NMR和TOF-SIMS研究烷基双膦酸与CaCO3表面Ca2+的键合模式

NMR and TOF-SIMS investigation of alkylbisphosphonic acid binding to Ca2+ on CaCO3 surface

双膦酸与含钙矿物表/界面作用的键合模式仍需深入探索.本文分别选择CaCO3与具有线性长链的十五烷基双膦酸作为双膦酸与钙离子反应的模型,使烷基双膦酸在CaCO3表面自组装形成单分子层,通过13C CP/MAS NMR、31P MAS NMR和TOF-SIMS等手段表征了双膦酸与Ca CO3表面Ca^2+作用的键合模式.结果表明,一个双膦酸头基[–CH(PO3H2)2]能与三个钙离子以双三齿键合模式螯合形成6个P–O–Ca键,导致碳酸钙表面被全部活化,这为理解双膦酸与含钙矿物的作用机理提供了科学依据,并为碳酸钙的表面改性提供了一条潜在途径.

The mode of the bisphosphonic acid binding to the surface/interface of the calcium-containing mineral remains partly unexplored. In this paper, the bisphosphonate containing a long alkyl chain self-assembled monolayers on CaCO3 surfaces, and the mode of bisphosphonate binding to Ca^2+on CaCO3 surfaces were investigated by13 C CP/MAS NMR,31 P MAS NMR and TOF-SIMS. The results showed that a bisphosphonate headgroup [–CH(PO3 H2)2] chelates with three calcium ions in a double-tridentate bonding mode, and forms six bonds of P–O–Ca, and thus the CaCO3 surface is fully activated, which provides a theoretical basis for the understanding of the interaction between bisphosphonic acid and calcium mineral, and also a potential path for the surface modification of CaCO3.