Removal of lead (II) ions from synthetic and real effluents using immobilized Pinus sylvestris sawdust: Adsorption on a fixed-bed column

doi:10.1016/j.jhazmat.2005.03.032

Journal of Hazardous Materials

Volume 123, Issues 1–3, 31 August 2005, Pages 135-144

https://doi.org/10.1016/j.jhazmat.2005.03.032 Get rights and content

Abstract

The purpose of this work was to evaluate the potential of Pinus sylvestris sawdust, in a continuous flow removal of lead (II) ions from synthetic and industrial aqueous effluents. The kinetic parameters obtained in a batch process were used to scale-up the process on a mini-column and to choose the breakthrough model. The column experimental data concerning the volumes treated were correlated using the bed depth service time model. These experimental data closely fitted the bed depth service time model at 10% of the breakthrough curve.

The results from the bed depth service time model on the mini-column were then used to design a pilot plant adsorption unit. The performance of the pilot plant column accurately agreed with that obtained from the mini-column. The experiments carried out in a dynamic reactor allowed to bring out the influence of various parameters on the efficiency of the P. sylvestris sawdust. In addition, the process was checked for the treatment of industrial aqueous effluents on a pilot plant scale and the results were in accordance with those obtained from synthetic effluents.

Introduction

The removal of toxic heavy metal contaminants from aqueous waste streams is currently one of the most important environmental issues being researched. Although this issue has been studied for many years, effective treatment options are still limited. Chemical precipitation, ion exchange, reverse osmosis and solvent extraction are the methods most commonly used for removing heavy metals ions from dilute aqueous streams [1]. Studies carried out to look for new and innovative treatment technologies have focused attention on the metal binding qualities of various types of biomass [2], [3]. It was shown that some microorganisms and biomass are able to adsorb toxic and heavy metals from dilute aqueous solutions. The factors affecting the metal binding qualities of these biomaterials or their affinity for a metal dissolved in aqueous media include: (i) the chemical nature of the metal ions (e.g. size, valence, electron orbital structure, stability of the chemical forms in nature) and that of the biomass (e.g. charge density and structure of the polymer chain, functional groups), (ii) medium conditions (e.g., pH, temperature, ionic strength, presence of competing organic or inorganic metal chelators). Biosorptive processes are generally rapid and theoretically suitable for extracting metal ions from large volumes of water [4].

Results obtained in previous studies carried out on a batch reactor showed that the removal of lead and cadmium through their binding onto Pinus sylvestris sawdust is possible. The latter biomaterial contains various organic compounds such as lignin (with polyphenolic groups), cellulose (with numerous hydroxyl functions) and hemicelluloses (with carboxylic and hydroxyl groups). These functional groups may be useful for binding ions of heavy metals [5]. Although various types of reactors, e.g. batch, continuously stirred tank reactors and fluidized-bed columns can be used, adsorption on packed-bed columns presents numerous advantages. It is simple to operate, gives high yields and can be easily scaled up from a laboratory process.

The purpose of this study was to investigate the influences of bed depth, linear flow rate and concentrations of feed metal ions on the performance of lead (II) adsorption onto P. sylvestris sawdust immobilized in a packed-bed column. This work was firstly carried out on a mini-column and the results were then checked on a pilot scale unit.

Section snippets

Methods

In this work, studies were starting from the mass balance of the packed-bed reactor. The variation of this balance during the reaction can be illustrated by Fig. 1, where u is the linear flow rate, which is the average rate of the liquid flow when the column is empty. The equation of mass balance material is: input flow = output flow + flow inside pores volume + matter adsorbed onto sawdust. For this system, the balance can be expressed according to the following equation $Q_{v} C_{0} = Q_{v} C + V_{p} \frac{d C}{d t} + m \frac{d q}{d t}$ where Q_v is

Mini-column scale

The results of lead (II) adsorption onto P. sylvestris sawdust are presented in the form of breakthrough curves where the concentration ratio C_t/C₀ is plotted versus time. Several parameters were studied.

Conclusion

Adsorption of lead (II) ions through sawdust in a packed bed column is an economically feasible technique for removing metal ions from a solution. The process allows treatment of a given volume of effluent by using a minimal mass of adsorbent which concentrates maximal content of metal.

The adsorption breakthrough curves obtained at different flow rates indicate that an increase in flow rate decreases the volume treated until the breakthrough point and therefore decreases the service time of the

Acknowledgements

The authors would like to thank the Agence Nationale pour la Valorisation de la Recherche (ANVAR) for their financial support. We are also sincerely grateful to Dr. Monin (Génie Analytique/Cnam Laboratory) for conducting the absorption atomic analysis. Our thanks also go to G. Le Buzit (Laboratoire des Sciences Nucléaires/Cnam Laboratory) for the design of the mini-column laboratory.

References (22)

C. Huang et al.
Water Res.
(1996)
V.C. Taty Costodes et al.
J. Hazard. Mater.
(2003)
G. McKay et al.
Environ. Pollut.
(1990)
D.C.K. Ko et al.
Water Res.
(2001)
E. Valdman et al.
Process Biochem.
(2001)
C. Rajagopal et al.
J. Hazard. Mater. B
(2001)
Y. Sağ et al.
Process Biochem.
(1995)
A.V. Pethkar et al.
J. Biotechnol.
(1998)
G. Rich et al.
Cited in Hazardous Waste Treatment Technology
(1987)
A.K. Bhattacharya et al.
J. Environ. Eng.—ASCE
(1984)

J.M. Brady et al.

J. Chem. Technol. Biotechnol.

(1999)

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Removal of lead (II) ions from synthetic and real effluents using immobilized Pinus sylvestris sawdust: Adsorption on a fixed-bed column

Abstract

Introduction

Section snippets

Methods

Mini-column scale

Conclusion

Acknowledgements

Water Res.

J. Hazard. Mater.

Environ. Pollut.

Water Res.

Process Biochem.

J. Hazard. Mater. B

Process Biochem.

J. Biotechnol.

Cited in Hazardous Waste Treatment Technology

J. Environ. Eng.—ASCE

J. Chem. Technol. Biotechnol.