Calcium sulfate dihydrate (gypsum) scale inhibition by PAA, PAPEMP, and PAA/PAPEMP blend

• Z. Amjad, R. T. Landgraf and J. L. Penn

Walsh University, Division of Mathematics and Sciences, North Canton OH 44720, USA

Abstract: The effects of poly(acrylic acid), PAA, polyamino polyether methylene phosphonic acid, PAPEMP, and PAA/PAPEMP blend on calcium sulfate dihydrate (gypsum) are reported in this paper. It has been found that gypsum inhibition by PAA increases with increasing PAA concentration. Among the various phoshonates (i.e., aminotris(methylene phosphonic acid), AMP; hydroxyphosphono acetic acid, HPA; hydroxyethylidene 1,1-diphosphonic acid, HEDP; 2-phosphonobutane 1,2,4-tricarboxylic acid, PBTC; and polyether polyamino phosphonic acid, PAPEP) evaluated, PAPEMP shows the best inhibition for gypsum precipitation. It has also been observed that presence of PAPEMP exhibits synergistic effect on the performance of PAA. Results on calcium ion compatibility of various phosphonates show that PAPEMP compared to other phosphonates tested show higher tolerance to calcium ions.

Keywords: calcium sulfate dihydrate, precipitation, inhibition, polymer, phosphonates

Int. J. Corros. Scale Inhib., 2014, 3, no. 1, 35-47 PDF (921 K)
doi: 10.17675/2305-6894-2014-3-1-035-047

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