基于CTAC改性活性炭的信封式膜包用于水溶液中六价铬去除

Envelope membrane packed with CTAC modified active carbon for Cr(Ⅵ) removal from aqueous solution

以阳离子表面活性剂十六烷基三甲基氯化铵(CTAC)改性粉末椰壳活性炭为载体制备了聚丙烯信封式膜包,用于水溶液中六价铬(Cr(Ⅵ))的吸附去除.对CTAC改性活性炭进行了扫描电镜和红外光谱表征,研究了膜包对水溶液中Cr(Ⅵ)的吸附去除性能.系统考察了改性活性炭的投加量、微孔滤膜的孔径、溶液pH值、吸附温度和吸附时间等因素对吸附效果的影响.实验结果表明,将50 mg改性活性炭包覆在孔径为3.0μm的膜内制成信封式膜包,在25℃条件下对pH值为2的Cr(Ⅵ)溶液吸附3 h,去除效率高于99.0%.室温下(25℃)对Cr(Ⅵ)的静态吸附行为符合Langmuir等温吸附模型,动态吸附过程符合准二级动力学模型.该膜包成功用于3种实际水样中Cr(Ⅵ)的吸附去除.CTAC改性与信封式膜包的结合使用大大简化了操作步骤,降低了成本.该研究有望为污水处理提供潜在、高效的吸附材料和吸附方法.

Polypropylene envelope-type membrane-package was prepared by using cationic surfactant hexadecyl trimethyl ammonium chloride(CTAC) modified coconut-shell activated carbon powder as carrier, and was applied for adsorptive-removal of Cr(Ⅵ) from aqueous solution. The CTAC modified activated carbon was well characterized by scanning electron microscopy and infrared spectra, and the adsorption performances of envelope-type membrane-package towards Cr(Ⅵ) were systematically studied. The influences of main parameters on the adsorption properties were investigated in detail, including the amount of modified activated carbon, pore diameter of microporous filter membrane, solution pH value, adsorption temperature and adsorption time. Accordingly, high removal efficiency above 99.0% was attained, when the membrane-package composed of 50 mg modified activated carbon in a membrane with pore diameter of 3.0 μm was employed to adsorb Cr(Ⅵ) with solution pH of 2 for 3 h at 25 ℃. The static adsorption behavior of Cr(Ⅵ) at room temperature(25 ℃) was well fitted with the Langmuir isothermal adsorption model, and the dynamic adsorption process obeyed the pseudo second-order kinetic model. Furthermore, the membrane-package was successfully applied to adsorptive-removal of Cr(Ⅵ) from three kinds of real water samples. The combined use of CTAC modification and envelope-type membrane-package greatly simplified operation steps and reduced experimental cost. The present study could provide a potential and effective adsorption material and adsorption method for actual sewage treatment.