Phosphate-Free Inhibition of Calcium Carbonate Dishwasher Deposits

Hong, Yuexian; Letzelter, Nathalie; Evans, John S.O.; Yufit, Dmitry S; Steed, Jonathan W.

Abstract

This paper reports the characterization of the composition and morphology of mineral formation on glass and plastic (polymethylmethacrylate) substrates in a dishwasher environment and the identification of suitable phosphate-free mineral crystallization inhibitors as environmentally benign candidates to replace the currently used phosphate-containing inhibitor 1-hydroxyethane 1,1-diphosphoric acid (HEDP). Screening of the calcium carbonate crystallization inhibition performance of twenty-eight different compounds resulted in the identification of two phosphate-free, cyclic polycarboxylic acid inhibitors, which were found in combination to be effective replacements. Each inhibitor proved to be highly substrate specific with all-cis-cyclohexane-1,2,3,4,5,6-hexacarboxylic acid (CHHCA) preventing deposition on glass (where calcite is the dominant polymorph) and cis,cis,cis,cis-cyclopentane-1,2,3,4-tetracarboxylic acid (CPTCA) inhibiting aragonite deposition on polymethylmethacrylate (PMMA). When used in combination, these two species prevented all forms of calcium carbonate deposition on both substrate types. The underlying inhibition mechanism and structural requirements of an efficient calcium carbonate inhibitor are also discussed.

Citation

Hong, Y., Letzelter, N., Evans, J. S., Yufit, D. S., & Steed, J. W. (2018). Phosphate-Free Inhibition of Calcium Carbonate Dishwasher Deposits. Crystal Growth and Design, 18(3), 1526-1538. https://doi.org/10.1021/acs.cgd.7b01508

• Journal Article Type: Article
• Acceptance Date: Jan 22, 2018
• Online Publication Date: Jan 22, 2018
• Publication Date: Mar 7, 2018
• Deposit Date: Jan 30, 2018
• Publicly Available Date: Jan 22, 2019
• Journal: Crystal Growth and Design
• Print ISSN: 1528-7483
• Electronic ISSN: 1528-7505
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 18
• Issue: 3
• Pages: 1526-1538
• DOI: https://doi.org/10.1021/acs.cgd.7b01508