Algae play a significant role in regulating the biogeochemical cycle of mercury(Hg),particularly its highly toxicform,methylmercury(MeHg),within wetlands and lakes.However,despite their widespread presence in paddyfield...Algae play a significant role in regulating the biogeochemical cycle of mercury(Hg),particularly its highly toxicform,methylmercury(MeHg),within wetlands and lakes.However,despite their widespread presence in paddyfields,their specific effects on MeHg dynamics are not yet fully understood.This study investigated the algae-mediated distribution and accumulation of MeHg in Hg-contaminated paddyfields,utilizingfield investigationand microcosm experiment.The results indicated that algae demonstrated a multi-source uptake pattern and hada high capacity to accumulate both total Hg(926±1.69 ng/g)and MeHg(83.6±1.12 ng/g).This accumulationwas predominantly characterized by inorganic Hg species,accounting for 88.4%.Algal capsular extracellularpolymeric substance(EPS)exhibited higher levels of labile organic fractions,such as cysteine(0.59±0.01μg/g),and increased MeHg concentration(84.2±4.51 ng/kg),which contrasted with the levels found in colloidal EPS(0.06±0.01 ng/g and 15.0±1.61 ng/kg).Meanwhile,a significant correlation(P<0.05)was observed betweenthiol-containing cysteine and MeHg concentrations in algal EPS.Algal incubation further revealed the formationof mineral-EPS-algae aggregates on algal surfaces,accompanied by the colonization of Hg-methylating bacteria.Therefore,the surface of algae may form a favorable matrix for microbial Hg methylation and the accumulationof MeHg.Thesefindings emphasize the crucial roles of algae in regulating MeHg dynamics within algae-watersystem in Hg-contaminated paddyfields.展开更多
Mercury(Hg),especially methylmercury(MeHg),accumulation in rice grain due to rice paddy possessing conditions conducive to Hg methylation has led to human Hg exposure through consumption of rice-based daily meals.In a...Mercury(Hg),especially methylmercury(MeHg),accumulation in rice grain due to rice paddy possessing conditions conducive to Hg methylation has led to human Hg exposure through consumption of rice-based daily meals.In addition to being a food staple,rice is widely used as a raw material to produce a vast variety of processed food products.Little is known about Hg levels in snacking rice-food products and potential Hg exposure from consumption of them,besides previous studies on infant rice cereals.Aiming to provide complementary information for a more complete assessment on Hg exposure risk originated from Hgcontaining rice,this study determined total Hg(THg)and MeHg levels in 195 rice-containing and rice-free processed food products covering all major types of snack foods marketed in China and the estimated daily intake(EDI)of dietary Hg from the consumption of these foods.The results clearly showed THg and MeHg contents in rice-containing foods were significantly higher than rice-free products,suggesting the transfer of Hg and MeHg from the rice to the end products,even after manufacturing processes.Moreover,significant positive correlations were observed between THg,MeHg,or MeHg/THg ratio and rice content for samples containing multiple grains as ingredients,further indicating the deciding role of rice for Hg levels in the end food products.Although the EDI of THg and MeHg via ricebased food products were relatively low compared to the reference dose,it should be considered these snacking food products would contribute additive Hg intake outside of the daily regular meals.展开更多
The high-pressure mercury intrusion (HPMI) experiment is widely used to assess the pore architecture oftight sandstone reservoirs. However, the conventional analysis of the high- pressure mercury intrusionhas always f...The high-pressure mercury intrusion (HPMI) experiment is widely used to assess the pore architecture oftight sandstone reservoirs. However, the conventional analysis of the high- pressure mercury intrusionhas always focused on the mercury injection curves themselves, neglecting the important geologicalinformation conveyed by the mercury ejection curves. This paper quantitatively describes the fractalcharacteristics of ejection curves by using four fractal models, i.e.,. Menger model, Thermodynamicmodel, Sierpinski model, and multi- fractal model. In comparison with mercury injection curves, weexplore the fractal significance of mercury ejection curves and define the applicability of different fractalmodels in characterizing pore architectures. Investigated tight sandstone samples can be divided intofour types (Types A, B, C and D) based on porosity, permeability, and mercury removal efficiency. Type Dsamples are unique in that they have higher permeability (>0.6 mD) but lower mercury removal effi-ciency (<35%). Fractal studies of the mercury injection curve show that it mainly reflects the pore throatcharacteristics, while the mercury ejection curve serves to reveal the pore features, and porosity andpermeability correlate well with the fractal dimension of the injection curve, while mercury removalefficiency correlates only with the Ds' value of the ejection curve. The studies on the mercury ejectioncurves also reveal that the small pores and micropores of the Type C and Type D samples are moredeveloped, with varying pore architecture. The fractal dimension Ds' value of Type D samples is greaterthan that of Type C samples, and the dissolution of Type D samples is more intense than that of Type Csamples, which further indicates that the Type D samples are smaller in pore size, rougher in surface, andwith greater difficulty for the hydrocarbon to enter, resulting in their reservoir capacity probably lessthan that of Type C samples. In this regard, the important information characterized by the mercuryejection curve should be considered in evaluating the tight sandstone reservoirs. Finally, the Menger andThermodynamic models prove to be more suitable for describing the total pore architecture, while theSierpinski model is better for characterizing the variability of the interconnected pores.展开更多
Mercury removal from coal combustion flue gas remains a significant challenge for environmental protection due to the lack of cost-effective sorbents.In this study,a series of red mud(RM)-based sorbents impregnated wi...Mercury removal from coal combustion flue gas remains a significant challenge for environmental protection due to the lack of cost-effective sorbents.In this study,a series of red mud(RM)-based sorbents impregnated with sodium halides(NaBr and NaI)are presented to capture elemental mercury(Hg^(0))from flue gas.The modified RM underwent comprehensive characterization,including analysis of its textural qualities,crystal structure,chemical composition,and thermal properties.The results indicate that the halide impregnation substantially impacts the surface area and pore size of the RM.Hg^(0) removal performance was evaluated on a fixed-bed reactor in simulated flue gas(consisting of N_(2),O_(2),CO_(2),NO and SO_(2),etc.)on a modified RM.At an optimal adsorption temperature of 160℃,NaI-modified sorbent(RMI5)offers a removal efficiency of 98%in a mixture of gas,including O_(2),NO and HCl.Furthermore,pseudo-second-order model fitting results demonstrate the chemisorption mechanism for the adsorption of Hg^(0) in kinetic investigations.展开更多
Since scarce knowledge of soil mercury(Hg)concentrations and risks in the vulnerable Xinjiang,topsoils(0-15 cm)from its typical landscapes were extensively sampled.Topsoil total mercury(THg)concentrations varied broad...Since scarce knowledge of soil mercury(Hg)concentrations and risks in the vulnerable Xinjiang,topsoils(0-15 cm)from its typical landscapes were extensively sampled.Topsoil total mercury(THg)concentrations varied broadly between 0.9 and 35.3 ng/g,of which16.8%exceeded the background value of soil Hg for Xinjiang.Topsoil THg concentrations across various landscapes exhibited a declining order:farmland(11.7±6.0 ng/g)>grassland(10.5±8.5 ng/g)>woodland(10.2±8.2 ng/g)>desert(7.0±5.8 ng/g).The average topsoil THg concentration was higher in northwestern Xinjiang(11.3±7.2 ng/g)than that in southeastern Xinjiang(6.3±6.1 ng/g).Relatively high topsoil THg concentrations were observed near the cities with intensive human activities,followed by a gradual decline to the surroundings.The concentrations of topsoil THg were strongly correlated with the contents of total organic carbon(TOC),clay,silty,and sandy,and the distance from each sampling site to its nearest city,suggesting that the variation of topsoil Hg was significantly influenced by TOC content,soil granularity,and anthropogenic Hg emissions.Silty and TOC were the principal affecting factors,explaining 48.7%and 7.9%of the THg variation,respectively.The contamination and potential ecological risk evaluations revealed that topsoils in regions with dense populations were polluted with Hg and contained higher potential ecological risks.The health risk evaluations indicated that exposure risks of topsoil Hg were higher for children than those for adults.Fortunately,topsoil Hg posed acceptable risks to human health.展开更多
Carbon-supported mercury catalysts are extensivelyemployed in calcium carbide-based polyvinyl chloride(PVC)industries,but the usage of mercury-based catalysts can pose an environmental threat due to the release of mer...Carbon-supported mercury catalysts are extensivelyemployed in calcium carbide-based polyvinyl chloride(PVC)industries,but the usage of mercury-based catalysts can pose an environmental threat due to the release of mercury into the surrounding area during the operation period.In this study,a highly active and stable mercury-based catalyst was developed,utilizing the nitrogen atom of the support as the anchor site to enhance the interaction between active sites(HgCl_(2))and the carbon support(N-AC).Thermal loss rate testing and thermogravimetric analysis results demonstrate that,compared to commercial activated carbon,N-doped carbon can effectively increase the heat stability of HgCl_(2).The obtained mercury-based catalysts(HgCl_(2)/N-AC)exhibit significant catalytic performance,achieving 2.5 times the C2H2 conversion of conventional HgCl_(2)/AC catalysts.Experimental analysis combined with theoretical calculations reveals that,contrary to the Eley-Rideal(ER)mechanism of HgCl_(2)/AC,the HgCl_(2)/N-AC catalyst follows the Langmuir-Hinshelwood(LH)adsorption mechanism.The nitrogen sites and HgCl_(2) on the catalyst enhance the adsorption capabilities of the HCl and C2H2,thereby improving the catalytic performance.Based on the modification of the active center by these solid ligands,the loading amount of HgCl_(2) on the catalyst can be further reduced from the current 6.5%to 3%.Considering the absence of successful industrial applications for mercury-free catalysts,and based on the current annual consumption of commercial mercury chloride catalysts in the PVC industry,the widespread adoption of this technology could annually reduce the usage of chlorine mercury by 500 tons,making a notable contribution to mercury compliance,reduction,and emissions control in China.It also serves as a bridge between mercury-free and low-mercury catalysts.Moreover,this solid ligand technology can assist in the application research of mercury-free catalysts.展开更多
The pore structure of rocks significantly influences the porosity and permeability of reservoirs and the migration ability of oil and gas,and being the key task on the development of volcanic gas reservoirs.Nine volca...The pore structure of rocks significantly influences the porosity and permeability of reservoirs and the migration ability of oil and gas,and being the key task on the development of volcanic gas reservoirs.Nine volcanic rock samples from the Yingcheng Formation and Huoshiling Formation in the Longfengshan area of the Changling Fault Depression in the Songliao Basin were selected for this study.The pore structures of the volcanic rocks in the study area were investigated using high-pressure mercury injection,X-ray diffraction combined with fractal theory.The relationships between the fractal dimension and physical properties characteristics,pore structure parameters,and mineral content were analyzed to provide guidance for the development of volcanic rock gas reservoirs.The results show that the reservoir can be divided into 3 types(I,II,and III)based on the shape of the capillary pressure curve,and the physical properties deteriorate successively.Different types of reservoirs exhibit different fractal characteristics.For typesⅠ,ⅡandⅢ,the average total fractal dimensions were 2.3418,2.6850,and 2.9203,respectively.The larger the fractal dimension,the stronger the heterogeneity of reservoir.A small number of macro-pores primarily contributed to permeability.The fractal dimension was negatively correlated with porosity and permeability.The fractal dimension of the rock was strongly correlated with quartz and feldspar contents,and the mineral composition and content are closely related to the pore evolution of the reservoir,which are the internal factors affecting the fractal dimension of volcanic rock.展开更多
This study used steel slag,fly ash,and metakaolin as raw materials(SFM materials)to create silica-alumina-based geopolymers that can solidify Hg^(2+)when activated with sodiumbased water glass.The experiments began wi...This study used steel slag,fly ash,and metakaolin as raw materials(SFM materials)to create silica-alumina-based geopolymers that can solidify Hg^(2+)when activated with sodiumbased water glass.The experiments began with a triangular lattice point mixing design experiment,and the results were fitted,analyzed,and predicted.The optimum SFM material mass ratio was found to be 70%steel slag,25%fly ash,and 5%metakaolin.The optimum modulus of the activator was identified by comparing the unconfined compressive strength and solidifying impact on Hg^(2+)of geosynthetics with different modulus.The SFM geopolymer was then applied in the form of potting to cure the granulated mercury tailings.The inclusion of 50%SFM material generated a geosynthetic that reduced mercury transport to the surface soil by roughly 90%.The mercury concentration of herbaceous plant samples was also reduced by 78%.It indicates that the SFM material can effectively attenuate the migration transformation of mercury.Finally,characterization methods such as XPS and FTIR were used to investigate the mechanism of Hg^(2+)solidification by geopolymers generated by SFM materials.The possible solidification mechanisms were proposed as alkaline environment-induced mercury precipitation,chemical bonding s,surface adsorption of Hg^(2+)and its precipitates by the geopolymer,and physical encapsulation.展开更多
Mercury(Hg)pollution has been a global concern in recent decades,posing a significant threat to entire ecosystems and human health due to its cumulative toxicity,persistence,and transport in the atmosphere.The intense...Mercury(Hg)pollution has been a global concern in recent decades,posing a significant threat to entire ecosystems and human health due to its cumulative toxicity,persistence,and transport in the atmosphere.The intense interaction between mercury and selenium has opened up a new field for studying mercury removal from industrial flue gas pollutants.Besides the advantages of good Hg^(0) capture performance and lowsecondary pollution of the mineral selenium compounds,the most noteworthy is the relatively low regeneration temperature,allowing adsorbent regeneration with low energy consumption,thus reducing the utilization cost and enabling recovery of mercury resources.This paper reviews the recent progress of mineral selenium compounds in flue gas mercury removal,introduces in detail the different types ofmineral selenium compounds studied in the field ofmercury removal,reviews the adsorption performance of various mineral selenium compounds adsorbents on mercury and the influence of flue gas components,such as reaction temperature,air velocity,and other factors,and summarizes the adsorption mechanism of different fugitive forms of selenium species.Based on the current research progress,future studies should focus on the economic performance and the performance of different carriers and sizes of adsorbents for the removal of Hg^(0) and the correlation between the gas-particle flow characteristics and gas phase mass transfer with the performance of Hg^(0) removal in practical industrial applications.In addition,it remains a challenge to distinguish the oxidation and adsorption of Hg^(0) quantitatively.展开更多
Metal-organic frameworks(MOFs)attract broad interests in mercury(Hg)ion adsorption field,while unreasonable distribution of active groups commonly restricts their utilization efficiency.In this work,we constructed a n...Metal-organic frameworks(MOFs)attract broad interests in mercury(Hg)ion adsorption field,while unreasonable distribution of active groups commonly restricts their utilization efficiency.In this work,we constructed a new MOF(TYUST-6)with dense thiol-rich traps in the 1D pore wall.This accessible channel and rational distribution of thiols allow the smooth diffusion of Hg ions and thereby result in a high Langmuir adsorption capacity of 1347.6 mg/g,almost reaching the theoretical maximum(1444.3 mg/g).Adsorption equilibrium needs 10 and 30 min at the initial concentrations of 10 and 100 mg/L,respectively.Common co-existing ions and solution pH show almost negligible interferences on the adsorption,and adsorbent regeneration can be well achieved.Combining experimental characterizations and theoretical calculations,the thiol groups in the pore wall are proved to be the dominant interaction sites.Thus,this work reports a novel high-capacity adsorbent for Hg^(2+),and proposes a feasible guideline for designing effective adsorbents.展开更多
Rice paddy soil is recognized as the hotspot of mercury（Hg） methylation, which is mainly a biotic process mediated by many abiotic factors. In this study, effects of key soil properties on the production and bioaccu...Rice paddy soil is recognized as the hotspot of mercury（Hg） methylation, which is mainly a biotic process mediated by many abiotic factors. In this study, effects of key soil properties on the production and bioaccumulation of Hg and methylmercury（MeHg） in Hg-contaminated rice paddies were investigated. Rice and soil samples were collected from the active Hg smelting site and abandoned Hg mining sites（a total of 124 paddy fields） in the Wanshan Mercury Mine, China. Total Hg（THg） and MeHg in soils and rice grains, together with sulfur（S）,selenium（Se）, organic matter（OM）, nitrogen（N）, phosphorus（P）, mineral compositions（e.g., SiO2, Al2O3 and Fe2O3） and pH in soils were quantified. The results showed that long-term Hg mining activities had resulted in THg and MeHg contaminations in soil-rice system. The newly-deposited atmospheric Hg was more readily methylated relative to the native Hg already in soils, which could be responsible for the elevated MeHg levels in soils and rice grains around the active artificial Hg smelting site. The MeHg concentrations in soils and rice grains showed a significantly negative relationship with soil N/Hg, S/Hg and OM/Hg ratio possibly due to the formation of low-bioavailability Hg–S（N）–OM complexes in rhizosphere. The Hg–Se antagonism undoubtedly occurred in soil-rice system, while its role in bioaccumulation of MeHg in the MeHg-contaminated rice paddies was minor. However, other soil properties showed less influence on the production and bioaccumulation of MeHg in rice paddies located at the Wanshan Mercury Mine zone.展开更多
The mercury flux in soils was investigated, which were amended by gypsums from flue gas desulphurization （FGD） units of coal- fired power plants. Studies have been carried out in confined greenhouses using FGD gypsu...The mercury flux in soils was investigated, which were amended by gypsums from flue gas desulphurization （FGD） units of coal- fired power plants. Studies have been carried out in confined greenhouses using FGD gypsum treated soils. Major research focus is uptakes of mercury by plants, and emission of mercury into the atmosphere under varying application rates of FGD gypsum, simulating rainfall irrigations, soils, and plants types. Higher FGD gypsum application rates generally led to higher mercury concentrations in the soils, the increased mercury emissions into the atmosphere, and the increased mercury contents in plants （especially in roots and leaves）. Soil properties and plant species can play important roles in mercury transports. Some plants, such as tall fescue, were able to prevent mercury from atmospheric emission and infiltration in the soil. Mercury concentration in the stem of plants was found to be increased and then leveled off upon increasing FGD gypsum application. However, mercury in roots and leaves was generally increased upon increasing FGD gypsum application rates. Some mercury was likely absorbed by leaves of plants from emitted mercury in the atmosphere.展开更多
In order to remove gas-phase mercury and NOx from flue gas, experimental studies on flue gas mercury oxidation removal and denitration of Guizhou anthracite combustion with NH4Br addition were carried out. The influen...In order to remove gas-phase mercury and NOx from flue gas, experimental studies on flue gas mercury oxidation removal and denitration of Guizhou anthracite combustion with NH4Br addition were carried out. The influence of NH4Br addition on the ignition temperature and combustion characteristics was studied using a thermogravimetric analyzer. The effects of the NHaBr addition amount on gas-phase mercury oxidation and removal were investigated in a bench scale of 6 kW fluidized bed combustor （FBC）. Mercury concentrations in flue gas were determined by the Ontario hydro method （OHM） and the mercury mass balance was obtained. Results show that the NH4Br addition has little influence on the ignition temperature of Guizhou anthracite. With the mercury mass balance of 95.47%, the proportion of particulate mercury Hg^p, gaseous mercury Hg^0 and Hg^2＋ are 75.28%, 11.60% and 13. 12%, respectively, as raw coal combustion. The high particulate mercury Hg^p in flue gas is caused by the high unburned carbon content in fly ash. When the NH4Br addition amount increases from 0 to 0. 3%, the concentration of gaseous Hg^0 and Hg^2＋ in flue gas decreases continuously, leading to the Hg^p increase accordingly. The oxidation rate of Hg^0 is positively correlated to the Br addition amount. It demonstrates that coal combustion with NH4Br addition can promote Hg^0 oxidation and removal. NOx concentration in flue gas exhibits a descending trend with the NHaBr addition and the removal rate reaches 17.31% with the addition amount of 0.3%. Adding NH4Br to coal also plays a synergistic role in denitration.展开更多
The release of mercury from intertidal sediment to atmosphere was studied based on the simulated experiment. The experiment samples were collected from the Haibo Estuary (S1) and the Licun Estuary (S2) of the Jiaozhou...The release of mercury from intertidal sediment to atmosphere was studied based on the simulated experiment. The experiment samples were collected from the Haibo Estuary (S1) and the Licun Estuary (S2) of the Jiaozhou Bay in China,which are seriously polluted with mercury. The results show that the mercury in sediment releases rapidly to atmosphere under solar radiation. After 8 hours of solar radiation,mercury concentrations decrease from 5.62 μg/g and 2.92 μg/g to 2.34 μg/g and 1.39 μg/g in S1 and S2 sediments respectively in summer,and decrease from 5.62 μg/g and 2.92 μg/g to 4.58 μg/g and 2.13 μg/g respectively in winter. The mercury species in the sediment change markedly under solar radiation. The concentrations of mercury bound to organic matter decrease significantly from 2.73 μg/g to 0.31 μg/g in S1 and from 2.07 μg/g to 0.31 μg/g in S2,and the released mercury mainly comes from mercury bound to organic matter. Mercury flux shows distinguishing characteristic of diurnal change,and it increases rapidly in the morning with the rising of solar radiation intensity,but decreases in the afternoon. The mercury flux increases with sediment temperature and solar radiation intensity. The rapid release of mercury in intertidal sediment plays an important role in the regional mercury cycle.展开更多
Mercury pollution in the Three Gorges Reservoir area of P.R.China merits special attention.We investigated into the current situation in the Chongqing part of the Reservoir area,identified the pollution sources and pr...Mercury pollution in the Three Gorges Reservoir area of P.R.China merits special attention.We investigated into the current situation in the Chongqing part of the Reservoir area,identified the pollution sources and proposed some suggestions for the remediation and prevention of mercury pollution in this area.Atmospheric mercury in Chongqing was mainly from coal burning and releases of mercury-containing products such as various types of lights and fever thermometers.Urban drainage in Chongqing and Changshou,and runoffs from the high mercury background area in the lower reaches of the Wujiang River contributed most of the mercury in the water of the Yangtze River.A majority of the blame should be laid on mercury and gold mining in the Wujiang valley.We suggested foresting sloping lands to relieve soil erosion and prevent mercury-bearing soil from running into rivers,educational activities to discourage use of mercury-containing products and improved infrastructure to collect mercury-containing wastes for reducing mercury releases,more facilities for treating wastewater and solid waste to accommodate increased requirements of discharge,and growing selected perennial plants in mercury-contaminated land to absorb the mercury in soil.We also suggested concerted operation of a dedicated water-quality monitoring system,reinforced legislation and an effective administrative mechanism to ensure lasting efforts are invested in curbing mercury releases and restoring mercury contaminated land and water in the Reservoir area.展开更多
[Objective] The aim was to develop a rapid, simple method for determina- tion of arsenic and mercury in soil samples by atomic fluorescence spectrometry. [Method] The method for determination of As and Hg in soil by c...[Objective] The aim was to develop a rapid, simple method for determina- tion of arsenic and mercury in soil samples by atomic fluorescence spectrometry. [Method] The method for determination of As and Hg in soil by combined atomic fluorescence spectrometry and microwave digestion was used. [Result] The concentration curve was linear within the range of 0-80.0μg/L of As and 0-8.0 μg/L of Hg, and the detection limits of As and Hg was 0.036 μg/L and 0.015 μg/L, respectively. The precision for elevenfold determination of As at 40.0 ug/L level and Hg at 4.0μg/L level were 1.1% and 2.2%（RSD）, respectively. Recoveries of 103.0%-106.6% for As and 90.0%-95.0% for Hg were obtained for there soil samples. [Conclusion] The proposed method has the advantages of simple operation, high sensitivity, and high efficiency; it was successfully used for determination of As and Hg in soil samples.展开更多
The separation and enrichment of mercury and the recovery of elemental sulfur from flotation sulfur concentrate in zinc pressure leaching process were carried out by sodium sulfide leaching and carbon dioxide precipit...The separation and enrichment of mercury and the recovery of elemental sulfur from flotation sulfur concentrate in zinc pressure leaching process were carried out by sodium sulfide leaching and carbon dioxide precipitating. The results show that the leaching rate of elemental sulfur is more than 98%, and 98.13% of mercury is enriched in the residue, under the optimized conditions of sodium sulfide concentration 1.5 mol/L, liquid/solid ratio 6：1 and leaching time 30 min at room temperature. In addition, the content of mercury is enriched 5.23 times that in the leaching residue. The elemental sulfur is precipitated from leaching solution under conditions of carbon dioxide flow rate 200 mL/min and blowing time 150 min, while solution is stirred adequately. The recovery efficiency of elemental sulfur reaches 97.67%, and the purity of elemental sulfur is 99.75%, meeting the requirements of industrial first-rate product standard according to the national standard of GB/T 2449-2006 （PRC）.展开更多
基金supported by the Natural Science Foundation of China(Nos.22166009,42477268 and 42267032)the High-Level Talent Training Program in Guizhou Province(No.GCC[2023]045)the Post-funded Project of National Key Research and Development Program of China and the Natural Science Foundation of Chongqing(No.CSTB2022NSCQ-MSX0563).
文摘Algae play a significant role in regulating the biogeochemical cycle of mercury(Hg),particularly its highly toxicform,methylmercury(MeHg),within wetlands and lakes.However,despite their widespread presence in paddyfields,their specific effects on MeHg dynamics are not yet fully understood.This study investigated the algae-mediated distribution and accumulation of MeHg in Hg-contaminated paddyfields,utilizingfield investigationand microcosm experiment.The results indicated that algae demonstrated a multi-source uptake pattern and hada high capacity to accumulate both total Hg(926±1.69 ng/g)and MeHg(83.6±1.12 ng/g).This accumulationwas predominantly characterized by inorganic Hg species,accounting for 88.4%.Algal capsular extracellularpolymeric substance(EPS)exhibited higher levels of labile organic fractions,such as cysteine(0.59±0.01μg/g),and increased MeHg concentration(84.2±4.51 ng/kg),which contrasted with the levels found in colloidal EPS(0.06±0.01 ng/g and 15.0±1.61 ng/kg).Meanwhile,a significant correlation(P<0.05)was observed betweenthiol-containing cysteine and MeHg concentrations in algal EPS.Algal incubation further revealed the formationof mineral-EPS-algae aggregates on algal surfaces,accompanied by the colonization of Hg-methylating bacteria.Therefore,the surface of algae may form a favorable matrix for microbial Hg methylation and the accumulationof MeHg.Thesefindings emphasize the crucial roles of algae in regulating MeHg dynamics within algae-watersystem in Hg-contaminated paddyfields.
基金supported by the Shandong Provincial Natural Science Foundation (No.ZR2022QB242)the National Natural Science Foundation of China (No.22306111 and 22306108)+1 种基金the Shandong Provincial Natural Science Foundation (No.ZR2020ZD20)the Chinese Postdoctoral Science Foundation (No.2023M732059).
文摘Mercury(Hg),especially methylmercury(MeHg),accumulation in rice grain due to rice paddy possessing conditions conducive to Hg methylation has led to human Hg exposure through consumption of rice-based daily meals.In addition to being a food staple,rice is widely used as a raw material to produce a vast variety of processed food products.Little is known about Hg levels in snacking rice-food products and potential Hg exposure from consumption of them,besides previous studies on infant rice cereals.Aiming to provide complementary information for a more complete assessment on Hg exposure risk originated from Hgcontaining rice,this study determined total Hg(THg)and MeHg levels in 195 rice-containing and rice-free processed food products covering all major types of snack foods marketed in China and the estimated daily intake(EDI)of dietary Hg from the consumption of these foods.The results clearly showed THg and MeHg contents in rice-containing foods were significantly higher than rice-free products,suggesting the transfer of Hg and MeHg from the rice to the end products,even after manufacturing processes.Moreover,significant positive correlations were observed between THg,MeHg,or MeHg/THg ratio and rice content for samples containing multiple grains as ingredients,further indicating the deciding role of rice for Hg levels in the end food products.Although the EDI of THg and MeHg via ricebased food products were relatively low compared to the reference dose,it should be considered these snacking food products would contribute additive Hg intake outside of the daily regular meals.
基金The research project was co-funded by the National Natural Science Foundation of China(No.42072172,No.41772120)Shandong Province Natural Science Fund for Distinguished Young Scholars(No.JQ201311)the Graduate Scientific and Technological Innovation Project Financially Supported by Shandong University of Science and Technology(No.SDKDYC190313).
文摘The high-pressure mercury intrusion (HPMI) experiment is widely used to assess the pore architecture oftight sandstone reservoirs. However, the conventional analysis of the high- pressure mercury intrusionhas always focused on the mercury injection curves themselves, neglecting the important geologicalinformation conveyed by the mercury ejection curves. This paper quantitatively describes the fractalcharacteristics of ejection curves by using four fractal models, i.e.,. Menger model, Thermodynamicmodel, Sierpinski model, and multi- fractal model. In comparison with mercury injection curves, weexplore the fractal significance of mercury ejection curves and define the applicability of different fractalmodels in characterizing pore architectures. Investigated tight sandstone samples can be divided intofour types (Types A, B, C and D) based on porosity, permeability, and mercury removal efficiency. Type Dsamples are unique in that they have higher permeability (>0.6 mD) but lower mercury removal effi-ciency (<35%). Fractal studies of the mercury injection curve show that it mainly reflects the pore throatcharacteristics, while the mercury ejection curve serves to reveal the pore features, and porosity andpermeability correlate well with the fractal dimension of the injection curve, while mercury removalefficiency correlates only with the Ds' value of the ejection curve. The studies on the mercury ejectioncurves also reveal that the small pores and micropores of the Type C and Type D samples are moredeveloped, with varying pore architecture. The fractal dimension Ds' value of Type D samples is greaterthan that of Type C samples, and the dissolution of Type D samples is more intense than that of Type Csamples, which further indicates that the Type D samples are smaller in pore size, rougher in surface, andwith greater difficulty for the hydrocarbon to enter, resulting in their reservoir capacity probably lessthan that of Type C samples. In this regard, the important information characterized by the mercuryejection curve should be considered in evaluating the tight sandstone reservoirs. Finally, the Menger andThermodynamic models prove to be more suitable for describing the total pore architecture, while theSierpinski model is better for characterizing the variability of the interconnected pores.
基金supported by the National Natural Science Foundation of China(22278066,21776039)the National Key R&D Program of China(2023YFB4103001)The Fundamental Research Funds for the Central Universities(DUT2021TB03).
文摘Mercury removal from coal combustion flue gas remains a significant challenge for environmental protection due to the lack of cost-effective sorbents.In this study,a series of red mud(RM)-based sorbents impregnated with sodium halides(NaBr and NaI)are presented to capture elemental mercury(Hg^(0))from flue gas.The modified RM underwent comprehensive characterization,including analysis of its textural qualities,crystal structure,chemical composition,and thermal properties.The results indicate that the halide impregnation substantially impacts the surface area and pore size of the RM.Hg^(0) removal performance was evaluated on a fixed-bed reactor in simulated flue gas(consisting of N_(2),O_(2),CO_(2),NO and SO_(2),etc.)on a modified RM.At an optimal adsorption temperature of 160℃,NaI-modified sorbent(RMI5)offers a removal efficiency of 98%in a mixture of gas,including O_(2),NO and HCl.Furthermore,pseudo-second-order model fitting results demonstrate the chemisorption mechanism for the adsorption of Hg^(0) in kinetic investigations.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2019QZKK0605)the National Natural Science Foundation of China(No.42201161)the Startup Foundation for Introducing Talent of NUIST(No.2022r024)。
文摘Since scarce knowledge of soil mercury(Hg)concentrations and risks in the vulnerable Xinjiang,topsoils(0-15 cm)from its typical landscapes were extensively sampled.Topsoil total mercury(THg)concentrations varied broadly between 0.9 and 35.3 ng/g,of which16.8%exceeded the background value of soil Hg for Xinjiang.Topsoil THg concentrations across various landscapes exhibited a declining order:farmland(11.7±6.0 ng/g)>grassland(10.5±8.5 ng/g)>woodland(10.2±8.2 ng/g)>desert(7.0±5.8 ng/g).The average topsoil THg concentration was higher in northwestern Xinjiang(11.3±7.2 ng/g)than that in southeastern Xinjiang(6.3±6.1 ng/g).Relatively high topsoil THg concentrations were observed near the cities with intensive human activities,followed by a gradual decline to the surroundings.The concentrations of topsoil THg were strongly correlated with the contents of total organic carbon(TOC),clay,silty,and sandy,and the distance from each sampling site to its nearest city,suggesting that the variation of topsoil Hg was significantly influenced by TOC content,soil granularity,and anthropogenic Hg emissions.Silty and TOC were the principal affecting factors,explaining 48.7%and 7.9%of the THg variation,respectively.The contamination and potential ecological risk evaluations revealed that topsoils in regions with dense populations were polluted with Hg and contained higher potential ecological risks.The health risk evaluations indicated that exposure risks of topsoil Hg were higher for children than those for adults.Fortunately,topsoil Hg posed acceptable risks to human health.
基金supported by the National Key Research and Development Program of China(2024YFC3907904).
文摘Carbon-supported mercury catalysts are extensivelyemployed in calcium carbide-based polyvinyl chloride(PVC)industries,but the usage of mercury-based catalysts can pose an environmental threat due to the release of mercury into the surrounding area during the operation period.In this study,a highly active and stable mercury-based catalyst was developed,utilizing the nitrogen atom of the support as the anchor site to enhance the interaction between active sites(HgCl_(2))and the carbon support(N-AC).Thermal loss rate testing and thermogravimetric analysis results demonstrate that,compared to commercial activated carbon,N-doped carbon can effectively increase the heat stability of HgCl_(2).The obtained mercury-based catalysts(HgCl_(2)/N-AC)exhibit significant catalytic performance,achieving 2.5 times the C2H2 conversion of conventional HgCl_(2)/AC catalysts.Experimental analysis combined with theoretical calculations reveals that,contrary to the Eley-Rideal(ER)mechanism of HgCl_(2)/AC,the HgCl_(2)/N-AC catalyst follows the Langmuir-Hinshelwood(LH)adsorption mechanism.The nitrogen sites and HgCl_(2) on the catalyst enhance the adsorption capabilities of the HCl and C2H2,thereby improving the catalytic performance.Based on the modification of the active center by these solid ligands,the loading amount of HgCl_(2) on the catalyst can be further reduced from the current 6.5%to 3%.Considering the absence of successful industrial applications for mercury-free catalysts,and based on the current annual consumption of commercial mercury chloride catalysts in the PVC industry,the widespread adoption of this technology could annually reduce the usage of chlorine mercury by 500 tons,making a notable contribution to mercury compliance,reduction,and emissions control in China.It also serves as a bridge between mercury-free and low-mercury catalysts.Moreover,this solid ligand technology can assist in the application research of mercury-free catalysts.
基金Supported by Key Scientific and Technological Projects of Sinopec(No.P21104-2).
文摘The pore structure of rocks significantly influences the porosity and permeability of reservoirs and the migration ability of oil and gas,and being the key task on the development of volcanic gas reservoirs.Nine volcanic rock samples from the Yingcheng Formation and Huoshiling Formation in the Longfengshan area of the Changling Fault Depression in the Songliao Basin were selected for this study.The pore structures of the volcanic rocks in the study area were investigated using high-pressure mercury injection,X-ray diffraction combined with fractal theory.The relationships between the fractal dimension and physical properties characteristics,pore structure parameters,and mineral content were analyzed to provide guidance for the development of volcanic rock gas reservoirs.The results show that the reservoir can be divided into 3 types(I,II,and III)based on the shape of the capillary pressure curve,and the physical properties deteriorate successively.Different types of reservoirs exhibit different fractal characteristics.For typesⅠ,ⅡandⅢ,the average total fractal dimensions were 2.3418,2.6850,and 2.9203,respectively.The larger the fractal dimension,the stronger the heterogeneity of reservoir.A small number of macro-pores primarily contributed to permeability.The fractal dimension was negatively correlated with porosity and permeability.The fractal dimension of the rock was strongly correlated with quartz and feldspar contents,and the mineral composition and content are closely related to the pore evolution of the reservoir,which are the internal factors affecting the fractal dimension of volcanic rock.
基金supported by the National Key R&D Projects of China(No.2018YFC1801706-01)the National Natural Science Foundation of China(No.22162007)+2 种基金the Science and Technology Supporting Project of Guizhou Province(No.[2021]480,[2023]379)the Wengfu(Group)Co.,Ltd.Technology Development Project(No.WH-220787(YF))the Project from Guizhou Institute of Innovation and Development of Dual-carbon and New Energy Technologies(No.DCRE-2023-05)。
文摘This study used steel slag,fly ash,and metakaolin as raw materials(SFM materials)to create silica-alumina-based geopolymers that can solidify Hg^(2+)when activated with sodiumbased water glass.The experiments began with a triangular lattice point mixing design experiment,and the results were fitted,analyzed,and predicted.The optimum SFM material mass ratio was found to be 70%steel slag,25%fly ash,and 5%metakaolin.The optimum modulus of the activator was identified by comparing the unconfined compressive strength and solidifying impact on Hg^(2+)of geosynthetics with different modulus.The SFM geopolymer was then applied in the form of potting to cure the granulated mercury tailings.The inclusion of 50%SFM material generated a geosynthetic that reduced mercury transport to the surface soil by roughly 90%.The mercury concentration of herbaceous plant samples was also reduced by 78%.It indicates that the SFM material can effectively attenuate the migration transformation of mercury.Finally,characterization methods such as XPS and FTIR were used to investigate the mechanism of Hg^(2+)solidification by geopolymers generated by SFM materials.The possible solidification mechanisms were proposed as alkaline environment-induced mercury precipitation,chemical bonding s,surface adsorption of Hg^(2+)and its precipitates by the geopolymer,and physical encapsulation.
基金supported by the Basic Research Business Fund Grant Program for University of Science and Technology Beijing (No.06500227)the Fundamental Research Funds for the Central Universities (No.FRF-TP-22-091A1).
文摘Mercury(Hg)pollution has been a global concern in recent decades,posing a significant threat to entire ecosystems and human health due to its cumulative toxicity,persistence,and transport in the atmosphere.The intense interaction between mercury and selenium has opened up a new field for studying mercury removal from industrial flue gas pollutants.Besides the advantages of good Hg^(0) capture performance and lowsecondary pollution of the mineral selenium compounds,the most noteworthy is the relatively low regeneration temperature,allowing adsorbent regeneration with low energy consumption,thus reducing the utilization cost and enabling recovery of mercury resources.This paper reviews the recent progress of mineral selenium compounds in flue gas mercury removal,introduces in detail the different types ofmineral selenium compounds studied in the field ofmercury removal,reviews the adsorption performance of various mineral selenium compounds adsorbents on mercury and the influence of flue gas components,such as reaction temperature,air velocity,and other factors,and summarizes the adsorption mechanism of different fugitive forms of selenium species.Based on the current research progress,future studies should focus on the economic performance and the performance of different carriers and sizes of adsorbents for the removal of Hg^(0) and the correlation between the gas-particle flow characteristics and gas phase mass transfer with the performance of Hg^(0) removal in practical industrial applications.In addition,it remains a challenge to distinguish the oxidation and adsorption of Hg^(0) quantitatively.
基金supported by the National Natural Science Foundation of China(No.22208230)Fundamental Research Program of Shanxi Province(No.202103021223281)。
文摘Metal-organic frameworks(MOFs)attract broad interests in mercury(Hg)ion adsorption field,while unreasonable distribution of active groups commonly restricts their utilization efficiency.In this work,we constructed a new MOF(TYUST-6)with dense thiol-rich traps in the 1D pore wall.This accessible channel and rational distribution of thiols allow the smooth diffusion of Hg ions and thereby result in a high Langmuir adsorption capacity of 1347.6 mg/g,almost reaching the theoretical maximum(1444.3 mg/g).Adsorption equilibrium needs 10 and 30 min at the initial concentrations of 10 and 100 mg/L,respectively.Common co-existing ions and solution pH show almost negligible interferences on the adsorption,and adsorbent regeneration can be well achieved.Combining experimental characterizations and theoretical calculations,the thiol groups in the pore wall are proved to be the dominant interaction sites.Thus,this work reports a novel high-capacity adsorbent for Hg^(2+),and proposes a feasible guideline for designing effective adsorbents.
基金supported by the National Natural Science Foundation of China (No.41763017)the Program Foundation of Institute for Scientific Research of Karst Area of NSFC-GZGOV (No.U1612442)+2 种基金the Science and Technology Planning Project of Guizhou Province (No.Qiankehe-[2018]2336)the Key Discipline Construction Project,Guizhou (No.ZDXK [2016]11)the Topclass Discipline Construction Project of Ecology in Guizhou Province (No.GNYL[2017]007)
文摘Rice paddy soil is recognized as the hotspot of mercury（Hg） methylation, which is mainly a biotic process mediated by many abiotic factors. In this study, effects of key soil properties on the production and bioaccumulation of Hg and methylmercury（MeHg） in Hg-contaminated rice paddies were investigated. Rice and soil samples were collected from the active Hg smelting site and abandoned Hg mining sites（a total of 124 paddy fields） in the Wanshan Mercury Mine, China. Total Hg（THg） and MeHg in soils and rice grains, together with sulfur（S）,selenium（Se）, organic matter（OM）, nitrogen（N）, phosphorus（P）, mineral compositions（e.g., SiO2, Al2O3 and Fe2O3） and pH in soils were quantified. The results showed that long-term Hg mining activities had resulted in THg and MeHg contaminations in soil-rice system. The newly-deposited atmospheric Hg was more readily methylated relative to the native Hg already in soils, which could be responsible for the elevated MeHg levels in soils and rice grains around the active artificial Hg smelting site. The MeHg concentrations in soils and rice grains showed a significantly negative relationship with soil N/Hg, S/Hg and OM/Hg ratio possibly due to the formation of low-bioavailability Hg–S（N）–OM complexes in rhizosphere. The Hg–Se antagonism undoubtedly occurred in soil-rice system, while its role in bioaccumulation of MeHg in the MeHg-contaminated rice paddies was minor. However, other soil properties showed less influence on the production and bioaccumulation of MeHg in rice paddies located at the Wanshan Mercury Mine zone.
基金Financial support for this project was provided by the U.S.Department of Agriculture (No. 6445-12630-003-00D)
文摘The mercury flux in soils was investigated, which were amended by gypsums from flue gas desulphurization （FGD） units of coal- fired power plants. Studies have been carried out in confined greenhouses using FGD gypsum treated soils. Major research focus is uptakes of mercury by plants, and emission of mercury into the atmosphere under varying application rates of FGD gypsum, simulating rainfall irrigations, soils, and plants types. Higher FGD gypsum application rates generally led to higher mercury concentrations in the soils, the increased mercury emissions into the atmosphere, and the increased mercury contents in plants （especially in roots and leaves）. Soil properties and plant species can play important roles in mercury transports. Some plants, such as tall fescue, were able to prevent mercury from atmospheric emission and infiltration in the soil. Mercury concentration in the stem of plants was found to be increased and then leveled off upon increasing FGD gypsum application. However, mercury in roots and leaves was generally increased upon increasing FGD gypsum application rates. Some mercury was likely absorbed by leaves of plants from emitted mercury in the atmosphere.
基金The National Natural Science Foundation of China(No.51376046,51076030)the National Key Technology R&D Program of China during the 12th Five-Year Plan Period(No.2012BAA02B01)+2 种基金the United Creative Foundation of Jiangsu Province(No.BY2013073-10)the Fundamental Research Funds for the Central Universitiesthe Scientific Innovation Research of College Graduates in Jiangsu Province(CXZZ13_0093,KYLX_0115,KYLX_0184)
文摘In order to remove gas-phase mercury and NOx from flue gas, experimental studies on flue gas mercury oxidation removal and denitration of Guizhou anthracite combustion with NH4Br addition were carried out. The influence of NH4Br addition on the ignition temperature and combustion characteristics was studied using a thermogravimetric analyzer. The effects of the NHaBr addition amount on gas-phase mercury oxidation and removal were investigated in a bench scale of 6 kW fluidized bed combustor （FBC）. Mercury concentrations in flue gas were determined by the Ontario hydro method （OHM） and the mercury mass balance was obtained. Results show that the NH4Br addition has little influence on the ignition temperature of Guizhou anthracite. With the mercury mass balance of 95.47%, the proportion of particulate mercury Hg^p, gaseous mercury Hg^0 and Hg^2＋ are 75.28%, 11.60% and 13. 12%, respectively, as raw coal combustion. The high particulate mercury Hg^p in flue gas is caused by the high unburned carbon content in fly ash. When the NH4Br addition amount increases from 0 to 0. 3%, the concentration of gaseous Hg^0 and Hg^2＋ in flue gas decreases continuously, leading to the Hg^p increase accordingly. The oxidation rate of Hg^0 is positively correlated to the Br addition amount. It demonstrates that coal combustion with NH4Br addition can promote Hg^0 oxidation and removal. NOx concentration in flue gas exhibits a descending trend with the NHaBr addition and the removal rate reaches 17.31% with the addition amount of 0.3%. Adding NH4Br to coal also plays a synergistic role in denitration.
基金Under the auspices of National Natural Science Foundation of China (No. 40806045)the Program of the State Bureau of Oceanic Administration (No. 908-02-02-03)
文摘The release of mercury from intertidal sediment to atmosphere was studied based on the simulated experiment. The experiment samples were collected from the Haibo Estuary (S1) and the Licun Estuary (S2) of the Jiaozhou Bay in China,which are seriously polluted with mercury. The results show that the mercury in sediment releases rapidly to atmosphere under solar radiation. After 8 hours of solar radiation,mercury concentrations decrease from 5.62 μg/g and 2.92 μg/g to 2.34 μg/g and 1.39 μg/g in S1 and S2 sediments respectively in summer,and decrease from 5.62 μg/g and 2.92 μg/g to 4.58 μg/g and 2.13 μg/g respectively in winter. The mercury species in the sediment change markedly under solar radiation. The concentrations of mercury bound to organic matter decrease significantly from 2.73 μg/g to 0.31 μg/g in S1 and from 2.07 μg/g to 0.31 μg/g in S2,and the released mercury mainly comes from mercury bound to organic matter. Mercury flux shows distinguishing characteristic of diurnal change,and it increases rapidly in the morning with the rising of solar radiation intensity,but decreases in the afternoon. The mercury flux increases with sediment temperature and solar radiation intensity. The rapid release of mercury in intertidal sediment plays an important role in the regional mercury cycle.
基金the Natural Science Foundation of China under the Grant No.20377054
文摘Mercury pollution in the Three Gorges Reservoir area of P.R.China merits special attention.We investigated into the current situation in the Chongqing part of the Reservoir area,identified the pollution sources and proposed some suggestions for the remediation and prevention of mercury pollution in this area.Atmospheric mercury in Chongqing was mainly from coal burning and releases of mercury-containing products such as various types of lights and fever thermometers.Urban drainage in Chongqing and Changshou,and runoffs from the high mercury background area in the lower reaches of the Wujiang River contributed most of the mercury in the water of the Yangtze River.A majority of the blame should be laid on mercury and gold mining in the Wujiang valley.We suggested foresting sloping lands to relieve soil erosion and prevent mercury-bearing soil from running into rivers,educational activities to discourage use of mercury-containing products and improved infrastructure to collect mercury-containing wastes for reducing mercury releases,more facilities for treating wastewater and solid waste to accommodate increased requirements of discharge,and growing selected perennial plants in mercury-contaminated land to absorb the mercury in soil.We also suggested concerted operation of a dedicated water-quality monitoring system,reinforced legislation and an effective administrative mechanism to ensure lasting efforts are invested in curbing mercury releases and restoring mercury contaminated land and water in the Reservoir area.
基金Supported by Key Fund of Guangxi Academy of Agricultural Sciences(2013YZ07)~~
文摘[Objective] The aim was to develop a rapid, simple method for determina- tion of arsenic and mercury in soil samples by atomic fluorescence spectrometry. [Method] The method for determination of As and Hg in soil by combined atomic fluorescence spectrometry and microwave digestion was used. [Result] The concentration curve was linear within the range of 0-80.0μg/L of As and 0-8.0 μg/L of Hg, and the detection limits of As and Hg was 0.036 μg/L and 0.015 μg/L, respectively. The precision for elevenfold determination of As at 40.0 ug/L level and Hg at 4.0μg/L level were 1.1% and 2.2%（RSD）, respectively. Recoveries of 103.0%-106.6% for As and 90.0%-95.0% for Hg were obtained for there soil samples. [Conclusion] The proposed method has the advantages of simple operation, high sensitivity, and high efficiency; it was successfully used for determination of As and Hg in soil samples.
文摘The separation and enrichment of mercury and the recovery of elemental sulfur from flotation sulfur concentrate in zinc pressure leaching process were carried out by sodium sulfide leaching and carbon dioxide precipitating. The results show that the leaching rate of elemental sulfur is more than 98%, and 98.13% of mercury is enriched in the residue, under the optimized conditions of sodium sulfide concentration 1.5 mol/L, liquid/solid ratio 6：1 and leaching time 30 min at room temperature. In addition, the content of mercury is enriched 5.23 times that in the leaching residue. The elemental sulfur is precipitated from leaching solution under conditions of carbon dioxide flow rate 200 mL/min and blowing time 150 min, while solution is stirred adequately. The recovery efficiency of elemental sulfur reaches 97.67%, and the purity of elemental sulfur is 99.75%, meeting the requirements of industrial first-rate product standard according to the national standard of GB/T 2449-2006 （PRC）.
