De Luca Pierantonio, Mastroianni Carmelo, Siciliano Carlo, Nagy Janos B, Macario Anastasia
Department of Ingegneria Meccanica, Energetica e Gestionale, University of Calabria, Arcavacata di Rende, 87036 Rende (Cs), Italy.
Department of Ingegneria per l'Ambiente ed il Territorio ed Ingegneria Chimica, University of Calabria, Arcavacata di Rende, 87036 Rende (Cs), Italy.
Gels. 2019 Sep 2;5(3):42. doi: 10.3390/gels5030042.
The main scope of the present work is to synthesize pH-responsive Engelhard titanium silicate (ETS)-10 phase crystalline pellets through the smart modification of a synthetic process which was previously applied to the preparation of other phases. The original preparative method, which envisages the use of the same initial synthesis as a binder for the preparation of pellets, was modified by adding an appropriate pH indicator to a number of systems subject to this investigation. It should be noted that the modified process was never before used to give access to pH-responsive ETS-10 phase pellets, and it is disclosed here for the first time. The study started from the definition of the best experimental conditions, which were optimized by analyzing the effects of temperature and system composition. The addition of the pH indicator did not alter the physicochemical characteristics and reactivity of the system. The pH-responsive ETS-10 phase crystalline pellets were characterized by an adequate mechanical strength and by a high capability to change color. The latter aspect can be particularly useful when this material is used in catalytic processes whose performance is strictly dependent on the pH value. The amount of gel used, as well as the working temperature, were the main critical parameters to be controlled during the preparation of pH-responsive ETS-10 phase crystalline pellets. The pellets were fully characterized by X-ray diffraction in order to investigate and identify the possible phases, and by using a hardness tester to measure the compressive strength. Finally, toning tests were performed.
本工作的主要范围是通过对先前用于制备其他相的合成工艺进行巧妙改进，合成pH响应性的恩格尔哈德钛硅酸盐（ETS）-10相结晶颗粒。原始的制备方法设想使用与制备颗粒的粘合剂相同的初始合成物，通过向许多受此研究的体系中添加适当的pH指示剂对其进行了改进。应当指出，改进后的工艺以前从未用于制备pH响应性的ETS-10相颗粒，本文首次公开。该研究从最佳实验条件的定义开始，通过分析温度和体系组成的影响对其进行了优化。pH指示剂的添加并未改变体系的物理化学特性和反应性。pH响应性的ETS-10相结晶颗粒具有足够的机械强度和高变色能力。当这种材料用于性能严格取决于pH值的催化过程时，后一个方面可能特别有用。在制备pH响应性的ETS-10相结晶颗粒过程中，所用凝胶的量以及工作温度是需要控制的主要关键参数。通过X射线衍射对颗粒进行全面表征，以研究和识别可能的相，并使用硬度测试仪测量抗压强度。最后，进行了调色测试。
