活性炭纤维对废水中Cr(Ⅵ)的吸附性能及再生试验研究

Adsorption and Regeneration of Activated Carbon Fiber for Cr(Ⅵ)in Wastewater

研究了活性炭纤维吸附废水中Cr(Ⅵ)、再生及吸附过程热力学和动力学,并采用傅里叶变换红外光谱仪(FT-IR)和扫描电镜(SEM)对吸附前、后的活性炭纤维进行表征。结果表明:用活性炭纤维吸附Cr(Ⅵ),在废水体积50 mL、pH=2、Cr(Ⅵ)初始质量浓度40 mg/L、吸附时间200 min、吸附剂用量0.5 g条件下,Cr(Ⅵ)吸附去除率为98.81%,Cr(Ⅵ)吸附量为3.95 mg/g;影响吸附过程的最重要因素为吸附剂用量;吸附过程更符合Langmuir等温吸附模型和准二级动力学吸附模型;用0.1 mol/L盐酸溶液对吸附Cr(Ⅵ)后的活性炭纤维进行洗涤、再生,然后重复试验,连续5次吸附后,Cr(Ⅵ)吸附去除率仍维持在91.47%。活性炭纤维表面呈束状结构,束间存在许多凹陷空间,表面主要官能团为—OH、N—H、CO和CC,对Cr(Ⅵ)的吸附主要是化学吸附。

Adsorption and regeneration of activated carbon fiber(ACF)for Cr(Ⅵ)in wastewater,and adsorption thermodynamics and kinetics were studied.The adsorbent was characterized by FT-IR and SEM.The results show that the optimum conditions adsorbing Cr(Ⅵ)are solution pH of 2,adsorption time of 200 minutes,initial Cr(Ⅵ)concentration of 40 mg/L,adsorbent amount of 0.5 g/50 mL.Under the optimum conditions,the adsorption rate and adsorption capacity of activated carbon fiber for Cr(Ⅵ)are 98.81%and 3.95 mg/g,respectively.The adsorbent usage affects adsorption significantly,and the adsorption behavior is more consistent with Langmuir isotherm equation and quasi-second-order kinetic equation.The removal rate of Cr(Ⅵ)is over 91.47%after five cycles of activated carbon fiber regenerating by hydrochloric acid of 0.1 mol/L.A bundle structure occurs the surface of activated carbon fiber and there are many sunk spaces between the bundles.The main functional groups on the surface of activated carbon fiber are—OH,N—H,CO and CC group,which adsorbs Cr(Ⅵ)by mainly chemical adsorption.