Zhang Zhen-Guo, Jiang Yu-Feng, Mu Zhong-Feng, Sun Hang, Zhou Qi, Zhan Hui-Ying
School of Environmental & Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China.
College of Chemical Engineering, Lanzhou University of Arts and Science, Lanzhou 730000, China.
Huan Jing Ke Xue. 2016 Nov 8;37(11):4428-4436. doi: 10.13227/j.hjkx.201604174.
In the present study, nonylphenol (NP) was selected as the target pollutant to investigate the effect of biochar produced from wheat residue at different temperatures on loess soil based on the batch experiments. The research basically included adsorption kinetic, thermodynamic and some influencing factors such as biochar with different pyrolysis temperature, particle size and pH value. The results showed that the adsorption reaction of NP onto loess soil without biochar was 10 h during fast reaction, and after the addition of biochar into loess soil, the fast reaction time of NP adsorption was shortened. Meanwhile, in the fast stage the adsorption reaction of NP onto loess soil with biochar was significantly higher than loess soil without biochar, while the difference of adsorption capacity was small at different carbonization temperatures. The adsorption reaction of NP onto loess soil by adding biochar could be well described by the pseudo-second-order kinetics model and reached equilibrium in 16 h. The kinetic data showed that the adsorption of NP accorded well with the Freundlich isotherm model. The saturated adsorption capacity was improved as temperature increased with or without biochar. Thermodynamic parameter analysis indicated Gibbs free energy Δ<0, entropy Δ>0 and enthalpy Δ>0, demonstrating it was a spontaneous, endothermic and chaos-increasing adsorption process. At the same temperature, the adsorption capacity of NP in loess soils increased dramatically with the increase of carbonization temperature. The smaller particle size of the loess with the addition of biochar, the better the adsorption of NP. When the pH value was 4 to 7, the adsorption capacity of NP onto loess soil by adding biochar showed an increasing trend; in the pH range of 7 to 10, the adsorption saturation capacity decreased with the increase of pH value. Therefore, the adsorption of NP on loess with the addition of biochar had the best adsorption effect in the neutral range. Acid and alkalinity were not conducive to the adsorption of NP.
在本研究中，选择壬基酚（NP）作为目标污染物，基于批次实验研究不同温度下小麦秸秆制备的生物炭对黄土吸附NP的影响。研究内容主要包括吸附动力学、热力学以及一些影响因素，如不同热解温度的生物炭、粒径和pH值。结果表明，未添加生物炭的黄土对NP的快速吸附反应时间为10小时，向黄土中添加生物炭后，NP的快速吸附反应时间缩短。同时，在快速吸附阶段，添加生物炭的黄土对NP的吸附反应明显高于未添加生物炭的黄土，而不同碳化温度下吸附量差异较小。添加生物炭后黄土对NP的吸附反应可用准二级动力学模型很好地描述，并在16小时达到平衡。动力学数据表明，NP的吸附符合Freundlich等温线模型。无论有无生物炭，饱和吸附量均随温度升高而提高。热力学参数分析表明吉布斯自由能Δ<0、熵Δ>0、焓Δ>0，表明该吸附过程是自发、吸热且熵增的过程。在相同温度下，添加生物炭的黄土对NP的吸附量随碳化温度升高而显著增加。添加生物炭的黄土粒径越小，对NP的吸附效果越好。当pH值为4至7时，添加生物炭的黄土对NP的吸附量呈增加趋势；在pH值为7至10的范围内，吸附饱和量随pH值升高而降低。因此，添加生物炭的黄土对NP的吸附在中性范围内效果最佳。酸碱度不利于NP的吸附。
