Study on the effects of soluble microbial product on phosphate adsorption onto fresh hydrous ferric oxides by surface complexation models

2016 ◽  
Vol 74 (10) ◽  
pp. 2446-2453 ◽  
Author(s):  
Yanpeng Mao ◽  
Wenlong Wang ◽  
Chunyuan Ma
Keyword(s):  
Equilibrium Constants ◽  
Surface Complexation ◽  
Phosphate Adsorption ◽  
Stable Operation ◽  
Microbial Product ◽  
Music Model ◽  
Soluble Microbial Product ◽  
Hydrous Ferric Oxides ◽  
Ferric Oxides ◽  
Complexation Reactions

As one of the major soluble organic compounds in membrane bioreactors, soluble microbial product (SMP) can combine the surface sites on hydrous ferric oxides (HFO), which can compete with HFO for the uptake of phosphate. In this study, SMP was extracted from an MBR plant with long-term stable operation, and the effects of SMP on phosphate adsorption onto fresh HFO (FHFO) were investigated at pH values of 6.0 and 7.8 in a two-phase system composed of FHFO (solid phase) and SMP/phosphate (liquid phase). The phosphate adsorption capacity of FHFO was found to decrease significantly with increase in the pH value and SMP concentration. A diffuse layer model (DLM) and a charge distribution multisite complexation (CD-MUSIC) model, which take these factors into account, were developed to describe the speciation of SMP and phosphate on FHFO surface. Both of the models provided good description of phosphate adsorption behavior in the presence of SMP at different pH. The equilibrium constants of surface complexation reactions between SMP and HFO were obtained by inversion calculation as log10K = 15.1 ± 0.11 in DLM model and log10K = 12.1 ± 0.5 in CD-MUSIC model, which can improve the equilibrium constants database of surface complexation models.

scholarly journals Hydrous Ferric Oxides in Sediment Catalyze Formation of Reactive Oxygen Species during Sulfide Oxidation

2016 ◽  
Vol 3 ◽  
Author(s):  
Sarah A. Murphy ◽  
Shengnan Meng ◽  
Benson M. Solomon ◽  
Dewamunnage M. C. Dias ◽  
Timothy J. Shaw ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Sulfide Oxidation ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Hydrous Ferric Oxides ◽  
Ferric Oxides

Surface complexation modeling of the effects of phosphate on uranium(VI) adsorption

2007 ◽  
Vol 95 (5) ◽  
Author(s):  
Maria R. Romero-González ◽  
Tao Cheng ◽  
Mark O. Barnett ◽  
Eric E. Roden
Keyword(s):  
Ferric Oxide ◽  
Surface Complexation ◽  
Initial Approximation ◽  
Phosphate Adsorption ◽  
Published Data ◽  
Hydrous Ferric Oxide ◽  
Surface Complexation Modeling ◽  
Surface Complexation Model ◽  
Coated Material ◽  
Coated Sand

Previous published data for the adsorption of U(VI) and/or phosphate onto amorphous Fe(III) oxides (hydrous ferric oxide, HFO) and crystalline Fe(III) oxides (goethite) was examined. These data were then used to test the ability of a commonly-used surface complexation model (SCM) to describe the adsorption of U(VI) and phosphate onto pure amorphous and crystalline Fe(III) oxides and synthetic goethite-coated sand, a surrogate for a natural Fe(III)-coated material, using the component additivity (CA) approach. Our modeling results show that this model was able to describe U(VI) adsorption onto both amorphous and crystalline Fe(III) oxides and also goethite-coated sand quite well in the absence of phosphate. However, because phosphate adsorption exhibits a stronger dependence on Fe(III) oxide type than U(VI) adsorption, we could not use this model to consistently describe phosphate adsorption onto both amorphous and crystalline Fe(III) oxides and goethite-coated sand. However, the effects of phosphate on U(VI) adsorption could be incorporated into the model to describe U(VI) adsorption to both amorphous and crystalline Fe(III) oxides and goethite-coated sand, at least for an initial approximation. These results illustrate both the potential and limitations of using surface complexation models developed from pure systems to describe metal/radionuclide adsorption under more complex conditions.

Surface and Textural Heterogeneity of Fresh Hydrous Ferric Oxides in Water and in the Dry State

1993 ◽  
Vol 159 (1) ◽  
pp. 45-52 ◽  
Author(s):  
J.Y. Bottero ◽  
M. Arnaud ◽  
F. Villiéras ◽  
L.J. Michot ◽  
P. de Donato ◽  
...  
Keyword(s):  
Hydrous Ferric Oxides ◽  
Ferric Oxides
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