植酸对碳酸盐绿锈转化的影响

为研究植酸（IHP）对绿锈转化过程及机制的影响，通过空气氧化法合成碳酸盐绿锈GR1 （CO₃^2-）]，并利用X射线衍射、衰减全反射-傅里叶变换红外光谱、高分辨透射电子显微镜、扫描电子显微镜和能量色散X射线能谱对体系中的固体产物进行分析表征。研究表明：不存在IHP时GR1（CO₃^2-）在5 h左右完全转化为针铁矿，而存在IHP时GR1（CO₃^2-）的转化会受到抑制。在0~0.5mmol·L^-1的IHP浓度范围内，GR1 （CO₃^2-）的转化产物为针铁矿，而当IHP浓度高于1.0 mmol·L^-1时，GR1 （CO₃^2-）的转化产物为针铁矿和高铁绿锈。IHP对GR1（CO₃^2-）转化机制的影响与其浓度有直接关系，在低浓度IHP（0~0.5 mmol·L^-1）条件下，GR1（CO₃^2-）转化过程只涉及溶解-氧化-沉淀（DOP）机制；而高浓度IHP（1.0~5.0 mmol·L^-1）体系中，固态氧化（SSO）机制占主导地位，在其转化过程中，一部分GR1（CO₃^2-）通过溶解再沉淀机制转化为针铁矿，一部分GR1（CO₃^2-）通过原位脱质子反应转化为高铁绿锈。此外，在GR1 （CO₃^2-）转化过程中，IHP在GR1 （CO₃^2-）及其转化产物表面会形成内圈络合物和植酸（亚）铁沉淀。总体而言，IHP会抑制GR1 （CO₃^2-）的溶解再沉淀转化机制，阻碍针铁矿的结晶和晶体生长，且抑制作用与IHP浓度呈正相关。

Effects of myo-inositol hexakisphosphate on the transformation of carbonate green rust

Green rust exists widely in paddy soil, sediment, groundwater, and other environments, and its transformation is affected by various environmental geochemical factors. Carbonate green rustGR1(CO₃^2-)] was synthesized by air oxidation, and the effect of organic phosphorus(myo-inositol hexakisphosphate, IHP) on the transformation process and mechanism of green rust was investigated. The solid products in the system were characterized by X-ray diffraction, attenuated total reflection Fourier-transform infrared spectroscopy, highresolution transmission electron microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The results showed that GR1(CO₃^2-) was completely converted to goethite in approximately 5 h in the absence of IHP, while the transformation of GR1(CO₃^2-) was inhibited in the presence of IHP. In the presence of 0-0.5 mmol·L^-1 IHP, the transformation product of GR1(CO₃^2-) was goethite, while GR1(CO₃^2-) was transformed into goethite and ferric green rust when the concentration of IHP was above 1.0 mmol·L^-1. The effect of IHP on the conversion mechanism of GR1(CO₃^2-) was directly related to its concentration. In a system with a low concentration of IHP(0-0.5 mmol·L^-1), the conversion process of GR1(CO₃^2-) only involved the dissolution-oxidation-precipitation(DOP) mechanism. However, in a system with a high concentration of IHP(1.0-5.0 mmol·L^-1), the solid-state oxidation(SSO) mechanism dominated, and GR1(CO₃^2-) was partially converted into goethite through a dissolution reprecipitation mechanism, and GR1(CO₃^2-) was partially transformed into ferric green rust via an in situ deprotonation reaction. In addition, during the transformation of GR1(CO₃^2-), IHP formed inner-sphere complexes or(ferro) ferric phytate precipitates on the surface of GR1(CO₃^2-) and its transformation products. Overall, IHP inhibites the dissolutionreprecipitation transformation mechanism of GR1(CO₃^2-) and hinderes the crystallization and crystal growth of goethite, and the inhibition is positively correlated with the concentration of IHP.