Zhang Youyu, Xie Qingji, Yin Fan, Yao Shouzhuo
Chemical Research Institute, Hunan Normal University, Changsha, 410081, People's Republic of China
J Colloid Interface Sci. 2001 Apr 15;236(2):282-289. doi: 10.1006/jcis.2000.7397.
The piezoelectric quartz crystal (PQC) impedance technique was applied to monitor in situ generation and precipitation of the ferric hydroxide sol in aqueous solutions at 90 degrees C. Equivalent circuit parameters and resonant frequencies as well as the half-peak width of the electroacoustic conductance spectrum deltaf(G1/2) for the PQC resonance were obtained and analyzed. Three stages, sol generation and simultaneous adsorption, adsorption equilibrium, and precipitation of ferric hydroxide sol could be identified in the process of adding the ferric nitrate solution into the hot water. A scheme of two consecutive reactions occurring at the electrode/solution interface was used to analyze the adsorption kinetics of ferric hydroxide sol onto the Au electrode. In addition, the electrolyte-induced precipitation of the colloid was monitored and discussed. Temperature effect on the PQC resonance behavior in liquid was also investigated. Since the PQC impedance technique provides multidimensional piezoelectric information in situ, it is highly recommended for studying the process of sol-gel generation and precipitation. Copyright 2001 Academic Press.
采用压电石英晶体（PQC）阻抗技术原位监测90℃水溶液中氢氧化铁溶胶的生成和沉淀过程。获取并分析了PQC共振的等效电路参数、共振频率以及电声电导谱的半峰宽Δf（G1/2）。在将硝酸铁溶液加入热水的过程中，可以识别出三个阶段：溶胶生成与同步吸附、吸附平衡以及氢氧化铁溶胶的沉淀。采用在电极/溶液界面发生的两个连续反应的方案来分析氢氧化铁溶胶在金电极上的吸附动力学。此外，还监测并讨论了电解质诱导的胶体沉淀。还研究了温度对液体中PQC共振行为的影响。由于PQC阻抗技术能够原位提供多维压电信息，因此强烈推荐用于研究溶胶-凝胶的生成和沉淀过程。版权所有2001年学术出版社。
