Determination of Diffuse Double Layer protonation constants for hydrous ferric oxide (HFO): supporting evidence for the Dzombak and Morel compilation

Pretorius, P. J.; Linder, Peter

doi:10.3184/095422998782775808

Cited by 7 publications

(5 citation statements)

References 11 publications

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“…Reported values for the PZC of HFA are variable: Dzombak and Morel (31) report a pH of 8.11, which was confirmed by Pretorius and Linder (34). However, lower values around pH 6.6-6.7 have also been reported (35).…”

Section: Resultsmentioning

confidence: 90%

Forces between Colloid Particles in Natural Waters

Mosley

Hunter

Ducker

2003

Environ. Sci. Technol.

134

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The origin and nature of interparticle forces acting on colloid surfaces in natural waters has been examined using an atomic force microscope. Natural colloids were represented by a surface film of iron oxide precipitated onto spherical SiO2 particles, and the effects of adsorbed natural organic matter (NOM), solution pH, and ionic composition on the force-separation curves were investigated. NOM from both riverine and marine environments was strongly adsorbed to the iron oxide surface. Under conditions of low ionic strength, the interparticle forces were dominated by electrostatic repulsion arising from negative functional groups on the NOM, except at very small separations (<10 nm) where repulsive forces arising from steric interference of the NOM molecules were also present. At high ionic strength (e.g., seawater) or low pH, the electrostatic forces were largely absent, allowing steric repulsion forces to dominate. In addition, adhesive bridging between surfaces by adsorbed NOM was observed, creating a strong energy barrier to spontaneous disaggregation of colloid aggregates. Our results demonstrate that adsorbed NOM dominates the surface forces and thus stability with respect to aggregation of natural water colloids.

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Section: Resultsmentioning

confidence: 90%

Forces between Colloid Particles in Natural Waters

Mosley

Hunter

Ducker

2003

Environ. Sci. Technol.

134

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“…Hydrous ferric oxide materials are known to exhibit a predominantly positive surface potential with p.z.c. at approximately pH 8 [18], which could explain the exclusion of cations and the predominant transport of anions.…”

Section: Microbead Electrochemistry In Aqueous Kclmentioning

confidence: 98%

Electroanalysis with a single microbead of phosphate binding resin (FerrIX™) mounted in epoxy film

Thompson

Mathwig

Fletcher

et al. 2021

J Solid State Electrochem

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Commercial resin microbeads are widely applied in ion exchange and extraction. Here, a single anion-selective and phosphate binding resin microbead (FerrIX™) is mounted into an epoxy membrane and investigated by 4-electrode membrane voltammetry and membrane impedance spectroscopy. Anion transport properties are observed to dominate associated with three distinct potential domains: (I) a low bias ohmic potential domain (dominant at high electrolyte concentration), (II) a concentration polarisation potential domain, and (III) an over-limiting potential domain. Voltammetric responses show transient diffusion-migration features at higher scan rates and quasi-steady state features at lower scan rates. Inherent microbead conductivity is shown to be linked to two resistive elements, electrolyte concentration dependent and independent, in series. The effects of phosphate binding are revealed as transient pattern in impedance spectroscopy data. Preliminary data suggest phosphate concentration-dependent peak features in the imaginary impedance versus frequency plot due to phosphate binding into the microbead. Graphical abstract

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“…Different surface complexation models and the database of Dzombak and Morel [41], utilized by Hering et al [42], was incorporated in MINTEQ. The protonation/deprotonation properties of sorbent 2 was studied by glass electrode potentiometer, and corresponding constants were derived according to Diffuse Double Layer convention [43]. Protonation/deprotonation constants (logK) were given in Table S1, as well as arsenate intristic surface complexation constants and model parameters.…”

Section: Modeling Of the Sorption Processesmentioning

confidence: 99%

Ultrasonic assisted arsenate adsorption on solvothermally synthesized calcite modified by goethite, α-MnO2 and goethite/α-MnO2

Markovski

Djokić

Milosavljević

et al. 2014

Ultrasonics Sonochemistry

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A highly porous calcium carbonate (calcite; sorbent 1) was used as a support for modification with α-FeOOH (calcite/goethite; sorbent 2), α-MnO2 (calcite/α-MnO2; sorbent 3) and α-FeOOH/α-MnO2 (calcite/goethite/α-MnO2; sorbent 4) in order to obtain a cheap hybrid materials for simple and effective arsenate removal from aqueous solutions. The adsorption ability of synthesized adsorbents was studied as a function of functionalization methods, pH, contact time, temperature and ultrasonic treatment. Comparison of the adsorptive effectiveness of synthesized adsorbents for arsenate removal, under ultrasound treatment and classical stirring method, has shown better performance of the former one reaching maximum adsorption capacities of 1.73, 21.00, 10.36 and 41.94 mg g(-1), for sorbents 1-4, respectively. Visual MINTEQ equilibrium speciation modeling was used for prediction of pH and interfering ion influences on arsenate adsorption.

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Determination of Diffuse Double Layer protonation constants for hydrous ferric oxide (HFO): supporting evidence for the Dzombak and Morel compilation

Cited by 7 publications

References 11 publications

Forces between Colloid Particles in Natural Waters

Forces between Colloid Particles in Natural Waters

Electroanalysis with a single microbead of phosphate binding resin (FerrIX™) mounted in epoxy film

Ultrasonic assisted arsenate adsorption on solvothermally synthesized calcite modified by goethite, α-MnO2 and goethite/α-MnO2

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