Effects of Removal of Deposits on the Surface Charge Property of Toyoura Sand Grain and its Result in the Capture Efficiency of Kaolintie Particle in the Column Experiment

Abstract

Surface charge property of Toyoura sand prepared with two different ways and the capture of kaolinite particle of the column packed with those two kinds of sand were analyzed focusing the presence of surface deposits in order to clarify the surface properties of Toyoura sand as collector grains. Scanning electron microscopy (SEM) revealed that the deposits on the surface of Toyoura sand were removed by ultcasonication. Surface charge property of Toyoura sand before and after ultrasonication was measured by streaming potential method as functions of pH and ionic strength. Zeta potential of bare sand became higher below pH 7 and lower above pH 7 than those values of the sand covered with surface deposits. Electrophoretic mobility of the removed deposits was measured as functions of pH and ionic strength under ultramicroscopy. The zeta potential of the sand covered with deposits was found not to be the simple sum of surface deposits and bare sand The rate of particle capture through of the column packed with ultrasonicated sand turned out to be lower than the value of untreated one.