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氧化铝对硅酸的吸附去除机理
Adsorptive removal mechanism of alumina on silicic acid
【摘要】 探讨了氧化铝对水体中硅酸的吸附去除潜力、影响因素及机理。结果表明,pH 4~8时吸附量随pH、吸附剂投加量的增大而增加,说明氧化铝具有吸附去除硅酸的能力。吸附过程符合Langmuir吸附等温模式,最大吸附量达39.82 mg/g。结合27Al MAS NMR与SEM-EDX分析,氧化铝吸附硅酸的机理是通过硅酸分子与氧化铝中4配位的铝发生化学反应,硅原子取代原来Al—O—Al键上的铝原子形成Al—O—Si键而被固定在氧化铝表面。
【Abstract】 The adsorptive removal potential,influencing factors and adsorption mechanism of alumina on silicic acid in water were discussed. The results showed that the adsorption amount of silicic acid increased with the increase of pH( in the range of pH 4-8) and dosage of adsorbent,which showed that alumina had the potential ability to remove silicic acid. The adsorption process was well consistent with the Langmuir isotherm model with a maximum adsorption capacity of 39.82 mg/g. According to the results of 27Al MAS NMR and SEM-EDX analysis,the adsorption mechanism of alumina on silicic acid was that the silicic acid molecular reacted with tetra-coordinated aluminum to form Al—O—Si bond by substitution reaction of the aluminum atom by silicon atom on the original Al —O—Al bond and fixed on the surface of the alumina.
【Key words】 alumina; silicic acid; adsorption isotherm model; adsorption mechanism;
- 【文献出处】 工业水处理 ,Industrial Water Treatment , 编辑部邮箱 ,2019年07期
- 【分类号】X52
- 【下载频次】129