磁性Fe_3O_4/活性炭对电镀废水中Cr(Ⅵ)吸附性能的研究

The Adsorption Property of Magnetic Fe_3O_4/Active Carbon for Cr(Ⅵ) in Electroplating Waste Water

目的获得吸附性能、磁分离性能和再生性能较佳的磁性Fe_3O_4/活性炭吸附剂(MAC)。方法通过化学共沉淀法制备出磁性Fe_3O_4/活性炭吸附剂。采用X-射线衍射仪(XRD)和傅里叶变换红外光谱仪(FTIR)对活性炭进行表征。使用磁性Fe_3O_4/活性炭吸附电镀废水中的Cr(Ⅵ),考察吸附剂用量、吸附pH值和吸附时间对吸附性能的影响,并研究了吸附动力学模型。利用磁铁对磁性Fe_3O_4/活性炭进行了回收。结果制备的磁性Fe_3O_4/活性炭中含有纯度较高的立方相磁性Fe_3O_4粒子。在温度为25℃、pH=3、吸附时间为120 min、吸附剂用量为0.15 g时,对Cr(Ⅵ)的去除率最高,达到了97.44%,吸附动力学符合拟二级动力学模型。电镀废水中共存阳离子会使吸附性能增强,共存阴离子会使吸附性能降低。磁性Fe_3O_4/活性炭的回收率达93.58%,6次解吸-再生后,吸附量仍较高,为27.17 mg/g。结论磁性Fe_3O_4/活性炭吸附剂对电镀废水中的Cr(Ⅵ)具有较高的去除率,吸附剂回收方法简单,回收率高,具有较好的应用前景。

The work aims to obtain magnetic Fe3O4/active carbon with better adsorption capacity, magnetic separation property and regeneration performance. The magnetic Fe3O4/active carbon was prepared by chemical co-precipitation method, and were characterized by X-ray diffraction（XRD） and Fourier transform infrared spectroscopy（FTIR）. The magnetic Fe3O4/active carbon was used to adsorb Cr（VI） in electroplating waste water, and the effects of adsorbent dosage, pH and adsorption time on adsorption property were investigated, and the corresponding adsorption kinetics was researched. Then magnet was used to reclaim the magnetic Fe3O4/active carbon. The magnetic Fe3O4 active carbon contained high purity cubic phase magnetic Fe3O4 particles. The adsorption rate could reach 97.44% under the optimal conditions of dosage 0.15 g, pH=3 and absorption time 120 min at 25 ℃. The absorption kinetics could be described by pseu-do-second-order kinetics model. The co-existing cations could enhance the adsorption capacity, but the co-existing anion might reduce adsorption capacity. The recovery rate of magnetic Fe3O4/active carbon was 93.58% using magnet. Adsorption amount of Cr（VI） was 27.17 mg/L after six successive adsorption-regeneration cycles. the removal rate of Cr（VI） in electroplating waste water is better using magnetic Fe3O4/active carbon as adsorbent. The recovery method is simple and the recovery rate is high, so the adsorbent has a good application prospect.