NOPR Collection:

A modified correlation for drop size distribution at different gold concentrations in chloroauric acid/DBC system

2013-07-01T00:00:00Z

Title: A modified correlation for drop size distribution at different gold concentrations in chloroauric acid/DBC system Authors: Javanshir, Sepideh; Abdollahy, Mahmoud; Abolghasemi, Hossein; Sabeti, Hamid Abstract: The mean diameter of the distribution has been correlated to the mechanical input power, volume phase fraction and gold concentration in chloroauric acid/DBC system in a horizontal single stage mixer-settler in the frame of the classical Hinze–Kolmogorov theory. Sauter mean diameter (D₃₂) shows a decrease of 45% by increasing impeller speed. In contrast, holdup leads to larger drop size. The D₃₂increasing rate diminishes about 50% for a system containing 200 ppm gold concentration in aqueous phase with respect to the system with 100 ppm Au. Overall, empirical correlations for drop size at the different conditions are obtained, and a modified correlation for D₃₂is presented. The results reveal that D₃₂ depends on the impeller speed with a power low function, and on gold by a linear function as well. The correlation is found to be D₃₂/D=(–0.709C_Au+0.823)(1+2.022ϕ)W_e^–0.865. The calculated average absolute relative deviation is found to be less than 4.5%, showing good conformity to experimental data. Page(s): 259-264

Solvent extraction separation of zirconium (IV) with 2-octylaminopyridine from succinate media—Analysis of real samples

2013-07-01T00:00:00Z

Title: Solvent extraction separation of zirconium (IV) with 2-octylaminopyridine from succinate media—Analysis of real samples Authors: Noronha, Leena E; Kamble, Ganesh S; Kolekar, Sanjay S; Anuse, Mansing A Abstract: A systematic study on liquid-liquid extraction separation of zirconium (IV) from 25 mL 0.02 M sodium succinate solution using 10 mL 0.087 M 2-Octylaminopyridine (2-OAP) as an extractant has been carried out. Quantitative extraction of Zr (IV) is observed at pH 3.7 – 5.0 using 0.01 – 0.03 M sodium succinate with 0.087 M 2-OAP in xylene. Zirconium (IV) has been back extracted with 0.5 M HNO₃ (3×10 mL). The nature of extracted species in organic phase is determined by using conventional slope analysis method. The proposed method is applicable to separate Zr (IV) from associated metals like W(VI), Fe(III), Mo(VI), Y(III), Al(III), V(V), U(VI) and Th(IV) and also in the analysis of Zr (IV) from various synthetic mixtures, real samples of alloy, thin films and nanopowder. Page(s): 252-258

Equilibrium uptake and sorption dynamics for the removal of reactive dyes from aqueous solution using activated carbon prepared from Euphorbia tirucalli L wood

2013-07-01T00:00:00Z

Title: Equilibrium uptake and sorption dynamics for the removal of reactive dyes from aqueous solution using activated carbon prepared from Euphorbia tirucalli L wood Authors: Palanisamy, P N; Agalya, A; Sivakumar, P Abstract: Activated carbon prepared from Euphorbia tirucalli L wood (ETAC) by chemical activation with phosphoric acid has been analysed for the removal of Reactive Red and Reactive Blue dyes from aqueous solutions through batch adsorption technique. Lower solution pH favours the adsorption of reactive dyes. The amount of dye adsorbed per unit mass of adsorbent increases with the increase in temperature and initial dye concentration. Freundlich and Langmuir models are used to analyze the equilibrium data at different temperatures. The equilibrium data for the adsorption of both dyes are better described by the Langmuir isotherm model. The adsorption of reactive dyes follows second order kinetics along with intra-particle diffusion model. Thermodynamic parameters such as free energy change, enthalpy change and entropy change for adsorption of reactive dyes show that the adsorption of Reactive Red and Reactive Blue onto ETAC are spontaneous, endothermic and physical adsorption. Activation energy and isosteric heat of adsorption suggests that adsorption of reactive dyes onto ETAC is a physical process. Page(s): 245-251

Corrosion inhibition of brass in presence of 1, 4, 5, 6-tetrahydropyrimidine derivatives in chloride solution

2013-07-01T00:00:00Z

Title: Corrosion inhibition of brass in presence of 1, 4, 5, 6-tetrahydropyrimidine derivatives in chloride solution Authors: Ranjana; Banerjee, Ranu; Nandi, M M Abstract: The inhibition effects of L (-) aspartic acid (I) and its various derivatives namely N-benzenesulphonyl L (-) aspartic acid (II), α-benzenesulphonamido-β-2-(1, 4, 5, 6-tetrahydropyrimidinyl) propionic acid (III) and 1-benzenesulphonamido-1, 2-bis-2(1,4,5,6-tetrahydropyrimidinyl) ethane (IV) against the corrosion of brass in 0.6 M aqueous sodium chloride solution have been studied using potentiodynamic polarization and electrochemical impedance spectroscopy. The inhibition efficiency of these compounds increases in the order I < II < III < IV. The inhibition efficiency of IV with 4 × 10 ^-5 M concentration is the highest which reaches 94.9%. It is observed that the introduction of C₆H₅SO₂- group increases the inhibition efficiency of L (-) aspartic acid by 32.0%. Conversion of one –COOH group to 1, 4, 5, 6-tetrahydropyrimidine increases inhibition efficiency by 15.5% and when both the –COOH groups are converted to 1,4,5,6–tetrahydropyrimidine the inhibition efficiency becomes maximum (95%). This is due to higher molecular size, π – electron contribution of the benzene ring, and presence of more active adsorption sites. Page(s): 237-244