Water, Air, & Soil Pollution

, Volume 218, Issue 1, pp 499–515

Equilibrium, Kinetics and Mechanism of Removal of Methylene Blue from Aqueous Solution by Adsorption onto Pine Cone Biomass of Pinus radiata

Article

DOI: 10.1007/s11270-010-0663-y

Cite this article as:
Sen, T.K., Afroze, S. & Ang, H.M. Water Air Soil Pollut (2011) 218: 499. doi:10.1007/s11270-010-0663-y
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Abstract

The kinetics and mechanism of methylene blue adsorption onto raw pine cone biomass (Pinus radiata) was investigated under various physicochemical parameters. The extent of the methylene blue dye adsorption increased with increases in initial dye concentration, contact time and solution pH but decreases with the amount of adsorbent, salt concentration and temperature of the system. Overall the kinetic studies showed that the methylene blue adsorption process followed pseudo-second-order kinetics among various kinetic models tested. The different kinetic parameters including rate constant, half-adsorption time and diffusion coefficient are determined at different physicochemical conditions. Equilibrium data were best represented by Langmuir isotherm among Langmuir and Freundlich adsorption isotherm. The maximum monolayer adsorption capacity of pine cone biomass was 109.89 mg/g at 30°C. The value of separation factor, RL, from Langmuir equation and Freundlich constant, n, both give an indication of favourable adsorption. Thermodynamic parameters such as standard Gibbs free energy (∆G0), standard enthalpy (∆H0), standard entropy (∆S0) and the activation energy (A) were calculated. A single-stage batch absorber design for the methylene blue adsorption onto pine cone biomass has been presented based on the Langmuir isotherm model equation.

Keywords

Pinus radiata MB adsorption Kinetic model Isotherm Diffusion 

Nomenclature

A

Activation energy of adsorption (kJ/mol)

Cf

Final metal ion concentration, ppm (mg/l)

C0

Initial metal ion concentration, ppm (mg/l)

Ct

Metal ion concentration at time t, ppm (mg/l)

D

Diffusion coefficient (cm2/s)

∆G0

Gibbs free energy change (kJ/mole)

∆H0

Enthalpy change (kJ/mole)

∆S0

Entropy change (J/k mole)

k1

Pseudo-first-order rate constant (min−1)

k2

Pseudo-second-order rate constant (mg/g min)

Kf

Freundlich adsorption constant (mg/g)

Kid

Intra-particle rate constant [(mg/g) min0.5]

M

Mass of adsorbent per unit volume (g l−1)

m

Amount of adsorbent added (g)

n

Freundlich constant

q

Amount of adsorbate per gram of adsorbent (mg/g)

qe

Amount of adsorbate per gram of adsorbent at equilibrium, (mg/g)

qt

Amount of adsorbate per gram of adsorbent at any time, t

qm

Equilibrium adsorption capacity using model

qmax

Maximum adsorption capacity (mg/g)

R2

Linear correlation coefficient

RL

Separation factor

r0

Radius of adsorbent particle (cm)

t

Time (min)

T

Temperature (K)

V

Volume of the solution (ml)

β

Constant

Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  • Tushar Kanti Sen
    • 1
  • Sharmeen Afroze
    • 1
  • H. M. Ang
    • 1
  1. 1.Department of Chemical EngineeringCurtin UniversityBentleyAustralia

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