高炉渣制备Ca-Mg-A1类水滑石吸附水中Cr(Ⅵ)

Adsorption of Cr(Ⅵ) from Aqueous Solution on Ca/Mg/A1 Hydrotalcite Prepared by Blast Furnace Slag

以高炉渣为原料,通过酸浸取-除铁-共沉淀工艺制备了类水滑石介孔材料Ca-Mg-A1/LDH,并对其进行了表征,考察了对水中Cr(Ⅵ)的去除性能。结果表明,Ca-Mg-A1/LDH具有良好的结晶度,比表面积达87.98 m2/g。在30℃、初始Cr(Ⅵ)的质量浓度为20 mg/L、初始pH为2、吸附剂用量1 g/L的静态吸附条件下,Ca-Mg-A1/LDH对Cr(Ⅵ)吸附量为19.0 mg/g,Cr(Ⅵ)去除率为95.0%。Ca-Mg-A1/LDH对Cr(Ⅵ)的吸附过程更符合准2级动力学方程,属于Langmuir单分子层吸附。Ca-Mg-A1/LDH对模拟工业废水中Ni(Ⅱ)、Cu(Ⅱ)、Cr(Ⅵ)的吸附容量分别可达14.0、19.2、23.0mg/g,且吸附过程同时符合Thomos模型和Yoon-Nelson模型。

Ca-Mg-A1/LDH hydrotalcite-like mesoporous material was prepared by acid-leaching/iron recovery/co-precipitation process,and blast frunace slag as the raw material.The product was characterized,and the performance for Cr(Ⅵ)removal in aqueous solution was investigated.The results showed that,Ca-Mg-A1/LDH had good crystallinity and BET surface area reached 87.98 m2/g.Cr(Ⅵ)adsorption quantity on Ca-Mg-A1/LDH reached to 19.0 mg/g with Cr(Ⅵ)removal rate of 95.0%in static adsorption experiment under conditions of 30℃,initial mass concentration of Cr(Ⅵ)was 20 mg/L,pH of 2,and adsorbent dosage of 1 g/L.Cr(Ⅵ)adsorption on Ca-Mg-A1/LDH followed the pseudo second order kinetic model and Langmuir monolayer adsorption model.The adsorption capacity of Ca-Mg-A1/LDH for Ni(Ⅱ),Cu(Ⅱ)and Cr(Ⅵ)reached to 14.0,19.2 and 23.0 mg/g,respectively,and the adsorption process conformed to both Thomas model and Yoon-Nelson model.