NOPR Collection:

Vapor phase adsorption of xylene on granular activated carbon - Experimental and theoretical breakthrough curves

Tue, 01 Jan 2013 00:00:00 GMT

Title: Vapor phase adsorption of xylene on granular activated carbon - Experimental and theoretical breakthrough curves Authors: Gupta, Kaushal Naresh; Rao, Nandagiri Jagannatha; Agarwal, Govind Kumar Abstract: Experiments have been carried out to study adsorption of xylene (a volatile organic compound) on the granular activated carbon, using the experimental variables, such as inlet gas concentration (2400 – 6200 ppm), gas flow rate (50 mL/min) and height of the adsorbent bed (0.015 – 0.025 m). The breakthrough curves are then drawn between ratios of outlet gas concentration to inlet gas concentration and time for different operating conditions. A mathematical model is developed to predict the breakthrough curves of xylene on granular activated carbon. The model shows the effects of the gas-particle film mass transfer resistance, adsorbent pore diffusion and instantaneous local adsorption equilibrium at the pore surface. The experimental data and the corresponding model simulated results have been compared and are found to be in good agreement. The breakthrough time increases with increase in bed height and decreases with increase in inlet concentration. Page(s): 26-32

Equilibrium, kinetic and thermodynamic studies on biosorption of lead(II) and cadmium(II) from aqueous solution by polypores biomass

Tue, 01 Jan 2013 00:00:00 GMT

Title: Equilibrium, kinetic and thermodynamic studies on biosorption of lead(II) and cadmium(II) from aqueous solution by polypores biomass Authors: Suguna, M; Kumar, N Siva Abstract: Polypores (woody pore fungi) biomass has been used as an biosorbent for the removal of Pb(II) and Cd(II) from aqueous solution under batch equilibrium experimental conditions. The resulting biosorbent is characterized by SEM and FTIR techniques. The effect of experimental parameters, such as solution pH, biomass dosage, contact time, initial metal ion concentration and temperature of Pb(II) and Cd(II) have been evaluated on the metal uptake performance. The pH for optimum biosorption is found to be 5.0 for Cd(II) (92.5% removal) and Pb(II) (96.4% removal). The adsorption kinetic data are best described by pseudo-second-order kinetic model with good correlation coefficient and low error function values. The experimental results indicate that the Langmuir isotherm describes the biosorption of Cd(II) and Pb(II) ions onto the biomass better than the Freundlich, Dubinin-Radushkevich (D-R) and Temkin models at all the temperatures studied. The calculated thermodynamic parameters (∆G^o, ∆H^o and ∆S^o) show that the biosorption of both metal ions is feasible, spontaneous and exothermic in nature at 303–313 K. Based on the results obtained such as good uptake capacity and its low cost, polypores biomass appears to be a promising biosorbent material for the removal of Cd(II) and Pb(II) ions from aqueous media. Page(s): 57-69

Adsorption of Cu and Zn on calcium alginate immobilized Penicillium sp.

Tue, 01 Jan 2013 00:00:00 GMT

Title: Adsorption of Cu and Zn on calcium alginate immobilized Penicillium sp. Authors: Mishra, S P Abstract: Calcium alginate has been used for immobilization of Penicillium sp. (PS). The bio granules thus prepared by the immobilization technique, i.e. immobilized PS (IPS), are then used for Cu and Zn sorption from waste water. Various sorption parameters are studied to establish the optimum sorption conditions. The study shows that 5.0 pH and 200 min contact time are the optimum values for both Cu and Zn sorption. The activation energy for Cu sorption by IPS is found to be 19.4 kJ/mole and Zn sorption on IPS is found to be temperature independent. The sorption process obeys Freundlich sorption isotherm in both the cases. The sorption of Cu and Zn by IPS follows pseudo-first order reaction kinetics and is found to be diffusion controlled in nature. The dependence of the rate constant on different sorption parameters is observed and these dependence factors are included in the final rate expressions. Page(s): 21-25

Assessment of auto-oxidation cum self-heating tendency of Indian coals by DRIFT studies

Tue, 01 Jan 2013 00:00:00 GMT

Title: Assessment of auto-oxidation cum self-heating tendency of Indian coals by DRIFT studies Authors: Khan, Samit; Adak, Ashis K; Sen, Raja; Sarkar, Abhijit Abstract: Coal self-heating, due to low temperature oxidation of coal, is generally considered to be the primary cause of spontaneous ignition. With the purpose of having a more definitive quantization of this subtle stage of coal oxidation, study on proneness to coal towards auto-oxidation, vis-à-vis self-heating phenomenon, has been carried out. Various methods like crossing point temperature (CPT), diffuse reflectance infrared fourier transform spectroscopy (DRIFT), differential scanning calorimetry-thermogravimetric analysis (DSC-TGA) and wet oxidation method has been used for comparative study. It is observed that though CPT values alone are adequately indicative and are consistent with actual field experience, the combination of CPT and DRIFT data complements each other very well to provide greater information for better prediction of proneness to auto-oxidation vis-à-vis self-heating phenomenon of coals. Other methods tried are found to be comparatively inadequate. Page(s): 52-56