Diffusion kinetic study of cadmium(II) biosorption by Aeromonas caviae

Chemical Technology Division, School of Chemistry, Aristotle University, GR-54124 Thessaloniki, Greece
Journal of Chemical Technology & Biotechnology (Impact Factor: 2.35). 07/2004; 79(7):711 - 719. DOI: 10.1002/jctb.1043
Source: OAI


The removal of cadmium from aqueous solution by sorption on Aeromonas caviae particles was investigated in a well-stirred batch reactor. Equilibrium and kinetic experiments were performed at various initial bulk concentrations, biomass loads and temperatures. Biosorption equilibrium was established in about 1 h and biosorption was well described by the Langmuir and Freundlich biosorption isotherms. The maximum biosorption capacity was found as 155.32 mg Cd(II) g−1 at 20 °C. The obtained sorption capacity is appreciably high for most experimental conditions; so A caviae may be considered as a suitable biosorbent for the removal of cadmium. Moreover, the sorption rate of cadmium onto A caviae particles was particularly sensitive to initial bulk concentration and solid load. A detailed analysis was conducted, examining several diffusion (external and intraparticle) kinetic models in order to identify a suitable rate expression. The results are discussed and indicate that biosorption of cadmium is a complex process that is described more correctly by more than one model. Copyright © 2004 Society of Chemical Industry

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    • "Aeromonads (a bacterial strain) have been reported for remediation of metal because they are ubiquitous in fresh and marine water and tolerant toward heavy metals [19]. In this series, Aeromonas caviae has already been used for the removal of Cr(VI) and Cd(II) [20] [21] and Aeromonas hydrophila has also been used for the removal of Cr(VI) in our laboratory [22]. The present investigation is primarily aimed to test the potential of biomass of A. hydrophila for the sorption of lead from water and to optimize the parameters affecting the sorption for its maximum removal via a 2 4 full factorial central composite response surface methodology (RSM) experimental design with the help of software MINITAB ® version 15 software [23]. "
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    ABSTRACT: Biomass of Aeromonas hydrophila was successfully utilized for the removal of lead from aqueous solution. The effect of process variables such as pH, initial Pb(II) concentration, biomass dose and temperature on the uptake of lead were investigated using two level four factor (2(4)) full factorial central composite design with the help of MINITAB version 15 software. The predicted results thus obtained were found to be in good agreement (R(2)=98.6%) with the results obtained by performing experiments. The multiple regression analysis and analysis of variance (ANOVA) showed that the concentration has positive and temperature and biomass dose have negative whereas pH has curved relationship with the uptake of Pb(II). The maximum uptake of Pb(II) predicted by optimization plots was 122.18 mg/g at 20 degrees C, initial Pb(II) concentration of 259 mg/L, pH 5.0, temperature 20 degrees C and biomass dose 1.0 g. Langmuir isotherm model was applicable to sorption data and sorption capacity was found to be 163.3mg/g at 30 degrees C, pH 5.0 and Pb(II) concentration range 51.8-259 mg/L indicate that the biosorbent was better in comparison of the biosorbent reported in the literature. Dubinin-Radushkevich (D-R) isotherm model was also applied and it was found that sorption was chemisorption (E=12.98 kJ/mol). FT-IR studies indicate the involvement of various functional groups present on biomass surface in the sorption of Pb(II).
    Full-text · Article · Apr 2009 · Journal of hazardous materials
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    • "If a number of alternative mechanisms fit the data equally well, we must recognise perhaps that the model selected can only be considered to be one of the good fit, not one that represents reality. The kinetic mechanism of metal sorption on biosorbent particles was investigated (Loukidou et al., 2004a, 2004b) putting more emphasis on samples collected at short times after the initiation of the process (where the major part of the adsorption occurs) and following the known concept of the rate controlling step, being certainly a simplifying approach. For the case of a non-porous biomass, transport of solute inside the 'particle' may be neglected, and it can be assumed that biosorption occurs mainly at the particle surface (cell wall); this idea can be effectively extended to cases of relatively large macropores where the metal ions may have a ready access to react with internal surface sites. "
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    ABSTRACT: The use of biological materials for removing metals and, possibly, recovering them from contaminated wastewaters has emerged as a potential alternative method to conventional treatment techniques. The ability of microorganisms to separate metal ions is a well-known phenomenon. Various experimental data are presented for different metals and biomass types, and are reviewed and critically commented in comparison with the literature. Dead biomass is usually obtained from fermentation wastes or by-products. Focus of this paper constitutes, among others, the kinetics of the biosorption process, being still quite ambiguous. Bioaccumulation of metals is also discussed in comparison with biosorption, the latter is more effective.
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    ABSTRACT: The adsorption isotherms of cadmium(II) and zinc(II) onto activated carbons were obtained in a batch adsorber. The concentration decay data were obtained in a rotating basket adsorber and were interpreted by a mathematical model, which takes into account the adsorption rate, external mass transport and intraparticle diffusion. The results showed that the overall rate of adsorption of Cd(II) and Zn(II) was mainly controlled by the intraparticle diffusion which was solely due to pore volume diffusion. The contribution of the external mass transport resistance was negligible. The effective pore volume diffusivities of Cd(II) and Zn(II) were predicted reasonably well using the ionic diffusivity of the metal and the void fraction and tortuosity of activated carbon. Copyright © 2005 Society of Chemical Industry
    Full-text · Article · Jul 2005 · Journal of Chemical Technology & Biotechnology
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