Flue Gas Atmosphere Research Articles

Food industrial biowaste-based magnetic activated carbons as sustainable adsorbents for anthropogenic mercury emissions

Bio-derived magnetic activated carbons from industrial chestnut shell waste have been obtained through a novel, optimized and sustainable methodology where impregnation, pyrolysis, acid washing or other intermediate steps commonly used in the activation process were eliminated saving time, energy and costs. The resulting materials (MACs) were obtained at 220–800 °C showed interesting properties: textural (SBET up to 568 m2 g-1) and magnetic (different iron species developed), depending on the activation temperature employed.Data showed outstanding results when MACs were tested for Hg removal in pollution emissions at 150 °C in lab-scale device. In MACs obtained at 500–600 °C, where the highest concentration of magnetite was found, the best Hg adsorption capacity was achieved, while it decreased when metallic iron or iron carbides were present (MACs obtained at 800 °C). Moreover, the difference of Hg0 removal/adsorption in N2+O2 and Simulated Flue Gas atmosphere between MACs obtained at 500 and 600 °C pointed out the influence on Hg removal of additional parameters, as surface chemistry and the existence of sulfur or chloride. The determination of Hg species in post-retention solids confirmed the mercury oxidation by high-valence iron ions (Fe3+) and the involvement of physisorption and chemisorption processes for the gas-solid interaction mechanism.

CO2-induced dissolution of ZnO into ionic liquids and its catalytic application for the hydration of propargylic alcohols

An unexpected CO2-induced dissolution of ZnO into ionic liquids was discovered. This process exhibited high dissolution speed and the dissociated mixture was applied as an efficient Zn-based catalytic system for the CO2-promoted hydration of propargylic alcohols under atmospheric pressure with broad substrate scope. Moreover, this system could be recycled and reused for at least 16 times with excellent yields continuously obtained, which is an unprecedented record for this reaction. Significantly, this system could employ waste pigments as the ZnO source and work even under flue gas atmosphere. In the mechanistic investigations, the interaction between ZnO, CO2 and ionic liquids to give N-heterocyclic carbene/CO2 adducts proved to be the key factor for this specific dissolution. These adducts were further identified to exhibit better reactivity than the normal CO2 by experimental data and density functional theory (DFT) calculations, which might be responsible for the excellent performance of the abovementioned catalytic system.

Investigation on the gasification behavior and kinetic analysis of cattle manure under the flue gas atmosphere

Investigation on the gasification behavior and kinetic analysis of cattle manure under the flue gas atmosphere

Effect of auto thermal biomass gasification on the sintering of simulated ashes

Ash sintering is an essential factor for the competitiveness of biomass gasification. Compared to conventional air biomass gasification, the gasification temperature is reduced in the auto thermal biomass gasification, as the utilisation of thermal compensation for the CaO carbonation reaction, which ultimately could suppress the extent of ash sintering. This work firstly investigated the inhibition effect of this process on the sintering of simulated ashes (silica, potassium oxide and alumina) in a lab-scale fixed bed reactor. The results indicate that the alumina particles are present under different CO2 concentrations, gasification temperature and CaO/ biomass ratios. However, silica and potassium oxides react with CaO and disappear at high temperatures. Among the three simulated ashes, alumina particles are relatively stable in the auto thermal biomass gasification. The average particle size decreases from 116.9 µm to 64.9 µm and 93.8 µm when CaO/alumina ratio is 2 and 5, respectively, indicating the increase of CaO addition under the flue gas atmosphere could inhibit the sintering degree of simulated ash. Meanwhile, the reaction between CaO and CO2 in the carrier gas can reduce the formation of calcium silicate. Therefore, compared with conventional biomass gasification, auto thermal biomass gasification is favourable to restrain the degree of ash sintering because of the relatively low gasification temperature.

Analysis of functionality distribution and microstructural characteristics of upgraded rice husk after undergoing non-oxidative and oxidative torrefaction

Rice husk, a typical agricultural by-product was used for experimental investigation on characterizing the variations in fuel behaviors before and after torrefaction performed under different conditions. The effects of torrefaction temperature (493, 543 and 573 K), atmosphere (argon, air and flue gas) and duration (30 and 60 min) on the compositional variation, microstructural evolution, functional group distribution and surface hydrophobicity were evaluated systemically through the utilization of elemental analysis, FTIR, Raman spectra, XPS and contact angle. Oxidative torrefaction expressed a tendency to improve the torrefaction efficiency and increase the carbon content in torrefied sample due to the simultaneous occurrence of volatile release, carbonization and surface oxidation. Oxidizing agents could accelerate the decomposition or conversion of surface hydrophilic groups during oxidative torrefaction process effectively, strengthening the hydrophobicity of torrefied sample significantly. Furthermore, partial oxidation and thermal degradation tended to promote the crack of condense aromatic structures synergistically, increasing the proportion of active structures in the torrefied rice husk. Simultaneously, some nitrogen atoms initially located inside the aromatic structures with high thermal stability would migrate to the edge rapidly during the oxidative torrefaction (N-Q → N-5 + N-6). In the process of air torrefaction, excessive oxidants would reduce the content of reactive structure and functional group with low thermal stability through severe oxidation reaction, reducing the quality of torrefied sample, especially at high temperatures. The results in this study illustrated that torrefaction performed in flue gas atmosphere at 573 K for 30 min was the optimum torrefaction condition for rice husk upgradation, and employing flue gas as the carrier gas for biomass torrefaction was more effective and economical than N2 and air in improving the fuel quality of rice husk.

Mineral transformation during rapid heating and cooling of Zhundong coal ash

Zhundong (ZD) coalfield has a large number of coal reserves. However, the severe fouling and slagging problems that occurred in ZD coal-fired utility boilers have seriously hindered the large-scale utilization of ZD coal. Deep understanding of the mineral transformation of ZD coal during combustion and its impact on fouling and slagging can provide technical support for fouling and slagging prevention in utility boilers. In this paper, a novel temperature and atmosphere controlling method was proposed to study ash deposition. Wucaiwan (WCW) coal ash samples in different atmospheres and temperatures were collected efficiently by the established single thermocouple high-temperature online microscope observation test rig. The influence of rapid heating and cooling on the mineral transformation of WCW coal ash samples was systematically investigated using XRD and SEM-EDS, respectively. The effects of SO2 in the flue gas on the mineral transformation and the sulphates generation of the coal ash were analysed by comparing the experimental results in oxidizing atmosphere and simulated flue gas atmosphere. The experimental results showed that the microscopic morphology, mineral and element conversion of coal ash samples during heating and cooling were quite different. Compared with oxidizing atmosphere, SO2 in the flue gas significantly increase the S content of ash at 600 °C−1200 °C and the amount of molten minerals on the quenched ash sample surface during cooling. These results indicate that SO2 can promote the sulfation reactions of alkali/alkaline earth metal (AAEM) on the quenched ash sample surface and restrain the decomposition of S-containing minerals in ash cooling. The investigation also reveals that the molten AAEM sulphate on the ash surface is mainly generated at 800 °C−900 °C. The present study not only provides the fundamental understandings of mineral transformation but also guides industrial applications to reduce the risk of ash deposition.

Attrition performance and morphology of limestone under different conditions in fluidized bed

The attrition characteristics of limestone have an important influence on the material balance and the efficiency of desulfurization in circulating fluidized bed boiler. By means of XRD, XRF, SEM and BET analysis, the attrition behaviour and morphology of two kinds of limestone with different particle sizes were studied by investigating the effects of simultaneous reaction of sulfation and calcination, sulfation reaction, oxygen-enriched flue gas atmosphere.The variation trend of attrition rate constant under simultaneous reaction is similar to that under only sulfation condition. Both of these conditions decrease with time and then reach a stable value. The attrition rate of finer limestone is higher than that of coarser limestone in a certain size range. The attrition rate of limestone in air atmosphere is the largest, while, in SO2 atmosphere it's far less. This is mainly caused by the formation of CaSO4 layer that reduces the attrition rate. By calculating the conversion of Ca to CaSO4, it is found that the conversion increases with time, but the increasing rate decreases gradually. The increase of SO2 concentration leads to the increase of final conversion. In the oxygen-enriched flue gas atmosphere, the limestone is more attrition-resistant than that in the air.

Alkali removal with mineral sorbents – Part I: Sorption capacity and reaction kinetics

Aluminosilicate sorbents show the potential to reduce alkali-related problems during solid fuel conversion such as deposit build-up and corrosion damages. The alkali capacity, the reaction kinetics and the surface area development of the sorbents under operating conditions are essential parameters for the mathematical description of the alkali sorption. In this work, three sorbents, kaolin, bauxite and bentonite, are characterized in this regard by thermogravimetric analysis. The sorption behavior of kaolin surpasses the other sorbents due to the highest loading capacity and the temperature-stability of the porous structure. However, the suitability as sorbent in solid fuel conversion processes is given for all materials. A mathematical sorption model is applied to the experimental data in order to derive kinetic parameters of the sodium and potassium sorption under syngas and flue gas atmosphere. Thus, this work provides the necessary dataset for the design and optimization of the sorbent use in industrial processes.

Determination of corrosion products for steam and flue gas injection environments using thermodynamic simulation

Thermal recovery processes using steam injection with combustion gases (flue gas) have shown positive results in the recovery of heavy crude oil over the conventional process, by integrating different recovery mechanisms. However, under the operating conditions, the injection of these fluids generates highly corrosive environments that have an impact on the deterioration of the materials, resulting in risks and operational costs. Therefore, it is necessary to determine the theoretical corrosion products that can be generated in these processes. This research focused on the study of API N-80 carbon steel exposed to a steam and flue gas atmosphere, at pressure and temperature conditions in the ranges of 800 psia - 1100 psia (55 bar - 75 bar) and 520 °F - 560 °F (270 °C - 290 °C) respectively. Based on this environment, to determine the theoretical corrosion products, a thermodynamic simulation stage was developed using HSC Chemistry software, which was used to generate Pourbaix, Ellingham and thermodynamic equilibrium diagrams. It was found that the main theoretical corrosion products corresponded to oxides, carbonates, and hydroxides, among which the significant presence of iron (III) oxide (Fe2O3), iron (II, III) oxide (Fe3O4) and iron carbonate (II) (FeCO3) was corroborated.

Evaluation of thermal adsorption and desorption properties of dioxins on 11 adsorbents

筛选在低温下高效捕集并在一定的高温下可以快速完全脱附二噁英的吸附/脱附材料是二噁英在线热捕集的关键。该研究以1,2,3,4-四氯代二苯并-对-二噁英(1,2,3,4-TCDD)和1,2,3,8,9-五氯代二苯并呋喃(1,2,3,8,9-PCDF)为二噁英模型物,以电子捕获检测器(ECD)作为检测器,利用填充柱气相色谱系统,测定了这两种二噁英单体在11种吸附剂上4~5个温度点下的保留体积,并建立了相应的范特霍夫方程。结果表明,11种吸附剂的线性方程决定系数(R2)均大于0.96。根据范特霍夫方程,预测了吸附剂在120、150、180 ℃时的气固分配系数(KSA)。弗洛里硅土在120、150、180 ℃ 3个温度点下都具有最强的吸附能力,特别是在120 ℃时,1,2,3,4-TCDD、1,2,3,8,9-PCDF在弗洛里硅土上的KSA分别高达1.82×108 m3/g、1.46×1013 m3/g。碳基吸附剂的高分子多孔微球GDX系列的GDX-101、GDX-102、GDX-103、GDX-105、GDX-203在最高耐受温度270 ℃下都可以实现二噁英的热脱附,证实了碳基吸附剂作为二噁英热吸附/脱附的吸附剂的可行性。310 ℃下,在丝光沸石上1,2,3,4-TCDD可实现热脱附,而1,2,3,8,9-PCDF在相同条件下无法实现热脱附,体现了沸石对二噁英同系物的选择性吸附的特性。而硅藻土和蒙脱土对气相中的二噁英几乎没有吸附能力,不适合作为二噁英热捕集的吸附剂。弗洛里硅土、硅胶、氧化铝、GDX-102、GDX-103和GDX-203对1,2,3,4-TCDD、1,2,3,8,9-PCDF都具有很强的吸附能力,因此被初步选为二噁英的候选吸附剂。通过比较120 ℃下和270 ℃下二噁英在这6种吸附剂上的lnKSA,发现弗洛里硅土在两个温度点下的保留体积都是最大的;在侧重低温下二噁英的热捕集性能时,弗洛里硅土是捕集二噁英的最佳吸附剂;而GDX-102是6种吸附剂中lnKSA,270 ℃最小的,在侧重高温下二噁英的热脱附性能时,GDX-102是二噁英热脱附的最佳吸附剂。同时,硅胶、GDX-103和GDX-203的lnKSA,120 ℃和lnKSA,270 ℃与GDX-102相近,也可以作为快速热吸附/脱附的材料。该文通过系统评价1,2,3,4-TCDD和1,2,3,7,8-PCDF在11种吸附剂的热吸附/脱附性能,对简化二噁英的采样和制备过程提供了新的解决思路,为实现二噁英的热捕集提供了技术支撑。

Enhancement of fuel properties of yard waste through dry torrefaction

Yard waste or green waste is an abundant yet underutilized source of biomass around the world. Yard waste is rich in complex organic compounds, which is beneficial when used as feedstock for chemicals production, but undesirable components within the biomass are detrimental to the quality of the products. In this work, the prospect of yard waste upgrading as a solid fuel source by dry torrefaction (DT) was studied. Dry torrefaction of yard waste was conducted at 170 °C, 200 °C, 250 °C, and 300 °C under N2, CO2, and flue gas (25:75 vol% mixture of CO2:N2) atmosphere in a tubular reactor. As temperature was increased, the mass yield of the torrefied yard waste decreased while the HHV increased. The mass yields obtained were in the order of nitrogen < carbon dioxide < flue gas. HHV was in the order of flue gas < nitrogen < carbon dioxide. Overall, carbon dioxide was shown to be the best carrier gas for energy intensification, where HHV was enhanced from 15.6 to 22.2 MJ/kg at 300 °C, with an energy yield of 98.1%. Flue gas showed no visible improvement in properties up to temperatures of 250 °C. Thermogravimetric analysis (TGA) highlighted that within the given temperature range, hemicellulose was completely degraded as temperature approach 300 °C, while cellulose was partially degraded. Fourier transform infrared spectroscopy (FTIR) emphasised that flue gas was unable to degrade various functional groups to the same degree as the other gases. Field Emission scanning electron microscopy with Energy Dispersive X-ray analysis (FESEM-EDX) revealed that flue gas was unable to degrade the biomass as much as nitrogen or carbon dioxide.

Optimization of process parameters for preparation of powdered activated coke to achieve maximum SO2 adsorption using response surface methodology

Powdered activated coke (PAC) is a good adsorbent of SO2, but its adsorption capacity is affected by many factors in the preparation process. To prepare the PAC with a high SO2 adsorption capacity using JJ-coal under flue gas atmosphere, six parameters (oxygen-coal equivalent ratio, reaction temperature, reaction time, O2 concentration, CO2 concentration, and H2O concentration) were screened and optimized using the response surface methodology (RSM). The results of factor screening experiment show that reaction temperature, O2 concentration, and H2O (g) concentration are the significant factors. Then, a quadratic polynomial regression model between the significant factors and SO2 adsorption capacity was established using the central composite design (CCD). The model optimization results indicate that when reaction temperature is 904.74°C, O2 concentration is 4.67%,H2O concentration is 27.98%, the PAC (PAC-OP) prepared had a higher SO2 adsorption capacity of 68.15 mg/g while its SO2 adsorption capacity from a validation experiment is 68.82 mg/g, and the error with the optimal value is 0.98%. Compared to two typical commercial activated cokes (ACs), PAC-OP has relatively more developed pore structures, and its SBET and Vtot are 349 m2/g and 0.1475 cm3/g, significantly higher than the 186 m2/g and 0.1041 cm3/g of AC1, and the 132 m2/g and 0.0768 cm3/g of AC2. Besides, it also has abundant oxygen-containing functional groups, its surface O content being 12.09%, higher than the 10.42% of AC1 and 10.49% of AC2. Inevitably, the SO2 adsorption capacity of PAC-OP is also significantly higher than that of both AC1 and AC2, which is 68.82 mg/g versus 32.53 mg/g and 24.79 mg/g, respectively.

Preparation of powdered activated coke for SO2 removal using different coals through a one-step method under high-temperature flue gas atmosphere

Powdered activated coke (PAC) used for SO2 adsorption can be prepared using pulverized coal through a one-step method under a high-temperature flue gas atmosphere, and the PAC performance is significantly affected by the coal type. In this study, five coals with different ranks were used to prepare the PACs through this method in a drop-tube reactor. The pore structures, bulk densities, surface morphologies, and chemical functional groups of the PACs were characterized, and their yields and SO2 adsorption capacities were determined. Results show that the PACs prepared from low-rank coals (IN-coal and ZD-coal) had developed pore structures, abundant oxygen-containing functional groups and high SO2 adsorption capacities, but their yields were relatively low. As the degree of coalification increased, as in JJ-coal and RU-coal, the pore structure parameters, amount of oxygen-containing functional groups, and SO2 adsorption capacities of the PACs demonstrated a decreasing trend, whereas the yields increased. Besides, the XW-coal was found to be unsuitable for PAC preparation, because the resulting PAC had an undeveloped pore structure and a low SO2 adsorption capacity, and caking property of coal is an unfavorable factor in the PAC preparation. These conclusions can provide guidance for the selection of raw materials used to prepare PAC through the one-step method.

Laboratory evaluation of an efficient low interfacial tension foaming agent for enhanced oil recovery in high temperature flue-gas foam flooding

Flue-gas foam/surfactant polymer flooding is a novel technology to enhanced oil recovery for heavy oil reservoir after hot water flooding with safety and efficiency. However, high temperature and the complex composition of flue gas greatly influence the foaming ability of the foaming agent, and weaken the plugging and profile control ability of the foam. Hence, screening suitable foam agents is of great significance. Here, a typical terpolymer of N‒methyl butenone carboxylates, alkyl phenyl sulfonates and pyrrolidone was selected as an efficient foam agent. The foaming performance and stability of the foam agent remained unchanged after 300 °C aged for 72 h in the flue gas atmosphere. Foam performance and stability tests in the simulative flue gas environment, adsorption properties of oil sands, and resistance factor evaluation were carried out. It showed good foam performance and stability, low adsorption capacity (0.77 mg/g), low interfacial tension (10−2 mN/m) and high resistance factor (>418), which indicated that the terpolymer (PNCAS) can reduce the gas channeling and increase the sweep area. The results of homogeneous and heterogeneous model experiments and microscopic mechanism suggested that foam flooding can greatly improve oil recovery while the low permeable sand-pack recovery can increase almost 42% in comparison with the conventional hot water flooding.

Oxy-Fuel Combustion Characteristics of Pulverized Coal under O2/Recirculated Flue Gas Atmospheres

Oxy-fuel combustion is an effective technology for carbon capture and storage (CCS). Oxy-combustion for coal-fired power stations is a promising technology by which to diminish CO2 emissions. Unfortunately, little attention has been paid to the oxy-combustion characteristics affected by the combustion atmosphere. This paper is aimed at investigating the oxy-fuel combustion characteristics of Australian coal in a 0.3 MWth furnace. In particular, the influences of various oxygen flow rates and recirculated flue gas (RFG) on heating performance and pollutant emissions are examined in O2/RFG environments. The results show that with increases in the secondary RFG flow rate, the temperatures in the radiative and convective sections decrease and increase, respectively. At a lower oxygen flow rate, burning Australian coal emits lower residual oxygen and NO concentrations. In the flue gas, a high CO2 concentration of up to 94.8% can be achieved. Compared to air combustion, NO emissions are dramatically reduced up to 74% for Australian coal under oxy-combustion. Note that the high CO2 concentrations in the flue gas under oxy-coal combustions suggest great potential for reducing CO2 emissions through carbon capture and storage.

Preparations and Characterization on Fe Based Catalyst Supported on Coconut Shell Activated Carbon CS(AC) and SCR of NOx-HC

The SCR of NO by propene on coconut shell activated carbon CS(AC) supported with Fe has been undertaken in heated temperature programmed fixed bed vertical column reactor in simulated flue gas atmosphere at 100–550 °C. Catalysts were characterized by N2 adsorption–desorption, ICP, XRD, TEM, XPS, H2-TPR, Py-FTIR and NO-TPD. Series of experiments demonstrated that 10 Fe-CS(AC) showed 95% NO reduction at 350 °C. During the tests, different loadings of iron have a significant effect on acid sites, surface area and pore sizes, effects of O2, SO2, and H2O were investigated. The curves of the H2-TPR shows that there is a strong reduction activity of the catalyst at about 600 °C, which is caused by the strong reduction performance of Fe2O3. The analysis of Py-FTIR results defines the presence of Lewis and Brόnsted acids on the surface of the catalyst. At the higher temperature range, the reduction properties of 10 Fe-CS(AC) demonstrated better results than other catalysts.

Binary mineral sulfides sorbent with wide temperature range for rapid elemental mercury uptake from coal combustion flue gas

ABSTRACT Developing efficient sorbents with rapid kinetics is the main challenge encountered for Hg0 capture from coal combustion flue gas in a sorbent injection scenario. Binary mineral sulfide-based materials combining copper sulfide (CuS) and zinc sulfide (ZnS) to exert their capabilities for Hg0 capture at the low- and high-temperature was for the first time reported for Hg0 removal to realize a wide temperature range sorbents. When the molar ratio between CuS and ZnS was 10%, the as-synthesized 10Cu-Zn nanocomposite exhibited excellent Hg0 uptake rate at 150°C that could degrade 40 μg/m3 of Hg0 to undetectable level at the end of a 60-s experiment with the dosage of only 1 mg. This Hg0 uptake rate is folds higher compared to that when bare CuS or ZnS was adopted alone at this specific temperature. The typical flue gas atmospheres had negligible effect on Hg0 removal over 10Cu-Zn in a short contact time, which further suggests that the binary sorbents were proper to be injected before the electrostatic precipitator system. Moreover, it is found that, by adjusting the ratio between CuS and ZnS, it is potential to develop binary sorbent suiting any temperature conditions that may achieve an exceedingly high Hg0 capture performance. Thus, this work not only justified the candidature of 10Cu-Zn as a promising alternative to traditional activated carbon for Hg0 capture from coal combustion flue gas but also guided the future development of multi-component mineral sulfide-based sorbents for Hg0 pollution remediation from various industrial flue gases.

Influence of Potassic Additives on Sludge Gasification Under Model Flue Gas Atmosphere

In this study, the influence of potassic additives (K2CO3 and biomass ash (BA)) on sludge gasification under model flue gases was investigated. Two model gases consisting of O2/CO2/N2 and O2/CO2/H2O/N2 were used as gasifying agents. Under O2/CO2/N2 atmosphere, the lower heating values (LHV) of produced gas were in a range of 3.07–3.79 MJ/Nm3, and cold gas efficiency (CGE) were in a range of 47–66%. When steam was introduced into the gasification atmosphere, the efficiency of the process significantly improved. LHV of the produced gas under O2/CO2/H2O/N2 atmosphere was in a range of 6.48–7.18 MJ/Nm3, and CGE was in a range of 73–88%. K2CO3 had an obvious catalytic effect on sludge gasification process. Additionally, K2CO3 had stronger catalytic effect under steam-free atmosphere and it was better in promoting CO generation when compared with BA. BA exhibited the ability to increase gas yield under steam-free atmosphere, while it only had a slight effect under steam-containing atmosphere. Based on continuous monitoring of gas during gasification process, LHV of the produced gas could be increased by nearly twofold, possibly up to 11.96 MJ/Nm3, by controlling the proper reaction time (10–12 min) to prevent the dilution effect from excessive gasifying agents.

Influence of gas atmosphere on synergistic control of mercury and dioxin by non-thermal plasma

In this paper, narrow-pulse power discharge is used to study the synergistic control of mercury and dioxins, in which 1,2,4-trichlorobenzene (TCB) was used as a dioxin analog, by using a self-designed experimental system. The competitive effects of NO, SO2 and HCl on the TCB removal by non-thermal plasma are discussed. The influence of acid gas on TCB degradation is reflected in the competitive effect. NO has the greatest influence on TCB degradation efficiency. The oxidation efficiency of Hg0 decreased by about 10% in all three acidic gas atmospheres, and the effect of each gas component on Hg0 oxidation is complex. In the flue gas atmosphere of ‘acid gas + Hg0 + TCB’, the mechanism of the synergistic control of Hg0 and TCB by the non-thermal plasma is different, which has competition and promotion relationship between each other. The contribution of various flue gas components to the results was complicated, but the overall experimental results show that the synergistic control effect of the system can continue to improve. According to the generated product backstepping, ·OH plays an important role in the synergistic control of the degradation of Hg0 and TCB. Through this study, we hope to provide basic research data for the collaborative control of flue gas in the incineration industry.

Selenium Functionalized Metal-Organic Framework MIL-101 for Efficient and Permanent Sequestration of Mercury.

Abatement of mercury emission from coal-fired power plants remains a serious task for public health and environmental societies. Selenium functionalized metal-organic framework MIL-101 (Se/MIL-101) was prepared for mercury removal from power plants. The Se/MIL-101 exhibited a remarkable mercury adsorption capacity of 148.19 mg·g-1, which was about 154 to 705 times larger than that of commercial activated carbons exclusively applied for mercury removal from power plants. The initial mercury adsorption rate for Se/MIL-101 reached up to 44.8 μg·g-1·min-1, which was 89- to 1659-fold higher than those of mercury sorbents reported in the literature. The Se/MIL-101 maintained an excellent mercury adsorption stability under simulated flue gas atmosphere containing SO2, NO, and H2O. Gaseous elemental mercury (Hg0) converted on the Se/MIL-101 to stable and water-insoluble mercury selenide (HgSe), which guaranteed a minimum re-emission even sequestration of mercury. Moreover, the mercury-laden Se/MIL-101 could also immobilize mercury in gypsum and efficiently capture mercury ions from desulfurization effluent to an undetectable level (<0.0035 μg·L-1). With these advantages, Se/MIL-101 appears to be a promising material for efficient and permanent sequestration of mercury from power plants.