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Yamashita, Yuji*; Tanaka, Tadao; Adachi, Yasuhisa*
Colloids and Surfaces A; Physicochemical and Engineering Aspects, 417, p.230 - 235, 2013/01
Times Cited Count：11 Percentile：28.04(Chemistry, Physical)Transport behavior of humic acid was studied from the aspects of colloidal stability. Deposition kinetics of purified Aldrich humic acid was investigated over a wide range of monovalent and divalent electrolyte concentrations at pH 3.0 by using packed-bed technique. Spherical glass beads with diameters of 0.2 mm were utilized as model collectors. Breakthrough curves of humic acid were measured with UV-VIS spectrophotometer. The values of C/C0 (C and C0 are the effluent and influent concentrations of humic acid, respectively) decreased with increasing electrolyte concentrations. Experimental collision efficiencies were determined from measured single collector efficiencies. The results are presented as stability curves, which is the logarithm of the collision efficiency as a function of the logarithm of salt concentration. Stability curves of humic acid obviously showed favorable and unfavorable regimes and critical deposition concentration in the presence of both electrolytes. As a consequence, it is indicated that transport behavior of humic acid is primarily controlled by electrostatic interaction between humic acids and collectors.
Nagao, Seiya*; Aoyama, Masakazu*; Watanabe, Akira*; Tanaka, Tadao
Colloids and Surfaces A; Physicochemical and Engineering Aspects, 347(1-3), p.239 - 244, 2009/09
Times Cited Count：6 Percentile：14.14(Chemistry, Physical)Humic substances play important role in geochemical behavior of trace elements such as actinides in aquatic environments. The association properties of Am with humic substances were studied on the basis of structural feature of humic substances. Humic acids prepared from three types of soils, and separated two humic acids with different structural features: fluorescence-poor and higher molecular size fraction, HA and fluorescence-rich and lower molecular size fraction, FL. The association experiments were carried out in a medium of 0.01M NaClO
solution at a humus concentration of 10 mg/l and pH 6-8. The dominant size fractions of Am in the presence of the HA were 450nm - 100k Daltons and 100k - 30k Daltons. On the other hand, Am was presented in the size of 30k - 10k Daltons in the FL. These results indicate that characteristics of size-fractionated humic acids are related association properties with Am.
Ishida, Keisuke*; Kimura, Takaumi; Saito, Takumi*; Toraishi, Takashi*; Tanaka, Satoru*
no journal, ,
no abstracts in English
