Limits...
Chromium Biosorption from Cr(VI) Aqueous Solutions by Cupressus lusitanica Bark: Kinetics, Equilibrium and Thermodynamic Studies.

Netzahuatl-Muñoz AR, Cristiani-Urbina Mdel C, Cristiani-Urbina E - PLoS ONE (2015)

Bottom Line: CLB total Cr biosorption capacity strongly depended on operating variables such as initial Cr(VI) concentration and contact time: as these variables rose, total Cr biosorption capacity increased significantly.Results from the present kinetic, equilibrium and thermodynamic studies suggest that CLB biosorbs Cr ions from Cr(VI) aqueous solutions predominantly by a chemical sorption phenomenon.Low cost, availability, renewable nature, and effective total Cr biosorption make CLB a highly attractive and efficient method to remediate Cr(VI)-contaminated water and wastewater.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Ingeniería Bioquímica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México, D.F., México; Universidad Politécnica de Tlaxcala, San Pedro Xalcaltzinco, Tepeyanco, Tlaxcala, México.

ABSTRACT
The present study investigated the kinetics, equilibrium and thermodynamics of chromium (Cr) ion biosorption from Cr(VI) aqueous solutions by Cupressus lusitanica bark (CLB). CLB total Cr biosorption capacity strongly depended on operating variables such as initial Cr(VI) concentration and contact time: as these variables rose, total Cr biosorption capacity increased significantly. Total Cr biosorption rate also increased with rising solution temperature. The pseudo-second-order model described the total Cr biosorption kinetic data best. Langmuir´s model fitted the experimental equilibrium biosorption data of total Cr best and predicted a maximum total Cr biosorption capacity of 305.4 mg g(-1). Total Cr biosorption by CLB is an endothermic and non-spontaneous process as indicated by the thermodynamic parameters. Results from the present kinetic, equilibrium and thermodynamic studies suggest that CLB biosorbs Cr ions from Cr(VI) aqueous solutions predominantly by a chemical sorption phenomenon. Low cost, availability, renewable nature, and effective total Cr biosorption make CLB a highly attractive and efficient method to remediate Cr(VI)-contaminated water and wastewater.

No MeSH data available.


Related in: MedlinePlus

Dependence of separation factor (a) and surface coverage (b) on initial Cr(VI) concentration.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4564179&req=5

pone.0137086.g007: Dependence of separation factor (a) and surface coverage (b) on initial Cr(VI) concentration.

Mentions: The Langmuir model predicted a saturated monolayer adsorption capacity (Qo) of 305.4 mg g-1, which adequately matched the experimental value of total Cr biosorption capacity at equilibrium (275 mg g-1), and a biosorption equilibrium constant (b) of 0.0102 L mg-1 within the interval of b values (0–1) which indicate that the biosorption of total Cr onto CLB is favorable under the present experimental conditions. To confirm the favorability of the total Cr biosorption process, the dimensionless separation factor was calculated and found to decrease from 0.908 to 0.0895 as initial Cr(VI) concentration increased from 10 to 1200 mg L-1 (Fig 7a), which confirms that biosorption of total Cr onto CLB increases as the initial Cr(VI) concentration rises. Moreover, the RL values were between 0 and 1, which indicates favorable biosorption of total Cr onto CLB at all the metal concentrations assayed [60,63]. The surface coverage (θ) values approached unity with increasing initial Cr(VI) concentration (Fig 7b), which indicates that the CLB surface was nearly fully covered with a monomolecular layer at the higher metal concentrations. The effectiveness of CLB for the biosorption of total Cr is thus confirmed. It was also apparent that the surface coverage ceases to vary significantly at high concentrations of Cr(VI) and the reaction rate becomes almost independent of the metal concentration [63].


Chromium Biosorption from Cr(VI) Aqueous Solutions by Cupressus lusitanica Bark: Kinetics, Equilibrium and Thermodynamic Studies.

Netzahuatl-Muñoz AR, Cristiani-Urbina Mdel C, Cristiani-Urbina E - PLoS ONE (2015)

Dependence of separation factor (a) and surface coverage (b) on initial Cr(VI) concentration.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4564179&req=5

pone.0137086.g007: Dependence of separation factor (a) and surface coverage (b) on initial Cr(VI) concentration.
Mentions: The Langmuir model predicted a saturated monolayer adsorption capacity (Qo) of 305.4 mg g-1, which adequately matched the experimental value of total Cr biosorption capacity at equilibrium (275 mg g-1), and a biosorption equilibrium constant (b) of 0.0102 L mg-1 within the interval of b values (0–1) which indicate that the biosorption of total Cr onto CLB is favorable under the present experimental conditions. To confirm the favorability of the total Cr biosorption process, the dimensionless separation factor was calculated and found to decrease from 0.908 to 0.0895 as initial Cr(VI) concentration increased from 10 to 1200 mg L-1 (Fig 7a), which confirms that biosorption of total Cr onto CLB increases as the initial Cr(VI) concentration rises. Moreover, the RL values were between 0 and 1, which indicates favorable biosorption of total Cr onto CLB at all the metal concentrations assayed [60,63]. The surface coverage (θ) values approached unity with increasing initial Cr(VI) concentration (Fig 7b), which indicates that the CLB surface was nearly fully covered with a monomolecular layer at the higher metal concentrations. The effectiveness of CLB for the biosorption of total Cr is thus confirmed. It was also apparent that the surface coverage ceases to vary significantly at high concentrations of Cr(VI) and the reaction rate becomes almost independent of the metal concentration [63].

Bottom Line: CLB total Cr biosorption capacity strongly depended on operating variables such as initial Cr(VI) concentration and contact time: as these variables rose, total Cr biosorption capacity increased significantly.Results from the present kinetic, equilibrium and thermodynamic studies suggest that CLB biosorbs Cr ions from Cr(VI) aqueous solutions predominantly by a chemical sorption phenomenon.Low cost, availability, renewable nature, and effective total Cr biosorption make CLB a highly attractive and efficient method to remediate Cr(VI)-contaminated water and wastewater.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Ingeniería Bioquímica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México, D.F., México; Universidad Politécnica de Tlaxcala, San Pedro Xalcaltzinco, Tepeyanco, Tlaxcala, México.

ABSTRACT
The present study investigated the kinetics, equilibrium and thermodynamics of chromium (Cr) ion biosorption from Cr(VI) aqueous solutions by Cupressus lusitanica bark (CLB). CLB total Cr biosorption capacity strongly depended on operating variables such as initial Cr(VI) concentration and contact time: as these variables rose, total Cr biosorption capacity increased significantly. Total Cr biosorption rate also increased with rising solution temperature. The pseudo-second-order model described the total Cr biosorption kinetic data best. Langmuir´s model fitted the experimental equilibrium biosorption data of total Cr best and predicted a maximum total Cr biosorption capacity of 305.4 mg g(-1). Total Cr biosorption by CLB is an endothermic and non-spontaneous process as indicated by the thermodynamic parameters. Results from the present kinetic, equilibrium and thermodynamic studies suggest that CLB biosorbs Cr ions from Cr(VI) aqueous solutions predominantly by a chemical sorption phenomenon. Low cost, availability, renewable nature, and effective total Cr biosorption make CLB a highly attractive and efficient method to remediate Cr(VI)-contaminated water and wastewater.

No MeSH data available.


Related in: MedlinePlus