Li Kunquan, Zheng Zheng, Huang Xingfa, Zhao Guohua, Feng Jingwei, Zhang Jibiao
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, China.
J Hazard Mater. 2009 Jul 15;166(1):213-20. doi: 10.1016/j.jhazmat.2008.11.007. Epub 2008 Nov 14.
Activated carbon prepared from cotton stalk fibre has been utilized as an adsorbent for the removal of 2-nitroaniline from aqueous solutions. The influence of adsorbent mass, contact time and temperature on the adsorption was investigated by conducting a series of batch adsorption experiments. The equilibrium data at different temperatures were fitted with the Langmuir, Freundlich, Tempkin, Redlich-Peterson and Langmuir-Freundlich models. The Langmuir-Freundlich isotherm was found to best describe the experimental data. The adsorption amount increased with increasing temperature. The maximum adsorption capacity of 2-nitroaniline was found to be 383 mg/g for initial 2-nitroaniline concentration of 200mg/L at 45 degrees C. The kinetic rates were modeled by using the Lagergren-first-order, pseudo-second-order and Elovich models. The pseudo-second-order model was found to explain the adsorption kinetics most effectively. It was also found that the pore diffusion played an important role in the adsorption, and intraparticle diffusion was the rate-limiting step at the first 30 min for the temperatures of 25, 35 and 45 degrees C. FTIR and (13)C NMR study revealed that the amino and isocyanate groups present on the surface of the adsorbent were involved in chemical interaction with 2-nitroaniline. The negative change in free energy (Delta G degrees) and positive change in enthalpy (Delta H degrees) indicated that the adsorption was a spontaneous and endothermic process.
由棉秸秆纤维制备的活性炭已被用作吸附剂，用于从水溶液中去除2-硝基苯胺。通过进行一系列间歇吸附实验，研究了吸附剂质量、接触时间和温度对吸附的影响。将不同温度下的平衡数据与朗缪尔、弗伦德利希、坦普金、雷德利希-彼得森和朗缪尔-弗伦德利希模型进行拟合。发现朗缪尔-弗伦德利希等温线最能描述实验数据。吸附量随温度升高而增加。在45℃下，初始2-硝基苯胺浓度为200mg/L时，2-硝基苯胺的最大吸附容量为383mg/g。采用 Lagergren 一级、准二级和埃洛维奇模型对动力学速率进行建模。发现准二级模型最能有效地解释吸附动力学。还发现孔扩散在吸附中起重要作用，在25、35和45℃温度下，在前30分钟内颗粒内扩散是速率限制步骤。傅里叶变换红外光谱（FTIR）和碳-13核磁共振（¹³C NMR）研究表明，吸附剂表面存在的氨基和异氰酸酯基团与2-硝基苯胺发生了化学相互作用。自由能的负变化（ΔG°）和焓的正变化（ΔH°）表明吸附是一个自发的吸热过程。
