高炉渣对废水中砷和汞竞争吸附的初步研究

Competitive adsorption of arsenic and mercury in wastewater by blast furnace slag

目的研究高炉渣对废水中砷和汞的单组分吸附行为和双组分竞争吸附行为。方法采用静态吸附实验方法,研究了其在不同吸附时间（0～24 h）、不同砷和汞的初始浓度（5～80 mg/L）、不同初始p H（3～12）和不同温度（15～55℃）下对砷和汞的单组分吸附效果,并对吸附动力学和吸附等温线数据进行了拟合,同时探讨了在双组分体系中砷和汞的竞争吸附和偏好吸附。结果单组分体系中,在最佳条件（温度25℃、吸附时间8 h、砷和汞的初始浓度为10 mg/L）下,高炉渣对废水中砷和汞的吸附量分别达到476.7 mg/kg和285.2 mg/kg,去除率分别为95.34%和57.03%。准一级动力学模型能够较好地描述高炉渣对砷和汞吸附过程（R2〉0.99）。高炉渣对废水中砷和汞的吸附平衡数据符合Langmuir等温方程式。双组分体系中,汞对砷的吸附略有促进作用,砷对汞的吸附起到抑制作用,表明高炉渣对砷的选择吸附性更高。结论高炉渣可以较好地去除单组分和双组分体系中的砷和汞。

Objective To explore the adsorption behavior of arsenic and mercury in wastewater by the blast furnace slag both in single component system and two competitive system. Methods By static adsorption experiments,the effects of different adsorption time（0-24 h）,initial concentration of arsenic and mercury（5-80 mg/L）,initial p H value（3-12） and the reaction temperature（15-55 ℃） on arsenic and mercury adsorption in single component were studied,the adsorption kinetics and the adsorption isotherm data were fitted,and the competitive adsorption and preference adsorption of arsenic and mercury in the two-component system was discussed. Results In the single component system,the adsorption capacity of arsenic and mercury in the wastewater with the blast furnace slag were 476.7 mg/kg and 285.2 mg/kg,respectively,and the removal rate were95.34% and 57.03%,respectively. The pseudo first order kinetic model could well describe the adsorption process of arsenic and mercury onto the blast furnace slag（R2〉0.99）. The adsorption equilibrium data of arsenic and mercury in wastewater with the blast furnace slag was in accordance with the Langmuir equation. In the two-component system,the adsorption of arsenic was slightly promoted by mercury,while the adsorption of mercury was inhibited by arsenic. The adsorption choice of arsenic by blast furnace slag was higher. Conclusion Arsenic and mercury can be well removed by blast furnace slag in both single component system and two-component system.