Adsorption Kinetics and Surface Characterization of Microorganisms Grown under Different Conditions

Abstract:

The adsorption of bacteria onto minerals is the premise for bioleaching and plays an important role in minerals oxidation. Understanding of the adsorption kinetics onto the surface will give information on the effectiveness of bioleaching. Three kinds of mixed bacteria (Acidithiobacillus ferrooxidans, Leptospirillum ferrooxidans, Sulfobacillus) were cultured in different substrates - copper concentrate, elemental sulfur and ferrous iron and adsorbed onto different solid surface of elemental sulfur, silica and copper concentrate. Adsorption kinetics was examined and surface properties were investigated by Zeta-potential and FT-IR spectroscopy. Bacterial adsorption equilibrium data for bacteria grown on three different substrates were well fitted to Freundlich isotherms, indicating inhomogeneous and selective adsorption. Microorganisms grown on copper concentrate and S⁰ showed similar adsorption kinetics whereby cell adsorptions proceeded rapidly and reached equilibrium within 30 mins of interaction. With the average K_F value of 46.2, most copper concentrate-grown cells were strongly adsorbed to three solid surfaces. Microorganisms grown on copper concentrate and S⁰ also showed higher hydrophobicity and higher isoelectric point (IEP) (pH 3.4-3.8) as compared to the soluble Fe²⁺-grown cells (pH 2.1), indicating higher amount of EPS and proteins on the surfaces. The FT-IR spectra indicated the presence of COOH, NH₂, OH and PO₄ groups on all cell surfaces. However, more proteinaceous compounds were found on cells grown on copper concentrate and S⁰ substrates.

• Periodical: Advanced Materials Research (Volume 1130)
• Pages: 519-523
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1130.519
• Online since: November 2015
• Authors: Zeng Ling Wu*, Wei Zhang Kong, Jin Yan Liu, Zhi Wu, Shui Ping Zhong, Yong Guan Zhu
• Keywords: Adsorption Kinetics, Contact Leaching, Freundlich Isotherm, Hydrophobic, Surface Characterization, Zeta Potential

References

[1] W. Sand, T. Gehrke, P.G. Jozsa and A. Schippers: Hydrometallurgy. (2001) Vol. 59, p.159.

[2] H. Tributsch: Hydrometallurgy. (2001) Vol. 59, p.177.

[3] M. Vera, A. Schippers and W. Sand: Appl. Microbiol. Biotechnol. ( 2013) Vol. 97, p.7529.

[4] H.H.M. Rijnaarts, W. Norde, J. Lyklema and A.J.B. Zehnder: Colloids and Surfaces B- Biointerfaces (1995) Vol. 4, p.191.

DOI: 10.1016/0927-7765(94)01146-v

[5] K. A. Natarajan and A. Das: Int. J. of Miner. Process. (2003) Vol. 72, p.189.

[6] Y. Konishi, H. Nishimura and S. Asai: Hydrometallurgy. (1998) Vol. 47, p.339.

[7] G.Z. Su，J.J. Lu，X. Lu, J. Li and B.W. Tu: Acta. Petrologica. Et. Mineralogica. (2009) Vol. 6, p.575.

[8] P.K. Sharma, A. Das, R. Hanumantha and E. Forssberg: Hydrometallurgy. (2003) Vol. 71, p.285.

[9] H.H.M. Rijnaarts, W. Norde, J. Lyklema and A.J.B. Zehnder: Colloids and Surfaces B- Biointerfaces (1995) Vol. 4, p.191.

DOI: 10.1016/0927-7765(94)01146-v

[10] M. Chen, L. Zhang and G. Gu: T. Nonferr. Metal. Soc. (2008) Vol. 18, p.1421.