Abstract To improve the hydrophobic property of iron nanoparticle (INP) coated on palygorskite (P), cationic surfactant cetyltrimethyl ammonium bromide (CTMAB) was used to modify its surface properties through ion exchange. The structure of the composited P-INP/CTMAB was characterized by various analytical methods. The results showed that the long chain of CTMAB was coated on the surface of P-INP without intercalation effect. The morphology of P-INP was thus not obviously changed after the modification, but the special specific surface area increased from 30.63 m2 g− 1 to 127.04 m2 g− 1. The decoloration and degradation efficiency of P-INP/CTMAB towards acid orange 7 (AO7) was examined under different pH value, temperature and dosage conditions. The results showed that the reaction was preferred to the acidic environment and its first-order reaction rate constant (kobs) linearly depended on the dosage. With suitable conditions, the removal rate of AO7 and total organic carbon (TOC) by P-INP/CTMAB reached about 98.4% and 59.21% after 2 h, respectively. These values were both higher than that of the unmodified composition P-INP, suggesting the synergistic effects in surface adsorption and the following removal reaction. The degradation intermediate products were investigated using HPLC-MS, and the potential degradation pathway of AO7 by P-INP/CTMAB was determined.

中文翻译：

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坡缕石负载表面活性剂修饰的铁纳米颗粒去除酸性橙7：反应性和机理

摘要 为了提高包覆在坡缕石（P）上的铁纳米颗粒（INP）的疏水性，使用阳离子表面活性剂十六烷基三甲基溴化铵（CTMAB）通过离子交换改性其表面性质。复合 P-INP/CTMAB 的结构通过各种分析方法进行表征。结果表明，CTMAB的长链包覆在P-INP表面，无插层效应。因此改性后P-INP的形貌没有明显变化，但比表面积从30.63 m2 g− 1增加到127.04 m2 g− 1。 P-INP/CTMAB对酸性橙7的脱色降解效率(AO7) 在不同的 pH 值、温度和剂量条件下进行检测。结果表明，该反应优于酸性环境，其一级反应速率常数（kobs）与投加量呈线性关系。在合适的条件下，2h后P-INP/CTMAB对AO7和总有机碳（TOC）的去除率分别达到98.4%和59.21%左右。这些值均高于未改性组合物 P-INP 的值，表明在表面吸附和随后的去除反应中具有协同作用。使用 HPLC-MS 研究降解中间产物，并确定 P-INP/CTMAB 对 AO7 的潜在降解途径。这些值均高于未改性组合物 P-INP 的值，表明在表面吸附和随后的去除反应中具有协同作用。使用 HPLC-MS 研究降解中间产物，并确定 P-INP/CTMAB 对 AO7 的潜在降解途径。这些值均高于未改性组合物 P-INP 的值，表明在表面吸附和随后的去除反应中具有协同作用。使用 HPLC-MS 研究降解中间产物，并确定 P-INP/CTMAB 对 AO7 的潜在降解途径。