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ξ电势是胶体体系稳定性指标,ξ电势愈大,胶体带电量愈多,胶体愈加稳定,故研究和测定胶体体系的ξ电势具有十分重要的意义.测定胶体的ξ电势都用电动法,电泳法是电动法中之一.此种方法是高等师范院校物理化学实验内容之一.但在所查文献中,用此法测ξ电势均未注明实验条件,或者说均忽视了测定条件和各种影响因素,我们在过去的教学实践中,也由于忽视了这些问题,致使学生的实验结果五花八门,一时竟找不到产生误差的原因.笔者注意到这个问题,实验发现用此法测定胶体的ξ电势受多种因素的影响.本文以Fe(OH)_3溶胶为代表,着重从几个可能引起误差的因素如界面的清晰度,胶体的陈化时间,胶体溶液的浓度、电泳的外加电压(电势梯度)和电泳时间等对测定ξ电势作实验性的探讨,找出产生误差的原因,以改进实验教学.
The zeta potential is an indicator of the stability of the colloidal system. The larger the zeta potential, the more charged colloids, the more stable the colloids, so it is of great significance to study and determine the zeta potential of the colloidal system. Act is one of the electric law .This method is one of the physical and chemical experiments in normal colleges and universities.However, in the literature examined, using this method to test ξ potential are not indicated experimental conditions, or ignore the determination of the conditions And a variety of influencing factors, we in the past teaching practice, but also because of neglect of these problems, resulting in a variety of experimental results for students, could not find a moment to produce the error causes the author noticed this problem, the experiment found that the method of determination The potential of colloid ξ is affected by many factors.In this paper, Fe (OH) 3 sol is the representative, focusing on several factors that may cause error such as the definition of the interface, the aging time of the colloid, the concentration of colloidal solution, Applied voltage (potential gradient) and electrophoresis time for the determination of ξ potential for experimental study to find out the reasons for the error in order to improve the experimental teaching.