NOPR Collection:

Effect of inhibitors on corrosion of aluminium in acidic medium

2016-07-20T06:40:35Z

Title: Effect of inhibitors on corrosion of aluminium in acidic medium Authors: Meena, Shanker Lal; Verma, P S Abstract: Corrosion of aluminium in acidic medium (0.1 N HC1) has been studied by Tafel intercept logarithmic polarization and weight loss methods using two inhibitors, namely Triton X-100 and gelatin. Open circuit potential, inhibition efficiency, corrosion current and corrosion rate have been determined in the absence and presence of inhibitors at different concentrations such as 0.1, 0.2, 0.3, 0.4 and 0.6%. It is observed that the inhibition increases with the increase in concentration of the inhibitors in acidic media. The inhibition efficiency of the Triton X-100 is found to be higher than that of gelatin. Thus, Triton X-100 can be considered as a better inhibitor. Page(s): 220-223

Effect of mechanical activation on manganese extraction from manganese carbonate ore in acidic media

2016-07-20T06:40:33Z

Title: Effect of mechanical activation on manganese extraction from manganese carbonate ore in acidic media Authors: Yilmaz, Volkan Murat; Apaydin, Fatih Abstract: A manganese carbonate ore has been mechanically activated at different milling times and the effect of mechanical activation on the ore structure is analyzed by X-ray diffraction, scanning electron microscopy and particle size analysis. The activation procedure leads to amorphisation and structural disordering of the ore structure. Sulfuric acid leaching of the non-activated and activated manganese carbonate ore has been studied at different temperatures, durations, and acid concentrations. The results show that dissolution of manganese increases from 69% to 100% in acidic leaching with 1 M H₂SO₄ at 70°C after 30 min of mechanical activation, due to amorphisation in structure and creating more surface area. Page(s): 215-219

Estimation of mercury in industrial effluents by substoichiometric extraction with diphenyl carbazone

2016-07-20T06:40:26Z

Title: Estimation of mercury in industrial effluents by substoichiometric extraction with diphenyl carbazone Authors: Bag, Madhumita; Basu, Sukalyan Abstract: A method of quantification of mercury (II) content in industrial effluents based on the principle of substoichiometric isotope dilution analysis has been reported. It involves the extraction of spiked mercury (²⁰³Hg) with substoichiometric amounts of diphenyl carbazone in toluene media. Extraction condition has been optimized at pH 6.5 by pH variation study and slope ratio analysis data shows 1:2 composition of metal:ligand of the extracted metal-complex. The effects of various closely related foreign ions on the extraction process are critically studied and it is found that extraction was almost free from any interferences of the diverse ions adopting the present technique. Results are extrapolated to the determination of metal content in industrial effluents. Page(s): 211-214

Separation of divalent lead from ayurvedic (herbal) medicines and alloys using extraction chromatography

2016-07-20T06:40:20Z

Title: Separation of divalent lead from ayurvedic (herbal) medicines and alloys using extraction chromatography Authors: Kuchekar, Shashikant R; Phule, Sachin R; Zaware, Bhaskar H; Han, Sung H Abstract: A selective, sensitive, less expensive and more precise method has been developed for the separation of lead(II) using N-n-octylaniline (liquid anion exchanger) coated silica gel as stationary phase. The quantitative extraction of lead(II) is found with 0.087 molL^-1 N-n-octylaniline and 0.007 - 0.15 mol/L^-1 ascorbic acid at pH 9.0. The extracted lead(II) has been eluted from the column with 0.5 mol/L^-1 hydrochloric acid and analyzed by spectrophotometric method. The probable composition of the extracted species is deduced from log-log plots and extracted species is found to be [2RR'NH₂⁺.Pb(C₆H₇O₆)₄^2-]_(org.). The optimum extraction conditions are evaluated from a critical study of effects of pH, ascorbic acid concentration, N-n-octylaniline concentration and elution time. The proposed method is found simple and efficient as it avoids large number of cation and anion interferences. Lead(II) is successfully separated from binary mixtures with bismuth(III), gold(III) and osmium(VIII). The method is also extended for separation of lead(II) from ayurvedic medicine and synthetic mixtures corresponding to alloys. Page(s): 205-210