Coagulation of humic substances and dissolved organic matter with a ferric salt: An electron energy loss spectroscopy investigation

Jung, Aude-Valérie; Chanudet, Vincent; Ghanbaja, Jaâfar; Lartiges, Bruno; Bersillon, Jean-Luc

doi:10.1016/j.watres.2005.07.008

Cited by 65 publications

(33 citation statements)

References 47 publications

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“…Concerning the mechanism of flocculation, there is some controversy about whether organic compounds are scavenged by adsorption onto precipitated iron hydroxide colloids (Ying et al, 1988;Tseng et al, 1989) or the organic colloids are precipitated as a consequence of charge compensation by dissolved Fe (Schmitt et al, 1996;Vilgé-Ritter et al, 1999;Cheng, 2002;Jung et al, 2005). In fact, precipitates of humic acid and colloidal iron hydroxide look very similar.…”

Section: Flocculation Of Humic Acid On Addition Of Fementioning

confidence: 99%

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Competitive effect of iron(III) on metal complexation by humic substances: Characterisation of ageing processes

et al. 2007

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Section: Flocculation Of Humic Acid On Addition Of Fementioning

confidence: 99%

“…In flocculated Fe/HA precipitates, the presence of iron oligomers could be detected by X-ray spectroscopy (Vilgé-Ritter et al, 1999;Jung et al, 2005).…”

Section: Characteristics Of Fe-ha Interactionmentioning

confidence: 99%

Competitive effect of iron(III) on metal complexation by humic substances: Characterisation of ageing processes

et al. 2007

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“…Besides the traditional treatments of humic acids [5][6][7][8], studies of the degradation of HA have been carried out with advanced oxidation processes (AOPs) [9][10][11][12][13], among which the heterogeneous Fenton system has attracted great attention due to its formation of highly potent chemical species, • OH, for non-selective oxidation [14,15]. Zero valent iron has been widely used in different environmental treatment processes [16,17] and the direct electron transfer from Fe 0 to H 2 O 2 during a Fenton reaction is a very slow process at neutral pH [18].…”

Section: Introductionmentioning

confidence: 99%

Degradation characteristics of humic acid over iron oxides/Fe0 core–shell nanoparticles with UVA/H2O2

Nie

Zhou

et al. 2010

Journal of Hazardous Materials

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a b s t r a c tIron oxides coated on Fe 0 core-shell nanospheres (nIOCI) were synthesized through the reduction of ferrous sulfate aqueous solution by sodium borohydride at ambient atmosphere. The catalyst was highly effective for the degradation of humic acid (HA) in the presence of H 2 O 2 and UVA at neutral pH. Under deoxygenated conditions in the dark, the generation of hydroxyl radicals in aqueous nIOCI dispersion verified its galvanic cell-like performance, which enhanced the interfacial electron transfer and led to its higher reactivity. By the total organic carbon, the absorbance of UV 254 , FTIR, the molecular weight distribution and the chemical fractional character analysis, the degradation process of HA was shown to proceed by the disappearance of aromaticity, the increase of hydrophilic fraction and aromatic ring openings into CO 2 and small organic acid. The treated HA showed much lower reactivity toward chlorine and the disinfection byproduct (DBP) formation potential was also greatly reduced. Moreover, it was found that the DBP formation potential more depended on the structure of the intermediates of HA degradation than TOC removal.Crown

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“…Usually, several main mechanisms such as charge neutralization/complexation, enmeshment, and adsorption [8][9][10] are used to explain the interaction of humic substances with these metal salts. Charge neutralization/complexation is believed to preferentially occur at acidic pH [9][10][11], while physical enmeshment and/or adsorption commonly occurs under conditions favoring metal hydroxide precipitation, and humic substances are primarily transferred onto freshly formed precipitate [9,10,12,13].…”

Section: Introductionmentioning

confidence: 99%

“…Charge neutralization/complexation is believed to preferentially occur at acidic pH [9][10][11], while physical enmeshment and/or adsorption commonly occurs under conditions favoring metal hydroxide precipitation, and humic substances are primarily transferred onto freshly formed precipitate [9,10,12,13]. When FeCl 3 is employed in enhanced coagulation for HA removal, good performance has been gained at acidic pH and large doses, where in pH-coagulant concentration domains fresh iron hydroxide precipitation is formed [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Effect of polyferric chloride (PFC) doses and pH on the fractal characteristics of PFC–HA flocs

Wang

Feng

Dentel

et al. 2011

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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a b s t r a c tChanges in the fractal characteristics of PFC-HA flocs with polyferric chloride (PFC) doses and coagulation pHs were investigated in this study. A type of PFC coagulant with a hydrolysis degree (B*) of 0.6027 and a Fe(III) concentration of 0.202 mol/L was employed to coagulate HA solutions at five constant coagulation pHs. Zeta potential tests were employed to reveal the coagulation mechanisms. The physical properties of flocs formed in the coagulation process were analyzed by their CCD image morphology, size distribution, and fractal dimensions. Next, microscopic observations and nitrogen-adsorption-desorption methods were conducted to characterize the pore structure and surface fractal dimensions of powders prepared from these flocs through a cryofixation-vacuum-freeze-drying procedure. The PFC doses and coagulation pHs had an obvious effect on the physical characteristics of PFC-HA flocs and their corresponding powders. Generally, in the low PFC dose range, PFC-HA flocs formed under acidic coagulation pHs and charge neutralization mechanisms were larger, had less irregular boundaries or surfaces (lower D 1 value), a more compact structure (lower D 2 value) and more irregular pore surface or pore size distribution in their dried powder than those formed under neutral and alkaline coagulation pHs and physical enmeshment and/or fresh precipitate adsorption mechanisms involved in the coagulation process. After the PFC doses exceeded this range, a gradual reversal phenomenon occurred. Furthermore, there were different specific PFC dosages that were above the critical reversal point for each property of these flocs or powders, such as the median diameter, one-dimensional fractal dimension, two-dimensional fractal dimension, and pore surface fractal dimension. In addition to these characteristics, the most compact PFC-HA flocs were formed at coagulation pH = 6.00 ± 0.05 and a PFC dosage of 4.04 × 10 −4 mol/L (Fe 3+ ), and the loosest flocs were produced at coagulation pH = 7.00 ± 0.05 and a PFC dose of 1.01 × 10 −4 mol/L (Fe 3+ ).

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Coagulation of humic substances and dissolved organic matter with a ferric salt: An electron energy loss spectroscopy investigation

Cited by 65 publications

References 47 publications

Competitive effect of iron(III) on metal complexation by humic substances: Characterisation of ageing processes

Competitive effect of iron(III) on metal complexation by humic substances: Characterisation of ageing processes

Degradation characteristics of humic acid over iron oxides/Fe0 core–shell nanoparticles with UVA/H2O2

Effect of polyferric chloride (PFC) doses and pH on the fractal characteristics of PFC–HA flocs

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