Abstract Selective removal of petroleum hydrocarbons (PHCs) from soil washing effluents is the key to the surfactant-enhanced soil washing technology. In this study, the diatomite was modified by nonionic surfactant TX-100 and applied in the selective adsorption of PHCs in the soil washing effluents. The modified diatomites were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, N2 adsorption/desorption and X-ray photoelectron spectroscopy respectively. The adsorption process followed the pseudo-second-order model and the adsorption isotherms indicated that the interaction between PHCs and modified diatomite was monolayer adsorption. The important operating factors such as TX-100 dosage, adsorbent dosage, time and temperature were optimized. With the participation of the low-cost adsorbent TX3-Db with high adsorption capacity, the recovery efficiency of the washing effluents was still up to 78.9% after three cycles. A selective adsorption mechanism, based on steric hindrance and electrostatic repulsion, was proposed to explain the removal of PHCs from washing effluents.

中文翻译：

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改性硅藻土选择性吸附PHC及洗涤废水再生

摘要从土壤冲洗废水中选择性去除石油烃（PHCs）是表面活性剂增强土壤冲洗技术的关键。本研究采用非离子表面活性剂TX-100对硅藻土进行改性，并将其应用于土壤冲洗废水中PHCs的选择性吸附。分别采用扫描电镜、傅里叶变换红外光谱、X射线衍射、N2吸附/脱附和X射线光电子能谱对改性硅藻土进行了表征。吸附过程遵循准二阶模型，吸附等温线表明PHCs与改性硅藻土之间的相互作用为单层吸附。对TX-100用量、吸附剂用量、时间和温度等重要操作因素进行了优化。在低成本、高吸附容量的吸附剂TX3-Db的参与下，洗涤废水经过3个循环后的回收率仍高达78.9%。提出了一种基于空间位阻和静电排斥的选择性吸附机制来解释洗涤废水中 PHC 的去除。