Unraveling the role of oxygen vacancies in enhancing the SO2-resistance of α-MnO2 towards elemental mercury removal

IF 13.3 1区 工程技术 Q1 ENGINEERING, CHEMICAL
Qian Yu, Fei Lai, Shiwei Sheng, Yujia Wang, Bo Yuan, Dong Fu
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引用次数: 0

Abstract

Enhancing SO2-resistance has long been a persistent challenge for Mn-based catalytic adsorbents in the field of Hg0 removal. Herein, a straightforward strategy is proposed to mitigate SO2 toxicity via regulating oxygen vacancy (Ov) content. Defective α-MnO2 is prepared by impregnation with sodium borohydride, and systematic tests are performed to verify its anti-sulfur performance. Characterizations reveal that the impregnation causes little change in phase composition and intrinsic structure, but have an intuitive impact on surface species and Ov. Experiments confirm that the increased Ov not only increases the removal efficiency by 25 % in a 6 % O2 + 800 ppm SO2 atmosphere, also preserves 5-hour anti-poisoning stability, attributing to the weakened competitive adsorption and less sulfate deposition, due to the accelerated generation and migration of oxidative species, and enhanced oxidation ability. Theoretical calculations clarify: (i) the adsorption energy of SO2 at the same sites is significantly reduced after introducing Ov, weakening the inhibition of SO2; (ii) on defective surface, adsorbed SO3* generated by the reaction of adsorbed oxygen with SO2 is more easily desorbed, preventing sulfate accumulation and maintaining the active sites for Hg0 oxidation. These findings unravel the underlying mechanism by which Ov enhances the SO2-resistance of α-MnO2, offering a practical solution for ameliorating the sulfur tolerance.
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来源期刊
Chemical Engineering Journal
Chemical Engineering Journal 工程技术-工程:化工
CiteScore
21.70
自引率
9.30%
发文量
6781
审稿时长
2.4 months
期刊介绍: The Chemical Engineering Journal is an international research journal that invites contributions of original and novel fundamental research. It aims to provide an international platform for presenting original fundamental research, interpretative reviews, and discussions on new developments in chemical engineering. The journal welcomes papers that describe novel theory and its practical application, as well as those that demonstrate the transfer of techniques from other disciplines. It also welcomes reports on carefully conducted experimental work that is soundly interpreted. The main focus of the journal is on original and rigorous research results that have broad significance. The Catalysis section within the Chemical Engineering Journal focuses specifically on Experimental and Theoretical studies in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. These studies have industrial impact on various sectors such as chemicals, energy, materials, foods, healthcare, and environmental protection.
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