One-Pot Cation–Anion Double Hydrolysis Derived Ni/ZnO–Al2O3 Absorbent for Reactive Adsorption Desulfurization

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• 作者：Rooh Ullah ; Zhanquan Zhang ; Peng Bai ; Pingping Wu ; Dezhi Han ; U. J. Etim ; Zifeng Yan
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2016
• 出版时间：April 6, 2016
• 年：2016
• 卷：55
• 期：13
• 页码：3751-3758
• 全文大小：676K
• ISSN：1520-5045

文摘

In this study, a series of Ni/ZnO–Al₂O₃ adsorbents were synthesized by a one-pot cation–anion double hydrolysis (CADH) method. The materials were characterized by N₂ sorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet–visible diffuse reflectance spectroscopy (UV–vis), Raman spectroscopy, and H₂ temperature-programmed reduction (H₂-TPR). The reactive adsorption desulfurization (RADS) performance of the adsorbents was evaluated in a fixed bed reactor using thiophene in n-octane as a model fuel. Results showed that the adsorbents exhibited better RADS performance than those prepared using the conventional kneading method. The thiophene conversion and sulfur capacity of adsorbents decreased with increasing the crystallization temperature. Among all tested adsorbents, the Ni/ZnO–Al₂O₃ sample prepared at 28 °C presented the largest adsorption capacity and highest RADS reactivity. Textual characterization results indicated that the sample Ni/ZnO–Al₂O₃(28 °C) possessed relatively bigger pore size and larger pore volume than other samples, which may alleviate the pore shrinkage/blockage during the RADS process. A combination of XRD, UV–vis, and H₂-TPR characterization results demonstrate that a high crystallization temperature favors the growth of inactive ZnAl₂O₄ crystals and induce the formation of more less-reducible Ni²⁺ ion, causing the loss of active ZnO phase and Ni⁰ atoms, which may be the reason for the lower RADS activity of the adsorbent synthesized at higher crystallization temperatures.