Abstract
The interactions of hardness ions (i. e., Ca, Mg, Ba) with anionic polymeric scale inhibitors (SI) containing different functional groups has been investigated using a turbidity technique. It has been found that all SI tested form insoluble salts with hardness ions under the experimental conditions used (pH 7.0 to 10.0, 25 to 65 °C, 100 to 1,000 mg/L Ca). The results indicate that compatibility of hardness ions with SI decreases with increasing pH, temperature, and hardness ion concentrations and increases with increasing NaCl concentrations. It has also been found that compatibility of hardness ion with SI can be improved by incorporating bulkier and hydrophobic monomer into SI structure. In addition, the data suggest that SI architecture (i. e., molecular weight, monomer functional group, and nature of polymerization solvents) influences the interactions of hardness ions with SI in aqueous systems.
Kurzfassung
Die Wechselwirkungen zwischen härtebildenden Ionen (d. h., Ca, Mg, Ba) und anionischen polymeren Scaling-Inhibitoren (SI), die unterschiedliche funktionelle Gruppen besitzen, sind mittels einer Trübungsmethode untersucht worden. Dabei wurde gefunden, dass unter den experimentellen Bedingungen (pH 7.0 bis 10.0, 25 bis 65 °C, 100 bis 1000 mg/l Ca) alle getesteten SI mit den härtebildenden Ionen unlösliche Salze bilden. Die Ergebnisse zeigen, dass die Kompatibilität zwischen den härtebildenden Ionen und den SI abnimmt, wenn pH, Temperatur und die Konzentration an härtebildenden Ionen erhöht wird, und zunimmt, bei Erhöhung der NaCl Konzentration. Weiterhin wurde gefunden, dass die Kompatibilität zwischen den härtebildenden Ionen und den SI durch Einfügen von sterisch sperrigen und hydrophoben Monomeren in die SI-Struktur verbessert werden kann. Zusätzlich lässt sich aus den gewonnen Daten schließen, dass die SI-Konstitution (d. h., Molekulargewicht, funktionelle Gruppen der Monomere und Art des Polymerisationslösungsmittel) die Wechselwirkungen zwischen den härtebildenden Ionen und den SI in wässrigen Systemen beeinflussen.
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