| Phosphorus?P?is an essential nutrient for plant growth and is also the main cause of water eutrophication.Organic phosphates,especially myo-inositol hexakisphosphate,are important components of P pool in the environment.Adsorption and desorption reactions on soil and mineral surface impact the transport,transformation and bioavailability of organic phosphate.The aim of this study was to investigate the effects of humus acid?humic acid,HA,and fulvic acid,FA?on organic phosphates?glycerophosphate,GP;adenosine triphosphate,ATP;and myo-inositol hexakisphosphate,IHP?adsorption-desorption on boehmite-water interface under different conditions pH and concentration)by batch experiments.The effect of FA on IHP adsorption characteristics and mechanism on hematite was investigated using batch experiments and in situ attenuated total reflectance Fourier transform infrared spectroscopy?ATR-FTIR?.The main results are described as follows:?1?HA inhibits the adsorption of Pi,GP,ATP and IHP,and the inhibition effect increases with increasing HA concentration.?2?The adsorption of IHP is inhibited by organic acid molecules,among which FA has the strongest inhibiting effect,followed by HA,and the inhibition of citric acid is weak.?3?The inhibiting effect of HA on organic phosphates is in the following order:GP?72.58%?>ATP?36.15%?>IHP?31.58%?.?4?HA has the inhibition effect on Pi and IHP sorption on boehmite under different pH conditions.The inhibition decreases with increasing pH.?5?The desorption of Pi by HA and KCl is stronger than the desorption of IHP.The desorption of Pi/IHP by HA is more significantly than by KCl.?6?In-situ ATR studies show that IHP and FA exist competitive adsorption on hematite.?7?The adsorption rate and amount of FA is much greater when IHP and FA added simultaneously than that when IHP is added before HA.The addition of FA leads to the peak shift of the IHP complex.?8?The addition of Ca2+can promote the re-adsorption of IHP and FA after adsorption saturation on hematite. |
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