| Autor: |
Townsend ER; Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands., Brugman SJT; Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands., Blijlevens MAR; Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands., Smets MMH; Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands., de Poel W; Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands., van Enckevort WJP; Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands., Meijer JAM; Akzo Nobel Industrial Chemicals, RD&I Salt, Zutphenseweg 10, 7418 AJ Deventer, The Netherlands., Vlieg E; Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands. |
| Abstrakt: |
The role that additives play in the growth of sodium chloride is a topic which has been widely researched but not always fully understood at an atomic level. Lead chloride (PbCl 2 ) is one such additive which has been reported to have growth inhibition effects on NaCl {100} and {111}; however, no definitive evidence has been reported which details the mechanism of this interaction. In this investigation, we used the technique of surface x-ray diffraction to determine the interaction between PbCl 2 and NaCl {100} and the structure at the surface. We find that Pb 2+ replaces a surface Na + ion, while a Cl - ion is located on top of the Pb 2+ . This leads to a charge mismatch in the bulk crystal, which, as energetically unfavourable, leads to a growth blocking effect. While this is a similar mechanism as in the anticaking agent ferrocyanide, the effect of PbCl 2 is much weaker, most likely due to the fact that the Pb 2+ ion can more easily desorb. Moreover, PbCl 2 has an even stronger effect on NaCl {111}. |
