Sondi Ivan, Matijevic Egon
Center for Advanced Materials Processing, Clarkson University, Potsdam, New York, 13699-5814
J Colloid Interface Sci. 2001 Jun 1;238(1):208-214. doi: 10.1006/jcis.2001.7516.
Catalytic decomposition of urea by urease in aqueous calcium chloride solutions was used to rapidly prepare calcium carbonate polymorphs at room temperature. The nature of the resulting particles depended on the concentration of the enzyme and, in a strong manner, on the agitation of the reacting solutions. In an undisturbed system an amorphous precipitate is formed first, which readily crystallized to vaterite and upon aging changed to calcite. Under the influence of magnetic stirring, the amorphous phase could be not observed; instead smaller particles were initially obtained, which aggregated to vaterite and calcite. Similarly, the application of ultrasonic energy produced small vaterite particles at the early stages. It is apparent that enzyme macromolecules are important in the development of calcite faces and, as such, they exert significant influence on calcite morphology, without being present in detectable amounts in the resulting solids. Copyright 2001 Academic Press.
在室温下，利用脲酶在氯化钙水溶液中催化分解尿素的方法快速制备碳酸钙多晶型物。所得颗粒的性质取决于酶的浓度，并且很大程度上取决于反应溶液的搅拌情况。在未搅拌的体系中，首先形成无定形沉淀，该沉淀很容易结晶成球霰石，并且在老化后转变为方解石。在磁力搅拌的影响下，观察不到无定形相；相反，最初会得到较小的颗粒，这些颗粒聚集成球霰石和方解石。同样，施加超声能量在早期阶段会产生小的球霰石颗粒。很明显，酶大分子在方解石晶面的形成过程中很重要，因此，它们对方解石的形态有显著影响，而在所得固体中却检测不到其存在。版权所有2001年学术出版社。
