Faculty Publications

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2015 - 20173

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Author: search.filters.author.Selvaraju, N.Has files: No

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    Evaluation of optimization methods for solving the receptor model for chemical mass balance
    (Serbian Chemical Society, 2015) Anu, N.; Selvasembian, S.; Rahul, A.; Selvaraju, N.
    The chemical mass balance (CMB 8.2) model has been extensively used in order to determine source contribution for particulate matters (size diameters less than 10 and 2.5 ?m) in air quality analysis. A comparison of the source contribution estimated from three CMB models was realized through optimization techniques, such as 'fmincon' (CMB-fmincon) and genetic algorithm (CMB-GA) using MATLAB. The proposed approach was validated using a San Joaquin Valley Air Quality Study (SJVAQS) California Fresno and Bakersfield PM10 and PM2.5 followed with Oregon PM10 data. The source contribution estimated from CMB-GA was better in source interpretation in comparison with CMB 8.2 and CMB-fmincon. The performance accuracies of three CMB approaches were validated using R2, reduced X2 and percentage mass tests. The R2 (0.90, 0.67 and 0.81, 0.83), X2 (0.36, 0.66 and 0.65, 0.43) and percentage mass (67.36, 55.03 and 94.24 %, 74.85 %) of CMB-GA showed high correlation for PM10, PM2.5, Fresno and Bakersfield data, respectively. To make a complete decision, the proposed methodology was bench marked with Portland, Oregon PM10 data with the best fit with R2 (0.99), X2 (1.6) and percentage mass (94.4 %) from CMB-GA. Therefore, the study revealed that CMB with genetic algorithm optimization method exhibiting better stability in determining the source contributions.
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    Hydrous Cerium Oxide Nanoparticles Impregnated Enteromorpha sp. for the Removal of Hexavalent Chromium from Aqueous Solutions
    (American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2016) Selvasembian, S.; Selvaraju, N.; Raj Mohan, B.; Muhammed Anzil, P.K.; Amith, K.D.; Ushakumary, E.R.
    A novel nanobiocomposite, hydrous cerium oxide nanoparticles impregnated Enteromorpha sp. (HCONIE) was used effectively for the adsorption of Cr(VI) from aqueous solutions. The chemical and structural characteristics of the nanobiocomposite were investigated using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analysis. Adsorption studies were determined as a function of pH, contact time, initial concentration of Cr(VI), HCONIE dose, and temperature. The equilibrium adsorption data were modeled using two parameter isotherms, including Langmuir, Freundlich, Dubinin-Radushkevich (D-R), Temkin, Jovanovic, Halsey, and Harkin-Jura. Adsorption data were well described by the Freundlich and Halsey isotherm. The kinetics data were analyzed using adsorption kinetic models like the pseudo-first-order, pseudo-second-order and intraparticle diffusion equation. Kinetic data showed good agreement with the pseudo-second-order kinetic model. The obtained thermodynamic parameters showed that the adsorption of Cr(VI) onto the HCONIE was exothermic in nature. The presence of foreign ions showed a decreased effect on the adsorption capacity of HCONIE towards Cr(VI) removal. The desorption study was carried out with 0.1 and 0.5 M of three different desorbing agents. The study suggests that HCONIE nanobiocomposite could be used for the removal of Cr(VI) from aqueous solution. © 2015 American Society of Civil Engineers.
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    Equilibrium and Kinetic Studies of Hexavalent Chromium Removal Using A Novel Biosorbent: Ruellia Patula Jacq
    (Springer Verlag, 2017) Saranya, N.; Nakkeeran, E.; Shrihari, S.; Selvaraju, N.
    The present work utilized Ruellia patula Jacq leaves as biosorbent for hexavalent chromium removal. Sulfuric acid modification was done and checked for enhanced biosorption capacity. Electron microscopy–energy-dispersive X-ray spectroscopy, Fourier transform infrared spectrometry, elemental analysis were performed for characterization of biosorbents. Batch experiments were conducted to optimize contact time, solution pH, initial Cr(VI) concentration, biosorbent dose, agitation speed and temperature for maximum Cr(VI) removal. Also, the study attempted to show polyphenols present in the biosorbent reduce Cr(VI) through adsorption. Equilibrium data were analyzed using Langmuir, Freundlich and Dubinin–Radushkevich isotherms. Monolayer adsorption capacities of raw and acid-modified biosorbents were found to be 37.03 and 62.50 mg/g, respectively. Pseudo-second-order kinetic model suited well than other models like pseudo-first-order and intraparticle diffusion models examined. Determination of ? H?, ? S? and ? G? from thermodynamic studies showed that the biosorption is exothermic, stable and thermodynamically feasible. Desorption studies using NaOH as desorbing agent showed considerable performances up to three cycles. These findings revealed that Ruelliapatula leaves serve as potent biosorbent for the removal of hexavalent chromium from aqueous solutions. © 2017, King Fahd University of Petroleum & Minerals.