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采用X射线衍射分析了煅烧凹凸棒石的水化处理对其结构演化的影响;通过NH3吸附试验表征煅烧凹凸棒石水化处理后表面性质的变化,揭示了凹凸棒石对NH3的吸附机理。结果表明:随着煅烧温度的不断提高,凹凸棒石中的结晶水和结构水逐步脱除,内孔道结构发生折叠塌陷,凹凸棒石的内孔道折叠温度在250～300℃之间,只有低于300℃煅烧的凹凸棒石经过水化处理折叠的内孔道才能恢复。凹凸棒石经过200～300℃煅烧再水化处理,对NH3的吸附量比未处理的凹凸棒石显著增加,尤其是250℃煅烧的凹凸棒石经水化处理后对NH3的吸附量增加了75%,250℃是煅烧凹凸棒石水化处理吸附NH3的最佳温度点。低于300℃煅烧的凹凸棒石水化处理恢复了部分结晶水,推测NH3与这部分结晶水发生了氢键作用,凹凸棒石对NH3的吸附既有外表面吸附,又有内孔道吸附。
The effect of hydration of calcined attapulgite on its structure evolution was analyzed by X-ray diffraction. The surface property of calcined attapulgite after hydration treatment was characterized by NH3 adsorption experiment, and the adsorption mechanism of attapulgite to NH3 was revealed. The results show that with the increase of calcination temperature, the crystal water and structured water in attapulgite are gradually removed, and the inner channel structure collapses and collapses. The folding temperature of the inner channel of attapulgite is between 250 and 300 ℃, and only low The attapulgite calcined at 300 ℃ can be restored by hydration of the folded inner channels. Attapulgite calcined at 200 ~ 300 ℃ rehydration, the adsorption capacity of NH3 significantly increased than the untreated attapulgite, especially the attapulgite calcined at 250 ℃ hydration increased the amount of adsorbed NH3 75%, 250 ℃ is calcination attapulgite hydration adsorption NH3 the best temperature point. Hydration of attapulgite calcined at temperatures below 300 ° C restores part of the water of crystallization, suggesting that hydrogen bonds occur between this portion of NH3 and NH3. Adsorption of NH3 by the attapulgite both has adsorption on the external surface and adsorption on the internal channels.