Synthesis and applications of fluorescent-tagged scale inhibitors in water treatment. A review

Oshchepkov, Maxim; Tkachenko, Sergey; Popov, Konstantin

doi:10.17675/2305-6894-2019-8-3-2

Cited by 4 publications

(4 citation statements)

References 53 publications

(90 reference statements)

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“…Normally, the method sensitivity corresponds to the ppb level for both solid and liquid samples. For example, the detection limit of Rhodamine is in the range of 0.01 ppb in distilled water (25 mm cuvette) [35], and fluorescence quantum yield of our fluorescent inhibitor is quite close to Rhodamine [35,36]. Thus, localization of fluorescent inhibitor upon crystals/particles of scale is a valid approach.…”

Section: Tentative Mechanism Of Gypsum Membrane Fouling Inhibition Bymentioning

confidence: 81%

“…On the other hand PAA-F1 is expected to be a better antiscalant for CaSO 4 ·2H 2 O deposits relative to HEDP-F. This was demonstrated for the non-fluorescent prototypes 1-hydroxyethane-1,1-bis(phosphonic acid) (HEDP) and polyacrylate (PAA) [34].The fluorescent-tagged polyacrylates have gained increasing interest as the reagents for on line antiscalant concentration monitoring in water treatment applications recently [35]. However, they have not been applied, so far, for scale formation mechanisms studies.…”

Section: Reagents Membrane Materials and Model Solutionsmentioning

confidence: 99%

“…At the same time, the fluorescent antiscalants may become a promising tool in scale formation studies. This method has very high sensitivity and is widely used in analytical applications [35] as well as a powerful traceability approach in medicine [40]. Normally, the method sensitivity corresponds to the ppb level for both solid and liquid samples.…”

Section: Tentative Mechanism Of Gypsum Membrane Fouling Inhibition Bymentioning

confidence: 99%

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Gypsum Crystallization during Reverse Osmosis Desalination of Water with High Sulfate Content in Presence of a Novel Fluorescent-Tagged Polyacrylate

et al. 2020

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Gypsum scaling in reverse osmosis (RO) desalination process is studied in presence of a novel fluorescent 1,8-naphthalimide-tagged polyacrylate (PAA-F1) by fluorescent microscopy, scanning electron microscopy (SEM), dynamic light scattering (DLS) and a particle counter technique. A comparison of PAA-F1 with a previously reported fluorescent bisphosphonate HEDP-F revealed a better PAA-F1 efficacy, and a similar behavior of polyacrylate and bisphosphonate inhibitors under the same RO experimental conditions. Despite expectations, PAA-F1 does not interact with gypsum. For both reagents, it is found that scaling takes place in the bulk retentate phase via heterogeneous nucleation step. The background "nanodust" plays a key role as a gypsum nucleation center. Contrary to popular belief, an antiscalant interacts with "nanodust" particles, isolating them from calcium and sulfate ions sorption. Therefore, the number of gypsum nucleation centers is reduced, and in turn, the overall scaling rate is diminished. It is also shown that, the scale formation scenario changes from the bulk medium, in the beginning, to the sediment crystals growth on the membrane surface, at the end of the desalination process. It is demonstrated that the fluorescent-tagged antiscalants may become very powerful tools in membrane scaling inhibition studies.However, in spite of numerous relevant studies, some controversy regarding both the dominant scaling mechanism in particular situations and the mechanism of antiscalant activity still exists [12][13][14][15][16][17][18]. Recent reviews on scale formation control in RO technologies [6,19] mention two main hypothetic mechanisms of inhibition: (i) antiscalant molecules adsorb on the active growth sites at the crystal surface of sparingly soluble inorganic salt and retard nucleation and crystal growth by distorting its crystal structure; (ii) antiscalant molecules provide similar electrostatic charge, and thus, repulsion between particles prevents them from agglomeration.Nevertheless, our recent static [20,21] and RO [22] experiments operating gypsum as a model scale in presence of a novel fluorescent-tagged bisphosphonate antiscalant 1-hydroxy-7-(6-methoxy-1,3dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)heptane-1,1-diyl-bis(phosphonic acid), HEDP-F (H 4 hedp-F) revealed a paradoxical effect: an antiscalant does not interact with gypsum at all, but provides nevertheless retardation of corresponding deposit formation. According to the classical crystallization theory [23], this is possible only in the case, when gypsum passes bulk heterogeneous nucleation, and exactly the "nanodust" plays the role of the solid phase template. Indeed, it is demonstrated that HEDP-F molecules being immersed into the stock solution (undersaturated against gypsum) occupy a significant part of "nanodust" crystallization centers and form there their own solid phase Ca 2 hedp-F·nH 2 O. However, polyacrylates are much less sensitive to calcium environment than phosphonates [20,21]. In this way, it was reasonable to study the trace...

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Section: Tentative Mechanism Of Gypsum Membrane Fouling Inhibition Bymentioning

confidence: 81%

Section: Reagents Membrane Materials and Model Solutionsmentioning

confidence: 99%

Section: Tentative Mechanism Of Gypsum Membrane Fouling Inhibition Bymentioning

confidence: 99%

See 1 more Smart Citation

Gypsum Crystallization during Reverse Osmosis Desalination of Water with High Sulfate Content in Presence of a Novel Fluorescent-Tagged Polyacrylate

et al. 2020

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“…A possible solution might be associated with antiscalant molecule visualization during BaSO 4 crystallization from a supersaturated barite aqueous solution. Such visualization can be provided by fluorescent-tagged antiscalants, developed over past decade for scale inhibitor on-line monitoring in industrial water circulation facilities [18]. Surprisingly, till 2019 no attempts have been registered to apply these compounds to the scale formation mechanism studies.…”

Section: Introductionmentioning

confidence: 99%

Barite crystallization in presence of novel fluorescent-tagged antiscalants

2019

Int. J. Corros. Scale Inhib.

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Formation of barite crystals in a bulk supersaturated aqueous solution at ambient temperature is studied in presence of two novel fluorescent-tagged antiscalants: a bisphosphonate 1-hydroxy-7-(6-methoxy-1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)heptane-1,1-diyldi-(phosphonic acid), HEDP-F, and a co-polymer of N-allyl-4-methoxy-1,8-naphtalimide with acrylic acid, PAA-F1 by fluorescent microscopy, scanning electron microscopy (SEM), turbidimetry, dynamic light scattering (DLS) and a particle counter technique. Both scale inhibitors at a 20 mg·dm -3 dosage are found to be effective in supersaturated BaSO 4 solutions with saturation index (SI) 10 at 25°C (0.001 mol·dm -3 ). Herewith PAA-F1 reveals a higher efficacy than HEDP-F. At the same time a dramatic impact of foreign background "nanodust" particles on antiscalant efficacy is detected and interpreted in terms of barite nucleation. It is demonstrated, that barite nucleation takes place exclusively on "nanodust" particles as a bulk heterogeneous process. Thus an antiscalant molecule acts not so much as barite nuclei surface modifiers, but as the modifiers of "nanodust" particles. It is shown that inter alia the lower efficacy of HEDP-F relative to PAA-F1 is associated with insoluble barium salts formation by the former reagent (tentatively by Ba 2 HEDP-F·nH 2 O or BaH 2 HEDP-F·mH 2 O). Thus an efficacy evaluation may be strongly affected by the way of antiscalant introduction into the system. Being initially added to the barium brine both antisclants demonstrate greater difference in barite scale inhibition, than in the case of the sulfate brine. Both fluorescent-tagged reagents reveal perfectly an antiscalant location on barite crystals. Despite expectations they cover BaSO 4 crystal surface uniformly, and indicate no special concentration of antiscalant on crystal's kinks, edges etc. Thus the scale inhibitors affect rather the primary nucleation step of barite solid phase formation than the secondary one (macro-crystal growth phase).

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Continuous flow microfluidic implementation of a fluorescent marker into a polyacrylate moiety

et al. 2020

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Synthesis and applications of fluorescent-tagged scale inhibitors in water treatment. A review

Cited by 4 publications

References 53 publications

Gypsum Crystallization during Reverse Osmosis Desalination of Water with High Sulfate Content in Presence of a Novel Fluorescent-Tagged Polyacrylate

Gypsum Crystallization during Reverse Osmosis Desalination of Water with High Sulfate Content in Presence of a Novel Fluorescent-Tagged Polyacrylate

Barite crystallization in presence of novel fluorescent-tagged antiscalants

Continuous flow microfluidic implementation of a fluorescent marker into a polyacrylate moiety

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