生物炭对西北黄土吸附壬基酚的影响

发布时间：2018-07-28 18:09

【摘要】：以壬基酚(nonylphenol,NP)为目标污染物,采用批量实验法研究其在添加不同温度制备的小麦秸秆生物炭的黄土中的吸附动力学、吸附热力学,以及粒径、pH等影响因素.结果表明,不添加生物炭黄土吸附NP的快反应时间为10 h,而加入生物炭后,黄土对NP吸附的快反应时间缩短,为6 h;且快反应阶段添加生物炭黄土明显比不添加生物炭黄土对NP的吸附量多,但碳化温度不同的生物炭在此阶段吸附量差别较小.黄土和添加生物炭黄土对NP的吸附平衡时间均为16 h且符合准二级动力学模型.无论是否添加生物炭,NP在黄土上的热力学吸附过程都较好地符合Freundlich等温吸附模型,符合L-型吸附等温模式;随着系统温度的升高,黄土和添加生物炭的黄土对NP的饱和吸附量都呈增大趋势;NP的吸附自由能ΔGθ0,焓变ΔHθ0,熵变ΔSθ0,表明此吸附是一个自发吸热且混乱程度增大的吸附过程.在同一温度下,随着生物炭碳化温度的升高,NP在添加生物炭黄土中的吸附量逐渐增大.添加生物炭黄土的粒径越小,对NP的吸附量越大.pH值为4~7时,添加生物炭黄土吸附量随pH值的增大而增加;pH为7~10时,吸附量又随pH值增大而减小;表明添加生物炭黄土在中性范围内对NP的吸附效果最好,酸性和碱性都不利于NP的吸附.
[Abstract]:The adsorption kinetics, adsorption thermodynamics and particle size pH of nonylphenolphenol (NP) in loess prepared by adding wheat straw biochar at different temperatures were studied by batch experiment. The results showed that the rapid reaction time of NP adsorption on loess without adding biochar was 10 h, but the fast reaction time of NP adsorption on loess was shortened after adding biochar. The amount of NP adsorbed by biochar loess was significantly higher than that without adding biochar loess at the rapid reaction stage, but the adsorption capacity of biochar at different carbonization temperature was smaller. The adsorption equilibrium time of NP on loess and biochar loess is 16 h and accords with the quasi-second-order kinetic model. The thermodynamic adsorption process of biochar NP on loess is in accordance with the Freundlich isotherm model and the L- type adsorption isotherm model with the increase of system temperature. The saturated adsorption capacity of NP on loess and loess with biochar is increasing. The adsorption free energy 螖 G 胃 0, enthalpy change 螖 H 胃 0 and entropy change 螖 S 胃 0 of NP are increased, which indicates that the adsorption is a spontaneous endothermic adsorption process with increasing degree of confusion. At the same temperature, with the increase of carbon carbonization temperature, the adsorption capacity of NP in the added biochar loess increased gradually. The smaller the particle size of biochar loess is, the larger the adsorption capacity of NP is. The pH value is 4 ~ 7, the adsorption capacity of added biochar loess increases with the increase of pH value, the pH is 7 ~ 10:00, and the adsorption capacity decreases with the increase of pH value. The results showed that biochar loess had the best adsorption effect on NP in neutral range, acid and alkalinity were unfavorable to the adsorption of NP.
【作者单位】：兰州交通大学环境与市政工程学院;兰州文理学院化工学院;
【基金】：国家自然科学基金项目(41363008;21067005;41272147)
【分类号】：X505;O647.3

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