Growth and Dissolution of Calcite in the Presence of Adsorbed Stearic Acid

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• 作者：Maria Ricci ; Juan Jos茅 Segura ; Blake W. Erickson ; Georg Fantner ; Francesco Stellacci ; Kislon Vo茂tchovsky
• 刊名：Langmuir
• 出版年：2015
• 出版时间：July 14, 2015
• 年：2015
• 卷：31
• 期：27
• 页码：7563-7571
• 全文大小：571K
• ISSN：1520-5827

文摘

The interaction of organic molecules with the surface of calcite plays a central role in many geochemical, petrochemical, and industrial processes and in biomineralization. Adsorbed organics, typically fatty acids, can interfere with the evolution of calcite when immersed in aqueous solutions. Here we use atomic force microscopy in liquid to explore in real-time the evolution of the (1014) surface of calcite covered with various densities of stearic acid and exposed to different saline solutions. Our results show that the stearic acid molecules tend to act as 鈥減inning points鈥?on the calcite鈥檚 surface and slow down the crystal鈥檚 restructuring kinetics. Depending on the amount of material adsorbed, the organic molecules can form monolayers or bilayer islands that become embedded into the growing crystal. The growth process can also displaces the organic molecules and actively concentrate them into stacked multilayers. Our results provide molecular-level insights into the interplay between the adsorbed fatty acid molecules and the evolving calcite crystal, highlighting mechanisms that could have important implications for several biochemical and geochemical processes and for the oil industry.