Department of Chemical Engineering

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End date: 2009Subject: search.filters.subject.Kinetics

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    Biodegradation kinetics of methyl iso-butyl ketone by acclimated mixed culture
    (Elsiever, 2009-06-26) Raghuvanshi, Smita
    Methyl iso-butyl ketone (MIBK) is a widely used volatile organic compound (VOC) which is highly toxic in nature and has significant adverse effects on human beings. The present study deals with the removal of MIBK using biodegradation by an acclimated mixed culture developed from activated sludge. The biodegradation of MIBK is studied for an initial MIBK concentration ranging from 200–700 mg l−1 in a batch mode of operation. The maximum specific growth rate achieved is 0.128 h−1 at 600 mg l−1of initial MIBK concentration. The kinetic parameters are estimated using five growth kinetic models for biodegradation of organic compounds available in the literature. The experimental data found to fit well with the Luong model (R 2 = 0.904) as compared to Haldane model (R 2 = 0.702) and Edward model (R 2 = 0.786). The coefficient of determination (R 2) obtained for the other two models, Monod and Powell models are 0.497 and 0.533, respectively. The biodegradation rate found to follow the three-half-order kinetics and the resulting kinetic parameters are reported.
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    Utilization of waste product (tamarind seeds) for the removal of Cr(VI) from aqueous solutions: Equilibrium, kinetics, and regeneration studies
    (Elsiever, 2009-07) Gupta, Suresh
    In the present study, an adsorbent was prepared from tamarind seeds and used after activation for the removal of Cr(VI) from aqueous solutions. The tamarind seeds were activated by treating them with concentrated sulfuric acid (98% w/w) at a temperature of 150 °C. The adsorption of Cr(VI) was found to be maximum at low values of initial pH in the range of 1–3. The adsorption process of Cr(VI) was tested with Langmuir, Freundlich, Redlich–Peterson, Koble–Corrigan, Tempkin, Dubinin–Radushkevich and Generalized isotherm models. Application of the Langmuir isotherm to the system yielded a maximum adsorption capacity of 29.7 mg/g at an equilibrium pH value ranging from 1.12 to 1.46. The adsorption process followed second-order kinetics and the corresponding rate constants obtained were 2.605 × 10−3, 0.818 × 10−3, 0.557 × 10−3 and 0.811 × 10−3 g/mg min−1 for 50, 200, 300 and 400 mg/L of initial Cr(VI) concentration, respectively. The regenerated activated tamarind seeds showed more than 95% Cr(VI) removal of that obtained using the fresh activated tamarind seeds. A feasible solution is proposed for the disposal of the contaminants (acid and base solutions) containing high concentrations of Cr(VI) obtained during the regeneration (desorption) process.
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    Removal of toxic metal Cr(VI) from aqueous solutions using sawdust as adsorbent: Equilibrium, kinetics and regeneration studies
    (Elsiever, 2009-08-01) Gupta, Suresh
    In the present study, a low-cost adsorbent is developed from the naturally and abundantly available sawdust which is biodegradable. The removal capacity of Cr(VI) from aqueous solutions and from the synthetically prepared industrial effluent of electroplating and tannery industries is obtained. The batch experiments are carried out to investigate the effect of the significant process parameters such as initial pH, change in pH during adsorption, contact time, adsorbent amount, and the initial Cr(VI) concentration. The maximum adsorption of Cr(VI) on sawdust is obtained at an initial pH value of 1. The value of pH increases with increase in contact time and initial Cr(VI) concentration. The equilibrium data for the adsorption of Cr(VI) on sawdust is tested with various adsorption isotherm models such as Langmuir, Freundlich, Redlich–Peterson, Koble–Corrigan, Tempkin, Dubinin–Radushkevich and Generalized equation. The Langmuir isotherm model is found to be the most suitable one for the Cr(VI) adsorption using sawdust and the maximum adsorption capacity obtained is 41.5 mg g−1 at a pH value of 1. The adsorption process follows the second-order kinetics and the corresponding rate constants are obtained. Desorption of Cr(VI) from sawdust using acid and base treatment exhibited a higher desorption efficiency by more than 95%. A feasible solution is proposed, for the disposal of the contaminant (acid and base solutions) containing high concentration of Cr(VI) obtained during the desorption process. The interference of other ions which are generally present in the electroplating and tannery industrial effluent streams on the Cr(VI) removal is investigated.
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    Removal of Cr(VI) from wastewater using activated tamarind seeds as an adsorbent
    (ICE Publishing, 2008-07-30) Gupta, Suresh
    In the present study, an adsorbent was prepared from tamarind seeds and batch studies were conducted for Cr(VI) removal from aqueous solutions. Tamarind seeds were activated by heat treatment and with concentrated sulfuric acid (98% w/w). The parameters investigated include initial pH, contact time, initial Cr(VI) concentration, and adsorbent dosage. The adsorption of Cr(VI) was found to be maximum at low values of initial pH in the range of 1–3. The adsorption process of Cr(VI) was tested with Langmuir and Freundlich isotherm models. Application of the Langmuir isotherm to the systems yielded maximum adsorption capacity of 29.08 mg g–1. The adsorption process followed second order kinetics and the corresponding rate constant was found to be 0.0026 g mg–1 min–1.