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Item CORROSION RESISTANCE OF CISSUS QUADRANGULARIS EXTRACTS ON METAL IN AGGRESSIVE MEDIUM: GRAVIMETRIC AND SURFACE EXAMINATIONS(Rasayan Journal of Chemistry, 2019-09) Anitha, R; Subramanian, ChitraThe corrosion resistance of Cissus quadrangularis in acid and ethanol medium have been investigated by diverse techniques. It has been noticed that as the concentration (2 to 12v/v %) of C. quadrangularis rises the efficiency of the inhibitor also increases. The maximum inhibition efficiencies of 89.45 % and 75.54 % were attained for acid and ethanol extracts respectively. The emergence of a protective layer on the mild steel surface was assessed by electrochemical impedance studies. The influence of the active ingredients in the extracts was examined by GC-MS analysis. The inhibitor adsorption ensued in the protective layer on the surface was analyzed using SEM and AFM.Item ANTICORROSIVE PROPERTY OF SPIRAEA CANTONIENSISIS EXTRACT AS AN ECO-FRIENDLY INHIBITOR ON MILD STEEL SURFACE IN ACID MEDIUM(Taylor & Francis Online, 2019) Ill-Min, Chung; Kathirvel, Kalaiselvi; Asokan, Sasireka; Seung-Hyun, Kim; Mayakrishnan, PrabakaranThe inhibitive performance of methanolic extract of eco-friendly green inhibitor Spiraea cantoniensis (S. cantoniensis) on inhibiting corrosion of mild steel (MS) in 1 M HCl was studied by weight loss, AC-impedance, Fourier transform infrared spectroscopy (FT-IR), Raman, x-ray diffraction (XRD), ultraviolet-visible (UV-Vis), atomic absorption spectroscopy (AAS), and scanning electron microscopy (SEM) analysis. The results showed that the corrosion rate significantly decreased in the presence of the S. cantoniensis inhibitor with a gradual increase in inhibition efficiency at an increased inhibitor concentration. The temperature studies were conducted which included activation energy (Ea), change in enthalpy (ΔH°ads), change in entropy (ΔS°ads), change in free energy (ΔG°ads) and heat of adsorption (Qads). These calculations were helpful to determine the reaction mechanism and proved it as a physisorption type following the Langmuir adsorption isotherm. The analysis of the protective film using FT-IR, Raman, XRD, and SEM analysis clearly showed the potentiality of S. cantoniensis in blocking the MS surface to prevent corrosion by 1 M HCl. The solution analysis via AAS and UV-Vis showed the inhibitive effect of the inhibitor (S. cantoniensis) in both inhibitive and the uninhibitive solution exhibiting the adsorption of the phytochemical molecules on the MS surface.Item ASSESSMENT OF LOW CARBON STEEL CORROSION INHIBITION BY ECO-FRIENDLY GREEN CHAENOMELES SINENSIS EXTRACT IN ACID MEDIUM(The Korean Electrochemical Society, 2018-07-16) Ill-Min, Chung; Venkatesan, Hemapriya; Kanchana, Ponnusamy; Natarajan, Arunadevi; Subramanian, Chitra; Chi-Hee, Youn; Seung-Hyun, Kim; Mayakrishnan, PrabakaranThe impact of methanol extract of Chaenomeles sinensis (C. sinensis) leaves on acid corrosion of low carbon steel was assessed by gravimetric and electrochemical methods. Phytochemical characterization by total phenolic content (TPC), and total flavonoids content (TFC) of the extract was performed. The TPC and TFC concentrations were identified as 193.50 and 40.55 mg/g. Efficiency increased remarkably in the presence of inhibitor and found as concentration dependent. A maximum inhibition efficiency of 93.19% was achieved using 2000 ppm of the C. sinensis inhibitor. Impedance and surface morphology analysis by SEM and AFM revealed that the anticorrosive activity results from the protective film of phytochemical components of C. sinensis extract adsorbed on the metal surface.Item CARICA PAPAYA PEEL MEDIATED SYNTHESIS OF SILVER NANOPARTICLES AND ITS ANTIBACTERIAL ACTIVITY AGAINST HUMAN PATHOGENS(ScienceDirect, 2017-09-28) Balavijayalakshmi, J; Ramalakshmi, VMetallicnanoparticlesaretraditionallysynthesizedbywetchemicaltechniques,inwhichthechemicalsusedarequiteoftentoxicandflammable.Ripecaricapapayapeelisfoundtobeasuitablesourceforgreensynthesisofsilvernanoparticles.Inthepresentwork,acosteffectiveandenvironmentalfriendlytechniqueforthegreensynthesisofsilvernanoparticlesfrom1mMsilvernitrate(AgNO3)solutionthroughtheextractofripeCaricapapayapeelofvariousconcentrations(5ml,10ml,15ml,20ml,25ml)isdescribed.ThesynthesizedsilvernanoparticlesarecharacterizedbyusingtheUV–visabsorptionspectroscopy,FT IR,XRD,SEMandTEM.Theformationofsilvernanoparticlesisconfirmedbysurfaceplasmonresonance,determinedbyUV–visspectraat400–435nm.Theshiftintheabsorptionbandsandvariationinthecalculatedopticalbandgapsforthevariousconcentrationsofpapayapeelsextractsarealsoobserved.TheFT-IRspectrarevealthatanincreaseintheconcentrationofthepapayapeelextractshiftsthebandstohigherwavelengths.TheaveragecrystallitesizeforvariousconcentrationsofpapayapeelextractisobservedfromXRDspectralanalysisandisfoundtobearound16–20nm,whichisingoodagreementwiththeTEManalysis.TheSEManalysisshowsthesphericalstructureofthesilvernanoparticleswithsomeagglomerationforhigherconcentrationsofpapayapeelextract.ThesynthesizedsilvernanoparticlesshowgoodantibacterialactivityagainsthumanpathogenssuchasEscherichiacoliandStaphylococcusaureusandithasmanymedicalapplicationsItem SOYA BEAN OIL BASED POLYURETHANES FOR CORROSION INHIBITION OF MILD STEEL IN ACID MEDIUM(Taylor & Francis Online, 2016) Valarmathi, Eswaramoorthi; Saranya, Jagadeesan; Sounthari, Palanisamy; Parameswari, Kandhasamy; Subramanian, ChitraPolyurethanes synthesized from soya bean oil were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy (SEM), X-ray diffraction and energy-dispersion X-ray analysis methods. Thermal stability of the polyurethanes was investigated by thermogravimetric analysis. The corrosion inhibition effect of polyurethanes on mild steel in 1 M H2SO4 was studied using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy methods. The effect of temperature on the corrosion behaviour of mild steel was studied in the temperature range (303–333 K) with optimum inhibitor concentration. The adsorption of the inhibitors was found to obey the Langmuir adsorption isotherm. It was found that the inhibition efficiency increased with increase in concentration but decreased with increase in temperature. The associated activation energy and other thermodynamic parameters such as adsorption–desorption equilibrium constant (Kads), standard free energy of adsorption (ΔG), enthalpy of adsorption (ΔH) and entropy of adsorption (ΔS) were calculated to elaborate the corrosion inhibition mechanism. Surface morphology of the mild steel plate immersed in 1 M H2SO4 was characterized by SEM and AFM techniques.Item POLYESTER-BENTONITE CLAY COMPOSITE: SYNTHESIS, CHARACTERIZATION AND APPLICATION AS ANTICORROSIVE AGENT(Oriental Journal of Chemistry, 2015-08-20) Subramanian, Chitra; Sounthari, Palanisamy; Kiruthika, Ayyasamy; Parameswari, KandasamyNew polyester-bentonite clay composite was prepared and characterized by FTIR, TGA, SEM& XRD. The XRD and SEM studies are quite supportive of well dispersed polymer clay composite formation. The thermal stability of the polymer was significantly improved as indicated by TGA. The composite was evaluated for its inhibition performance for mild steel corrosion in 1M H2 SO4 by weight loss, polarization and electrochemical impedance techniques. The studies reveal that the clay composite was an excellent adsorption type inhibitor and obeys Langmuir adsorption isotherm. Electrochemical studies showed that the polymer composite was a mixed inhibitor retarding both anodic metal dissolution and cathodic hydrogen evolutionItem SYNTHESIS AND CHARACTERIZATION OF CUPRIC CHLORIDE DOPED ZINC SULPHIDE NANOPARTICLES(Sphinx Knowledge House, 2014) Balavijayalakshmi J; Manju S; Lavanya SIn recent years, the research on semiconductor nanoparticles has stimulated much interest because of their unique optical and electrical properties. The nanosized semiconductor crystallites could produce optical properties which are different from bulk materials. Among the semiconductor nanoparticles, Zinc Sulphide is an important II–VI semiconductor material researched extensively because of its wide range of applications in electroluminescence devices, phosphors, light emitting displays and optical sensors. Semiconductor nanoparticles doped with transition metal ions have attracted much attention because of their luminescent properties. Hence an attempt is made to synthesize cupric chloride doped zinc sulphide nanoparticles. The synthesized nanoparticles are subjected to Xray diffraction to calculate the average nano-crystalline size using Debye – Scherrer formula and are found to be 2nm. The morphological analysis of the sample is studied using Scanning Electron Microscope. The UV-Visible spectrophotometer shows the absorption edge of the nanoparticles in range 292 to 261 nm. A FT-IR spectrum confirms the characteristic ZnS vibration peaks.Item BRANCHED POLYMERS AND THEIR APPLICATION IN CORROSION INHIBITION FOR MILD STEEL IN 1M H2SO4 MEDIUM(Oriental Journal of Chemistry, 2014-12-25) Sounthari, P; Kiruthika, A; Saranya, J; Parameswari, K; Chitra, SThe adsorption and corrosion inhibiting effect of branched polymers (BATP, BAAZ, BETP & BEAZ) on mild steel in 1M H2SO4 at 30±1˚C was investigated using gravimetric, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization techniques. The experimental findings revealed that BATP inhibited the corrosion reaction in the acid environment to greater extend compared to BAAZ, BETP and BEAZ. Impedance results indicate that the polymers were adsorbed on the metal/solution interface, while polarization data showed that the polymers behaved mostly as mixed-type inhibitors. Kinetic parameters (activation energy, pre-exponential factor, enthalpy of activation and entropy of activation) as well as thermodynamic parameters (enthalpy of adsorption, entropy of adsorption and Gibbs free energy) were calculated and discussed. Scanning electron microscopy technique was used to confirm the effectiveness of inhibition of mild steel in sulphuric acid medium.Item CARICA PAPAYA PEEL MEDIATED SYNTHESIS OF SILVER NANOPARTICLES AND ITS ANTIBACTERIAL ACTIVITY AGAINST HUMAN PATHOGENS(Journal of Applied Research and Technology, 2017-08-28) Balavijayalakshmi, J; Ramalakshmi, VMetallic nanoparticles are traditionally synthesized by wet chemical techniques, in which the chemicals used are quite often toxic and flammable. Ripe carica papaya peel is found to be a suitable source for green synthesis of silver nanoparticles. In the present work, a cost effective and environmental friendly technique for the green synthesis of silver nanoparticles from 1 mM silver nitrate (AgNO3 ) solution through the extract of ripe Carica papaya peel of various concentrations (5 ml, 10 ml, 15 ml, 20 ml, 25 ml) is described. The synthesized silver nanoparticles are characterized by using the UV–vis absorption spectroscopy, FT-IR, XRD, SEM and TEM. The formation of silver nanoparticles is confirmed by surface plasmon resonance, determined by UV–vis spectra at 400–435 nm. The shift in the absorption bands and variation in the calculated optical band gaps for the various concentrations of papaya peels extracts are also observed. The FT-IR spectra reveal that an increase in the concentration of the papaya peel extract shifts the bands to higher wavelengths. The average crystallite size for various concentrations of papaya peel extract is observed from XRD spectral analysis and is found to be around 16–20 nm, which is in good agreement with the TEM analysis. The SEM analysis shows the spherical structure of the silver nanoparticles with some agglomeration for higher concentrations of papaya peel extract. The synthesized silver nanoparticles show good antibacterial activity against human pathogens such as Escherichia coli and Staphylococcus aureus and it has many medical applications.Item BRANCHED POLYMERS AND THEIR APPLICATION IN CORROSION INHIBITION FOR MILD STEEL IN 1M H2SO4 MEDIUM (Article)(Oriental Journal of Chemistry, 2014-12-25) Sounthari., P; Kiruthika, A; Saranya, J; Parameswari, K; Chitra, SThe adsorption and corrosion inhibiting effect of branched polymers (BATP, BAAZ, BETP & BEAZ) on mild steel in 1M H2SO4 at 30±1˚C was investigated using gravimetric, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization techniques. The experimental findings revealed that BATP inhibited the corrosion reaction in the acid environment to greater extend compared to BAAZ, BETP and BEAZ. Impedance results indicate that the polymers were adsorbed on the metal/solution interface, while polarization data showed that the polymers behaved mostly as mixed-type inhibitors. Kinetic parameters (activation energy, pre-exponential factor, enthalpy of activation and entropy of activation) as well as thermodynamic parameters (enthalpy of adsorption, entropy of adsorption and Gibbs free energy) were calculated and discussed. Scanning electron microscopy technique was used to confirm the effectiveness of inhibition of mild steel in sulphuric acid medium.