viscosity of the surfactants was found to be more in presence of ethylene glycol among the studied systems. The effect of temperature on relative viscosity for these systems has also been discussed. Page(s): 34-43

Internal pressure, free volume and excess thermodynamic properties of methyl acrylate+1-alkanols (C₄-C₁₀) binary mixtures from ultrasonic speed and density

2016-07-20T06:20:56Z

Title: Internal pressure, free volume and excess thermodynamic properties of methyl acrylate+1-alkanols (C₄-C₁₀) binary mixtures from ultrasonic speed and density Authors: Nain, A K; Droliya, P Abstract: The experimental values of ultrasonic speeds and densities, of binary mixtures of methyl acrylate with 1-butanol, 1-hexanol, 1-octanol and 1-decanol have been used to calculate the internal pressures, free volumes, excess internal pressures, excess free volumes, excess free energy, excess enthalpy and excess entropy of mixing over the entire composition range at 298.15 K using regular solution theory. The results have been interpreted in terms of intermolecular interactions between the component molecules in the mixture. The variations of these excess properties with composition indicate that the methyl acrylate-alkanol interaction in these mixtures follows the order: 1-butanol > 1-hexanol > 1-octanol > 1-decanol. It is observed that the order of interactions in these mixtures depends upon the length of alkyl chain in the studied 1-alkanol molecules. In addition, the values of ultrasonic speeds have also been calculated theoretically for these mixtures using scaled particle theory and found to be in good agreement with experimental findings. Page(s): 23-33

Photocatalytic degradation of ciprofloxacin·HCl using Aeroxide^® P-25 TiO₂ photocatalyst: Comparative evaluation of solar and artificial radiation

2016-07-20T06:19:18Z

Title: Photocatalytic degradation of ciprofloxacin·HCl using Aeroxide^® P-25 TiO₂ photocatalyst: Comparative evaluation of solar and artificial radiation Authors: Shetty, Rohit; Kothari, Gaurav; Tambe, Amruta S; Kulkarni, Bhaskar D; Kamble, Sanjay P Abstract: The photocatalytic degradation of ciprofloxacin (CFX) has been investigated using Aeroxide^® P-25 TiO₂ photocatalyst in the presence of solar as well as artificial radiation. The effects of different operating parameters like initial concentration of CFX, catalyst loading, pH of solution and effect of co-existing ions on photocatalytic degradation of CFX have been investigated with a view to establish the optimum operating conditions. It is observed that as the initial concentration of CFX increases, the rate of photocatalytic degradation decreases. Optimum catalyst loading is observed at 1 g L^-1 for CFX concentration of 100 mg L^-1. Over the pH range 3-11, maximum degradation rate occurs at pH 9. The mechanism and intermediates formed during the photocatalytic degradation of CFX are discussed based on UPLC-MS/MS analysis. From kinetic studies, it is found that the photocatalytic degradation obeys pseudo-first order kinetics. The degradation rate constant using solar radiation is about 1.7 times higher than that under artificial radiation. Page(s): 16-22

Photocatalytic degradation of methylene blue and methyl violet using cation doped (Sn²⁺ and Ag⁺) barium tellurite phosphate, Ba₂TeO(PO₄)₂

2016-07-20T06:13:07Z

Title: Photocatalytic degradation of methylene blue and methyl violet using cation doped (Sn²⁺ and Ag⁺) barium tellurite phosphate, Ba₂TeO(PO₄)₂ Authors: Reddy, CH Sudhakar; Sreenu, K; Reddy, J R; Ravi, G; Guje, Ravinder; Malathi, M; Vithal, M Abstract: One-dimensional barium tellurite phosphate of composition, Ba₂TeO(PO₄)₂, is prepared by solid state method. Tin (Sn²⁺) and silver (Ag⁺) doped Ba₂TeO(PO₄)₂ materials are prepared via a facile room temperature ion-exchange method. Structural, morphological, and optical properties of all the materials are characterized by powder X-ray diffraction, FT-IR, SEM-EDS, and UV-visible diffuse reflectance spectroscopy techniques. The band gap energy (E_g) of all the phosphates is deduced from their Kubelka–Munk (KM) plot. The synthesized phosphates are used as photocatalyst for the degradation of methylene blue and methyl violet dyes under the visible light irradiation. The systematic degradation pathways of the dyes are studied in the presence of all the photocatalysts and scavengers. The stability and reusability of all the photocatalyst are assessed by the cycling runs in the photodegradation experiment. Page(s): 9-15

NOPR Collection:

Influence of organic solvents, head-groups and temperature on the micellization behavior of some cationic surfactants

Internal pressure, free volume and excess thermodynamic properties of methyl acrylate+1-alkanols (C4-C10) binary mixtures from ultrasonic speed and density

Photocatalytic degradation of ciprofloxacin·HCl using Aeroxide® P-25 TiO2 photocatalyst: Comparative evaluation of solar and artificial radiation

Photocatalytic degradation of methylene blue and methyl violet using cation doped (Sn2+ and Ag+) barium tellurite phosphate, Ba2TeO(PO4)2

Internal pressure, free volume and excess thermodynamic properties of methyl acrylate+1-alkanols (C₄-C₁₀) binary mixtures from ultrasonic speed and density

Photocatalytic degradation of ciprofloxacin·HCl using Aeroxide^® P-25 TiO₂ photocatalyst: Comparative evaluation of solar and artificial radiation

Photocatalytic degradation of methylene blue and methyl violet using cation doped (Sn²⁺ and Ag⁺) barium tellurite phosphate, Ba₂TeO(PO₄)₂