Inhibition of Calcite Crystal Growth by HEDP and its Analogues - A Molecular Modelling Study

                 

Principal Investigator

Andrew Rohl

School of Applied Chemistry,

Curtin University of Technology

Crystals are amongst the most beautiful structures in the universe - including diamonds, snowflakes,
and stalactites. However, more mundane crystals grow in pipes and vessels of industrial plants. Calcite is one of these crystals, which can eventually block water pipes, scale boilers and in general cost industry many millions of dollars in downtime and wasted energy. By understanding the mechanisms by which these crystals grow are changed in the presence of other chemicals, it is hoped that an effective inhibitor of this unwanted crystallisation can be designed.
The current study models the crystal surface as it grows. By placing chemicals on the surface at the growth sites, its effectiveness at hindering crystal growth can be calculated.
 

Co-Investigators

     

Michael Wilson

School of Applied Chemistry,

Curtin University of Technology

     
             

Projects

g98 - PC

           

   
             
                 

What are the results to date and the future of this work?

Three chemical species with the same backbone but different arrangements of functional groups have been docked onto the growing crystal surface and the effects on the crystal growth determined. The location of the docked species on the crystal face is very important in determining the effect on the crystal growth. The species that fit most easily into gaps in the crystal surface have the greatest effect on the crystal growth. Polarity of the species is also important. The results have suggested several areas for future investigation to determine improved crystal growth inhibitors. The work has been submitted to the Journal of the American Chemical Society.

What computational techniques are used?

The computer package used was MARVIN, a program for the relaxation of crystal surfaces and the docking of molecules onto these surfaces. The calculations consisted of energy minimization of a complex stepped crystal surface with a docked growth inhibitor. Simulation cells of ~1600 atoms were energy minimized using a quasi Newton minimiser.

                 

 

Appendix B -