活性炭吸附Cr(Ⅵ)的稳定性评价  

Stability Evaluation of Adsorption of Hexavalent Chromium by Modified Activated Carbons

作　　者：李振昌 毛磊 LI Zhenchang;MAO Lei(Key Laboratory of Hubei Province for Coal Conversion and New Carbon MaterialsWuhan 430081)

机构地区：[1]煤转化与新型炭材料湖北省重点实验室,武汉430081 [2]武汉科技大学化学与化工学院,武汉430081

出　　处：《工业安全与环保》2019年第3期88-92,共5页Industrial Safety and Environmental Protection

基　　金：国家自然科学基金(51204125)

摘　　要：采用热重分析(TG)、X射线光电子能谱(XPS)结合能分析和吸附-解吸过程的专性吸附研究活性炭对Cr(Ⅵ)的吸附稳定性,提出了热脱附活化能、化学结合能变化值和解吸率3种评价指标。结果表明,商品活性炭(AC)、硝酸氧化改性活性炭(OAC)、氨改性活性炭(NAC)和硫改性活性炭(SAC)的热脱附活化能分别为17.75,5.09,25.47和3.93 kJ/mol,活性炭热脱附活化能与活性炭表面官能团的热稳定性相关。计算活性炭吸附Cr(Ⅵ)前后结合能变化值,表明参与吸附的含氧、含硫官能团对Cr(Ⅵ)的化学结合作用较强。AC,OAC,NAC和SAC上Cr(Ⅵ)的解吸率分别为6.38%,0.71%,20.73%和2.13%,说明Cr(Ⅵ)大部分以专性吸附形式结合于活性炭上,含氧与含硫官能团的化学作用能有效增强对Cr(Ⅵ)吸附的稳定性。The adsorption stability of Cr(Ⅵ)on activated carbons was evaluated by thermogravimetric analysis(TG),binding energy analysis with X ray photoelectron spectroscopy(XPS)and the specific adsorption of adsorption-desorption process.Desorption activation energy,chemical binding energy variation,and desorption rate were employed as the evaluation index.The desorption activation energy for commercial activated carbon(AC)and activated carbons modified with HNO 3(OAC),NH 3(NAC)and N 2S(SAC)respectively were 17.75,5.09,25.47 and 3.93 kJ/mol,suggesting that desorption activation energy was related with the thermal stability of surface groups on the activated carbons.The calculated values of chemical binding energy variation after adsorption of Cr(Ⅵ)indicated that the chemical action of the oxygen-containing and sulfur-containing functional groups involved in the adsorption was stronger.It was shown that Cr(Ⅵ)was mostly adsorbed on activated carbons by specific adsorption,for the desorption rate of Cr(Ⅵ)on AC,OAC,NAC and SAC were respectively 6.38%,0.71%,20.73%and 2.13%.The results revealed that the oxygen and sulfur-containing functional groups had greatly enhanced the adsorption stability of Cr(Ⅵ)via chemical adsorption.

关 键 词：活性炭 六价铬 热脱附活化能 结合能 解吸率 稳定 

分 类 号：X703[环境科学与工程—环境工程]