Search

Rice husk, as an abundant agricultural waste and renewable biomass, is adopted to produce porous silica which is used as a potential carbon-free adsorbent for mercury emission control of coal-fired power plants. The rice husk derived porous silica (RHS) exhibits a good Hg0 adsorption capability with Hg0 removal efficiency above 80% in the temperature range of 60–140 °C, which is plausibly due to the big specific surface area and mesoporous structure. The mercury removal performance of RHS can be evidently reinforced by KBr modification. The optimal KBr loading value and reaction temperature are 2 wt% and 140 °C, respectively. Acidic gas components, such as NO and SO2, both show slight inhibitive effects on Hg0 adsorption process probably owing to the competitive adsorption or the elimination of adsorption sites.

Recently, graphitic carbon nitride (g-C₃N₄) has been proven to be a novel and effective carbon-based adsorbent for elemental mercury (Hg⁰) removal in flue gas due to its peculiar π-conjugated electronic structure and chemical and thermal stability. However, the active sites and detailed reaction pathways occurring on the g-C₃N₄ surface are still unknown. Here, g-C₃N₄ nanoplates with abundant active edge sites (surface defects) are successfully prepared via a thermal polymerization method, which display good Hg⁰ adsorption ability. The adsorption behavior of Hg⁰ over g-C₃N₄ is further studied using quantum chemistry calculations based on density functional theory (DFT), aiming at gaining a better understanding of the Hg⁰ adsorption structures and bonding mechanisms on the g-C₃N₄ surface at the atomic level. The calculation results show that the adsorption of Hg⁰ on intact g-C₃N₄ surfaces is poor due to the stable chemical structure of intact g-C₃N₄ and lack of active electron orbitals. In contrast, g-C₃N₄ with surface defects, i.e., exposed C or N sites, possesses enhanced Hg⁰ adsorption ability probably owing to the unsaturated coordination bond environment and the formation of chemical bonds with mercury atoms at the defective sites. The location of defects also has a big influence on the mercury capture ability of g-C₃N₄. The exposed surface nitrogen is more favorable for mercury capture than the exposed surface carbon.

Two-dimensional transition-metal dichalcogenides have gained increasing concerns because of their distinct structural features and also display great potential in mercury removal. Herein, a defect-rich MoS2 nanosheet is synthesized by using hydrothermal method and applied for adsorptive capture of elemental mercury (Hg0) in simulated flue gas at low temperature. It exhibits excellent Hg0 removal performance due to its ultra-thin lamellar and defective structures with ample exposed adsorption sites. The Hg0 removal efficiency of the defective MoS2 nanosheet is all above 93% when the reaction temperature is within 25–150 °C. Besides, presence of NO has no influence on Hg0 removal, while SO2 subtly reduces the Hg0 removal efficiency due to competitive adsorption. Mo4+, S2−, and S22− ions take part in the Hg0 removal process, which transfers Hg0 into Mo–Hg amalgam and HgS. The process of Hg0 adsorption on the defective MoS2 nanosheet obeys the pseudo-first-order and pseudo-second-order kinetic model.

Hexagonal boron nitride (h-BN), as a novel carbon-free layered material, has received extensive attention owing to its high mechanical strength and excellent chemical and thermal stability. Herein,...

Mercury emission from industrial activities has become a major environmental health concern, because mercury is one of the most toxic metals encountered in the environment. Elemental mercury is the dominant Hg species in gas streams. Adsorption is regarded as a practical technique for Hg0 removal, for which developing efficient and economic adsorbents are needed. Chalcogenides have recently gained increasing research interest owing to their high binding affinity for Hg0. Chalcogen-based adsorbents include S-modified adsorbents, H2S- and SO2-activated adsorbents, polysulfide chalcogels, mineral sulfides and metal selenides. This article reviews chalcogen-based adsorbents for Hg0 capture from gas streams, with focus on removal performances, mechanisms, advantages and disadvantages. Results show that S modification, and H2S and SO2 activation generate a great variety of active sulfur species on the adsorbent surface, resulting in enhanced Hg0 removal activity. Sulfur species include elemental sulfur, sulfide, thiophene and sulfate. Nonetheless, removal efficiency decreases to some extent due to the presence of acidic flue gas components and steam. On the other hand, mineral sulfides and metal selenides exhibit outstanding Hg0 removal performances with fast adsorption rate, high mercury capacity and excellent resistance to SO2 and H2O. Yet most mineral sulfides and metal selenides perform well below 100 °C, which might limit industrial applications.

In this study, biochars prepared under 500–900 °C interacted with cellulose volatiles at 500 °C, and the effects of volatile–char interactions on the changes of biochar functional groups and its re...

A novel two-step sorption enhanced staged gasification of biomass for H2 production was proposed and studied using Aspen Plus software. An equilibrium model based on Gibbs free energy minimization was developed and validated. The results showed that the two-step process was more advantageous for H2 production compared with the conventional steam gasification and the one-step process. The independent control of each stage could realize a high temperature steam gasification in the first stage and a subsequent lower temperature steam reforming in the second stage, which thus promoted the gasification of biomass and benefited the water gas shift (WGS) reaction to produce more H2. Meanwhile, the in situ CO2 absorption of CaO in the second stage could enrich the H2 concentration in the product gas, and also further shifted the WGS reaction equilibrium to convert more CO to H2. With further introduction of catalyst for steam methane reforming (SMR), high-purity H2 with the concentration of 99.7 vol% and yield of 142.8 g/kg daf biomass could be achieved.

Pyrolysis is an important thermochemical route to decompose lignocellulose biomass into biogas, bio-oil, and biochar, which can be then converted into value-added biofuels, chemicals, and biomateri...

Metal chloride-impregnated seaweed bio-chars, derived from waste algae (Enteromorpha), are served as solid sorbents for Hg0 capture from simulated flue gas. The impacts of various metal chloride modification on Hg0 removal performance, i.e. FeCl3, CuCl2, ZnCl2, CoCl2, and CeCl3, are studied. The results display that the Hg0 removal performances of Enteromorpha derived bio-chars are greatly enhanced by immersing metal chlorides. FeCl3-and CeCl3-modified bio-chars exhibits the optimal Hg0 removal performance. Oxygen and NO show a promotional effect on Hg0 removal, whereas H2O suppresses Hg0 adsorption. Lower concentration of SO2 favors Hg0 removal, but higher concentration of SO2 inhibits Hg0 adsorption. Hg0 is oxidized by covalent chloride groups and metal oxides on the metal chloride-impregnated bio-chars.

Graphite-phase carbon nitrides (g-C3N4), composed of only C, N, and some impurity H, have been synthesized by direct thermal polymerization of urea in air and employed to capture elemental mercury ...

Air pollution caused by mercury emissions from combustion and pyrolysis of fossil fuels, biomass, and solid wastes is a major health issue. Elemental mercury (Hg0), the dominant species in flue gas, is poorly captured by actual control equipments because Hg0 has a high volatility and is insoluble in water. Alternatively, photocatalytic processes can oxidize Hg0 into Hg compounds that are easier to remove. Here we review the recent research on oxidative removal of Hg0 by photocatalysts, with focus on titanium dioxide, bismuthides, silver compounds and hybrid photocatalysts. We discuss the Hg0 removal performances and mechanisms of catalytic oxidation. The TiO2 photocatalyst often suffers from low absorption of solar energy and easy recombination of photoinduced electron–hole couples. BiOIO3 appears as a promising photocatalyst due to its high Hg0 oxidation activity under visible light irradiation. Silver carbonates and silver halides are newly developed visible-light-responsive photocatalysts for Hg0 removal. Fast separation and transformation of photogenerated electrons and holes control the performance of Hg0 removal by photocatalysts.

Here, an inexpensive, widely available, and environmentally benign precursor, guanidine hydrochloride, has been employed for the synthesis of graphitic carbon nitride and applied for elemental mercury adsorption. The GH600 attained via polycondensation of guanidine hydrochloride at 600 °C displays good mercury capture ability probably owing to the bigger BET surface area and the presence of chemisorbed oxygen species. The mercury removal performance of GH600 can be profoundly reinforced by modifying with small amounts of potassium iodide. The acidic gas components, such as NO and SO2, presents almost no impact on the Hg0 removal ability of KI-loaded GH600.

Integrated gasification combined cycle (IGCC) and solid oxide fuel cell (SOFC) systems are considered as the most promising clean coal technologies. Syngas derived from coal gasification is the major fuel sources for IGCC and SOFC power systems; however, large amounts of sulfur compounds, mainly in the form of hydrogen sulfide, are produced during gasification. Hydrogen sulfide has to be removed prior to syngas utilization to protect downstream equipment from high-temperature corrosion. Therefore, hydrogen sulfide removal from raw syngas plays a key role in successful application of IGCC and SOFC systems. Hot coal gas desulfurization using solid sorbents is a more efficient technique for hydrogen sulfide removal, compared with conventional cold coal gas desulfurization with amine solution. This article reviews solid sorbents for high-temperature desulfurization, e.g., transition metal oxides, rare-earth oxides, spinel oxides, perovskite oxides, nanoelemental metals and mesoporous desulfurizers. Composite oxides that combine the properties of diverse metal oxides are promising candidates for hot coal gas desulfurization. The extensive background knowledge and the state of the art on high-temperature sorbents for hydrogen sulfide removal in this review provides inspiration and guidance to develop new cost-effective sorbents.

Graphitic carbon nitride (g-C3N4) as a 2D layered carbon material with exceptional electronic, thermal, and catalytic property has attracted increasing research attention. A porous g-C3N4 nanosheet (PCNN) has been synthesized via a facile two-step thermal etching oxidation approach and applied in low-temperature elemental mercury (Hg0) removal. PCNN exhibits good reactivity toward Hg0 adsorption at temperatures of 40–200 °C. CuO impregnation can prominently enhance the Hg0 capture performance of PCNN on account of the intimate interaction of CuO and PCNN. Temperature has a positive effect on Hg0 capture ability of PCNN and CuO/PCNN. Hg0 is mainly oxidized by the chemisorbed oxygen species that are generated from the O–C–N of g-C3N4 and the lattice oxygen of CuO. CuO modification can efficiently activate g-C3N4 with significantly improved Hg0 capture ability presumably owing to the Mott–Schottky effect at the interface of CuO and g-C3N4.

Graphene oxide (GO) nanosheets of planar flake-like structures are fabricated by using a modified Hummers method. Fractal theory is introduced to characterize the topological surfaces and porous structures of the GO nanosheets, the fractal dimensions estimated by using box-counting method are close to 2, indicating that the GO nanosheets possess perfectly smooth surfaces, which agrees well with high resolution transmission electron microscopy (HRTEM) images, and the higher porous fractal dimension of 2.74 determined by using Frenkel-Halsey-Hill (FHH) model suggests a wealth of microporous structures of the GO nanosheets.

Coke formation during the rapid quenching of volatiles produced from fast pyrolysis of cellulose was investigated in a fixed-bed reactor. The coke sample was collected at the reactor outlet. The chemical structure of the coke was characterized with a Fourier Transform Infrared spectroscopy (FTIR) and a Raman spectroscopy. The thermal stability of the coke was determined with a thermogravimetric analyzer. The results showed that the coke yield decreased from 19.70 wt% to 14.10 wt% with the pyrolysis temperature increasing from 400 to 600 °C. A high oxygen content of 41.31–46.04 wt% was observed for the cokes which was quite similar as that of volatiles, illustrating the close relationship between volatile composition and coke formation. The FTIR results showed that the coke contained abundant oxygen-containing functional groups such as alcohol O–H, aldehydes/ketones C O and alcohol/ether C–O, and aliphatic C–H groups. With the combination of the Raman spectroscopy results, the coke structure appeared to be more aliphatic than polyaromatic. Changes in pyrolysis temperature would alter the coke properties by changing the volatile composition. The dominant coking reactions were finally inferred as the condensation/polymerization of anhydrosugars and aldehydes/ketones.

Sorption enhanced gasification of biomass is a novel technology for high purity H2 production and simultaneous carbon negative emission. The effect of CaO on the H2 production process was normally qualitatively explained. To quantitatively study the enhancing mechanism of CaO, the sorption enhanced gasification of cellulose for H2 rich syngas production was carried out in a fixed-bed pyrolysis-gasification system, the amount of CO2 absorbed, the carbon conversion rate of volatiles as well as the changes in the role of CaO under different gasification conditions were quantitatively studied. The results showed that CaO acted as a CO2 absorbent and/or a catalyst depending on the gasification temperature. It functioned as both a CO2 absorbent and a catalyst at lower temperatures of 550–700 °C, and a maximum amount of CO2 absorbed by CaO was achieved at 550 °C as 189.88 ml/g cellulose, CaO catalyzed the volatiles gasification to produce more H2 and achieve more sufficiently conversion with increasing temperature. While when the gasification temperature ≥750 °C, CaO acted only as a catalyst. The optimized condition for sorption enhanced pyrolysis-gasification of cellulose was of gasification temperature of 650 °C and of mass ratio of CaO/cellulose of ≥4, under which the actual carbon conversion rate of volatiles achieved ∼90 wt.%.

The mercury emission pollution of coal-fired power plants has posed big threatens to the human heath and the environment. Here, a graphene-analogous carbon nitride (GCN) is used to capture Hg0 from simulated flue gas in a fixed-bed reactor at low temperatures. The GCN displays good Hg0 adsorption capability with Hg0 removal efficiency of 32.4–69.4% within 25–200 °C. CuS incorporation can greatly reinforce the Hg0 capture ability of the GCN. The optimal loading value of CuS is 10 wt%. Complete mercury capture is reached over 10CuS/GCN in the temperature range of 25–100 °C. Existence of NO marginally suppresses the Hg0 removal process, while presence of SO2 has hardly influence on Hg0 capture. The copper and polysulfide active sites as well as the graphene-analogous nanosheet structure of the GCN contribute to the prominent Hg0 capture performance of CuS-anchored GCN.

Graphitic carbon nitride (g-C3N4) as a nanocarbon material has attracted accelerated concern because of its layered structure, facile synthesis route and lower capital cost. Here, three kinds of g-C3N4 are fabricated via simply thermal polycondensation of dicyandiamide, melamine, and urea at high temperature, and they are applied for elemental mercury (Hg0) capture in a fixed-bed reactor. We found that the g-C3N4 attained by urea pyrolysis exhibited prominent Hg0 capture ability with Hg0 removal efficiency of ∼84% which is much higher than that of the g-C3N4 derived from dicyandiamide and melamine pyrolysis, probably attributed to its bigger BET surface area and pore volume.

The Co3O4/g-C3N4 hybrids are constructed via the incipient wetness impregnation method by depositing Co3O4 onto the exterior of g-C3N4, and then employed for Hg0 capture within 60&ndash, 240 &deg, C. The results show that the Co3O4/g-C3N4 hybrid with a Co3O4 content of 12 wt% performs optimally with the highest Hg0 removal efficiency of ~100% at or above 120 &deg, C. The high performances of the Co3O4/g-C3N4 hybrids are probably attributed to the tight interfacial contact between Co3O4 and g-C3N4, with its improved electron transfer, inferring that cobalt oxide and g-C3N4 display a cooperative effect towards Hg0 removal. NO and SO2 shows a significant suppressive influence on the mercury capture performance, plausibly owing to the competing adsorption and side reactions.

The separation of Pd and CeO2 on the inner surface of controlled porous glass (CPG, obtained from phase-separated borosilicate glass after extraction) yields long-term stable and highly active methane combustion catalysts. However, the limited availability of the CPG makes such catalysts highly expensive and limits their applicability. In this work, porous silica obtained from acid leached rice husks after calcination (RHS) was used as a sustainable, cheap and broadly available substitute for the above mentioned CPG. RHS-supported Pd-CeO2 with separated CeO2 clusters and Pd nanoparticles was fabricated via subsequent impregnation/calcination of molten cerium nitrate and different amounts of palladium nitrate solution. The Pd/CeO2/RHS catalysts were employed for the catalytic methane combustion in the temperature range of 150–500 °C under methane lean conditions (1000 ppm) in a simulated off-gas consisting of 9.0 vol% O2, and 5.5 vol% CO2 balanced with N2. Additionally, tests with 10.5 vol% H2O as co-feed were carried out. The results revealed that the RHS-supported catalysts reached the performance of the cost intensive benchmark catalyst based on CPG. The incorporation of Pd-CeO2 into RHS additionally improved water-resistance compared to solely Pd/CeO2 lowering the required temperature for methane combustion in presence of 10.5 vol% H2O to values significantly below 500 °C (T90 = 425 °C).

Effective charge-carrier separation and molecular oxygen activation are crucial factors for photocatalytic environmental purification. Herein, an efficient Fe-doped Bi7O9I3 microflowers photocatalyst was synthesized. It was discovered that Fe doping could not only tune the concentration of oxygen vacancies of Bi7O9I3 to optimize the dissociation of excitons, but also promote the separation of charge-carriers and the activation of oxygen molecules. Meanwhile, the inducing of surface oxygen vacancies and Fe3+/Fe2+ by Fe optimal doping can act as the activation center for catalytic reactions, which also significantly enhances the photocatalytic activity. Benefiting from the optimized properties, the photocatalytic activity of Fe-doped Bi7O9I3 photocatalyst has been significantly improved by more than 4 times. Finally, we proposed that a highly efficient catalytic oxidation reaction mechanism can be achieved via modulating Fe doping to induce oxygen vacancies to promote charge separation and molecular oxygen activation. This work provides a novel approach for designing efficient photocatalysts.

The high-temperature H2S removal was conducted over xLayCu/ZSM-5 sorbents prepared via citric acid method. The sorbents showed good desulphurization performance, the maximal sulfur capacity of 2240.5 μmol S/g over 5La5Cu/ZSM-5 was achieved at 700 °C. The presence of H2 obviously shortened the breakthrough time and reduced the sulfur capacity. However, the presence of CO had little influence on the desulphurization behavior. The sulfidation activity of La2O3 can be significantly enhanced by introduction of Cu due to the intimate mixing of La2O3 and CuO, the formation of La2CuO4 compound.

Performance of CeO2-La2O3/ZSM-5 sorbents for sulfur removal was examined at temperature ranging from 500 oC to 700 oC. The sulfur capacity of 5Ce5La/ZSM-5 was much bigger than that of CeO2/ZSM-5. H2 had a negative impact on the sulfidation; however, CO had little influence on sulfur removal. The characterization results showed that CeO2 and La2O3 were well dispersed on ZSM-5 because of the intimate admixing of La2O3 and CeO2, the major sulfidation products were Ce2O2S and La2O2S, the XRD and SEM results revealed that ZSM-5 structure could remain intact during preparation and sulfidation process, the H2-TPR showed that the reducibility of CeO2 can be remarkably enhanced by addition of La.

Perovskite LaMnO3/ZSM-5 was used for reactive adsorption of hydrogen sulfide at 500–700 °C. The sorbents showed good desulphurization performance, the highest sulfur capacity of 1020 µmol S/g over 5La5Mn/ZSM-5 was obtained at 600 °C. The reducing gases (H2 and CO) can obviously shorten the breakthrough time and reduce the sulfur capacity. Incorporating Mn ions into La2O3 lattice improved the sulfidation activity due to the formation of perovskite LaMnO3 with good reducibility and structure stability.

xCeyMn/ZSM-5 sorbents were prepared using sol–gel method and employed for H2S removal in the temperature range of 600–800 °C. The sorbents exhibited high performance in sulfur removal due to the cooperative effect of CeO2 and MnOx. The presence of H2 was unfavorable for sulfidation and obviously shortened the breakthrough time and reduced the sulfur capacity. However, the existence of CO had little impact on the sulfur-removal performance. The characterization results revealed that the ZSM-5 structure remained intact during preparation and sulfidation process. And active species, such as CeO2 and Mn2O3, were well dispersed on ZSM-5, which would suppress the mechanical disintegration and improve the thermal stability of xCeyMn/ZSM-5.

A CuS microsphere is facilely synthesized by using one-pot template-free hydrothermal method and applied for the capture of elemental mercury (Hg0) from flue gas at low temperature. It exhibits outstanding Hg0 removal performance due to the presence of multiform sulfur active sites and the spherical-like morphology with abundant exposed active sites. The Hg0 removal efficiencies are all nearly 100% within 25−100 °C. Besides, NO and SO2 exert negligible impacts on Hg0 adsorption over the CuS microsphere. Cu2+ and S2− ions both participate in mercury removal process, which converts Hg0 into HgS. Therefore, the CuS microsphere seems to be a promising non-carbon adsorbent for Hg0 capture from flue gas.

Graphitic carbon nitride (g-C3N4) has attracted increasing interest owing to its unique electronic property, facile synthesis, chemical and thermal stability. In this work, a graphene-like g-C3N4 is synthesized by direct thermal polymerization of environmentally benign guanidine thiocyanate. The graphene-like g-C3N4 is further modified with NH4Br via incipient-wetness impregnation approach and applied to remove Hg0 from coal-fired flue gas. The results indicate that the optimal polymerization temperature is 700 °C. The Hg0 removal performance of g-C3N4 is enhanced by NH4Br modification. The optimal NH4Br content and reaction temperature range are 3 wt% and 120–180 °C, respectively. NO exerts a promotional effect on mercury removal, while SO2 displays a dual impact on Hg0 adsorption. Low concentration of SO2 is beneficial for mercury removal, whereas high concentration of SO2 restrains Hg0 removal to some extent. The edge carbons of g-C3N4 may function as the principal reactive sites for Hg0 removal. The Hg0 might be captured on the armchair edge carbons of the g-C3N4 by forming covalent carbon-mercury bonds via Lewis acid-base conjugation. Loading NH4Br onto g-C3N4 may produce carbenium bromine ion pairs at the zigzag edge carbons that represent as oxidation sites, which convert Hg0 into HgBr2. Besides, the adsorbed Hg0 may also be oxidized into HgO by the chemisorbed oxygen.

The [Formula: see text]-conjugated graphitic carbon nitride (g-C3N[Formula: see text] has gained increasing attention due to its unique electronic property, accessible nanoporous framework, chemical and thermal stability. The nanopore structure of g-C3N4 is believed to be favorable for adsorption process owing to the improved mass transfer process. Here, a honeycomb-like mesoporous g-C3N4 is synthesized by direct thermal polymerization of the mixture of urea and ammonium carbonate. It displays an excellent affinity with elemental mercury at reaction temperatures of 50–[Formula: see text]C. The optimal mass ratio of ammonium carbonate/urea is 2 with the highest Hg0 removal efficiency of 87.5% at [Formula: see text]C. NO has a negative effect on Hg0 removal, whereas SO2 slightly reinforces Hg0 adsorption in the presence of oxygen. The Hg0 is probably captured on the carbon atoms of g-C3N4 by producing a covalent carbon-mercury (C–Hg) bond via Lewis acid-base interactions.

Mercury emission, derived from natural gas exploitation, metal sintering, coal gasification and combustion, gold mining, etc., has posed great threaten to the environment and human beings due to its volatility, mobility, toxicity, and bioaccumulation in ecosystem and food chains. Adsorption using carbon materials is regarded as one of the most promising techniques for mercury emission control due to its simple equipment, convenient operation, high removing efficacy, less secondary pollution, etc. This review comments the new research progress of elemental mercury capture by novel carbon-based sorbents in recent five years, particularly emerging carbon materials, such as bio-chars, graphene and graphene oxide, carbon nanotubes and nanofibers, carbon spheres, carbon aerogels, metal-organic frameworks, and graphitic carbon nitrides. The mercury removal performances and reaction mechanisms of diverse carbon-based sorbents along with their merits and drawbacks are fully discussed, which aims to strengthen the understanding of this emerging research topic and outline future research directions for the development of sustainable, recyclable, and cost-effective carbon-based mercury sorbents.

Many factors influence human facial morphology, including genetics, age, nutrition, biomechanical forces, and endocrine factors. Moreover, facial features clearly differ between males and females, and these differences are driven primarily by the influence of sex hormones during growth and development. Specific genetic variants are known to influence circulating sex hormone levels in humans, which we hypothesize, in turn, affect facial features. In this study, we investigated the effects of testosterone-related genetic variants on facial morphology. We tested 32 genetic variants across 22 candidate genes related to levels of testosterone, sex hormone-binding globulin (SHGB) and dehydroepiandrosterone sulfate (DHEAS) in three cohorts of healthy individuals for which 3D facial surface images were available (Pittsburgh 3DFN, Penn State and ALSPAC cohorts; total n = 7418). Facial shape was described using a recently developed extension of the dense-surface correspondence approach, in which the 3D facial surface was partitioned into a set of 63 hierarchically organized modules. Each variant was tested against each of the facial surface modules in a multivariate genetic association-testing framework and meta-analyzed. Additionally, the association between these candidate SNPs and five facial ratios was investigated in the Pittsburgh 3DFN cohort. Two significant associations involving intronic variants of SHBG were found: both rs12150660 (p = 1.07E-07) and rs1799941 (p = 6.15E-06) showed an effect on mandible shape. Rs8023580 (an intronic variant of NR2F2-AS1) showed an association with the total and upper facial width to height ratios (p = 9.61E-04 and p = 7.35E-04, respectively). These results indicate that testosterone-related genetic variants affect normal-range facial morphology, and in particular, facial features known to exhibit strong sexual dimorphism in humans. ispartof: Frontiers in Genetics vol:9 ispartof: location:Switzerland status: published

Graphitic carbon nitride (g-C3N4) with unique and versatile properties has gained increasing research concerns. Here, CuO/g-C3N4 nanocomposite is fabricated and employed for gas-phase mercury (Hg0) removal at low temperature. Pure g-C3N4 performs well toward Hg0 adsorption at 40–200 °C with the optimal Hg0 removal efficiency of ~ 54.5% at 120 °C. CuO-modification can significantly promote the Hg0 capture ability of g-C3N4, probably due to the intimate interface contact of CuO and g-C3N4. The Hg0 removal efficiency of g-C3N4 first increases and then decreases with rising temperature, while temperature shows a promotional effect on Hg0 removal efficiency of CuO/g-C3N4. Hg0 is oxidized into HgO by the chemisorbed oxygen originated from the O–C–N structure of g-C3N4 and the lattice oxygen of CuO. g-C3N4 can be efficiently activated by modifying with CuO toward enhanced Hg0 oxidation ability, presumably attributed to the electron transfer at the interface of CuO and g-C3N4.

By using the density functional theory, the first-principles calculations were used to research the gas sensitive properties of small gas molecules (H 2 S, SO 2 , NH 3 , H 2 O, O 2 ) on the blue phosphorene monolayer. Parameters of adsorption energy, adsorption distance as well as charge transfer helped us find the optimum adsorption point from three adsorption sites: Center; P; Bridge. By the results of electronic density of states and electron localization function, we can make a conclusion that these five gas molecules are physically adsorbed on blue phosphorene. Besides, it is also clear that small gas molecules adsorption can tune the band gap and work function of blue phosphorene in different degrees. Our studies can provide a theoretical guidance for practical applications.

Fe2O3, Co3O4 and NiO nanoparticles were prepared via a citrate method and further functionalized with Pd by impregnation. The pure oxides as well as Pd/Fe2O3, Pd/Co3O4, and Pd/NiO (1, 5 and 10 wt % Pd) were employed for catalytic methane combustion under methane lean (1 vol %)/oxygen rich (18 vol %, balanced with nitrogen) conditions. Already, the pure metal oxides showed a high catalytic activity leading to complete conversion temperature of T100 ≤ 500 °C. H2-TPR (Temperature-programmed reduction) experiments revealed that Pd-functionalized metal oxides exhibited enhanced redox activity compared to the pure oxides leading to improved catalytic combustion activity at lower temperatures. At a loading of 1 wt % Pd, 1Pd/Co3O4 (T100 = 360 °C) outperforms 1Pd/Fe2O3 (T100 = 410 °C) as well as 1Pd/NiO (T100 = 380 °C). At a loading of 10 wt % Pd, T100 could only be slightly reduced in all cases. 1Pd/Co3O4 and 1Pd/NiO show reasonable stability over 70 h on stream at T100. XPS (X-ray photoelectron spectroscopy) and STEM (Scanning transmission electron microscopy) investigations revealed strong interactions between Pd and NiO as well as Co3O4, respectively, leading to dynamic transformations and reoxidation of Pd due to solid state reactions, which leads to the high long-term stability.

It is well known that the support of sorbents plays a crucial role in gas diffusion and sulfidation reaction, and the supports of big specific areas and large pore volumes are beneficial for H2S adsorption [1]. Mesoporous carbon aerogel, a 3-D network structure of interconnected nanosized primary particles, is regarded to be a preferable support. Carbon aerogels have a unique porous structure, including well-developed and controlled interparticle mesopores and intraparticle micropores, huge pore volume, and large specific surface area. Additionally, the carbon aerogels remain stable under high temperature, and they could be formed into various shapes and can be used without any further forming treatment, which makes these materials attractive as the support of the desulfurizer [2, 3, 4].

Coal is found in huge amounts throughout the world and has lower cost as compared to other fossil fuels, it represents at present about 70% of the world’s proven fossil fuel resources; therefore, coal is probably to remain one of the most important sources of primary energy for a long time, playing a strategic role in the medium–long-term energy production systems. However, coal utilization has a few negative impacts on the environment and atmosphere; the critical issue in promoting coal utilization is environmental pollution control without reducing the energy efficiency. Coal is a complex chemical mixture composed of carbon, hydrogen, and dozens of trace elements. When coal is severed as a fuel source, some of these elements would convert to gaseous emissions, such as sulfur dioxide (SO2) or hydrogen sulfide (H2S), nitrogen oxides (NO x ), mercury, and other chemical by-products via the coal combustion or thermal decomposition. These emissions have been established to possess detrimental effects on the environment and human health, which contributes to acid rain, lung cancer, and cardiovascular disease.

The IGCC coarse gas derived from coal gasification process usually contains large amounts of sulfur containing components, such as H2S, COS, and CS2, 90% of them are H2S (~0.1 to 1.5 vol.%) which could cause severe corrosion of the pipelines, facilities, and catalysts in the subsequent coal gas conversion process; thus, the sulfur compounds need to be removed prior to syngas utilization. The hot coal gases are often purified with solid sorbents (single metal oxides or bimetal oxides), namely, called as dry desulfurization. Recently, the most commonly used sorbents are transition-metal oxides and their composites, for instance, zinc oxide, copper oxide, ferric oxide, and manganese oxide as well as zinc ferrite, zinc titanate, which are called as the first-generation high-temperature desulfurizers (FHDs)

Hydrogen sulfide, the chemical compound with the formula H2S, is a colorless gas with the characteristic foul odor of rotten eggs, and it is very poisonous, corrosive, acidic, and flammable [1]. Swedish chemist Carl Wilhelm Scheele has firstly discovered hydrogen sulfide in 1777. Hydrogen sulfide usually results from the microbial breakdown of organic matters in the absence of oxygen gas, such as in swamps and sewers; this process is commonly known as anaerobic digestion. Hydrogen sulfide could also occur in volcanic gases, natural gas, and in some sources of well water. The human body produces small amounts of hydrogen sulfide and uses it as a signaling molecule.

OBJECTIVE Little consistent evidence is available for the association between the risk of non-syndromic cleft lip with or without cleft palate (NSCL/P) and any of the individual genes in the folate/homocysteine metabolic pathway. We investigated the genes in the folate pathway to further clarify its potential influence on the risk of NSCL/P considering gene-gene (G×G) interaction. SUBJECTS AND METHODS We selected markers in 18 genes from the pathway and applied Cordell's method to test for G×G interaction using 1,908 NSCL/P case-parent trios ascertained in an international consortium where a genomewide association study (GWAS) of oral clefts was conducted. RESULTS We found intriguing signals among Asian and European ancestry groups for G×G interaction between markers in betaine-homocysteine methyltransferase gene (BHMT/BHMT2) and dimethylglycine dehydrogenase gene (DMGDH) attaining genomewide significance. In the pooled data, the top significant interaction was found between rs13158309 (BHMT) and rs10514154 (DMGDH, p = 1.45 × 10-12 ). CONCLUSIONS Our study illustrated the importance of taking into account potential G×G interaction for genetic association analysis in NSCL/P, and this study suggested both BHMT/BHMT2 and DMGDH should be considered as candidate genes for NSCL/P in future studies.

We predict that there is a critical value of Al2O3/ZnO nano thin interface thickness based on two assumptions according to an interesting phenomenon, which the thermal conductivity (TC) trend of Al2O3/ZnO nano thin interface is consistent with that of relevant single nano thin interface when the nano thin interface thickness is > 300 nm; however, TC of Al2O3/ZnO nano thin interface is higher than that of relevant single nano thin interface when the thin films thickness is < 10 nm. This prediction may build a basis for the understanding of interface between two different oxide materials. It implies an idea for new generation of semiconductor devices manufacturing.

Zeolite (ZSM-5), as a kind of carbon-free sorbent or catalyst, has been widely applied in many fields due to its big surface area, good chemical and thermal stability, and excellent adsorption performance. In this study, Mn-Fe modified ZSM-5 are synthesized via sol-gel approach and employed for elemental mercury (Hg0) removal from simulated flue gas at low temperature. The results show that pure ZSM-5 shows poor mercury capture ability with Hg0 removal efficiency of ~8.5–18.8% at 100–300 °C. Mn or Fe modification can both efficiently enhance the Hg0 removal efficiency of the ZSM-5. The sorbent with Mn/Fe molar ratio of 1:2 exhibits the optimal mercury capture ability with the highest Hg0 removal efficiency near 100% at temperatures of 200 and 250 °C due to the significant synergy effect between Mn2O3 and Fe2O3. The presence of NO has a negligible effect on the Hg0 removal performance of Mn/ZSM-5 and Mn1Fe2/ZSM-5, while the existence of SO2 considerably degrades the Hg0 capture performance of Mn/ZSM-5 owing to competing adsorption and side reactions. Fe addition can protect Mn active sites from SO2 poisoning and thereby enhancing the SO2 resistance of Mn/ZSM-5 to some extent.

The kinetic behavior of gas phase mercury sorption on ZSM-5 supported cerium- and lanthanum-based composite oxides in the temperature range of 120–240∘C is investigated. The Hg0 sorption abilities all first increase and then decrease with the elevation of the temperatures, the cerium-based composite oxides show better Hg0 sorption abilities than that of the lanthanum-based composite oxides. CeO2–Mn2O3/ZSM-5 performs the best Hg0 sorption ability with Hg0 removal efficiency of nearly 100% at 180∘C. Doping Cu or Mn into La2O3 lattice causes the decrease in the Hg0 removal efficiency of the lanthanum-based composite oxides due to the formation of perovskite or perovskite-like compounds. The sorption of elemental mercury over metal oxides is governed both by diffusion processes as well as chemical reactions, and the sorption of elemental mercury on the cerium- and lanthanum-based composite oxides are chemisorption processes.

To investigate multi-residual pesticide monitoring data in commercial Chinese herbal medicines on major markets, an easy, rapid, and selective gas chromatography with mass spectrometry (GC/MS/MS) method was established for simultaneously determining multi-residual pesticides including organochlorine, pyrethroid, carbamate, and organophosphorus pesticides in Chinese herbal medicines. The analytical method was based on an efficient extraction procedure and further cleanup steps by solid-phase extraction columns, yielding recovery rates in the range of 70.0–120.0 % for the majority of pesticides, except for hexachlorobenze, diazinon, β-HCH, δ-HCH, and omethoate, with precision values expressed as relative standard deviation of 0.1–14.7 %. The limits of detection of the established GC/MS/MS method for all investigated pesticides ranged from 0.01 to 3.6 μg kg−1 and limits of quantification from 0.03 to 11.88 μg kg−1. With this validated method, multi-residual pesticides of 132 Chinese herbal medicine samples were analyzed. The monitoring results indicated that pesticide residue was found in 74 samples. In total, 51 pesticides were found with detection rate ranging from 0.76 to 18.94 %. An 82.3 % of positive pesticides were found in less than 6 % of samples. Hexachlorobenzene was found in 25 samples, quintozene in 15 samples, and acephate and simazine in 13 samples. Concentrations of pesticide residue from monitoring data obtained ranged from 0.5 to 203.5 μg kg−1. The simple and rapid method can be used as routine analysis method in multi-residual pesticide monitoring of Chinese herbal medicines.

Low-temperature hydrogen production from natural gas via steam reforming requires novel processing concepts as well as stable catalysts. A process using zeolite membranes of the type MFI (Mobile FIve) was used to enrich natural gas with liquefied petroleum gas (LPG) alkanes (in particular, propane and n-butane), in order to improve the hydrogen production from this mixture at a reduced temperature. For this purpose, a catalyst precursor based on Rh single-sites (1 mol% Rh) on alumina was transformed in situ to a Rh1/Al2O3 catalyst possessing better performance capabilities compared with commercial catalysts. A wet raw natural gas (57.6 vol% CH4) was fully reformed at 650 &deg, C, with 1 bar absolute pressure over the Rh1/Al2O3 at a steam to carbon ratio S/C = 4, yielding 74.7% H2. However, at 350 &deg, C only 21 vol% H2 was obtained under these conditions. The second mixture, enriched with LPG, was obtained from the raw gas after the membrane process and contained only 25.2 vol% CH4. From this second mixture, 47 vol% H2 was generated at 350 &deg, C after steam reforming over the Rh1/Al2O3 catalyst at S/C = 4. At S/C = 1 conversion was suppressed for both gas mixtures. Single alkane reforming of C2&ndash, C4 showed different sensitivity for side reactions, e.g., methanation between 350 and 650 &deg, C. These results contribute to ongoing research in the field of low-temperature hydrogen release from natural gas alkanes for fuel cell applications as well as for pre-reforming processes.

External contamination sources (pesticide residues, heavy metals, solvent residues, and aflatoxin) and measurements and restriction standards that were published in previous studies, along with the authors' data were analyzed. It was found that the key to addressing the contamination is to place contamination source under control using mandatory standards.