Collection and identification of bioactive organic compounds occurring in natural water

点击翻译按钮获取中文摘要

To develop adsorption collection methods applicable to. bioactive organic compounds occurring and circulating in natural waters, usefulness of hydrous iron oxide (HIO) and its analogous materials as an adsorbent was examined. The outlines and results of the research are as follows. (1)At first, 34 kinds of carboxylic acid and its derivatives were selected as an example of bioactive organic compounds and were tested to be adsorbed onto HIO or not. As the results, those molecules which have more than two HOOC-residues are adsorbed quantitatively onto HIO from solutions with pH 4.0〜5.5. The presence of a HO-residue along with the HOOC-residue facilitated the adsorption, but that of a CI-residue suppressed the adsorption. The effect of the HO- or CI-residue was enhanced when it was located adjacent to the HOOC-residue in the molecule. (2)Similarly, the adsorption behaviors of orthophosphate, tripolyphosphate, pyrophosphate, monomethylphosphate, phosphite, α-and β-glycerophosphates, dimethy … More lphospahte, and hypophosphate on HIO was studied. Orthophosphate was adsorbed quantitatively at pH 4.0〜6.8, triphosphate and pyrophosphate at pH 4〜9.3 and the next three compounds at pH 4〜6.8. The last two compounds were only slightly adsorbed at any pH examined. Then, it was concluded that at least two free P-O terminals in each phosphorus compound are necessary for the adsorption and that the more the P-O terminals, the stronger the adsorption. (3)A selection of sugars including seventeen monosaccharides and sucrose were adsorbed on HIO and hydrous zirconium oxide (HZO) and their strengths of adsorption were compared according to the Langmuir adsorption isotherm. The adsorption selectivity which was observed as the Langmuir constants of "a" and "W" was correlated to the configuration of HO-residues (evaluated as the R value) on each sugar molecule. (4)A silica gel collector modified with HIO was prepared for preconcentrating extremely dilute phosphate and was applied to the determination of orthophosphate-phosphorus at a level of several nM contained in lake and sea water samples. (5)Adsorption of dissolved organic carbon (DOC) onto HIO was also examined as a function of pH. Less