Water

Weingärtner, Hermann; Franck, E. U.; Wiegand, G.; Dahmen, Nicolaus; Schwedt, Georg; Frimmel, Fritz H.; Gordalla, Birgit C.; Johannsen, Klaus; Summers, R. Scott; Höll, Wolfgang H.; Jekel, Martin; Gimbel, R.; Rautenbach, R.; Glaze, William H.

doi:10.1002/14356007.a28_001

Cited by 6 publications

(4 citation statements)

References 79 publications

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“…Values can range from 0.45 to 0.75. 10 Using the measurements of TDS and σ in Table 1 to estimate β, we find 0.52 and 0.53 for Evian and Ballygowan, respectively, which can be used to relate changes in conductivity (Δσ) to changes in TDS (ΔTDS). Ca 2+ and CO 3 2– ions bound in neutral DOLLOPs do not contribute to the electrical conductivity.…”

Section: Discussionmentioning

confidence: 92%

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Interaction and Stability of Nanobubbles and Prenucleation Calcium Clusters during Ultrasonic Treatment of Hard Water

Fitzgerald,

Kumar,

Poulose

et al. 2024

ACS Omega

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To investigate the stability of nanobubbles in natural hard water, a series of eight samples ranging in hardness from 0 to 332 mg/L CaCO 3 were sonicated for periods of 5−45 min with an ultrasonic horn. Conductivity, temperature, ζ-potential, composition, and pH of the water were analyzed, together with the crystal structure of any calcium carbonate precipitate. Quasistable populations of bulk nanobubbles in Millipore and soft water are characterized by a ζ-potential of −35 to −20 mV, decaying over 60 h or more. After sonicating the hardest waters for about 10 min, they turn cloudy due to precipitation of amorphous calcium carbonate when the water temperature reaches 40 °C; the ζ-potential then jumps from −10 to +20 mV and remains positive for several days. From an analysis of the change of conductivity of the hard water before and after sonication, it is estimated that 37 ± 5% of calcium was not originally in solution but existed in nanoscale prenucleation clusters, which decorate the nanobubbles formed in the early stages of sonication. Heating and charge screening in the nanobubble colloid cause the decorated bubbles to collapse or disperse, leaving an amorphous precursor of aragonite. Sonicating the soft supernatant increases its conductivity and pH and restores the negative ζ-potential associated with bulk nanobubbles, but there is no further precipitation. Our study of the correlation between nanobubble production and calcium agglomeration spanning the hardness and composition ranges of natural waters shows that the sonication method for introducing nanobubbles is viable only for hard water if it is kept cold; the stability of the nanobubble colloid will be reduced in any case by the presence of dissolved calcium and magnesium.

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Section: Discussionmentioning

confidence: 92%

“…Water’s capacity for self-dissociation into its constituent ionic species distinguishes it as a universal amphiprotic solvent 10 exhibiting acidic or basic properties depending on the solute and temperature …”

Section: Introductionmentioning

confidence: 99%

Interaction and Stability of Nanobubbles and Prenucleation Calcium Clusters during Ultrasonic Treatment of Hard Water

Fitzgerald,

Kumar,

Poulose

et al. 2024

ACS Omega

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“…Die Dehydratisierung von d-Fructose zu 5-HMF [Gl. (7)] gelang im Temperaturbereich von 250 bis 350 8C bei einem Druck von 250 bar und einem Umsatz von ca. 60 % mit einer Selektivität von etwa 30 %.…”

Section: Fructoseunclassified

Chemie in überkritischem Wasser

et al. 1999

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Wasser ist ein besonderer Saft – nicht nur unter „normalen”︁ Bedingungen. Wasser im überkritischen Zustand (gerasterte Fläche im Phasendiagramm) zeichnet sich durch Eigenschaften aus, die von denen des normalen Wassers erheblich abweichen. Bisher wurden diese meistens zur Abwasserreinigung, z. B. zur Totaloxidation schwer abbaubarer Stoffe, genutzt. Doch wie sieht es mit dem Synthesepotential von überkritischem Wasser aus? Antworten werden hier anhand von thermodynamischen und kinetischen Untersuchungen sowie von Korrosionsmessungen gegeben.

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“…7 e , f On the other hand, bisulfate (HSO 4 − ) plays an important role in the detoxification of many endogenous and exogenous compounds. 8 However, it has adverse environmental effects when exposed as fertilizers, industrial raw materials and nuclear fuel waste. 9 In a recent review article, Paul et al 10 a highlighted the two burning challenges of the optical detection of HSO 4 − especially in an aqueous medium: the high Gibbs energy of hydration (Δ G h = −1080 kJ mol −1 ) of HSO 4 − , 10 b and significant interference from H 2 PO 4 − owing to similar tetrahedral geometry.…”

Section: Introductionmentioning

confidence: 99%