Browsing by Author "SowmyaRamkumar"

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CHARACTERISATION OF POLYANILINE COPPER COMPOSITES PREPARED VIA IN-SITU MECHANICAL MIXING, MICROWAVE ASSISTED AND INTERFACIAL METHOD OF POLYMERISATION
(PSGR Krishnammal College for Women, 2018-09-06) S, Yuvasree; R, Viveka; SowmyaRamkumar
The present study deals with green synthesis of copper nanoparticles by using leaf extract of AzadirachtaIndica. It acts as reducing as well as capping agent for the nanoparticles. PAni –Cu (polyaniline copper) composite was then prepared by in-situ mechanical, microwave and interfacial methods of polymerization using Cu nanoparticles as addition agent. The obtained polymers were then characterized by UV - Visible, FT - IR, XRD and SEM. The effect of copper on the structure and property of polyaniline was studied showing an excellent in its property compared to the polymer.
COMPARISON OF CORROSION INHIBITION OF MILD STEEL IN ACID MEDIA BYIMIDAZOLINE DERIVATIVE SYNTHESIZED BY CONVENTIONAL AND MICROWAVE SYNTHESIS
(Vivekanandha Arts and Science College for Women, 2020-02-07) SowmyaRamkumar; S, Rajakumari; D, Nalini
Acid solutions are widely used in industry, some important field of application being acid pickling, industrial cleaning, acid descaling, petrochemical processes etc. The majority of the corrosion inhibitors employed during production of steel form thin barrier layers between the steel surface and the corroding fluid. It was found that the formation of donor-acceptor surface complex between free or π-electrons of an organic inhibitor and vacant d-orbital of a metal is responsible for the inhibition of corrosion process. In the present study, Imidazoline derivative synthesized by conventional and microwave method is investigated for its anti-corrosion potential against mild steel in 1M HCl and 0.5M H2SO4 solution using electrochemical impedance spectroscopy, Potentiodyamic polarization and quantum chemical studies. Synthesized inhibitor is characterised by FTIR Spectra, DLS and SEM. The inhibition efficiency was evaluated at different concentrations of the inhibitor. The present investigation is carried out to find whether the greater inhibition efficiency for inhibitor synthesized by microwave method than conventional method. Electrochemical impedance spectroscopy: Nyquist plots for mild steel in 1M HCl and 0.5M H2SO4 with and without inhibitor results in increase in Rct values and decrease in Cdl shows the formation of the protective film of the inhibitor on the metal increases the efficiency of the inhibitor. The maximum inhibition efficiency of the inhibitor 98% and 79% at 20 ppm in HCl and H2SO4 synthesized by microwave method and by conventional method it shows the maximum efficiency of 89% and 70% respectively. From the Polarisation Measurements the Tafel constants obtained from the potentiodynamic polarisation curves indicate that the investigated compound was mixed type inhibitor. Molecular modelling has been conducted to correlate the corrosion inhibition properties with the calculated quantum chemical parameters. Quantum chemical parameters were studied by DFT BLYP 6-31G (d,p) basis set. The energy of the HOMO (EHOMO) provides information about the tendency of the molecule to donate electrons to an electron poor species. The higher the (EHOMO) is the greater tendency of a molecule to donate its electrons to the electron poor species. Therefore the studied compound provides an indication that it would have highest tendency to donate its electrons to the metal surface and therefore bind strongly to the metal surface. Adsorption sites is mainly over the Nitrogen atoms.
CORROSION ABATEMENT IN ACID PICKLING INDUSTRIES BY EFFECTIVE N-HETEROCYCLIC COMPOUNDS: DRY AND WET LAB STUDIES
(NACE International, 2016) SowmyaRamkumar; D, Nalini
During 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-triaza-cyclopenta[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.
ELECTROCHEMICAL AND QUANTUM CHEMICAL STUDIES OF CORROSIONINHIBITION OF MILD STEEL IN 1M HCL AND 0.5M H2SO4
(PSGR Krishnammal College for Women, 2019-09-16) Menaga M; Nalini D; SowmyaRamkumar
Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarizationmeasurements were used to examine the inhibition effect of drug Pregabalin (PGB) on thecorrosion of mild steel in 1M HCl and 0.5M H2SO4 solution. EIS results indicate that thestudied compound inhibit the acid corrosion by adsorption mechanism. Potentiodynamicpolarization measurement suggest that the inhibitor system act as a mixed type by affectingboth anodic and cathodictafel slopes during the acid corrosion of both the studied medium.Quantum chemical studies are in accordance with the experimental values.
INSITU POLYMERIZATION OF POLYMER – NANO COMPOSITE: SYNTHESIS ANDCHARACTERIZATION
(Vellalar College for Women, 2020-02-27) SowmyaRamkumar; R S, Yuvasree; Viveka
Nanotechnology is gaining tremendous impetus in the present century due toits capability of modulating metals into their nanosize. Research in nanotechnologyhighlights the possibility of green chemistry pathway to produce technologicallyimportant nanomaterials. The present study deals withgreen synthesis of coppernanoparticles by using leaf extract of AzadirachtaIndica.It acts as reducing as well ascapping agent for the nanoparticles. PANI –Cu (polyaniline copper) composite wasthen prepared by in-situ microwave assisted method of polymerization using Cunanoparticles as addition agent .The obtained polymer were then characterized by UV- Visible ,FI - IR , XRD and SEM. The effect of copper on the structure and propertyof polyaniline was studied showing an excellent in its property compared to thepolymer.
POLYANILINE/GRAPHENE COMPOSITE: AN ECO-FRIENDLY POLYMER FOR THE REMOVAL OF DYESFROM AQUEOUS SOLUTION
(Bharathiar University, 2020-03-05) Viveka; G, SathyaPriyadarshini; SowmyaRamkumar
In this work, glucose grafted polyaniline/graphite composite has been used as an efficientadsorbent for the removal of methylene blue (MB) and reactive red M5B (RR-M5B) from aqueoussolution. The adsorption performance of the polymer was investigated by varying the parameterssuch as pH (2-11), agitation time (100 min), adsorbent dose (0.02 g – 0.12 g) and temperature (30°C-50 °C) at different initial concentration of dyes (10 mg/L-100 mg/L). The pseudo-second orderequation and the Langmuir model exhibited good correlation with the adsorption kinetic andisotherm data for both the dyes, respectively. The thermodynamic studies (ΔG < 0, ΔH < 0, ΔS <0) implied that the adsorption of dyes were endothermic and spontaneous in nature. The maximumremoval efficiency of MB was 93.22% and 84.21 % for RRM5B under optimum conditions withadsorption equilibrium time of 60 min. A possible adsorption mechanism has been proposed,where H-bonding and electrostatic interactions dominated the adsorption of the organic dyes.
RELIABLE CORROSION INHIBITION OF MILD STEEL DURING ACID DESCALING USINGORGANIC NITROGENOUS COMPOUND: A COMBINED ELECTROCHEMICAL ANDCOMPUTATIONAL ASSESSMENT
(NIGIS, 2016) SowmyaRamkumar; D, Nalini
The objective of this paper is to give an overview assessment for alleviation of metal lossconsidering internal corrosion protection, safety aspects and meets industrial requirements. Theultimate goal of this study is to have inhibitor for mild steel protected against corrosive environmentsin order to mitigate heavy metal loss during acid pickling. Acid- used to reduce the formationdamage around the oil well or to remove scale - readily attacks the metal. In the oil extraction andprocessing industries, inhibitors have been considered to be the first line of defense againstcorrosion. Most of the inhibitors currently used in producing wells are organic nitrogenouscompounds. The present work aims at the study of a new imidazoline derivative, 2-[2-(4-Nitrophenyl)-vinyl]-tetrahydro-1,3,8-triaza-cyclopenta[a]indene (NVI) as mild steel corrosion inhibitor inH2SO4 acid medium by electrochemical methods. NVI was found to inhibit corrosion with efficiencyabove 85 % in sulphuric acid medium. Electrochemical impedance studies proved that NVI inhibitsmetal loss by physically adsorbing on the surface through its hetero atoms. Polarization studiesproved the mixed mode of inhibition by NVI. Theoretical evidences obtained by structuraloptimization of NVI using GAUSSIAN software employing DFT also support the experimentalfinding.
THE ROLE OF TOR AS A DRUG ON THE CORROSION INHIBITOR FOR MILD STEEL SURFACE
(Vivekanandha Arts and Science College for Women, 2020) Menaga M; NaliniD; SowmyaRamkumar
The inhibition performance of tor on mild steel in 1 M hydrochloric acid solution was studied by weight loss and electrochemical methods. The results show the inhibition efficiency was found to increase with increasing the concentration of the inhibitor from 1 to 50 ppm. The maximum inhibition efficiency 95.4% was observed in the presence of 50 ppm inhibitor. The inhibition action of tor was explained in terms of adsorption on the mild steel surface. Electrochemical Impedance spectroscopic technique (EIS) exhibits, the corrosion reaction is controlled by charge transfer process. Polarization measurements showed that the inhibitor is of a mixed type. The results obtained from the different methods are in good agreement. The computational calculations are performed to find a relation between their electronic and structural properties.
SUBSTITUTED 2-IMIDAZOLINE DERIVATIVE: NEW AND EFFICIENT CORROSION INHIBITORS FOR MILD STEEL IN SULPHURIC ACID SOLUTION
(SASEST, 2014-08-21) SowmyaRamkumar; D, Nalini; R, Rajalakshmi
The aim of this work is to obtain deeper insight into the mechanism of the protective action of the imidazole-based corrosion inhibitor, 2-(4’-N, N-Dimethylaminophenyl)-imidazoline (DMAP2I). Investigations were performed on mild steel in 0.5 M H2SO4 by electrochemical methods and non - electrochemical methods. Maximum protection efficiency reaches about 85% for DMAP2I at 200 ppm concentration level. The adsorption of the imidazoline derivative on mild steel surface follows Langmuir and Tempkin isotherm. The adsorption free energy on mild steel (20 – 30 kJ/mol) reveals a comprehensive (physical and chemical) adsorption of the inhibitors on the metal surface. Polarization curves reveal that DMAP2I act as a mixed-type inhibitor. Results obtained from potentiodynamic polarization and impedance measurements are in good agreement. Quantum chemical method is used to explore the relationship between the inhibitor molecular properties and its inhibition efficiency. The density function theory (DFT) is also used to study the structural properties of the inhibitor. It is found that when the imidazole derivative adsorbs on the mild steel surface, molecular structure influences their interaction mechanism. The inhibition efficiencies of the compound showed a certain relationship to highest occupied molecular orbital (HOMO) energy and Mulliken atomic charges.