Analysis of synthetic humic substances for medical and environmental applications by capillary zone electrophoresis

Schmitt‐Kopplin, Philippe; Freitag, D.; Kettrup, A.; Hertkorn, Norbert; Schoen, U.; Klöcking, R.; Helbig, B; Andreux, F.; Garrison, Arthur W.

doi:10.1051/analusis:1999270390

Cited by 11 publications

(12 citation statements)

References 26 publications

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“… Hosse and Wilkinson [2001] reported a direct dependence of μ with ionic strength (salinity) for three humic substances including a peat humic acid. Since a good correlation between μ and EDL charge density for humic substances has been reported elsewhere [ Schmitt‐Kopplin et al , 1999], a correlation between ionic strength and EDL charge density can be assumed for humic substances, and therefore for peat soils. It therefore seems valid to expect a similar decrease in the EDL charge mobility (and consequent decrease in σ″ surf ) at high σ w for peat, as observed for inorganic sediments.…”

Section: Discussionmentioning

confidence: 96%

“…Although nonelectrostatic models have been used in the past to describe the chemical properties of natural organic matter (NOM), electrostatic models based on EDL theory are well accepted [e.g., Milne et al , 1995; Avena et al , 1999; Dudal and Gérard , 2004]. The particle surface potential can be characterized by using electrophoretic measurements, determining the separation of ionic solutes based on differences in the rates of migration in an applied electric field [ Schmitt‐Kopplin et al , 1999; Hosse and Wilkinson , 2001]. The ratio between the rate of migration and the electric field strength is known as the electrophoretic mobility (μ), which is dependent on pH and ionic strength.…”

Section: Discussionmentioning

confidence: 99%

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Low‐frequency electrical properties of peat

Comas

Slater

2004

Water Resources Research

113

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[1] Electrical resistivity/induced polarization (0.1-1000 Hz) and vertical hydraulic conductivity (K v ) measurements of peat samples extracted from different depths (0-11 m) in a peatland in Maine were obtained as a function of pore fluid conductivity (s w ) between 0.001 and 2 S/m. Hydraulic conductivity increased with s w (K v / s w 0.3 between 0.001 and 2 S/m), indicating that pore dilation occurs due to the reaction of NaCl with organic functional groups as postulated by previous workers. Electrical measurements were modeled by assuming that ''bulk'' electrolytic conduction through the interconnected pore space and surface conduction in the electrical double layer (EDL) at the organic sediment-fluid interface act in parallel. This analysis suggests that pore space dilation causes a nonlinear relationship between the ''bulk'' electrolytic conductivity (s el ) and s w (s el / s w 1.3 ). The Archie equation predicts a linear dependence of s el on s w and thus appears inappropriate for organic sediments. Induced polarization (IP) measurements of the imaginary part (s 00 surf ) of the surface conductivity (s* surf ) show that s 00 surf is greater and more strongly s w -dependent (s 00 surf / s w 0.5 between 0.001 and 2 S/m) than observed for inorganic sediments. By assuming a linear relationship between the real (s 0 surf ) and the imaginary part (s 00 surf ) of the surface conductivity, we develop an empirical model relating the resistivity and induced polarization measurements to s w in peat. We demonstrate the use of this model to predict (a) s w and (b) the change in K v due to an incremental change in s w from resistivity and induced polarization measurements on organic sediments. Our study has implications for noninvasive geophysical characterization of s w and K v with potential to benefit studies of carbon cycling and greenhouse gas fluxes as well as nutrient supply dynamics in peatlands.

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Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

Low‐frequency electrical properties of peat

Comas

Slater

2004

Water Resources Research

113

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“…For a better comparison between electropherograms obtained in different conditions, effective mobility scale can be used [29]. The effective electrophoretic mobility m ep is related to the apparent (m app ) and the electroosmotic (m eo ) mobilities according to Eq.…”

Section: Effective Mobility Scalementioning

confidence: 99%

Separation of living and dead polymers in synthetic polypeptide mixtures by nonaqueous capillary electrophoresis using differences in ionization states

Souaïd

Cottet

2005

Electrophoresis

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The complexity in the mechanisms of polymerization of N-carboxyanhydrides requires the development of new analytical techniques able to separate mixtures of synthetic polypeptides. This work focuses on the separation of poly(N(epsilon)-trifluoroacetyl-L-lysine) (PTLL) mixtures by nonaqueous capillary electrophoresis (CE). The main goal of this work was to find electrophoretic conditions that permit the separation and the quantification of the dead polymer families that were previously identified in the samples. The influence of the pH of the electrolyte on the selectivity of the separation was carefully investigated. The mechanisms of separation of the PTTLs are discussed as a function of their ionization state. The separations obtained on a noncovalently coated capillary were compared with those obtained on a fused-silica capillary. Finally, using two different electrolytes, it is possible to quantify the three families of PTLLs, namely, the living PTLLs, the dead PTLLs with N-formyl end group and the dead PTLLs with a carboxylic end group. These results confirm the importance of CE for the separation of synthetic organic polymers in nonaqueous electrolytes.

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“…Natural organic matter (NOM) has been proven to be the most common cause of fouling in membrane processes (Kweon and Lawler, 2005). Major constituents of NOM include polysaccharides, lipids, proteins, peptides, amino acids and humic substances which can in some cases account for 50% of NOM (Schmitt-Kopplin et al, 1999;Van Geluwe et al, 2011). Application of ozone in presence of those substances causes their degradation to smaller molecules.…”

Section: Introductionmentioning

confidence: 99%

Application of Ozone-Assisted Membrane Cleaning for Natural Organic Matter Fouled Membranes

Khayrullina

Tizaoui

Williams

et al. 2017

Ozone: Science & Engineering

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The popularity of membrane technology in water treatment has been rising for over last 50 years due to wide range of filtration processes and applications, cost effective production and installation as well as safe and efficient water production. However, the development and improvement of membranes is ongoing due to number of weaknesses. Membrane fouling is a major drawback of membrane application in water and waste water treatment. Mostly caused by natural organic matter (NOM), fouling forms a layer on top of the membrane and blocks pores reducing the water permeation and can be potentially destructive to the membrane structure. The issue of membrane fouling can be addressed during membrane manufacturing, maintenance and operation. In the current study, the graphene-based nanomaterials (GBN) were incorporated in polyvinylidene fluoride (PVDF) to manufacture membranes via the phase-inversion technique. The resulting membranes show significant improvement to the properties of the pure PVDF membranes and their antifouling ability. The addition of GBN enhanced the water permeation by over 79% as a result of increased membrane hydrophilicity. Although this enhancement is beneficial, membrane fouling remained an issue despite the observed improvement. In this study, ozone, which is an effective oxidant, was 2 evaluated as a novel technique for the cleaning of humic acid-fouled membranes. When ozone cleaning was applied to the humic acid fouled membranes, reestablishment of close to original flux values was observed after just 30 minutes of cleaning. This statement is supported by SEM images that give an insight into the fouling of the membrane surface after the application of the cleaning methods. The data indicate that ozone is an effective technique for membrane cleaning against NOM induced fouling.

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Analysis of synthetic humic substances for medical and environmental applications by capillary zone electrophoresis

Cited by 11 publications

References 26 publications

Low‐frequency electrical properties of peat

Low‐frequency electrical properties of peat

Separation of living and dead polymers in synthetic polypeptide mixtures by nonaqueous capillary electrophoresis using differences in ionization states

Application of Ozone-Assisted Membrane Cleaning for Natural Organic Matter Fouled Membranes

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