2.Article (04)
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Item REMOVAL OF METHYLENE BLUE FROM AQUEOUS SOLUTION BY ADSORPTION ON TO ACTIVATED CARBON(Indian Journal of Environmental Protection, 2004) Manickavasakam, K; Krishnan, S M; Sameena, Y; Vennilamani, N; Pattabhi, SThe adsporption capacity of the activated carbon prepared from Gulmohar tree fruits was evaluated by the removal of methylene blue from aqueous solution by adsorption under different conditions, such as agitation time, initial dye concentration, adsorbent dosage, particle size and pH. Desorption study was carried out to elucidate the mechanism of adsorption. The time required to attain equilibrium was found to be 45 and 60 min for 20, 40 and 60, 80 mg/L dye concentration, respectively. The adsorption followed a pseudo first order rate equation and the experimental data follows Freundlich and Langmuir isotherm models. The adsorption capacity was found to be 96.15 mg/g of Gulmohar tree fruit carbon (GTFC) at the pH of 6 ± 0.2 and at room temperature (30 ± 2 °C) for the particle size of 125-250 μm. The complete removal of the dye from 20 and 40 mg/L of aqueous solution was possible with 1.2 and 1.4 g of the activated carbon, respectively. The percent removal was increased with decrease in the particle size of the adsorbent. The influence of pH on dye removal was insignificant and the adsorbed dye could not recover in both acidic acid basic conditions.Item MERCURY (II) ADSORPTION BY ACTIVATED CARBON MADE FROM SAGO WASTE(Elsevier, 2004) Kadirvelu, K; Kavipriya, M; Karthika, C; Vennilamani, N; Pattabhi, SThe preparation of activated carbon (AC) from sago industry waste is a promising way to produce a useful adsorbent for Hg (II) removal, as well as dispose of sago industry waste. The AC was prepared using sago industry waste with H2SO4 and (NH4)2S2O8 and physico-chemical properties of AC were investigated. Adsorptive removal of mercury (II) from aqueous solution onto AC prepared from sago industry waste has been studied under varying conditions of agitation time, metal ion concentration, adsorbent dose, particle size and pH to assess the kinetic and equilibrium parameters. Adsorption equilibrium was obtained in 105 min for 20 mg l−1 and 120 min for 30, 40, and 50 mg l−1 Hg (II) concentrations. The Langmuir and Freundlich equilibrium isotherm models were found to provide an excellent fitting of the adsorption data, with r2 0.9999 and 0.9839, respectively. The adsorption capacity of Hg (II) (Qo) obtained from the Langmuir equilibrium isotherm model was found to be 55.6 mg g−1 at pH 5.0 for the particle size range of 125–250 μm. The percent removal increased with an increase in pH from 2 to 10. This adsorbent was found to be effective and economically attractive.Item EVALUATION OF A COMPOSITE CORROSION INHIBITING ADMIXTURES AND ITS PERFORMANCE IN PORTLAND POZZOLANA CEMENT(Elsevier, 2004-08) Muralidharan, S; Saraswathy, V; Merlin Nima, S P; Palaniswamy, NThe effect of various inhibitive and complexing ions like hydroxide, citrate and stannate for the corrosion of steel in concrete was studied by weight loss measurements, potential–time behaviour studies, potentiodynamic polarisation studies and electrochemical impedance measurements. The salient features of these investigations were, in 100% PPC extract the passivity of steel was readily destroyed even in the presence of 10 000 ppm of chloride. However, in 100% PPC extracts containing inhibitive and complexing agents like hydroxide, citrate and stannate, the passivity of steel was maintained even in the presence of 30 000 ppm of chloride. The addition of inhibitive ions like hydroxide, citrate and stannate decreased the corrosion of steel in simulated concrete environments. Citrates, stannates and calcium oxide are very effective inhibitors for corrosion of steel in Portland pozzolana cement.Item THE INFLUENCE OF BENZOYL HYDRAZINE AND SOME OF ITS SUBSTITUENTS ON CORROSION INHIBITION OF CARBON STEEL IN SULPHURIC ACID SOLUTION(Emerald Publishing Limited, 2004-12-01) Gowrani, T; Yamuna, J; Parameswari, K; Chitra, S; Selvaraj, A; Subramania, AThe influence of synthesised benzoyl hydrazine and some of its substituents on the inhibition of corrosion of carbon steel in 1M sulphuric acid solution were investigated using weight loss, gasometric measurements, potentiodynamic polarisation studies and impedance measurements. Corrosion kinetic parameters clearly revealed the fact that the inhibition of corrosion of carbon steel by these compounds was under mixed control. The effect of temperature on the corrosion behaviour of carbon steel in 1M H2SO4 with optimum concentration of inhibitors was studied in the temperature range 40°‐60°C. The activation energy (Ea) and free energy of adsorption (ΔGads0) were determined for all the inhibitors. The adsorption of these compounds on the carbon steel surface from 1M H2SO4 was observed to obey the Langmuir adsorption isotherm relationship.