B-Scopus
Permanent URI for this communityhttps://dspace.psgrkcw.com/handle/123456789/3730
Browse
15 results
Search Results
Item SORPTION CHARACTERISTICS OF AGRO WASTE PRODUCT IN THE REMOVAL OF LEAD (II)(EPA United States Environmental Protection Agency, 2008) Muthulakshmi Andal, N; Shyamaladevi, NThe influence of particle size, contact time, initial concentration of the adsorbent, adsorbent dose, pH, cation, anions and co-ions, and temperature on the adsorption capacity of sawdust to remove Pb(II) from aqueous systems was determined. The adsorption of Pb(II) over sawdust revealed maximum capacity for the sorbents with the smallest particle size. The mimimum contact time required to attain equilibrium for the system was 20 minutes at an initial concentration of 10 mg/litre. The sorptive behaviour was observed to improve under the conditions of pH 5. The adsorption of the metal ion was significantly inhibited by the presence of cations, anions and co-ions. The adsorption dynamics and equilibrium factors were confirmed with the use of the Fruendlich, Langmuir and Tempkin isotherm models. Sawdust was found to be effective with higher chelating ability in the removal of Pb(II).Item DIANILINE SCHIFF BASES AS INHIBITORS OF MILD STEEL CORROSION IN ACID MEDIA(Elsevier, 2010-11) Chitra, S; Parameswari, K; Selvaraj, AA 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.Item MACROCYCLIC COMPOUNDS AS GREEN CORROSION INHIBITORS FOR ALUMINIUM: ELECTROCHEMICAL, SURFACE AND QUANTUM CHEMICAL STUDIES(International Journal of Corrosion and Scale Inhibition, 2018-09-28) Ansari, K R; Ramkumar, S; Chauhan, D S; Salman, Md; Nalini, D; Srivastava, V; Quraishi, M AIn the present work, two macrocyclic compounds namely 5,6,11,12-tetramethyl1,2,4,7,8,10 hexaazacyclododeca-4,6,10,12-tetraene-3,9-dithione (TMCD) and 5,6,11,12- tetraphenyl-1,2,4,7,8,10-hexaazacyclododeca-4,6,10,12-tetraene-3,9-dithione (TMPD) have been synthesized and for the first time reported as inhibitors against the corrosion of aluminium in 1 M hydrochloric acid. The synthesized compounds were characterized using 1H NMR and 13C NMR. The corrosion inhibition behaviour of TMCD and TMPD was studied using gravimetric measurements, electrochemical impedance spectroscopy and potentiodynamic polarization studies. The surface analysis was carried out using AFM and SEM. Theoretical studies on the adsorption behaviour of inhibitor were carried out using the Density Functional Theory method. A detailed study of the effect of temperature and the influence of immersion time is presented using weight loss technique. Potentiodynamic polarization study proves that the corrosion inhibition efficiencies of TMCD and TMPD at 400 mg L –1 concentration are 97.30% and 89.71% respectively. Both the inhibitors behaved as mixed type but exhibit cathodic predominance. The results of EIS-Nyquist plots show inductive behavior at low frequency characteristic of the electrochemical behaviour of aluminium. The increase in polarization resistance with concentration suggests the adsorption and corrosion inhibition behaviour for both TMCD and TMPD. The AFM studies reveal a considerable decrease in surface roughness in the presence of inhibitors compared to blank sample and the SEM images show a highly smooth surface of the metal sample in the presence of inhibitors. The Fukui functions, global softness and Mulliken charges reveal that the sites for electrophilic attack are the hetero atoms. The frontier molecular orbital energies, the molecular orbital energy gap and the other quantum chemical parameters corroborated the experimental observations and suggested a better performance of TMCD compared to TMPD molecule.Item QUANTUM CHEMICAL STUDY ON THE CORROSION INHIBITION PROPERTY OF SOME HETEROCYCLIC AZOLE DERIVATIVES(Oriental Journal of Chemistry, 2015-08-20) Anusuya, N; Sounthari, P; Saranya, J; Parameswari, K; Chitra, SQuantum chemical calculations based on density functional theory (DFT) method were performed on heterocyclic azole derivatives as corrosion inhibitors for mild steel in acid media to investigate the relationship between molecular structure of the inhibitors and the corresponding inhibition efficiencies (%). Quantum chemical parameters most relevant to their potential action as corrosion inhibitors have been calculated in the non-protonated and protonated forms in aqueous phase for comparison. Results obtained in this study indicate thatin acidic media, both the protonated and non-protonated forms of the azoles represent the better actual experimental situation.Item ADSORPTION OF REACTIVE BLUE 171 FROM AQUEOUS SOLUTION USING LOW COST ACTIVATED CARBON PREPARED FROM AGRICULTURAL SOLID WASTE: ALBIZIA AMARA(Applied Science Innovations Pvt. Ltd., India, 2015-08-25) Anitha, K; Syed Shabudeen, P S; Karthikeyan, S; Aruna devi, NThe adsorption of Reactive Blue 171 (Reactive Dye) from aqueous solution using activated carbon prepared from Albizia amara pod shell waste as an adsorbent have been carried out. The experimental adsorption data fitted reasonably well to Langmuir and Freundlich adsorption isotherms. Kinetic parameters as a function of Initial dye concentration have been calculated and the kinetic data were substituted in Pseudo First Order, Elovich and Pseudo Second order equations. A probable explanation is offered to account for the results of kinetic study. The thermodynamic parameter enthalpy change (∆H) suggests the exothermic nature of absorption of Reactive Blue 171 onto activated Albizia amara pod shell waste carbon.Item CORROSION ABATEMENT IN ACID PICKLING INDUSTRIES BY EFFECTIVE N-HETEROCYCLIC COMPOUNDS: DRY AND WET LAB STUDIES(NACE - International Corrosion Conference Series, 2016-03-06) Sowmya, Ramkumar; Nalini, DDuring the chemical cleaning process using acids, in many electroplating and other descaling industries, there exists the problem of heavy metal loss. Hence there is always a need for abatement of this metal loss. A critical (steady state) value of the resistivity to corrosion of two organic compounds, 5-[2-(4-methoxyphenyl)-vinyl]-3-phenyl isoxazole (MVI) and 5-[2-(4-methoxyphenyl)-vinyl]-1,3,8-triazacyclopenta[ a]indene (MCI) were determined by a combination of non-electrochemical and electrochemical monitoring techniques. The behavior of organic compound, on a metallic alloy, i.e., mild steel, was investigated over a temperature range of 30 to 70°C. Efficiency of MVI and MCI were determined by correlating the electrochemical response of the compound (by electrochemical impedance and potentiodynamic polarization) in 1M HCl and 0.5M H2SO4 solution with their structural features. EIS measurement predicted the physical adsorption of both MVI and MCI on the metal surface from PZC calculation. Polarization studies proved that the inhibitors retard both the electrode process during inhibition. The integrity of the inhibitors efficiency with respect to time was assessed from mass loss measurements at different immersion period. Mass loss measurements proved that both MVI and MCI inhibit corrosion of mild steel in 1M HCl with a maximum efficiency of 91.07% and 78.23% at 20 ppm in HCl and H2SO4 respectively for MVI, 97.72% and 88.64% at 20 ppm in HCl and H2SO4 respectively for MCI. Hence MVI and MCI were found to be effective inhibitors for acid cleaning process in industries. The mechanism of the inhibition process was discussed in the light of the chemical structure and quantum chemical calculations of the investigated inhibitor. MVI and MCI were modeled in order to assess its absorbability using density functional theory (DFT) and revealed remarkably high interaction energies, which corroborate the experimental findings.Item RECENT REVIEWS ON QUINOLINE DERIVATIVES AS CORROSION INHIBITORS(De Gruyte, 2018-02-21) Lavanya K; Saranya J; Chitra STraditionally, controlling corrosion has been managed by various methods like cathodic protection, process control, reduction of the metal impurity content and application of surface treatment techniques as well as incorporation of suitable alloys. However, the use of corrosion inhibitors has proven to be the easiest and cheapest method for corrosion protection and prevention in acidic media. These inhibitors slow down the corrosion rate and thus prevent economic losses due to metallic corrosion on industrial vessels, equipment or surfaces. Many researchers have recently focused on corrosion prevention methods using organic inhibitors for mild steel in acidic solutions to mimic industrial processes. This paper arranges for an overview of types of corrosion, corrosion process and mainly recent work done on the application of quinolone derivatives as corrosion inhibitors for different metalsItem EXPERIMENTAL AND QUANTUM CHEMICAL STUDIES ON THE INHIBITION POTENTIAL OF SOME QUINOXALINE DERIVATIVES FOR MILD STEEL IN ACID MEDIA(Oriental Journal of Chemistry, 2014-11-15) Saranya, J; Sounthari, P; Kiruthika, A; Saranya, G; Yuvarani, S; Parameswari, K; Chitra, SThe inhibition potential of four Quinoxaline derivatives namely 1,4-dihydroquinoxaline-2,3-dione, (3E)-3-hydrazinylidene-3,4-dihydroquinoxalin-2(1H)-one, 1-[(2E)-3-oxo-3,4-dihydroquinoxalin-2(1H)-ylidene]urea and 1-[(2E)-3-oxo-3,4-dihydroquinoxalin-2(1H)-ylidene]thiourea have been investigated against mild steel in 1M H2SO4 solution using conventional weight loss, electrochemical impedance spectroscopy, potentiodynamic polarization and atomic absorption spectroscopy. The percentage inhibition efficiency was found to increase with increase in the inhibitor concentration due to the adsorption of the inhibitor molecules on the metal surface. In addition, it was established that the adsorption follows Langmuir adsorption isotherm. Moreover, some thermodynamic data were calculated and discussed. The density functional theory at the B3LYP/6-311G (d,p) basis set level was performed for two inhibitors namely 1,4-dihydroquinoxaline-2,3-dione and (3E)-3-hydrazinylidene-3,4-dihydroquinoxalin-2(1H)-one. The quantum chemical parameters such as highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO), energy gap (∆E), dipole moment (µ), softness (σ), hardness (η), electronegativity (χ), Mulliken atomic charges, the fraction of electrons transferred from the inhibitor to the metal surface (∆N) and the total energy (TE) have been calculated for these compounds. It was found that theoretical data support the experimental results.Item MACROCYCLIC COMPOUNDS AS GREEN CORROSION INHIBITORS FOR ALUMINIUM: ELECTROCHEMICAL, SURFACE AND QUANTUM CHEMICAL STUDIES(International Journal of Corrosion and Scale Inhibition, 2018-09-28) Ansari, K R; Ramkumar, S; Chauhan, D S; Salman, MD; Nalini, D; Srivastava, V; Quraishi, M AIn the present work, two macrocyclic compounds namely 5,6,11,12-tetramethyl1,2,4,7,8,10 hexaazacyclododeca-4,6,10,12-tetraene-3,9-dithione (TMCD) and 5,6,11,12- tetraphenyl-1,2,4,7,8,10-hexaazacyclododeca-4,6,10,12-tetraene-3,9-dithione (TMPD) have been synthesized and for the first time reported as inhibitors against the corrosion of aluminium in 1 M hydrochloric acid. The synthesized compounds were characterized using 1H NMR and 13C NMR. The corrosion inhibition behaviour of TMCD and TMPD was studied using gravimetric measurements, electrochemical impedance spectroscopy and potentiodynamic polarization studies. The surface analysis was carried out using AFM and SEM. Theoretical studies on the adsorption behaviour of inhibitor were carried out using the Density Functional Theory method. A detailed study of the effect of temperature and the influence of immersion time is presented using weight loss technique. Potentiodynamic polarization study proves that the corrosion inhibition efficiencies of TMCD and TMPD at 400 mg L –1 concentration are 97.30% and 89.71% respectively. Both the inhibitors behaved as mixed type but exhibit cathodic predominance. The results of EIS-Nyquist plots show inductive behavior at low frequency characteristic of the electrochemical behaviour of aluminium. The increase in polarization resistance with concentration suggests the adsorption and corrosion inhibition behaviour for both TMCD and TMPD. The AFM studies reveal a considerable decrease in surface roughness in the presence of inhibitors compared to blank sample and the SEM images show a highly smooth surface of the metal sample in the presence of inhibitors. The Fukui functions, global softness and Mulliken charges reveal that the sites for electrophilic attack are the hetero atoms. The frontier molecular orbital energies, the molecular orbital energy gap and the other quantumItem BIOSORPTION OF DIVALENT ION ONTO TREATED PROSOPIS JULIFLORA BARK FROM AQUEOUS SOLUTIONS - ISOTHERMAL AND STATISTICAL ANALYSIS(Oriental Journal of Chemistry, 2016-04-13) Muthulakshmi Anda, N; Charulatha, S; Gayathri, N SThe present work emphasizes the utilization of Prosopis juliflora bark, an agro waste material for the adsorption of Cu(II). The raw Prosopis juliflora bark (PJB) is treated using 0.1N hydrochloric acid to enhance the sorption efficiency. The characterization studies of TPJB using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDAX), Brunauer-Emmet-Teller(BET) and Barrett-Joyner-Halenda (BJH) analyses carried out. The batch mode experimental set up is verified to assess the sorption capacity of the chosen material for the operating factors viz., particle sizes/ doses of the sorbent material upon a range of initial concentrations of Cu(II) at different temperatures, agitation time and pH of the Cu(II)- TPJB system. The amount of Cu(II) ion adsorbed on to TPJB surface is found to be 43.11 mg/g (97.4%) under optimized conditions, its efficiency 3 fold times more than the Ce values reported by other researchers. The sorption characteristic of TPJB is quantitatively estimated through column experiments based on the Ce value by batch mode. The removal is observed as 98%. Langmuir, Freundlich and Tempkin isothermal curves at various initial concentrations are plotted for Cu(II)-TPJB system wherein the straight line fit is best suited for the Freundlich isotherm model. The results show that the response of TPJB in trapping Cu(II) ions are influenced by various parameters being statistically verified using SPSS software, indicative of good correlation.