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采用X射线衍射(XRD),傅立叶红外光谱(FT-IR)和魔角旋转核磁共振波谱(27Al-MASNMR)研究了在不同碱化度(R=OH/Al)下合成的Al胶体的结构.结果表明:在不同碱化度(R=2.6,2.7,2.8,2.9,3.0)下合成的新鲜Al胶体具有无定形性质,红外光谱中725 cm-1处(Al-O)Td键和核磁共振中6.3×10-5化学位移处的Al(O)4信号峰同时证明不同碱化度Al胶体和Al13溶液一样具有特殊的Keggin结构;红外光谱中(Al-O)Td强度随碱化度的增加而增强,表明高碱化度Al胶体(R=3.0)具有更多的Keggin结构;红外光谱中分为位于622 cm-1和550cm-1处(Al-O)oh和(Al-OH2)oh键的减少和消失表明高碱化度Al胶体(R=3.0)胶体中Keggin结构聚合程度更高;由于Keggin结构具有较高的正电荷数,高碱化度胶体具有更高的吸附性能.
The structures of Al colloids synthesized at different alkalization degree (R = OH / Al) were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and magic angle rotatory nuclear magnetic resonance spectroscopy (27Al-MASNMR). The results show that the amorphous Al colloid synthesized at different alkalization degree (R = 2.6, 2.7, 2.8, 2.9, 3.0) has amorphous character. The 725 cm-1 Al-O bond and the nuclear magnetic resonance The Al (O) 4 signal peak at 6.3 × 10-5 chemical shifts also shows that the Al colloid has the same Keggin structure as the Al13 solution. The intensity of (Al-O) Td in the infrared spectrum varies with the degree of alkalization (Al-O) oh and (Al-OH2) at 622 cm-1 and 550 cm-1 in the IR spectra. The decrease and disappearance of the oh bond indicate that the degree of Keggin structure polymerization in the highly alkalized Al colloid (R = 3.0) colloids is higher; the higher alkalinity colloid has higher adsorption properties due to the higher positive charge number of the Keggin structure.