A. Sivalingam

Spectroscopic investigation on kinetics, thermodynamics and mechanism for electron transfer reaction of iron(III) complex with sulphur centered radical in stimulated biological system

Electron transfer reactions of biological organic sulphides with several metal ions to generate sulphide radical cations are a great concern in biochemical process. To understand the mechanism, a stimulated biological system having model compounds, iron(III)-bipyridyl complex with thio-diglycolic acid (TDGA) was investigated. Spectroscopic study reveals the kinetics and thermodynamics of the reaction in aqueous perchloric acid medium. The reaction follows first and fractional order of 0.412 with respect to [Fe(bpy)3](3+) and TDGA, respectively. The oxidation is insensitive to variation in [H(+)] but slightly decreases with increase in ionic strength ([I]). Addition of acrylamide, a radical scavenger has no effect on the rate of the reaction. The high negative value of ΔS(#) (-74.3±1.09 J K(-1) mol(-1)) indicates the complex formed has a definite orientation higher than the reactants. Based on the above results, a suitable reaction mechanism for this reaction is proposed.

Optimization of Biodiesel Synthesis from Calophyllum inophyllum

In this study, nano-size calcium-based heterogeneous catalyst derived from lime sludge was used for biodiesel production. Its catalytic activity in transesterification of Calophyllum inophyllum (C. inophyllum) oil and the physicochemical properties of synthesized biodiesel were systematically investigated. Due to high free fatty acids two-step acid esterification and alkali transesterification were performed. Transesterification reaction follows pseudo-first-order kinetics and their rate constants were determined. Activation energy and frequency factor were found to be 20.69 kJ mol–1 and 0.219 s–1, respectively. The fuel properties of the derived biodiesel was analyzed according to ASTM methods.

Colour Removal of Direct Red Dye Effluent by Adsorption Process Using Rice Husk

To show that rice husk could be employed as low-cos t and effective adsorbent for the removal of Direct Red 23 from dye effluent and also to stud y the effect of concentration of dye solution and t he effect of amount of adsorbent on the percentage rem oval of dye. Azo dyes and their degradation product s such as aromatic amines are highly carcinogenic. Ad sorption of dyes is a new technology for treatment of waste water containing different types of dyes.A dsorption process is adopted for removal of direct d 23 dye from the dye effluent using rice husk as the adsorbent in treated and untreated form. The proce ss involves: washing and drying of rice husk at 105° c ,followed by soaking in 0.6 M Citric acid for 2 hou rs and heated to 120 °C.Further it is dried and washed repeatedly to obtain treated rice husk.This treate d and untreated rice husk are used for removal of Dir ect Red 23 dye. Dye solutions of different concentrations were prepared and a known amount of adsorbent were added to study the Effect of concentration of dye solution and effect of amount of adsorbent on the percentage of removal of Direct Red 23.