The study of competitive sorption of inositol hexaphosphate and orthophosphate by several soils from Taiwan

• Main Authors: Yi-Fang Hung, 洪逸芳
• Other Authors: 何聖賓
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/18166916391789313853

碩士 === 國立臺灣大學 === 農業化學研究所 === 93 === The sorption of inorganic orthophosphate (Pi) and inositol hexaphosphate (IHP) on twelve surface soils from arable land in Taiwan was studied in this thesis. Emphasis was laid on the competitive sorption between these two phosphates. The sorption of Pi on most of soils was nearly complete after 50 hours and the subsequent sorption experiments were done in this period. Sorption isotherms for Pi in soils could be well described by the Langmuir equation. The sorption maxima obtained by nonlinear curve fitting to Langmuir equation were shown to correlate significantly with the soil pH, CBD-extractable iron and aluminum, and oxalate extractable aluminum. The sorption of Pi on acid soils was shown to decrease with the increase of solution pH in the ranges of pH 4 to pH 10. However, the sorption of Pi on calcareous soils was shown to decrease with the increase of solution pH from pH 5 to pH 7 and then to increase with the increase of solution pH above pH 7. The sorption amounts of IHP on neutral and alkaline soils were extremely high and might involve the precipitation of calcium-IHP. Sorption isotherms for IHP in soils after displacing with sodium perchlorate solution could be described fairly well by the Langmuir equation and the obtained sorption maxima were shown to correlate significantly only with the CBD-extractable iron and oxalate extractable aluminum. The sorption maxima of IHP on soils were generally higher than those of Pi. The effect of pH on the sorption of IHP on soils was similar to those of Pi. The IHP depressed the sorption of Pi. The sorption sites were apparently the same for the two phosphates. The significance of this phenomenon still need further studies.