酸改性凹凸棒土去除水中六价铬的改性条件研究

为了考察酸改性后的凹凸棒土吸附污水中重金属离子的效能,选取水中毒性强、风险高的Cr(Ⅵ)作为目标物,研究了不同改性条件对Cr(Ⅵ)吸附的影响规律。通过X射线衍射(XRD)和扫描电镜(SEM)对改性前后的结构进行表征,结果表明,改性后的凹凸棒土分散性好、杂质减少、比表面积增大,但内部结构并没有发生改变;改性凹凸棒土对Cr(Ⅵ)的吸附实验表明,吸附速率很快,120min基本达到吸附平衡,与未经改性的凹凸棒土去除效果相比,经酸改性的凹凸棒土的吸附能力显著提高。并在盐酸浓度为4mol/L,改性时间为5h,改性温度为40℃时,改性效果达到最佳。此外,分析了改性凹凸棒土吸附性能提高的原因:形貌的变化加强了对目标物的吸附作用;无机阴离子的引入与目标物发生反应。

Modification Condition of the Removal of Cr(VI) in Solution by Acid-modified Attapulgite

In order to investigate the efficiency of acid-modified attapulgite in adsorbing pollutants, Cr(Ⅵ) with high water toxicity and high risk was selected as the target pollutant to study the influence of different modification conditions on the adsorption of Cr(Ⅵ). The structure of the modified attapulgite was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the modified attapulgite had good dispersion, reduced impurities and increased specific surface area, but the internal structure did not change. Adsorption experiment of modified attapulgite for Cr(Ⅵ) showed that the adsorption rate was very fast, adsorption equilibrium was achieved after 120 min and compared with the unmodified attapulgite, the adsorption capacity of acid-modified attapulgite was significantly improved. When the concentration of hydrochloric acid was 4 mol/ L, the modification time was 5 h, and the modification temperature was 40 ℃, the modification effect reached the best. In addition, the reason of improving adsorption property of modified attapulgite was analyzed and it was shown that the adsorption of the target was enhanced by the morphological changes and the introduction of inorganic anions reacted with the target.