Abstract Iron oxides in general and especially hematite, α-Fe2O3 have been proved promising materials for efficient removal of various organic pollutants. Herein, we report a successful preparation of hematite (α-Fe2O3) by a facile precipitation method and its potential application in the removal of phenol from wastewater. The prepared material was subjected to extensive characterization using a variety of techniques such as scanning electron microscope coupled with energy-dispersive X-ray spectroscopy (SEM/EDX), X-ray diffraction (XRD), and the Brunauer Emmett Teller (BET) method. The operating conditions were optimized to improve the adsorption process efficiently. The adsorption analysis showed an adsorption capacity of 16.17 mg g−1 towards phenol at 30 °C. The reaction kinetics and potential rate-limiting steps were studied by Lagergren's pseudo-first-order and pseudo-second-order models, and it was found that the pseudo-second-order accurately described the adsorption kinetics. Freundlich and Langmuir adsorption isotherms models were applied, and the quality of the fittings clearly shows that the Langmuir model well describes the phenol adsorption on the hematite. The interaction mechanism between phenol and α-Fe2O3(0 0 1) surface was further addressed by Density Functional Theory (DFT) calculations and molecular dynamics (MD) simulations. Experimental and theoretical results indicate that there is strong evidence for the decisive effect of π–π interactions and H-bonds on the adsorption capacity.

中文翻译：

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赤铁矿 (α-Fe2O3) 吸附去除水溶液中的苯酚：实验和理论研究的机理探索

摘要 铁氧化物，尤其是赤铁矿，α-Fe2O3 已被证明是有效去除各种有机污染物的有前途的材料。在此，我们报告了通过简便的沉淀法成功制备赤铁矿 (α-Fe2O3) 及其在去除废水中苯酚方面的潜在应用。使用各种技术对制备的材料进行了广泛的表征，例如扫描电子显微镜与能量色散 X 射线光谱 (SEM/EDX)、X 射线衍射 (XRD) 和 Brunauer Emmett Teller (BET) 方法相结合. 优化操作条件以有效地改进吸附过程。吸附分析表明，在 30 °C 下对苯酚的吸附容量为 16.17 mg g-1。Lagergren' 研究了反应动力学和潜在的限速步骤 s 准一级和准二级模型，发现准二级准确地描述了吸附动力学。应用了 Freundlich 和 Langmuir 吸附等温线模型，拟合的质量清楚地表明，Langmuir 模型很好地描述了赤铁矿上的苯酚吸附。通过密度泛函理论 (DFT) 计算和分子动力学 (MD) 模拟进一步解决了苯酚和 α-Fe2O3(0 0 1) 表面之间的相互作用机制。实验和理论结果表明，有强有力的证据表明 π-π 相互作用和氢键对吸附容量的决定性影响。应用了 Freundlich 和 Langmuir 吸附等温线模型，拟合的质量清楚地表明，Langmuir 模型很好地描述了赤铁矿上的苯酚吸附。通过密度泛函理论 (DFT) 计算和分子动力学 (MD) 模拟进一步解决了苯酚和 α-Fe2O3(0 0 1) 表面之间的相互作用机制。实验和理论结果表明，有强有力的证据表明 π-π 相互作用和氢键对吸附容量的决定性影响。应用了 Freundlich 和 Langmuir 吸附等温线模型，拟合的质量清楚地表明，Langmuir 模型很好地描述了赤铁矿上的苯酚吸附。通过密度泛函理论 (DFT) 计算和分子动力学 (MD) 模拟进一步解决了苯酚和 α-Fe2O3(0 0 1) 表面之间的相互作用机制。实验和理论结果表明，有强有力的证据表明 π-π 相互作用和 H 键对吸附容量的决定性影响。