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Decontamination of Hg0 from coal-fired flue gas remains an enormous challenge. It is an imperative pursuit to design adsorbents bearing an abundance of accessible chelating sites with a high affinity toward mercury, thus achieving both rapid uptake and high capacity for Hg0. Herein, an electrostatically directed assembly strategy was designed to construct Cu 2 Se decorated commercial polyurethane sponge (Cu 2 Se/PUS) as an efficient Hg0 trap. The surface coverage of Cu 2 Se on the Cu 2 Se/PUS can be rationally adjusted by turning the charge density of Cu 2 Se and PUS. The saturated Hg0 adsorption capacity of Cu 2 Se/PUS was achieved at 217.04 mg g−1 (normalized to the Cu 2 Se coating amount), which was much higher than that of powdery Cu 2 Se (43.66 mg g−1). Multiform selenium active sites (Se- and Se2-) and copper-terminated active centers of Cu 2 Se/PUS co-participated in Hg0 adsorption, instead of the individual role of Se- over powdery Cu 2 Se. The macroporous skeleton structure and the highly dispersed Cu 2 Se boosted the diffusion of mercury to the active sites for immobilization, thus accelerating the consumption of multiple active sites on the Cu 2 Se/PUS. This work not only provided an efficient Hg0 trap but also showed great inspiration for the potential of electrostatically directed assembly methods in constructing adsorbents for diverse environmental remediations. [Display omitted] • Integrated macroporous skeleton molding material as an efficient Hg0 trap. • Electrostatically directed assembly strategy was designed to construct Cu 2 Se/PUS. • The Hg0 adsorption capacity of Cu 2 Se/PUS was as high as 217.04 mg g−1. • Se-, Se2- and Cu-terminated centers of Cu 2 Se/PUS co-participated in Hg0 adsorption. [ABSTRACT FROM AUTHOR]

Samples of magnetic iron–manganese binary oxide supported on activated carbon fiber (Fe 3−x Mn x O 4 /CNF) were prepared for Hg 0 removal from flue gas. The results showed that the Hg 0 removal performance of Fe 3−x Mn x O 4 /CNF was significantly promoted with the increase of Mn incorporating content into Fe 3 O 4 spinel structure. The optimal sample of Fe 2 MnO 4 /CNF, at the optimal reaction temperature of 150–200 °C, attained above 90% of Hg 0 removal efficiency (E a ). CNF played an important role in Hg 0 removal by Fe 3−x Mn x O 4 /CNF due to the disperation of Fe 3−x Mn x O 4 particles and the enhancement for electron transfer process. O 2 enhanced the Hg 0 removal via the Mars-Maessen mechanism, and NO improved the Hg 0 removal performance slightly because of the formation of NO 2 . SO 2 and H 2 O played an inhibitive role in Hg 0 removal due to the competition of active sites for Hg 0 adsorption. A mechanism of Hg 0 removal over Fe 3−x Mn x O 4 /CNF is proposed, in which both Mn cations and lattice/chemisorbed oxygen were thought to the active sites for Hg 0 adsorption/oxidation. Further, the spent Fe 3−x Mn x O 4 /CNF could be regenerated with no obvious decrease of Hg 0 removal performance by water washing followed by thermal treatment at 450 °C in N 2 and calcination at 200 °C in air. [ABSTRACT FROM AUTHOR]

The Hg 0 removal capacities of magnetospheres from fly ash collected from different power plants were investigated at a wide temperature range of 100–400 °C. The relationship between Hg 0 removal efficiency ( η T ) and iron content/species of magnetospheres was investigated. The magnetospheres attained the optimal Hg 0 removal capacity at 250 °C. The reaction temperature played an important role in Hg 0 adsorption and oxidation behaviors. At low reaction temperature (100 °C and 150 °C), the adsorption of Hg 0 played a predominant role in Hg 0 removal, while the Hg 0 removal mainly depended on the Hg 0 oxidation capacity at high temperature (200–400 °C). The Hg 0 removal capacity increased with the increase of iron content. The percentage of ferrospinel and hematite in magnetospheres is a key factor for determining the Hg 0 removal capacity as well. Hydrogen fluoride (HF) could remove the glass-phase materials on the magnetospheres and the active iron species embedded in the glass phase could be exposed and accessible. After fluorinated by HF, the Hg 0 removal capacity increased in different degree for different magnetospheres, which depended on the content of active iron species in raw magnetospheres. [ABSTRACT FROM AUTHOR]

Several modified adsorbents were developed by impregnating palygorskite (Pal) with the active substances CuCl 2 , CuBr 2 , NaBr, sulfur (S), MnO 2 and Co 3 O 4 , which were used to conduct experiments via a bench-scale fixed-bed reactor system in simulated flue gas for evaluating their elemental mercury removal capacity. In addition, a variety of characterization methods were applied to understand the physicochemical properties of these adsorbents. Furthermore, adsorbents, namely, CuCl 2 /CuBr 2 -impregnated Pal (Cu-Pal), were chosen for deep exploration under various gas conditions. The results showed that the mercury removal capability of Pal was greatly improved after impregnation. At 120 °C in pure N 2 , the mercury removal efficiency of the adsorbents modified by CuCl 2 and CuBr 2 could reach 90.9% and 95.2%, respectively, while it could be > 80% for the adsorbents modified by the others. The overall trend showed that O 2 and HCl were beneficial to increasing the mercury removal efficiency of Cu-Pal. To be specific, for CuCl 2 -Pal and CuBr 2 -Pal, when adding in 8% O 2 , their efficiencies could be increased by 6.6% and 1.9% respectively, while 50 ppm HCl increased their efficiencies by 2.8% and 2.1%, respectively. Different from O 2 and HCl, SO 2 and NO had negative effects. The removal efficiencies could be reduced by 6.5% for CuCl 2 -Pal and 4.7% for CuBr 2 -Pal with 1200 ppm SO 2 , while they could be reduced by 4.2% and 2.6% with 300 ppm NO. Compared with CuCl 2 -Pal, CuBr 2 -Pal performed better. Combined with the characterization results, Cu 2 + was reduced to Cu + and halogen migrated into new compounds on the surface of Cu-Pal after reaction. Eventually, the mercury removal mechanism of Cu-Pal was analysed and proposed. [ABSTRACT FROM AUTHOR]

The Hg 0 adsorption and oxidation sites on the CuCl 2 -MF catalyst as well as the role of atomic Cu and Cl in Hg 0 removal were identified by a temperature programmed desorption (TPD) experiment. The reaction mechanism with the participation of O 2 and HCl was investigated. The changes in surface chemistry of fresh, spent and in situ pretreated catalyst with O 2 and/or HCl were investigated by EPR and XPS to better understand the intermediate reaction products and steps. The results suggested that different mercury adsorption sites are existed on the catalyst: Cl adsorption sites and Cu adsorption sites. The binding energy of mercury on the Cu adsorption sites is higher than that on the Cl adsorption sites. O 2 and HCl significantly affected the state of Cu and Cl on the spent catalyst. The interaction between Hg 0 and CuCl 2 with the participation of O 2 and/or HCl follows three steps mechanism: (1) the reduction of CuCl 2 to CuCl for the interaction with Hg 0 , (2) the reoxidation of CuCl for the interaction with O 2 forming an intermediate copper oxygen chloride species, (3) the rechlorination of oxychloride species resulting in the restoration of CuCl 2 . This demonstrated that the interaction between Hg 0 and CuCl 2 is a cycle when O 2 and HCl are contained in the reaction system. [ABSTRACT FROM AUTHOR]

To remove Hg 0 from coal combustion flue gas and eliminate secondary pollution of spent sorbent, a novel magnetic catalyst based on CuCl 2 modified magnetospheres from fly ash (CuCl 2 -MF) was developed. The solubility tests, electron paramagnetic resonance (EPR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and physical property measurement system with vibrating sample magnetometer (PPMS-VSM) were employed to characterize the catalyst. The effects of CuCl 2 loading value and reaction temperature on Hg 0 removal performance were studied using a laboratory-scale fixed-bed reactor. The results suggested that the CuCl 2 loaded on the support is present mostly in an amorphous phase. Different copper coordinations are existed in the catalyst with different Cu loading: at low Cu loading, isolated Cu 2+ ions existed in a chlorine-free coordination; at high Cu loading, associated Cu 2+ ions existed in a chlorine-enriched coordination. The catalyst with optimal loading 6% CuCl 2 attained the highest Hg 0 removal efficiency (90.6%) at 150 °C. The chlorine-enriched coordination acted as the active adsorption sites for Hg 0 , while the chlorine-free coordination is inactive for Hg 0 removal. The CuCl 2 -MF catalyst showed good resistance to SO 2 for Hg 0 removal in the presence of HCl. Further, the management method for spent catalyst containing mercury was proposed, and the economic analysis of the technology was also conducted. [ABSTRACT FROM AUTHOR]

The emission of mercury from coal combustion has caused consequential hazards to the ecosystem. The key challenge to abating the mercury emission is to explore highly efficient adsorbents. Herein, sulfur-functionalized carbon (S-C) was synthesized by using a molten-salt pyrolysis strategy and employed for the removal of elemental mercury from coal-combustion flue gas. An ideal pore structure, which was favorable for the internal diffusion of the Hg0 molecule in carbon, was obtained by using a SiO2 hard template and adjusting the HF etching time. The as-prepared S-C with an HF etching time of 10 h possessed a saturation Hg0 adsorption capacity of 89.90 mg·g−1, far exceeding that of the commercial sulfur-loaded activated carbons (S/C). The S-C can be applied at a wide temperature range of 25–125 °C, far exceeding that of commercial S/C. The influence of flue gas components, such as SO2, NO, and H2O, on the Hg0 adsorption performance of S-C was insignificant, indicating a good applicability in real-world applications. The mechanism of the Hg0 removal by S-C was proposed, i.e., the reduced components, including sulfur thiophene, sulfoxide, and C-S, displayed a high affinity toward Hg0, which could guarantee the stable immobilization of Hg0 as HgS in the adsorbent. Thus, the molten-salt pyrolysis strategy has a broad prospect in the application of one-pot carbonization and functionalization sulfur-containing organic precursors as efficient adsorbents for Hg0. [ABSTRACT FROM AUTHOR]

Porous carbons derived from one-pot carbonization and activation of wood sawdust in a molten salt (LiCl-KCl) medium were employed for Hg0 removal. The carbons derived from molten salt carbonization (MSC) displayed much superior Hg0 removal performance comparing with the carbons derived from N 2 pyrolysis method (NC). The best molar ratio of LiCl-KCl was 59:41, the optimal molten salt temperature was 700 °C, and the best mass ratio of wood sawdust to molten salt was 1:10. The MSC displayed good applicability at 50–125 °C. The saturation Hg0 adsorption capacity of MSC was about 7828.39 μg·g−1, far exceeding those for carbonaceous adsorbents reported in literatures. A Hg0 removal mechanism over MSC was proposed, i.e., the hierarchical porous structure accelerated mass transfer of Hg0, and the C O groups served as electron acceptors from Hg0 atoms to form organic matter bonded mercury (Hg-OM). The molten salt could be easily separated from the mixture of MSC for recycling multiple times. Thus, molten salt carbonization method appears to be promising in one-pot carbonization and activation of biomass as efficient adsorbents for gaseous Hg0. [Display omitted] • Porous carbon was prepared by one-pot carbonization and activation of biomass in molten salt. • The Hg0 adsorption capacity of porous carbon reached about 7828.39 µg·g−1. • The porous carbon can be adopted in a wide temperature range of 50–125 °C. • The spent molten salt can be effectively seperated with carbon for reusing. [ABSTRACT FROM AUTHOR]

• CuFeS 2 was adopted as an efficient and recyclable trap for Hg0 sequestration. • The adsorption capacity and rate was high as 37.24 mg·g−1 and 63.40 μg·g−1·min−1. • The flue gas components played insignificant roles in Hg0 removal over CuFeS 2. • The spent CuFeS 2 could be effectively replenished and regenerated for reusing. The development of cost-effective and high-efficient technologies for degrading Hg0 pollution from coal combustion flue gas remains a tremendous challenge. In this work, an earth-abundant mineral, i.e., chalcopyrite (CuFeS 2), was adopted as an efficient trap for Hg0 sequestration. The CuFeS 2 exhibited approximately excellent Hg0 removal performances in a wide temperature ranging from 40 to 100 °C. Typical flue gas components including oxygen (O 2), sulfur dioxide (SO 2), nitrogen monoxide (NO), and water vapor (H 2 O) negligibly interfered the Hg0 adsorption ability, which further solidify the application potential of CuFeS 2 in coal-fired power plant. The Hg0 adsorption capacity and uptake rate was 37.24 mg·g−1 and 63.40 μg·g−1·min−1, respectively, significantly suppressing those of commercial activated carbons. The superior performance of CuFeS 2 were primarily attributed that the disulfide ligands (S 2 2−) could oxidize Hg0 into Hg2+ and subsequently immobilize Hg2+ into mercury sulfide (HgS). The spent CuFeS 2 sorbent could be replenished and regenerated by a thermal decomposition method, which pronouncedly save the operation cost. Therefore, the CuFeS 2 is a potential trap for cost-effective and efficient Hg0 remediation from coal combustion flue gas. [ABSTRACT FROM AUTHOR]

The mercury removal performance of a low-cost recyclable CuCl 2 modified magnetospheres (Cu-MF) was investigated at a 50 MWth coal-fired power plant. An increase in the Cu-MF injection rate facilitated the mercury removal and recovery process. With the combination of the existing pollutant control devices and the Cu-MF injection, an overall mercury removal efficiency of 99.3% could be achieved. Under optimal conditions, the mercury emitted from the stack was reduced to 0.10 μg/m3. Most of the mercury in the flue gas migrated to the fly ash with the spent Cu-MF. Subsequently, through magnetic separation, 67.4% of the input mercury could be recovered. The comparison of experimental results showed that Cu-MF was more effective than fly ash in removing and recovering mercury from the flue gas. With the injection of Cu-MF, HgCl 2 was formed on the magnetospheres and was identified by the mercury-temperature-programmed decomposition (Hg-TPD) experiments. The magnetospheres with the lowest particle size showed the highest mercury removal capacity. This work is expected to provide valuable guidance for optimising the mercury removal technology in large scale commercial applications in future. [ABSTRACT FROM AUTHOR]

A key challenge in elemental mercury (Hg0) decontamination from flue gas lies in the design of a sorbent with abundant reactive adsorption sites that exhibit high affinity toward Hg0 to simultaneously achieve rapid capture and large capacity. Herein, zeolitic imidazolate framework‐8 (ZIF‐8) supported copper selenide (CuSe) nanocomposites are synthesized by a newly designed two‐step surfactant‐assisted method. The as‐prepared CuSe/ZIF‐8 with CuSe to ZIF‐8 mass ratio of 80% (0.8NC‐ZIF) exhibits unparalleled performance toward Hg0 adsorption with equilibrium capacity and average rate reaching 309.8 mg g−1 and 105.3 µg g−1 min−1, respectively, surpassing all reported metal sulfides and traditional activated‐carbon‐based sorbents. The impressive performance of 0.8NC‐ZIF for Hg0 immobilization is primarily attributed to the adequate exposure of the Se‐terminated sites with high affinity toward Hg0 resulted from the layered structure of CuSe. The adsorbed mercury selenide exhibits even higher stability than the most stable natural mercury ore—that is, mercury sulfide—hence minimizing its environmental impact when the CuSe/ZIF‐8 sorbent is dumped. This work provides a new mindset for future design of sorbents for efficient Hg0 capture from industrial flue gas. The results also justify the candidature of CuSe/ZIF to be applicable for mercury pollution remediation in real‐world conditions. [ABSTRACT FROM AUTHOR]

• A cupric ion stabilization strategy was proposed to successfully prevent iron sulfides from self-combusting. • Cupric ion stabilized iron sulfide (Cu-FeS x) was functionalized as an efficient mercury trap with hydrophobicity. • The Hg0 adsorption capacity and rate of Cu-FeS x was high up to 433.2 mg g−1 and 847.4 μg g−1 min−1. • Under-coordinated sulfur ligands were the primary active sites. Iron sulfides (FeS x) characterized by the nonstoichiometric coordination between iron and sulfur are promising sorbents for elemental mercury (Hg0) adsorption from industrial flue gas. However, the unstable nature of FeS x tending to self-combust under ambient conditions impedes its scalable synthesis. To overcome this critical challenge, this work developed a cupric ion incorporation method to stabilize FeS x. When the compositional ratios of cupric ion and FeS x both equaled 50%, the composite sorbent as synthesized (50Cu-FeS x) exhibited ultra-high Hg0 adsorption capacity and uptake rate that reached 433.2 mg g−1 and 847.4 μg g−1 min−1, outperforming those benchmark metal sulfides as reported in previous studies for practical uses. In this sample, the copper ion well-incorporated into the lattice of amorphous FeS x was an indispensable fundamental that contributed to its outstanding performance and hydrophobic ability. The stabilized FeS x thus enriched its surface with abundant under-coordinated sulfur due to the nonstoichiometric coordination environment, which acted as the primary active sites for the conversion of Hg0 because only under-coordinated sulfur could accept electrons Hg0 donated. The main product after 50Cu-FeS x adsorbed Hg0 was HgS, an extremely stable mercury form in nature. From these perspectives, it is proper to declare that this work not only proposed an efficient sorbent holding great potential for Hg0 removal from high-humidity industrial flue gas but also provided a novel method for the rational design of FeS x -based materials with extensive applicability in the future. [ABSTRACT FROM AUTHOR]

Sulfur abundant S/FeS 2 prepared by a hydrothermal method was employed for removing elemental mercury (Hg 0 ) from coal-fired flue gas at low temperature. The S/FeS 2 exhibited optimal Hg 0 adsorption performance at 80 °C, which matched the temperature window between the flue gas desulfurization (FGD) and wet electrostatic precipitator (WESP) systems. The adverse effects of H 2 O and SO 2 on Hg 0 adsorption were slight. The Hg 0 adsorption capacity of S/FeS 2 was up to 2732 μg/g when achieved 50% breakthrough threshold. Both elemental sulfur (S) and FeS 2 in the S/FeS 2 contributed to the excellent Hg 0 adsorption capacity. The mercury leaching tests show that only 0.00076% mercury adsorbed on the S/FeS 2 was leached out. The mercury concentration in leachate was 0.694 μg·L −1 , which was much lower than that for a commercial AC (1.214 μg·L −1 ). Furthermore, the S/FeS 2 presented about 95% oxidized mercury (Hg 2+ ) adsorption efficiency from WESP effluent. The Hg 2+ concentration could decreased rapidly from 50 μg·L −1 to below 2.5 μg·L −1 in 30 min, which was much lower than the World Health Organization (WHO) guideline (6 μg·L −1 ). With these advantages, S/FeS 2 appears to be a promising material for co-beneficial gaseous Hg 0 and aqueous Hg 2+ removal from power plants by injecting upstream of a WESP system. [ABSTRACT FROM AUTHOR]

• The effect mechanisms of SO 2 and H 2 O on Hg0 adsorption over CeO 2 (1 1 1) surface was investigated. • SO 2 was oxidized to SO 3 on the substrate and redistributed the surface charge. • H 2 O dissociatively adsorbed on CeO 2 (1 1 1) surface to form Ce-OH group. Ceria (CeO 2) based catalysts have been widely reported as potential materials for elemental mercury (Hg0) oxidation in flue gas. However, the effect of sulfur dioxide (SO 2) and water vapor (H 2 O) on Hg0 adsorption over CeO 2 , which is critical for subsequent Hg0 oxidation are still unclear. The detail reaction mechanisms involved in Hg0 adsorption on CeO 2 (1 1 1) surface in the presence of SO 2 and H 2 O were investigated with first-principles calculations based on density functional theory. The results suggest that SO 2 was chemical adsorbed on CeO 2 (1 1 1) surface through S atom interacting with O top site. The adsorption energies and density of state indicate that SO 2 interacted with the surface lattice oxygen of CeO 2 to form a SO 3 -like species. The surface charge was redistributed during the formation of SO 3 , which promoted the adsorption of Hg0 on the CeO 2 (1 1 1) surface. H 2 O leaned to bond with surface Ce atoms. The inhibitive impact of H 2 O on Hg0 adsorption was ascribed to the following two reasons: 1) H 2 O competed with Hg0 for active sites; 2) H 2 O dissociatively adsorbed on CeO 2 surface to generate Ce-OH group, and hence occupied the lattice oxygen on catalyst surface. [ABSTRACT FROM AUTHOR]

Phthalate esters (PAEs) are a group of endocrine disrupting compounds, which have been widely used as plasticizers. To alleviate the environmental and health threats from water resources polluted by PAEs, we prepared phenyl functionalized mesoporous silica materials (ph-SBA-15) were synthesized by a simple post-modification approach for rapid and efficient removal of low concentration of di- n- butyl phthalate (DBP) from aqueous solution. Mesostructure, texture, surface chemistry and surface charges were systemically characterized. The obtained ph-SBA-15 possesses a highly ordered mesostructure, a high surface area (418 m 2 /g), uniform mesopores (6.5 nm) and high-density organic groups around 11 wt.%. Batch adsorption experiments revealed that phenyl modified SBA-15 had an excellent ability to remove DBP with the maximum adsorption capacity up to ∼40 mg/g at 25 °C. The thermodynamics and kinetics for the adsorption were also investigated, demonstrating an exothermic, multi-layer and fast adsorption process. In addition, DBP adsorption was found to be sensitive to the pH and the uptake was observed to be greatest at around pH 7.0. Furthermore, this material can be effectively regenerated by ethanol. [ABSTRACT FROM AUTHOR]

Abstract: Lead (Pb) contamination in the air is a severe global problem, most notably in China. Removal of Pb from polluted air remains a significant challenge. It is unclear what potential effects silica nanoparticles (SiNPs) exposure can have on atmospheric Pb. Here we first characterized the features of SiNPs by measuring the particle size, zeta potential and the specific surface area of SiO2 particles using a Nicomp 380/ZLS submicron particle sizer, the Brunauer–Emmett–Teller (BET) method and transmission electronic microscopy (TEM). We measured the content of the metal Pb adsorbed by SiNPs exposed to two Pb polluted electric battery plants using inductively coupled plasma mass spectrometry (ICP-MS). It is found that SiNPs exposed to two Pb polluted electric battery plants absorb more atmospheric Pb compared to either blank control or micro-sized SiO2 particles in a time-dependent manner. This is the first study demonstrating that SiNPs exposure can absorb atmospheric Pb in the polluted environment. These novel findings indicate that SiNPs have potential to serve as a significant adsorbent of Pb from industrial pollution, implicating a potentially novel application of SiNPs in the treatment of environmental heavy metal pollution. [Copyright &y& Elsevier]

• A comprehensive review of mercury abatement by mineral chalcogenides was conducted. • Mercury removal performances of mineral chalcogenides and the primary influence factors were comprehensively summarized. • The involved mechanisms for mercury removal by mineral chalcogenides were discussed. • The restrictions and future perspectives for mercury adsorption by mineral chalcogenide were presented. Mercury contamination has attracted global attentions in the past decades, which posed great threats to the whole ecosystem and human health because of its cumulative hypertoxicity, persistence and migration in the atmosphere. Due to the inferior mercury capture performances and tedious modification procedures of carbon-based sorbents, mineral chalcogenides were regarded as the preferable candidates for gaseous elemental mercury (Hg0) immobilization from industrial flue gas. Mineral chalcogenides exhibit several advantages, such as simple preparation, excellent capture performance, and less secondary pollution in Hg0 adsorption. This review focuses on the latest research advances in Hg0 abatement by mineral chalcogenides. At the beginning, the research status of different typical sorbents for Hg0 removal was overviewed. Then, the performances and application conditions of most mineral chalcogenides for Hg0 removal were introduced in detail. The Hg0 adsorption performance comparison of various mineral chalcogenides was also conducted. Moreover, the influential factors, i.e. reaction temperature, flue gas components, and involved mechanisms for Hg0 removal over different mineral chalcogenides were discussed comprehensively. The objective of this review was to strengthen the comprehension of the developing field and generalize the research directions in the future. [ABSTRACT FROM AUTHOR]

• Amalgam plays an important role in the Hg0 immobilization process by CuS. • Light irradiation excited electron transfer on the Cu-terminated sites of CuS. • Light irradiation inhibited the formation of Cu amalgam and subsequent Hg0 capture. • Light irradiation in ESPs may limit Hg0 removal by mineral sulfide sorbents. An applicable way of mineral sulfide based remediators such as copper sulfide (CuS) for effective abatement of elemental mercury (Hg0) from coal-fired flue gas is to inject them prior to electrostatic precipitators (ESPs), in which light irradiation widely exists because of the corona discharge. A systematical investigation of Hg0 removal by CuS sorbent under light irradiation was conducted for the first time. The results show that light irradiation significantly inhibited the Hg0 removal efficiency of the CuS sorbent. The normalized Hg0 concentration at the reactor outlet even quickly increased from 0 to 0.45 once a lamp was turned on. Light irradiation excited a transfer of electrons on the Cu-terminated sites from inner Cu 3d orbit to outer Cu 4s orbit, and hence inhibited the formation of copper amalgam, which was supposed to be a key step in Hg0 immobilization by the CuS sorbent. Moreover, light irradiation accelerated the decomposition of copper amalgam to Hg0 which re-emitted to the gas flow. With these novel insights into the role of light irradiation concerning Hg0 removal over mineral sulfides, this work can provide guidance for selecting and adopting proper mineral sulfides in real-world coal combustion conditions to replace traditional activated carbons. [ABSTRACT FROM AUTHOR]

• ·A brand new Fe 3 O 4−x Se y sorbent was purposefully designed for Hg0 immobilization. • ·The Fe 3 O 4−x Se y exhibited excellent Hg0 capture capacity and rate. • ·The Fe 3 O 4−x Se y transferred Hg0 into extremely stable HgSe. • ·A scheme was proposed for the applications and recycling of Fe 3 O 4−x Se y. Abatement of elemental mercury (Hg0) pollution in coal combustion flue gas remains a challenging task especially for the optimal trade-off among effectiveness, environmental-friendliness and cost. In this work, magnetite (Fe 3 O 4) was simply selenized (Fe 3 O 4−x Se y) as an efficient and recyclable sorbent for Hg0 sequestration from coal combustion flue gas. The Fe 3 O 4−x Se y as obtained exhibited an advantageous core-shell like spherical structure, in which the interior Fe 3 O 4 core kept unchanged during the selenization process and warranted the recyclability of Fe 3 O 4−x Se y , while the exterior part exposed to Hg0 was selenized into iron diselenide (FeSe 2) that has high affinity towards Hg0. Moreover, the selenization process introduced more mesopores that were favorable for Hg0 migration and accommodation. Co-benefitted from these perspectives, the Fe 3 O 4−x Se y exhibited a Hg0 adsorption capacity and uptake rate as high as 8.8 mg g−1 and 3.7 μg g−1 min−1, respectively, far exceeding the capacity and rate of bare Fe 3 O 4 and traditional Hg0 remediators. The Hg0 stably immobilized by Fe 3 O 4−x Se y primarily as mercury selenide (HgSe) indicates the Hg-laden Fe 3 O 4−x Se y has negligible mercury re-emission concerns when it is dumped and landfilled. The spent Fe 3 O 4−x Se y can also be effectively retrieved and regenerated for reusing purpose with mercury recovery simultaneously, which could dramatically save the operation costs. Thus, the Fe 3 O 4−x Se y can be expected to be a promising alternative to traditional sorbents for Hg0 sequestration from coal combustion flue gas considering its high efficiency, negligible environmental risk and decent recyclability and reusability. [ABSTRACT FROM AUTHOR]