| 二氧化钛对地下水中砷硅的吸附及再生回用 |
| 摘要点击 1740 全文点击 647 投稿时间：2017-06-13 修订日期：2017-08-11 |
| 查看HTML全文
查看全文 查看/发表评论 下载PDF阅读器 |
| 中文关键词 二氧化钛 砷硅共存 硅聚合体 再生回用 微观机制 |
| 英文关键词 titanium dioxide coexisting arsenic and silicate silicate polymer regeneration and reuse molecular-level study |
|
| 中文摘要 |
| 二氧化钛（TiO2）材料作为性能优异的吸附材料被广泛应用于地下水砷（As）的去除中.结果表明，地下水中共存硅离子（Si）会占据TiO2的吸附位点，从而影响As的吸附及TiO2材料的再生回用.本文通过同步辐射扩展X射线吸收精细结构（EXAFS）研究了Si对As微观吸附机制的影响，表明Si的存在不会影响As在TiO2上的吸附构型.衰减全反射傅里叶变换红外光谱（ATR-FTIR）原位研究表明Si在TiO2表面形成Si单体、低聚体和多聚体，从而竞争As的吸附位点，同时增加TiO2再生的难度.为了实现TiO2材料的高效再生，本研究进一步考察了氟化钠（NaF）对TiO2表面Si的脱附效果，发现NaF可以有效地洗脱Si，再生后的TiO2吸附性能稳定.ATR-FTIR光谱原位分析发现，NaF的加入可有效脱附TiO2表面的Si单体和多聚体.当利用NaF和NaOH共同洗脱TiO2表面的As和Si时，3次循环中As的脱附率为86.8%~100.3%，Si的脱附率为67.9%~82.0%.本研究为地下水砷硅共吸附材料的再生提供了一种有效方法. |
| 英文摘要 |
| Titanium dioxide (TiO2) was widely used to remove arsenic (As) from groundwater due to its excellent properties. Previous studies show that the coexisting silicate ions (Si) could occupy the available surface sites of TiO2 and further inhibit As adsorption and TiO2 regeneration. To investigate the effect of Si adsorption on the As molecular surface structure, an extended X-ray absorption fine structure (EXAFS) analysis was conducted in this work. The results indicated that the presence of Si exhibited no impact on the As adsorption configuration on TiO2. In situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy results demonstrated that the polymerization of Si that formed on the TiO2 surface compete with As adsorption sites, increasing the difficulty for TiO2 regeneration. To effectively regenerate TiO2, the removal efficiency of Si polymers on TiO2 via sodium fluoride (NaF) was studied. The results showed that NaF could remove Si monomer and polymer from TiO2, and the regenerated TiO2 could be reused with a stable adsorption performance. In situ ATR-FTIR spectroscopy suggested that NaF desorbed the Si monomer and polymer effectively. When spent TiO2 was regenerated with NaOH and NaF in three treatment cycles, As and Si desorption rates were 86.8%-100.3% and 67.9%-82.0%, respectively. The present study provides a new insight into regenerating absorbents with coadsorbed As and Si in groundwater. |
