Iron oxide dispersants for industrial water systems: types, performance, and selection criteria

• Z. Amjad

Department of Chemistry, Division of Mathematics and Sciences, Walsh University, N. Canton, Ohio 44270, USA

Abstract: Dispersion of solid particles separating out from fluids is very important for fouling due to deposition of unwanted materials. Dispersion and stabilization of suspended matter i.e., clay, silt, corrosion products, precipitating salts, etc., is often overcome by incorporating a dispersant in the water treatment formulation. In this paper a variety of non-polymeric, natural polyelectrolytes, synthetic, and hybrid polymers were evaluated for their efficacy as iron oxide (Fe2O3, hematite) dispersants for industrial water systems. Results reveal that performance of dispersants strongly depends on dispersant dosage, dispersing time, dispersant architecture, and the impurities present in water. Among the non-polymeric additives evaluated phosphonates perform better than polyphosphates. Surfactants (anionic, non-ionic) tested are ineffective iron oxide dispersants. Performance data on natural polyelectrolytes show that lignosulfonate exhibits better performance compared to humic, fulvic, and tannic acids. Based on the performance of synthetic polymers the order of effectiveness is: terpolymer > copolymer > homopolymer. Results on the impact of impurities (i.e., trivalent metal ions, biocides, hardness ions, etc.) suggest that these impurities show negative influence on the polymers performance. Discussion on dispersion mechanism and dispersant selection criteria is also presented.

Keywords: iron oxide, suspension, stabilization, mechanism, dispersant, types, performance, cooling system impurities

Int. J. Corros. Scale Inhib., 2017, 6, no. 2, 162–179 PDF (1 371 K)
doi: 10.17675/2305-6894-2017-6-2-6

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