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以天然沸石为基质材料,采用硫酸、氢氧化钠和氯化铁对其改性,对模拟含氟水进行静态吸附试验,研究改性沸石对水中氟离子的吸附性能,探讨并提出了最佳改性条件。对沸石进行比表面积和孔径分布测定,并利用X射线荧光分析沸石改性前后的元素组成及含量变化。结果表明采用氯化铁单独改性效果最好。吸附速率可用拟二级动力学方程描述。氯化铁改性沸石对F-的吸附符合Langmuir吸附等温模式,饱和吸附量为0.087 mg·g-1,较未改性沸石有很大提高,吸附平衡常数为0.28 L·mg-1。改性后沸石的比表面积减小,Fe元素含量增加,Ca2+、Mg2+等离子的含量降低,说明氯化铁改性沸石除氟主要基于化学吸附与复杂的离子交换作用。
Using natural zeolite as matrix material, the modified zeolite was modified with sulfuric acid, sodium hydroxide and ferric chloride, the static adsorption experiment was carried out on the simulated fluorine-containing water to study the adsorption capacity of the modified zeolite to fluoride in water, and the best Modification conditions. The specific surface area and pore size distribution of zeolite were determined. The elemental composition and content of zeolite before and after modification were analyzed by X-ray fluorescence. The results show that the use of ferric chloride alone modified the best. The adsorption rate can be described by pseudo second-order kinetic equation. Ferric chloride modified zeolite adsorbed F- in line with the Langmuir adsorption isotherm model, with a saturated adsorption amount of 0.087 mg · g-1, which was much higher than that of the unmodified zeolite with an adsorption equilibrium constant of 0.28 L · mg-1. After the modification, the specific surface area of zeolite decreases, the content of Fe increases and the content of Ca2 + and Mg2 + decreases. It is indicated that fluoride removal by ferric chloride modified zeolite is mainly based on chemisorption and complex ion exchange.