(440b) Methods to Study Influence of Surfaces in Crystallization Processes: Scaling and Supersaturation Depletion

Methods to study influence of
surfaces in crystallization processes: scaling and supersaturation depletion

Jacob Hutfles¹, Sankaranarayanan
A. Ravichandran¹, and John Pellegrino*

Department of Mechanical
Engineering, University of Colorado-Boulder, Boulder, CO 80309-0427

*corresponding author: john.pellegrino@colorado.edu

Abstract

We present methods to study the effects of
various polymeric surfaces on the heterogeneous crystallization of calcium
carbonate from supersaturated aqueous solutions using shaken jars. The
methodology allows for bench scale evaluation of different materials, the
extent of mixing and the interaction of these parameters on crystallization
kinetics. The crystallization process was quantified using turbidity, crystal
collection, and depletion on Ca ions in solution using ICP-MS. From measuring
the aforementioned parameters, we identified surfaces that were able to promote
heterogeneous crystallization while avoiding scale build up.  Our experimental
variables were the type of polymer, time, and mixing energy input. An
unanticipated observation was that the polyethylene and polymers contributed to
similar levels of overall supersaturation depletion, but then poly
(ethylene-co-vinyl alcohol) was found to resist surface build-up i.e. was
resistant to calcium carbonate scaling. The methodology we have developed can
aid in improving crystallizer designs to increase efficient water recovery from
brine waste in terms of the material of construction and mixing devices.

¹both authors contributed equally to the research and manuscript
preparation

Figure 1.
Observe the that polyethylene shows significantly more scaling than poly
(ethylene-co-vinyl alcohol)