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Coal burning emits a significant amount of elemental mercury (Hgo) into the atmosphere, which can cause severe damage to the environment and human health. Here, magnetic FeS2 nanorods are facilely obtained via a low-temperature (200–350 °C) molten salt (KSCN) route. The annealing temperature is found to notably affect the structure and Hgo capture performance of FeS2, while precursors exert subtle effects on the mercury adsorption performance. The Hgo capture ability of FeS2 first increases and then decreases with increasing annealing temperature. The highest magnetism (12 emu/g) and optimal mercury capture performance (Hgo removal efficiency of 96.2%) are achieved over FeS2 nanorods synthesized at 250 °C. This material shows superior performance in the temperature range of 60–180 °C owing to its rod-like structure with ample number of exposed adsorption sites. NO and SO2 are found to only slightly intervene in the mercury removal process. Hgo vapor first adsorbs on the FeS2 surface via physical adsorption followed by conversion into mercury sulfide (HgS) and mercury oxide (HgO) by the oxidation of disulfide ions (S22–) and chemisorbed oxygen (O*) species, respectively. [ABSTRACT FROM AUTHOR]

A SnS 2 @Fe 3 O 4 composite has been easily synthesized via a KSCN fused salt approach and adopted for capturing elemental mercury at low temperature. Calcination temperature significantly impacts the mercury capture performance of SnS 2 -T. The optimal synthesis temperature for SnS 2 -T is 250 °C. Pristine SnS 2 -250 obtained at 250 °C exhibits a moderate Hg0 adsorption capability with mercury removing efficiency less than 65% within 80–120 °C. Fe 3 O 4 incorporation can notably improve the mercury capture ability of SnS 2 -250 probably due to the cooperative effect between SnS 2 nanoflakes and magnetic Fe 3 O 4 microspheres. SnS 2 -250@Fe 3 O 4 holds a good magnetism (saturation magnetization: 23 emu/g), which performs optimally at 100 °C with Hg0 capture efficiency of 95.2%. Sn4+, S2−, Fe3+ ions and chemisorbed oxygen species are principal active sites for Hg0 capture over SnS 2 -250@Fe 3 O 4 , which convert adsorbed Hg0 into HgO, HgS, and HgSO 4. • A SnS 2 @Fe 3 O 4 composite has been facilely obtained via a KSCN molten salt method. • Calcination temperature can notably influence the Hg0 capture performance of SnS 2. • SnS 2 nanoflakes and Fe 3 O 4 microspheres may show a synergy toward Hg0 capture. • Fe 3 O 4 addition can evidently enhance the mercury capture ability of tin disulfide. [ABSTRACT FROM AUTHOR]

[Display omitted] • The different morphologies of BiOI and Bi modified Bi 4 O 5 I 2 catalysts were successfully synthesized by three methods. • The synergistic effect of oxygen vacancies and built-in electric field promotes the separation of photogenerated electron-holes. • The 3D Bi/Bi 4 O 5 I 2 microspheres with rich oxygen vacancies exhibits an excellent photocatalytic activity and durability. • Possible photo-induced charges transfer mechanism and photocatalytic reaction mechanism were proposed. A 3D hierarchical metallic Bi modified Bi 4 O 5 I 2 microspheres with rich oxygen vacancies (Vos) was successfully prepared via a one-pot solvothermal method. In this work, the different morphologies of BiOI and Bi modified Bi 4 O 5 I 2 were prepared by precipitation, hydrothermal and solvothermal methods. It was discovered that using the solvothermal method with ethylene glycol as the solvent could not only prepare microspheres Bi 4 O 5 I 2 with rich oxygen vacancies but also control the content of Bi by changing the reaction duration. The doping of metallic Bi created a built-in electric field between Bi and Bi 4 O 5 I 2 , which is helpful to improve the efficiency of carrier separation. Benefited from the synergistic effect of oxygen vacancies and built-in electric field, the as-prepared Bi/Bi 4 O 5 I 2 exhibits an excellent mercury removal efficiency, high-performance stability, and satisfactory sulfur resistance as well as nitric oxide resistance. Finally, the mechanism of catalytic oxidation reaction was proposed, photo-generated holes and superoxide radicals were predominant in the photocatalytic reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carbon nitride microsphere (CNS) is synthesized via a hydrothermal method. • Heterojunction interface between CNS and CeO 2 activate Hg0 adsorption process. • DFT guided design of microstructure is used to construct efficient mercury sorbents. • Hg0 is chemically adsorbed on the heterojunction interface of CeO 2 /CNS sorbent. Engineering sorbent microstructure to regulate their interfacial activity is a promising strategy for enhancing mercury adsorption activity. In this work, carbon nitride microsphere (CNS) synthesized via a hydrothermal route is used for Hg0 adsorption. Bare CNS shows a moderate Hg0 capture performance with mercury removal efficiency of 43.1%. To accomplish effective mercury capture by CNS, the heterojunction structure is rationally developed via density functional theory (DFT). Calculation results reveal a considerable charge interaction at the heterojunction interface of CNS and CeO 2. Mercury adsorption energy at the heterojunction interface is significantly higher than that of pristine CNS. x CeO 2 /CNS composites are prepared by wetness impregnation method under the guidance of DFT results. Optimal performance is observed over 5CeO 2 /CNS with Hg0 removal efficiency of 98.3%, which testifies that constructing a heterojunction interface can distinctly enhance the mercury capture ability of CNS. These results contribute a lot to the deep understanding of the structural properties and mercury adsorption behaviors of x CeO 2 /CNS composites, which also indicate that DFT-assisted design of the microstructures of sorbents is a feasible way to improve their mercury removal performances. [ABSTRACT FROM AUTHOR]