Effective Diffusivity of Phenol in Activated Carbon

Bhatia, Suresh K.; Kalam, A.; Joglekar, H.S.; Joshi, Jigar

doi:10.1080/00986449008911566

Cited by 17 publications

(9 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Assumptions 1−3 are justified to be reasonably true by our observations. Assumptions 4−6 have been justified in many previous efforts for simplification of general adsorption process modeling (Bhatia, 1990; Price and Varma, 1988; Allen et al, 1988; Huang and Cao, 1988; Do and Rice, 1987).…”

Section: Methodsmentioning

confidence: 99%

“…Equation 1 includes both pore‐diffusion and surface‐ (or solid‐) diffusion mechanisms for intraparticle metal transport. According to the literature, the pore‐diffusion model, the surface‐diffusion model, and the combined‐diffusion model have all been successfully applied to the modeling of traditional adsorption dynamics (Bhatia, 1990; Price and Varma, 1988; Allen et al, 1988; Huang and Cao, 1988; Do and Rice, 1987). For a mathematical description of our uranium biosorption kinetic process, we selected the pore‐diffusion model that corresponded to effective diffusivity, D e = ( D p ϵ p /τ), a more useful engineering parameter in process design and prediction.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Biosorption of Uranium by Pseudomonas aeruginosa Strain CSU Immobilized in a Novel Matrix

Reeves

1997

Biotechnol. Prog.

113

View full text Add to dashboard Cite

Pseudomonas aeruginosa CSU, a nongenetically engineered bacterial strain previously shown to bind dissolved hexavalent uranium (as UO 2 2+ and/or its cationic hydroxy complexes), shows promise as the basis of an immobilized-cell process for removal of dissolved uranium from contaminated wastewaters. A number of polymeric materials, including calcium alginate, polyacrylamide, polysulfone, and polyurethane, were evaluated as possible immobilization matrices for lyophilized biomass of P. aeruginosa CSU. Polyurethane-based materials such as hydrogel were identified as superior candidates for biomass immobilization. A novel polyurethane gel-bead fabrication technique was developed and successfully demonstrated at pilot-plant scale for producing mass quantities of spherical, uniform-size beads. The immobilized bacterial biomass was evaluated via the measurement of sorption isotherms and dynamics within a batch, stirred-tank reactor; and loading and elution behavior within a continuous, upflow, packed-bed columnar reactor. Sorption equilibrium and dynamics in a batch stirred tank were modeled with a pore-diffusion mass transfer model, by which a pore-diffusion coefficient was determined to be approximately 2.0 × 10 -6 cm 2 /s for uranyl ion transport through the polyurethane gel matrix. The biosorbent beads were regenerable with dilute (0.01-0.1 M) sodium carbonate solutions. Preliminary column breakthrough-elution studies indicated that P. aeruginosa CSU biomass immobilized within polyurethane gel beads was effective for removal of uranium from low-concentration, acidic wastewaters.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Biosorption of Uranium by Pseudomonas aeruginosa Strain CSU Immobilized in a Novel Matrix

Reeves

1997

Biotechnol. Prog.

113

View full text Add to dashboard Cite

show abstract

“…= 62 pm (largest value of radius) Values of diffusivities under desorbing conditions have been measured at various temperatures by Bhatia et al (1990) for phenol on AC. An activation energy of 31400 kJ/kmol is obtained therefrom, and diffusivity at 150°C is estimated as 3.94 x m2/s Rate constant of the homogeneous reaction is measured at 150°C as 3.2 x Concentration of oxygen is estimated at 0.0833 kmol/m3 Pore volume to particle volume ratio.…”

Section: Appendixmentioning

confidence: 99%

Regeneration of spent activated carbon by wet air oxidation

et al. 1991

View full text Add to dashboard Cite

The regeneration of activated carbon was studied using the wet air oxidation process in the temperature range of 150-240°C and oxygen partial pressure range of 0.2 to 1 .O MPa. Phenol was used as substrate. The overall mechanism of regeneration has been analysed and the different steps taking place during the regeneration process were individually investigated. Kinetics of oxidation of phenol and oxygen mass transfer coefficients have been estimated in the ranges of temperature and pressure studied. Oxidative degeneration characteristics of activated carbon were also studied. The conditions of temperature and pressure have been found at which the extent of regeneration is favourable.On a ktudi6 la rCgCnCration du charbon actif au moyen d'un procCdC d'oxydation a air humide a des temperatures comprises entre 150 et 240°C et des pressions partielles d'oxyghe variant de 0,2 5 1 ,O MPa. On a utilise du phknol comrne substrat. Le mCcanisrne global de rCgCnCration a ktk analysC et on a CtudiC s6parCment les diffkrentes etapes marquant le processus de rCgCnkration. La cinktique d'oxydation du phenol et les coefficients du transfert de matitre de I'oxygkne ont CtC estimis dans les gammes de tempkratures et depressions CtudiCes. On a kgalernent CtudiC les caractkristiques de dCgCnCrescence oxydante du charbon actif. Les conditions de tempCrature et de pression ont CtC deter-minCes 18 oh le degrC de dCgCnCrescence est favorable.

show abstract

“…The experimental operating conditions of the reactions and the physical properties of the reactants used for calculations are summarized in Table 3 and 4, respectively. Bhatia et al, (1990) The corresponding values of the calculated mass transfer groups k l a and k S a p , are collected in Table 5 and 6, respectively. The wetting efficiency, F w =a w /a p , was calculated from two correlations (Tucka and Hanika, 1998;ElHisnawi et al, 1981) The Wheeler-Weisz criterion has been used to test whether slow internal diffusion was limiting the reaction:…”

Section: Mass Transfer Considerationsmentioning

confidence: 99%

“…The value of effective diffusivity (D eff ) of phenol in ACs at 127 ºC is around 1.1·10 -9 m 2 /s (Table 4) (Bhatia et al, 1990). To calculate the observed kinetic rate constant, a pseudo-first order plug flow model has been used.…”

mentioning

confidence: 99%

Kinetics of the Wet Oxidation of Phenol over an Fe/Activated Carbon Catalyst

Quintanilla

Casas

Rodriquez

et al. 2007

International Journal of Chemical Reactor Engineering

View full text Add to dashboard Cite

Wet oxidation of phenol over an Fe/activated carbon catalyst has been studied in a trickle-bed reactor in the following operational window: inlet C phenol=0.5 and 1 g/L, T=100-127• C, PT=3-8 atm, W=0-4.8 g, QL=0.125-2 mL/min and QO2=91.6 NmL/min. The experiments were carried out in the absence of mass transfer limitations. Oxidation and mineralization reactions of phenol are proven to take place on the catalyst surface through a heterogeneous mechanism. Due to the complexity of the phenol oxidation route, simple reaction schemes have been assumed by lumping the intermediate species and generalized kinetic models for phenol and TOC abatement have been proposed. Two kinetic expressions, a power law rate and a Langmuir-Hinshelwood type rate expression, have been considered but only a convergence with statistically reliable parameters was found for the former model. A power law model with first order for phenol and 0.74 for oxygen and apparent activation energy of 74 kJ/mol described the experimental results in the oxidation of phenol well. Mineralization of phenol (TOC abatement) was described by a similar rate expression and takes into account the presence of refractory species such as the low molecular weight acids formed upon phenol oxidation.

show abstract

Effective Diffusivity of Phenol in Activated Carbon

Cited by 17 publications

References 12 publications

Biosorption of Uranium by Pseudomonas aeruginosa Strain CSU Immobilized in a Novel Matrix

Biosorption of Uranium by Pseudomonas aeruginosa Strain CSU Immobilized in a Novel Matrix

Regeneration of spent activated carbon by wet air oxidation

Kinetics of the Wet Oxidation of Phenol over an Fe/Activated Carbon Catalyst

Contact Info

Product

Resources

About