2.Article (08)

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    STUDY ON THE INHIBITION OF MILD STEEL CORROSION BY BENZOISOXAZOLE AND BENZOPYRAZOLE DERIVATIVES IN H2SO4 MEDIUM
    (Portugaliae Electrochimica Acta, 2010) Parameswari, K; Rekha, S; Subramanian, Chitra; Kayalvizhy, E
    Four heterocyclic compounds, namely 4- phenyl-5-acetyl/carbethoxy-3-methyl-6-hydroxyl-6-methyl-4,5,6,7-tetrahydro-2,1-benzoisoxazole and benzopyrazole (BIS1, BP1and BIS2, BP2), were synthesized and their influence on the inhibition of corrosion of mild steel in 1 M H2SO4 was investigated by means of weight loss, potentiodynamic polarization, electrochemical impedance (EIS) and scanning electron microscopy (SEM). The values of activation energy and free energy of adsorption of these compounds were also calculated. Adsorption obeys Langmuir adsorption isotherm. The IE of the compounds was found to vary with concentration and temperature. Synergistic effect was also investigated for the four compounds at 0.05 mM concentration by weight loss method in 1 M H2SO4 medium in presence of KI, KBr and KCl. Results obtained revealed that all the four compounds performed excellently as a corrosion inhibitor for mild steel in 1 M H2S04 and their efficiency attains more than 90% at 0.6 mM at 298 K. Polarisation studies showed them to be mixed type inhibitors.
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    EFFECT OF AZLACTONES ON CORROSION INHIBITION OF MILD STEEL IN ACID MEDIUM
    (Journal of Applied Sciences Research, 2010) Parameswari, K; Chitra, S; Nusrath Unnisa, C; Selvaraj, A
    The inhibition efficiency of azlactones on corrosion behaviour of mild steel in 1M H2SO4 has been evaluated using weight loss, gasometry and atomic absorption spectroscopy techniques which shows increase in inhibition efficiency with increase in concentration.Effect of temperature strongly ensures stronger physisorption of the compounds, which obeys Langmuir adsorption isotherm. The inhibition efficiency has been synergistically enhanced by the addition of halide ions. The kinetic corrosion parameters analysed in terms of impedance data shows a satisfactory agreement with those obtained by potentiodynamic polarisation method.
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    XYLAN - EXTRACTION FROM AGRO RESIDUES
    (Global Science Publications, 2010) Usha, R; Sashi, V; Malathy, N S; Gnana Soundari, S
    Large quantities of agro residues dumped on the ecosystem create an environmental pollution. The main aim of this present study is to minimize the pollution creating residues and use such residues in an biotechnological manner. Since the agricultural residues are rich in lignocellulosic materials especially xylan a major polymer, using the polymer as a carbon source for the production of xylanase makes as a cheap alternative source. In this review. 1) Chemical composition 2) Xylan extraction method 3) Usage of agro residues (rich in xylan as a carbon source for xylanase production studied by few workers) are discussed.
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    SELECTIVE BIS-N-ARYL THIOSEMICARBAZONES AS EFFICIENT CORROSION INHIBITORS
    (ProQuest, 2010-07-29) Shamitha Begum, A; Nalini, D; Suvarnna, K
    The study of the effect of the Bis-N-aryl thiosemicarbazone compounds on the corrosion behaviour of mild steel in 1M sulphuric acid and in1M hydrochloric acid shows that these compounds are very efficient inhibitors. Their inhibition efficiency increased with increase in concentration and also increased with temperature. The inhibitors showed a mixed type of inhibition in potentiodynamic polarization study and in impedance method in presence and absence of inhibitors. The adsorption of inhibition followed Langmuir adsorption isotherm. The thermodynamic parameters such as activation energy (Ea) and free energy of adsorption Gads were calculated. The Ea value of the uninhibited solution was less than the inhibited solutions revealing chemisorption of the inhibitor on the mild surface.
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    A COMPARATIVE STUDY ON THE SORPTION CHARACTERISTICS OF PB(II) AND HG(II) ONTO ACTIVATED CARBON
    (Hindawi Publishing Corporation, 2010) Muthulakshmi Andal, N; Sakthi, V
    Biosorption equilibrium and kinetics of Pb(II) and Hg(II) on coconut shell carbon (CSC) were investigated by batch equilibration method. The effects of pH, adsorbent dosage, contact time, temperature and initial concentration of Pb(II) and Hg(II) on the activated carbon of coconut shell wastes were studied. Maximum adsorption of Pb(II) occurred at pH 4.5 and Hg(II) at pH 6. The sorptive mechanism followed the pseudo second order kinetics. The equilibrium data were analysed by Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. The equilibration data fitted well with both Langmuir and Freundlich isotherm model. The Langmuir adsorption capacity for Pb(II) was greater than Hg(II). The mean free energy of adsorption calculated from Dubinin-Radushkevich (D-R) isotherm model indicated that the adsorption of metal ions was found to be by chemical ion exchange. Thermodynamic parameter showed that the sorption process of Pb(II) onto SDC was feasible, spontaneous and endothermic under studied conditions. A comparison was evaluated for the two metals.
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    REMOVAL OF PB(II) IONS FROM AQUEOUS SOLUTIONS USING BOMBAX CEIBA SAW DUST ACTIVATED CARBON
    (Taylor & Francis Online, 2010) Sakthi, V; Muthulakshmi Andal, N; Rengaraj, S; Milka, Sillanpää
    The isotherms, kinetics and thermodynamics of Pb(II) ions from aqueous solution by activated carbon prepared from Bombax ceiba sawdust (SDC) were carried out in a batch adsorption system. The effects of pH, adsorbent dosage, contact time, initial concentration of Pb(II) and temperature on the adsorption were studied. Maximum adsorption of Pb(II) occurred at pH 5. Pseudo first order, pseudo second order and intraparticle diffusion models were applied to kinetic data. The sorptive mechanism followed the pseudo second-order kinetics and intra particle diffusion model. The equilibration data fitted well with both Langmuir and Freundlich isotherm model with maximum sorption capacity of 209 mg g−1. The mean free energy of adsorption calculated from Dubinin-Radushkevich (D-R) isotherm model indicated that the adsorption of metal ions was found to be by chemical ion exchange. Thermodynamic parameters and Tempkin constant showed that the sorption process of Pb(II) onto SDC was feasible, spontaneous and endothermic under studied conditions.
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    SYNTHESIS, CHARACTERIZATION AND CORROSION PROTECTIVE EFFICIENCY OF SOME 1,3,4-THIADIAZOLINES ON MILD STEEL IN ACID MEDIA
    (Oriental Journal of Chemistry, 2010) Shamitha Begum, A; Nalini, D; Manjula Devi, T
    The Inhibition effect of corrosion of mild steel using Thiadiazolines in H2SO4 medium by weight loss, electrochemical methods was investigated. The corrosion inhibition was studied in H2SO 4 by weight loss method for about 3hrs at room temperature and It was found that the corrosion inhibition behaviour of Thiadiazolines is greater in sulphuric acid. Results were fitted into suitable adsorption isotherm. The Electrochemical parameters for mild steel in H2SO4 solution with and without inhibitor were calculated. The data revealed that Electrochemical polarization shows the Mixed Mode of inhibition and the results of Electrochemical impedance spectroscopy have shown that the change in the impedance parameters, charge transfer resistance and double layer capacitance with the change in concentration of the inhibitor is due to the adsorption of the molecules leading to the formation of a protective layer on the surface of mild steel. The Effect of Temperature on the corrosion rate, activation energy and free energy of adsorption were also calculated.
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    DIANILINE SCHIFF BASES AS INHIBITORS OF MILD STEEL CORROSION IN ACID MEDIA
    (Elsevier, 2010-11) Chitra, S; Parameswari, K; Selvaraj, A
    A new class of corrosion inhibitors namely dianiline Schiff bases was synthesized and its inhibiting action on the corrosion of mild steel in 1M sulphuric acid at 30°C was investigated by various corrosion monitoring techniques. A preliminary screening of the inhibition efficiency was carried out using weight loss measurements. Potentiodynamic polarization studies showed that the Schiff bases were mixed type inhibitors. The effect of temperature on the corrosion behaviour of mild steel in 1M sulphuric acid with the addition of the Schiff bases was studied in the temperature range from 40°C60°C. The adsorption of these compounds on a mild steel surface from sulphuric acid obeyed the Langmuir adsorption isotherm. The decrease in inhibition efficiency with increase in temperature and the less negative ∆G°ads values suggest predominant physisorption of the Schiff base molecules on the steel surface.