镁铝层状超分子化合物去除废水中的六价铬

doi:10.11944/j.issn.1000-0518.2017.01.160115

摘要/Abstract

摘要：

实验比较了Na₂CO₃/NaOH、NaOH和NH₄OH沉淀法制备的镁铝层状化合物对模拟废水中Cr(Ⅵ)的去除效果,并通过X射线衍射和Brunauer-Emmett-Teller(BET)方法分析了材料的结构特征。结果表明,以Na₂CO₃/NaOH为沉淀剂制备的镁铝层状化合物结晶度高、层状结构完整、比表面积较大、孔径适宜、吸附Cr(Ⅵ)的效果最佳,其优化吸附工艺为:固液比为1 g/500 mL,体系pH值为7~9,室温下震荡9 h。在最佳吸附条件下,镁铝层状化合物对Cr(Ⅵ)的饱和吸附量达到199.4 mg/g。镁铝层状化合物通过与含铬阴离子形成层状超分子化合物的方式实现了废水中铬的去除,对含Cr(Ⅵ)226.1 mg/L的实验室废水经6次工艺处理后,残余量小于0.5 mg/L,低于国家污水综合排放标准(GB8978-1996)指标。镁铝层状化合物是一种处理实验室废水中Cr(Ⅵ)的优良吸附剂。

关键词: 镁铝层状超分子化合物, 记忆效应, 实验室废水, Cr(Ⅵ), 去除

Abstract:

Mg/Al layered compounds were prepared by using Na₂CO₃/NaOH, NaOH and NH₄OH as precipitants. Their Cr(Ⅵ) adsorption properties were studied using simulated wastewater containing Cr(Ⅵ). The structures of Mg/Al layered compounds were discussed in combination with X-ray diffraction XRD and Brunauer Emmett Teller(BET) methods surface area experiments. The results show that Mg/Al layered compounds have higher crystallinity, perfect layered structure, larger specific surface area and suitable pore distribution by using Na₂CO₃/NaOH as the precipitator. The optimal absorption efficiency of Cr(Ⅵ) can be reached when pH values are 7.0~9.0, and solid-liquid ratio at room temperature for 9 h is 1 g to 500 mL. The saturated adsorption capacity of Mg/Al layered compounds is 199.4 mg/g under the optimal conditions. The Cr(Ⅵ) in wastewater is removed by forming layered superamolecular compounds between anions containing Cr(Ⅵ) and Mg/Al layered compounds. The remaining Cr(Ⅵ) concentration of laboratory wastewater initially containing 226.1 mg/L is less than 0.5 mg/L after six absorption cycles with Mg/Al layered compounds. The treated wastewater is in line with national sewage comprehensive emission standard(GB8978-1996). Mg/Al layered compounds are excellent absorbents for disposing laboratory wastewater containing Cr(Ⅵ).

Key words: Mg/Al-layered superamolecular compounds, memory effect, laboratory wastewater, Cr(Ⅵ), removal

王雪瑾, 朱霞萍, 蓝路梅. 镁铝层状超分子化合物去除废水中的六价铬[J]. 应用化学, 2017, 34(1): 98-104.

WANG Xuejin, ZHU Xiaping, LAN Lumei. Efficient Removal of Cr(Ⅵ) in Wastewater by Mg/Al Layered Superamolecular Compounds[J]. Chinese Journal of Applied Chemistry, 2017, 34(1): 98-104.

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