Use of sodium polyaspartate for the removal of hydroxyapatite/brushite deposits from stainless steel tubing

Journal Article · Wed Jul 01 00:00:00 EDT 1998 · Industrial and Engineering Chemistry Research

DOI:https://doi.org/10.1021/ie980006l· OSTI ID:655526

Littlejohn, F; Saez, A E; Grant, C S ^[1]

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1. North Carolina State Univ., Raleigh, NC (United States). Dept. of Chemical Engineering

This research investigates the use of sodium polyaspartate, a nontoxic, biodegradable polycarboxylic sequestrant, for removing calcium phosphate deposit consisting of hydroxyapatite (HAP) and brushite or dicalcium phosphate dihydrate (DCPD) from stainless steel surfaces. Cleaning studies show that the use of sodium polyaspartate under alkaline conditions significantly enhances the removal rates when compared to deionized water. In acidic solutions, sodium polyaspartate concentrations below 300 ppm inhibit removal of HAP/DCPD deposits whereas higher concentrations increase the removal rate. Comparative cleaning studies at alkaline pHs show that sodium polyaspartate cleans the surface at a rate comparable to sodium citrate but slower than in ethylenediaminetetraacetic acid. Supplementary dissolution experiments show that sodium polyaspartate enhances the HAP/DCPD dissolution rate while inhibiting the release of Ca{sup 2+}. On the basis of these findings, the authors have concluded that sodium polyaspartate improves the HAP/DCPD dissolution and cleaning rates by Ca{sup 2+} sequestration.

• OSTI ID: 655526
• Journal Information: Industrial and Engineering Chemistry Research, Vol. 37, Issue 7; Other Information: PBD: Jul 1998
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
STAINLESS STEELS
COOLING SYSTEMS
SURFACE CLEANING
DESCALING
SCALE CONTROL
CALCIUM PHOSPHATES
REMOVAL