高锰酸钾改性活性炭的表征及吸附Cr(Ⅵ)性能的研究

Characterization and Cr(Ⅵ) Adsorption Capability of Activated Carbon Modified with KMnO_4

用KMnO_4改性活性炭对重金属离子Cr(Ⅵ)进行吸附。采用扫描电子显微镜(SEM)、傅里叶变换红外光谱仪(FT-IR)、N2吸附/解吸等方法对改性活性炭的理化性质进行表征,探讨各种参数(如pH、接触时间、吸附剂用量、温度和初始浓度)对吸附Cr(Ⅵ)的影响。研究证明,当pH 2时,KMnO_4改性活性炭对重金属离子Cr(Ⅵ)的吸附效果最佳,AC1和AC3吸附率分别达到65%和90%以上,而未改性AC0的吸附率约40%。随着pH的增加,吸附效果变弱。接触时间为4 h时,KMnO_4改性活性炭对重金属离子Cr(Ⅵ)的吸附基本达到平衡,而温度对其影响不大。当改性炭的投加量为50 mg、Cr(Ⅵ)溶液浓度为10 mg/L时,吸附效果最佳,AC3的吸附率可达90%以上,比AC0增加50%以上。改性活性炭吸附Cr(Ⅵ)过程符合准二级动力学方程。

The adsorption capacity of activated carbon modified with potassium permanganate （ KMnO4 ） for Cr（Ⅵ） from aqueous solution was investigated. The modified activated carbon was characterized by scanning electron microscopy（ SEM ）, Fourier trans- form infrared spectrometer （ FT-IR）, and N2 adsorption/desorption tests. The effects of various parameters such as pH, contact time,sorbent dosage,temperature,and initial concentration on the adsorption of Cr（Ⅵ） were determined. The results have shown that when the pH 2 ,the adsorption capacity of activated carbon modified with KMnO4 for heavy metal ions Cr（Ⅵ） from aqueous solution was the best,AC1 and AC3 adsorption rates were 65% and 90% ,AC0 adsorption rate was about 40%. Adsorption was becoming weaker with the increase of pH value. When contact time was 4 h, the adsorption capacity of activated carbon modified with KMnO4 for heavy metal ions Cr（Ⅵ） from aqueous solution was the basic balance,it has little influence on its temperature. When the dosage of modified carbon is 50 mg,Cr（Ⅵ） concentration of 10 mg/L was the adsorption best,AC3 adsorption rate can reach more than 90% , more than 50% increase over AC0. The adsorption process was well fitted to second-order kinetics equation.