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Thilagavathy P.,Professional Group of Institutions | Santhi T.,Karpagam University
Chinese Journal of Chemical Engineering | Year: 2014

The removal of cobalt ion from aqueous solution by Acacia nilotica leaf carbon (HAN), is described. Effect of pH, agitation time and initial concentration on adsorption capacities of HAN was investigated in a batch mode. The adsorption process, which is pH dependent, shows maximum removal of cobalt in the pH range 5 for an initial cobalt concentration of 50mg·L-1 The experimental data have been analyzed by using the Freundlich, Langmuir, Temkin and Dubinin-Radushkevich isotherm models. The batch sorption kinetics have been tested for a pseudo-first order, pseudo-second order and Elovich kinetic models. The rate constants of adsorption for all these kinetic models have been calculated. Results showed that the intraparticle diffusion and initial sorption of Co(II) into HAN was themain rate limiting step. The adsorption of cobalt ion was confirmed through instrumental analyses such as scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The desorption and recycling ability of HAN were also found. We conclude that HAN can be used for the efficient removal of cobalt from aqueous solution. © 2014 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved. Source

Thilagavathy P.,Professional Group of Institutions | Santhi T.,Karpagam University
BioResources | Year: 2014

In this work, sustainable and biodegradable Acacia nilotica leaf (AN) was chemically modified to remove Cu(II) from aqueous solutions, which is considered a versatile approach to clean contaminated aquatic environments. Zinc chloride-modified Acacia nilotica leaf (ZAN) was characterized by scanning electron microscopy (SEM) and other physico-chemical parameters like pHZPC. The aim was to assess the efficiency and mechanism of adsorption on Acacia nilotica via isotherm models (Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Harkin-Jura, and Frenkel-Halsey-Hill), kinetic models, and thermodynamic parameters. To optimize the removal efficiency, parameters such as effect of initial concentration, effect of pH, dosage, initial concentration, and contact time were studied by batch and column methods. Desorption studies illustrated that about 73% of the metal ions could be removed using 0.2N HCl. The results of the present investigation indicated that ZAN has a high potential for the removal of Cu(II) from aqueous solutions, and the resultant data can serve as a base line for designing treatment plants on an industrial scale. Source

Nagasubramaniam K.,TTJ Design and Engg Ltd | Chandramohan P.,Professional Group of Institutions
Journal of Engineering Science and Technology | Year: 2014

Pressure/velocity remains as main factors in a high pressure die casting machine to produce intricate components from the die. Rejection analysis was carried out in a die casting machine used in producing Aluminum components with a higher rejection rate. Three modifications have been carried out in the basic hydraulic design of the machine to increase the efficiency and in turn reduce the rejection of the components. The three modifications include (i) addition of nitrogen bottle to the system design (ii) Reducing the passage diameter of the Intensifier output (iii) Regeneration of Intensifier output. The first modification resulted with increase in pressure and the second with increase in velocity and finally the third one with optimum increase in both pressure and velocity. This has resulted in the improvement of machine efficiency thereby reducing the overall rejection of the components with intricate design. © School of Engineering, Taylor’s University. Source

Suresh N.,Coimbatore Institute of Technology | Chandrasekar P.,Professional Group of Institutions
Applied Mechanics and Materials | Year: 2014

The challenging problems for designers and engineers in the material science are to enhance the quality of the castings. The several numbers of methods using external forces have been applied to introduce fluid flow during solidification of molten metal in casting process. These include mechanical, electromagnetic and ultrasonic vibration. Many technical journals describe the improvement in mechanical properties of castings under the vibration during solidification. In this paper, an attempt has been made to review the casting process to refine the microstructure of cast product. The awareness gain of these processes and application of the procedures offer the scope for better cost savings in design and manufacturing of cast products. © (2014) Trans Tech Publications, Switzerland. Source

Thilagavathy P.,Professional Group of Institutions | Santhi T.,Karpagam University
BioResources | Year: 2013

The use of cheap and eco-friendly adsorbents prepared from freely and abundantly available Acacia nilotica leaves for the removal of highly toxic Cr(VI) from aqueous solutions in single and binary ion solutions as well as from a mixture of it with Co(II) & Cu(II) was investigated by batch methods. The effects of pH, contact time, and initial metal ion concentration of Cr(VI) onto H2SO4-treated Acacia nilotica leaves (HAN) was investigated. The linear form of the Freundlich model achieved high coefficients of determination R2 = 0.9808 for Cr(VI) adsorption. The R2 values for fitting the adsorption rate data were greater than 0.983 for Cr(VI) ion, which indicates the applicability of pseudo-second-order kinetic model. The desorption and recycling ability of Cr(VI) and HAN were found to be good. The studies showed that this low-cost adsorbent could be used as an efficient adsorbent material for the removal of Cr(VI) from aqueous solutions. Source

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