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Influence of Heat Treatment on the Performance of Polymers as Gypsum (CaSO4 · 2H2O) Scale Inhibitors for Industrial Water Applications

Einfluss der Wärmebehandlung auf die Wirksamkeit von Polymeren als Inhibitor von Gips (CaSO4 · 2H2O)- und Kalkablagerungen in Industriewässern
Zahid Amjad


The inhibition of gypsum precipitation by homo-, co-, and terpolymers has been examined in aqueous solution. It has been found that polymer performance as gypsum inhibitor depends upon polymer composition, type of comonomer, and functional groups. Results on the evaluation of polymers suggest that compared to co- and terpolymers, homopolymers containing carboxyl group are effective gypsum inhibitors. The impact of heat treatment (150°C to 240°C) on the performance of various homo-, co-, and teropolymers as gypsum inhibitors has also been investigated. It has been observed that all polymers lose performance to a varying degree when exposed to thermal treatment. Performance data on co- and terpolymers containing amido group show improved performance after heat treatment suggesting the formation of carboxyl group. Scanning electron microscopic investigations of gypsum crystals grown in the presence of polymers show that structures of these crystals are highly modified.


Es wurde die Hemmung von Gipsausfällungen durch Homo-, Co- und Terpolymere untersucht. Es wurde gefunden, dass die Wirksamkeit der Polymere als Inhibitor von der Polymerzusammensetzung, dem Comonomertyp und den funktionellen Gruppen abhängig ist. Die Bewertung der Polymere aufgrund der Ergebnisse zeigt, dass Homopolymere, die eine Carboxylgruppe enthalten, im Vergleich zu den Co- und Terpolymeren effektive Gipsinhibitoren sind. Der Einfluss einer Wärmebehandlung (150°C to 240°C) auf die Wirksamkeit der verschiedenen Homo-, Co- und Terpolymeren als Gipsinhibitor wurde untersucht. Man konnte feststellen, dass die Wirksamkeit aller Polymere nach einer thermischen Behandlung in unterschiedlichem Grad nach einer thermischen Behandlung verringert war. Co- und Terpolymere, die eine Amidogruppe besitzen, zeigen eine verbesserte Leistung nach der Wärmebehandlung, was auf die Bildung einer Carboxylgruppe hinweist. Rasterelektronenmikroskopische Untersuchungen an Gipskristallen, die in Anwesenheit von Polymeren gewachsen sind, zeigen, dass ihre Kristallstrukturen stark verändert sind.

Z. Amjad, Ph.D., Walsh University, Division of Mathematics and Sciences, 2020 East Maple Street, North Canton, Ohio 44720, E-Mail:

Zahid Amjad, Ph.D., has over 30 years experience in the water treatment, membrane processes, household, personal care, and pharmaceutical fields. He has published over 150 technical papers and is holder of 30 US patents. Dr. Amjad has edited six books and has presented papers at national and international conferences. Dr. Amjad is a member of several professional societies and is a recipient of Association of Water Technologies 2002 Ray Baum Memorial Water Technologist of the year award. His current research interests include development and applications of water soluble polymers, inhibition of mineral scale formation, and water purification. Dr. Amjad is the founder and president of Aqua Science and Technology LLC. He currently provides technical and marketing consultation to water treatment, separation processes, and related fields. Dr. Amjad is also a Visiting Professor in Chemistry at Walsh University, North Canton, Ohio.


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Received: 2012-07-25
Revised: 2012-08-24
Published Online: 2013-04-05
Published in Print: 2012-11-01

© 2012, Carl Hanser Publisher, Munich