酸碱改性活性炭吸附水中乙酰水杨酸的行为与机理

采用硝酸(HNO_3)和氢氧化钠(Na OH)对活性炭表面进行改性,并考察其对乙酰水杨酸(ASP)的吸附性能。借助傅里叶红外光谱(FTIR)和扫描电镜(SEM)对改性活性炭结构特性进行表征,考察孔隙结构和官能团与吸附性能的关系,推断改性活性炭中对ASP起主要作用的官能团是含氧官能团。结果表明,两种改性活性炭对ASP均有良好的吸附效果;与Freundlich方程相比,吸附过程更适合用Langmuir方程来进行描述;也表明了活性炭对ASP的吸附属于单分子层吸附。改性后活性炭的最大吸附量可达到96.129 8 mg/g,且吸附过程更符合二级动力学方程。

the Behaviour and Mechanism of Adsorption toAcetylsalicylicSAcid by Acid and Alkali Modified Activated Carbon

The surface of activated carbon was modified by nitric acid (HNO3) and sodium hydroxide (NaOH), and its adsorption capacity to acetylsalicylicSacid(ASP) was investigated. The structural characteristic was represented via Fourier transform infrared spectroscopy(FTIR) and scanning electron microscopy(SEM) and the relationship between pore structure and functional groups and adsorption capacity were investigated. It was deduced that the oxygen-containing functional groups were the one which plays a dominant role during adsorption to ASP. The results indicated that both modified activated carbon had a good adsorption capacity to acetylsalicylicSacid. Compared with Freundlich equation, the adsorption process could be better described by Langmuir equation. It was also demonstrated that the adsorption to ASP of activated carbon belongs to monomolecular layer adsorption. The maximum adsorption capacity of modified activated carbon could reach 96.1298 mg/g and the adsorption process was better followed with pseudo-second-order kinetic equation.