The influence of impurities on the crystal growth kinetics according to a competitive adsorption model

• Type: Article in International Scientific Journal
• Date: 2006

Authors

Pedro M Martins (Author) Other; Fernando A Rocha (Author) FEUP; Peter Rein (Author) Other

Journal

Title: Crystal Growth & Design

Vol. 6 No. 12

Pages: 2814-2821

ISSN: 1528-7483

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 20 Citations

ISI Web of Science

Scopus - 24 Citations

Scientific classification

FOS: Engineering and technology > Materials engineering

CORDIS: Technological sciences > Engineering > Chemical engineering

Other information

Authenticus ID: P-004-FHB

DOI: 10.1021/cg060448x

Abstract (EN): A mathematical model describing the growth of crystals in impure solutions is presented. Evidence of competitive surface adsorption involving the crystallizing solute and impurities is discussed in terms of the adsorption isotherm in equilibrium and of the mechanism of occupation of active sites for growth. The impurity effect on crystal growth rates is characterized by the Langmuir adsorption constants and by the parameter, measuring the ability of the foreign species to move across the surface and occupy a stable position at the surface steps. Experimental growth rate data taken from the literature is used to test the proposed competitive adsorption model (CAM). The reported effects of the impurity concentration on the crystal growth rate at constant supersaturation are quantitatively described. Additionally, growth rate curves obtained in pure and impure solutions are used to investigate the influence of supersaturation on the relative growth rates. In all the examples considered, the CAM adequately describes the experimental data. An application example is given using the crystal growth rates of sucrose measured in a pilot evaporative crystallizer at different impurity concentrations. The kinetic effect of nonsucrose compounds existing in cane sugar solutions is characterized by estimating the average CAM parameters.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8