This paper investigates the macroscopic and microscopic characteristics of viscosity reduction and quality improvement of heavy oil in a supercritical water environment through laboratory experiments and testing.The e...This paper investigates the macroscopic and microscopic characteristics of viscosity reduction and quality improvement of heavy oil in a supercritical water environment through laboratory experiments and testing.The effect of three reaction parameters,i.e.reaction temperature,reaction time and oil-water ratio,is analyzed on the product and their correlation with viscosity.The results show that the flow state of heavy oil is significantly improved with a viscosity reduction of 99.4%in average after the reaction in the supercritical water.Excessively high reaction temperature leads to a higher content of resins and asphaltenes,with significantly increasing production of coke.The optimal temperature ranges in 380–420℃.Prolonged reaction time could continuously increase the yield of light oil,but it will also results in the growth of resins and asphaltenes,with the optimal reaction time of 150 min.Reducing the oil-water ratio helps improve the diffusion environment within the reaction system and reduce the content of resins and asphaltenes,but it will increase the cost of heavy oil treatment.An oil-water ratio of 1︰2 is considered as optimum to balance the quality improvement,viscosity reduction and reaction economics.The correlation of the three reaction parameters relative to the oil sample viscosity is ranked as temperature,time and oil-water ratio.Among the four fractions of heavy oil,the viscosity is dominated by asphaltene content,followed by aromatic content and less affected by resins and saturates contents.展开更多
Heavy metal pollution in coastal waters is on the rise,presenting serious threats to both ecosystems and human health.Coastal aquaculture zones,such as those in Quang Ninh province,are especially vulnerable due to the...Heavy metal pollution in coastal waters is on the rise,presenting serious threats to both ecosystems and human health.Coastal aquaculture zones,such as those in Quang Ninh province,are especially vulnerable due to the accumulation of heavy metals from multiple sources,including industrial wastewater,land runoff,and maritime activities.This study applies the Heavy Metal Pollution Index(HPI)to assess pollution levels based on the concentrations of nine heavy metals(Cr,Mn,Fe,Cu,Zn,As,Cd,Hg,Pb)found in seawater samples collected from coastal aquaculture areas in Quang Ninh.According to the HPI method,values exceeding 100 indicate polluted water,serving as a benchmark for evaluating heavy metal contamination in the region.A total of 25 seawater samples were collected and analyzed;of these,18 samples(72%)had HPI values above 100,signaling a concerning level of heavy metal pollution,while only 7 samples(28%)fell below the threshold,suggesting no significant contamination.These results underscore the urgent need for enhanced monitoring of water quality and stricter regulation of pollution sources to protect both environmental and public health.展开更多
Controlling heavy metal pollution in agricultural soil has been a significant challenge.These heavy metals seriously threaten the surrounding ecological environment and human health.The effective assessment and remedi...Controlling heavy metal pollution in agricultural soil has been a significant challenge.These heavy metals seriously threaten the surrounding ecological environment and human health.The effective assessment and remediation of heavy metals in agricultural soils are crucial.These two aspects support each other,forming a close and complete decisionmaking chain.Therefore,this review systematically summarizes the distribution characteristics of soil heavy metal pollution,the correlation between soil and crop heavy metal contents,the presence pattern and migration and transformation mode of heavy metals in the soil-crop system.The advantages and disadvantages of the risk evaluation tools and models of heavy metal pollution in farmland are further outlined,which provides important guidance for an in-depth understanding of the characteristics of heavymetal pollution in farmland soils and the assessment of the environmental risk.Soil remediation strategies involve multiple physical,chemical,biological and even combined technologies,and this paper compares the potential and effect of the above current remediation technologies in heavy metal polluted farmland soils.Finally,the main problems and possible research directions of future heavy metal risk assessment and remediation technologies in agricultural soils are prospected.This review provides new ideas for effective assessment and selection of remediation technologies based on the characterization of soil heavy metals.展开更多
Agricultural soil is related to food security and human health,antibiotics and heavy metals(HMs),as two typical pollutants,possess a high coexistence rate in the environmental medium,which is extremely prone to induci...Agricultural soil is related to food security and human health,antibiotics and heavy metals(HMs),as two typical pollutants,possess a high coexistence rate in the environmental medium,which is extremely prone to inducing antibiotic-HMs combined pollution.Recently,frequent human activities have led to more prominent antibiotics-HMs combined contamination in agricultural soils,especially the production and spread of antibiotic resistance genes(ARGs),heavy metal resistance genes(MRGs),antibiotic resistant bacteria(ARB),and antibiotics-HMs complexes(AMCs),which seriously threaten soil ecology and human health.This review describes the main sources(Intrinsic and manmade sources),composite mechanisms(co-selective resistance,oxidative stress,and Joint toxicity mechanism),environmental fate and the potential risks(soil ecological and human health risks)of antibiotics and HMs in agricultural soils.Finally,the current effective source blocking,transmission control,and attenuation strategies are classified for discussion,such as the application of additives and barrier materials,as well as plant and animal remediation and bioremediation,etc.,pointing out that future research should focus on the whole chain process of“source-processterminal”,intending to provide a theoretical basis and decision-making reference for future research.展开更多
Coking industry is a potential source of heavy metals(HMs)pollution.However,its impacts to the groundwater of surrounding residential areas have not been well understood.This study investigated the pollution character...Coking industry is a potential source of heavy metals(HMs)pollution.However,its impacts to the groundwater of surrounding residential areas have not been well understood.This study investigated the pollution characteristics and health risks of HMs in groundwater nearby a typical coking plant.Nine HMs including Fe,Zn,Mo,As,Cu,Ni,Cr,Pb and Cd were analyzed.The average concentration of total HMswas higher in the nearby area(244.27μg/L)than that of remote area away the coking plant(89.15μg/L).The spatial distribution of pollution indices including heavy metal pollution index(HPI),Nemerow index(NI)and contamination degree(CD),all demonstrated higher values at the nearby residential areas,suggesting coking activity could significantly impact the HMs distribution characteristics.Four sources of HMs were identified by Positive Matrix Factorization(PMF)model,which indicated coal washing and coking emission were the dominant sources,accounted for 40.4%,and 31.0%,respectively.Oral ingestionwas found to be the dominant exposure pathway with higher exposure dose to children than adults.Hazard quotient(HQ)values were below 1.0,suggesting negligible non-carcinogenic health risks,while potential carcinogenic risks were from Pb and Ni with cancer risk(CR)values>10−6.Monte Carlo simulation matched well with the calculated results with HMs concentrations to be the most sensitive parameters.This study provides insights into understanding how the industrial coking activities can impact the HMs pollution characteristics in groundwater,thus facilitating the implement of HMs regulation in coking industries.展开更多
Gallium nitride(GaN)-based devices have significant potential for space applications.However,the mechanisms of radiation damage to the device,particularly from strong ionizing radiation,remains unknown.This study inve...Gallium nitride(GaN)-based devices have significant potential for space applications.However,the mechanisms of radiation damage to the device,particularly from strong ionizing radiation,remains unknown.This study investigates the effects of radiation on p-gate AlGaN/GaN high-electron-mobility transistors(HEMTs).Under a high voltage,the HEMT leakage current increased sharply and was accompanied by a rapid increase in power density that caused"thermal burnout"of the devices.In addition,a burnout signature appeared on the surface of the burned devices,proving that a single-event burnout effect occurred.Additionally,degradation,including an increase in the on-resistance and a decrease in the breakdown voltage,was observed in devices irradiated with high-energy heavy ions and without bias.The latent tracks induced by heavy ions penetrated the heterojunction interface and extended into the GaN layer.Moreover,a new type of N_(2)bubble defect was discovered inside the tracks using Fresnel analysis.The accumulation of N_(2)bubbles in the heterojunction and buffer layers is more likely to cause leakage and failure.This study indicates that electrical stress accelerates the failure rate and that improving heat dissipation is an effective reinforcement method for GaN-based devices.展开更多
The impact of heavy reduction on dendritic morphology was explored by combining experimental research and numerical simulation in metallurgy,including a detailed three-dimensional(3D)analysis and reconstruction of den...The impact of heavy reduction on dendritic morphology was explored by combining experimental research and numerical simulation in metallurgy,including a detailed three-dimensional(3D)analysis and reconstruction of dendritic solidification structures.Combining scanning electron microscopy and energy-dispersive scanning analysis and ANSYS simulation,the high-precision image processing software Mimics Research was utilized to conduct the extraction of dendritic morphologies.Reverse engineering software NX Imageware was employed for the 3D reconstruction of two-dimensional dendritic morphologies,restoring the dendritic characteristics in three-dimensional space.The results demonstrate that in a two-dimensional plane,dendrites connect with each other to form irregularly shaped“ring-like”structures.These dendrites have a thickness greater than 0.1 mm along the Z-axis direction,leading to the envelopment of molten steel by dendrites in a 3D space of at least 0.1 mm.This results in obstructed flow,confirming the“bridging”of dendrites in three-dimensional space,resulting in a tendency for central segregation.Dense and dispersed tiny dendrites,under the influence of heat flow direction,interconnect and continuously grow,gradually forming primary and secondary dendrites in three-dimensional space.After the completion of dendritic solidification and growth,these microdendrites appear dense and dispersed on the two-dimensional plane,providing the nuclei for the formation of new dendrites.When reduction occurs at a solid fraction of 0.46,there is a noticeable decrease in dendritic spacing,resulting in improved central segregation.展开更多
Phosphorus(P)poses a global challenge to the environment and human health due to its natural association with heavy metals.Sustainable use of P is crucial to ensure food security for future generations.An analysis of ...Phosphorus(P)poses a global challenge to the environment and human health due to its natural association with heavy metals.Sustainable use of P is crucial to ensure food security for future generations.An analysis of the 150 phosphate fertilizers stored at the Institute for Crop and Soil Science in Germany has been conducted,supplemented by previously published data.The elements Cd,Bi,U,Cr,Zn,Tl,As,B,Sb,Ni,and Se are found in higher concentrations in sedimentary derived phosphates compared to igneous derived phosphates.Mineral fertilizers contain more than ten times the amount of U,Cd,B,and As compared to farmyard manure.Principal component analyses(PCA)indicate that U,Cd,Be,and Cr are primarily present in sedimentary derived phosphates and their concentrations are 2 to 10 times higher than those in igneous derived phosphates.Regarding heavy metal contamination,over 1000 potential combinations were identified;36% of these were significant but weak(>0.1).It is estimated that approximately 707 t of uranium enter farmland annually through the application of mineral phosphate fertilizers in European countries.This contribution addresses environmental issues related to the utilization of rock phosphate as well as alternative production methods for cleaner and safer phosphate fertilizers while presenting a roadmap with measures for mitigation.展开更多
Abandoned mines,especially pyrite-rich ones,release acid mine drainage(AMD)with high acidity and excessive amounts of heavy metals,threatening regional ecosystems.Six samples of mine drainage,nine samples of surface w...Abandoned mines,especially pyrite-rich ones,release acid mine drainage(AMD)with high acidity and excessive amounts of heavy metals,threatening regional ecosystems.Six samples of mine drainage,nine samples of surface water,and twelve samples of sediment were analyzed in this case study of the Dashu pyrite mine in southwest China.A comprehensive analysis of the pollution levels,pollution sources,and potential hazards of eight metals(Ni,Cd,Cu,Zn,Fe,Al,Pb,and Mn)that exceeded regulatory standardswas conducted bymonitoring 24 conventional and characteristic indicators.Ultimately,this research evaluated the environmental hazards associated with abandonedmine water using the"pressure-response"model,thereby providing valuable insights for the effective protection of the environment in mining regions.The primary pollutants in mine water were determined to be SO_(4)^(2−),Fe,and Mn,with concentrations of 7700,1450,and 6.78mg/L,respectively.A clear"source-sink"dynamic was observed between themine water and the surrounding water system.surface water was primarily polluted by Ni and Mn,while water system sediments were primarily polluted by Cu and Hg.Ion ratio and Pearson correlation analyses indicated heavy metals in surface water and sediments originated from the same AMD source.The"pressureresponse"model was used to assess the environmental hazards of water from abandoned mines.Mines W1,W2,W5,and W6 were classified as high-risk,while W3 and W4 were medium-risk.This study offers a novel approach and valuable reference for identifying and classifying environmental risks in abandoned mines and targeting AMD treatment.展开更多
Two strains of Fe/Mn oxidizing bacteria tolerant to high concentrations of multiple heavy metal(loid)s and efficient decontamination for them were screened.The surface of the bio-Fe/Mn oxides produced by the oxidation...Two strains of Fe/Mn oxidizing bacteria tolerant to high concentrations of multiple heavy metal(loid)s and efficient decontamination for them were screened.The surface of the bio-Fe/Mn oxides produced by the oxidation of Fe(II)and Mn(II)by Pseudomonas taiwanensis(marked as P4)and Pseudomonas plecoglossicida(marked as G1)contains rich reactive oxygen functional groups,which play critical roles in the removal efficiency and immobilization of heavymetal(loid)s in co-contamination system.The isolated strains P4 and G1 can growwell in the following environments:pH 5-9,NaCl 0-4%,and temperature 20-30℃.The removal efficiencies of Fe,Pb,As,Zn,Cd,Cu,and Mn are effective after inoculation of the strains P4 and G1 in the simulated water system(the initial concentrations of heavy metal(loid)were 1 mg/L),approximately reaching 96%,92%,85%,67%,70%,54%and 15%,respectively.The exchangeable and carbonate bound As,Cd,Pb and Cu are more inclined to convert to the Fe-Mn oxide bound fractions in P4 and G1 treated soil,thereby reducing the phytoavailability and bioaccessible of heavy metal(loid)s.This research provides alternatives method to treat water and soil containing high concentrations of multi-heavy metal(loid)s.展开更多
Hydroxyapatite nanoparticles(HAP NPs)were synthesized by a one‐step hydrothermal method.The surface of HAP NPs was grafted-SH and-COOH chelating groups via in situ surface‐modification with iminodiacetic acid(IDA)an...Hydroxyapatite nanoparticles(HAP NPs)were synthesized by a one‐step hydrothermal method.The surface of HAP NPs was grafted-SH and-COOH chelating groups via in situ surface‐modification with iminodiacetic acid(IDA)and 3‐mercaptopropyl trimethoxysilane(MPS)to afford dual surface‐capped nano‐amendment HAPIDA/MPS.The structure of HAP‐IDA/MPS was characterized,and its adsorption performance for Hg^(2+),Cu^(2+),Zn^(2+),Ni^(2+),Co^(2+),and Cd^(2+)was evaluated.The total adsorption capacity of 0.10 g HAP‐IDA/MPS nano‐amendment for Hg^(2+),Cu^(2+),Zn^(2+),Ni^(2+),Co^(2+),and Cd^(2+)with an initial mass concentration of 20 mg·L^(-1) reached 13.7 mg·g^(-1),about 4.3 times as much as that of HAP.Notably,HAP‐IDA/MPS nano‐amendment displayed the highest immobilization rate for Hg^(2+),possibly because of its chemical reaction with-SH to form sulfide,possessing the lowest solubility product constant among a variety of metal sulfides.展开更多
The traditional techniques for treating wastewater contaminated by heavy metals mostly involve chemical precipitation,solvent extraction and adsorption,ion-exchange,chemical precipitation,and membrane separation.The m...The traditional techniques for treating wastewater contaminated by heavy metals mostly involve chemical precipitation,solvent extraction and adsorption,ion-exchange,chemical precipitation,and membrane separation.The main shortcomings of traditional procedures are low economic efficiency,lack of environmental friendliness,and poor selectivity.Cyclodextrins are artificial compounds that resemble cages.Through host-vip interaction,pollutants can be adsorbed by its stable inner hydrophobic chamber and exterior hydrophilic surface.It is not only inexpensive and environmentally friendly,but also quite selective.The synthesis and application of materials were reviewed,as well as the primary influencing factors,and the reaction principle of cyclodextrin adsorbent materials for better separation of heavy metal ions.And the future trend of discovery was described.展开更多
Industrial activities have contributed so much to the pollution of water bodies and these pollutions have adversely affected the aquatic ecosystem.This study aimed to investigate the ecological risk evaluation of heav...Industrial activities have contributed so much to the pollution of water bodies and these pollutions have adversely affected the aquatic ecosystem.This study aimed to investigate the ecological risk evaluation of heavy metal accumulation in Aba River bottom sediments:implications for soap and detergent industry wastewater management.Varian AA240 Atomic absorption spectrometer was used to analyse heavy metals.Individual and complex ecological indices were used to evaluate heavy metal contamination in bottom sediments.According to the results,the heavy metal properties of the wastewater indicated that Fe,Pb,Cd,Cr and Cu mean concentration values were higher than the World Health Organization(WHO)and the National Environmental Standards and Regulations Enforcement Agency(NESREA)permissible limits.Heavy metal properties of the surface water in Aba River(dry seasons)showed that Pb,Cd,Cu,Mn,Fe,and Cr,mean concentrations were above the NESREA,WHO and U.S.Environmental Protection Agency(USEPA)permissible limits.Heavy metal properties of the bottom sediments of Aba River(wet and dry season)showed that Pb,Cd,and Fe mean concentrations were significantly higher than the NESREA,WHO and USEPA permissible limits.The heavy metal contamination factor(CF)of sediments obtained from Aba River during the wet and dry season was low and the CFs of each of the assayed heavy metals were less than 1(CD<1).This also signifies the existence of a low contamination in the sediments of the course streams of Aba River during wet and dry season.The pollution load index(PLI)values of Aba River(sediment)indicated that there is no metal pollution at PLI<1 in the sampled sediments.The potential ecological risk index(RI)of Aba River was less than 150(RI<150)indicating a low ecological RI.Abatement of pollutants in the wastewater to permissible concentrations required for natural environment protection is needed.展开更多
The migration/transformation characteristics of heavy metals and polycyclic aromatic hydrocarbons(PAHs) during the co-liquefaction of pig manure and rice straw/wood sawdust were explored in this study.More than 87% of...The migration/transformation characteristics of heavy metals and polycyclic aromatic hydrocarbons(PAHs) during the co-liquefaction of pig manure and rice straw/wood sawdust were explored in this study.More than 87% of the heavy metals in feedstocks were enriched in hydrochars.The decreased proportion of active heavy metals in the hydrochars suggested partial passivation of the heavy metals.The pollution degree and risk of heavy metals were significantly mitigated from high and considerable levels in pig manure to moderate and low levels in hydrochar,respectively.Compared with commercial diesel,bio-oil products still contained an undesirable amount of heavy metals.PAHs were re-synthesized during liquefaction,with a net synthesis amount of 29.65-73.98 mg·kg^(-1).Moreover,the PAHs mainly existed in bio-oils,with a content of 57.32-132.33 mg·kg^(-1) and a toxicity equivalent of3.25-8.19 mg·kg^(-1).Compared to pig manure,the hydrochars presented a lower content of PAHs(1.76-3.53 mg·kg^(-1) versus 3.73 mg·kg^(-1)) and a smaller toxicity equivalent(0.14-0.22 mg·kg^(-1) versus0.26 mg·kg^(-1)).Interestingly,introducing lignocellulose(especially for rice straw) during the liquefaction of pig manure further mitigated the pollution degree/risk of heavy metals and PAHs.Overall,hydrochar reached a safe utilization level,while bio-oil products needed further clarification.展开更多
Urban rivers are one of the main water sources for local residents.However,the rapid industrialization and urbanization caused serious heavy metals pollution in urban rivers,which posed harmful impact on human health ...Urban rivers are one of the main water sources for local residents.However,the rapid industrialization and urbanization caused serious heavy metals pollution in urban rivers,which posed harmful impact on human health and ecosystem.In this study,134 sediment samples were collected fromurban rivers in a typical Economic and Technological Development Zone(ETDZ)to evaluate the contamination status,ecological risk,biotoxicity,and potential source of 8 heavy metals including arsenic(As),cadmium(Cd),chromium(Cr),copper(Cu),mercury(Hg),nickel(Ni),plumbum(Pb),and zinc(Zn).Results showed that the average concentrations of all 8 metals exceeded their corresponding background values and followed the trend:Cr(248.67 mg/kg)>Pb(123.58 mg/kg)>Zn(67.06 mg/kg)>Ni(47.19 mg/kg)>Cu(27.40 mg/kg)>As(16.15 mg/kg)>Cd(0.62mg/kg)>Hg(0.21mg/kg).A high contamination and accumulation tendency of Cd and Cr were found in the sediments.Moreover,Cd and Hg were the main contributors of ecological risk,and posed moderate to high risk.In terms of biotoxicity,all the sediment samples were harmful to benthic organisms.Two possible pollution sources of heavy metals were identified:one is a combined source of industrial and traffic pollution dominated by Cr and Pd,the other is an industrial pollution source consisting of six heavy metals(Ni,Zn,Cd,Hg,As,and Cu).This study provides insights into heavy metals pollution management and risk control in the ETDZ and similar urban rivers worldwide due to intense industrialization.展开更多
Nusantara,the new capital city of Indonesia,and its surrounding areas experienced intense heavy rainfall on 15-16 March 2022,leading to devastating and widespread flooding.However,the factors triggering such intense h...Nusantara,the new capital city of Indonesia,and its surrounding areas experienced intense heavy rainfall on 15-16 March 2022,leading to devastating and widespread flooding.However,the factors triggering such intense heavy rainfall and the underlying physical mechanisms are still not fully understood.Using high-resolution GSMaP(Global Satellite Mapping of Precipitation)data,we show that a mesoscale convective system(MCS)was the primary cause of the heavy rainfall event.The rainfall peak occurred during the MCS's mature stage at 1800 UTC 15 March 2022,and diminished as it entered the dissipation stage.To understand the large-scale environmental factors affecting the MCS event,we analyzed contributions from the MJO,equatorial waves,and low-frequency variability to column water vapor and moisture flux convergence.Results indicate a substantial influence of the MJO and equatorial waves on lower-level(boundary layer)meridional moisture flux convergence during the pre-MCS stage and initiation,with their contributions accounting for up to80%during the growth phase.Moreover,while La Nina and the Asian monsoon had negligible impacts on MCS moisture supply,we find a large contribution from the residual term of the water vapour budget during the maturation and decay phases of the MCS.This suggests that local forcing(such as small-scale convection,local evaporation,land-surface feedback,and topography)also contributed to modulation of the intensity and duration of the MCS.The results of this study can help in our understanding of the potential causes of extreme rainfall in Nusantara and could be leveraged to improve rainstorm forecasting and risk management across the region in the future.展开更多
Electroplating sludge(ES),a byproduct of the electroplating industry,is a significant environmental concern due to its high content of soluble heavy metals(HMs).The significance of spinel formation from ES lies in its...Electroplating sludge(ES),a byproduct of the electroplating industry,is a significant environmental concern due to its high content of soluble heavy metals(HMs).The significance of spinel formation from ES lies in its potential for HMs enrichment and environmental remediation,offering a sustainable solution for hazardous waste management.The article delves into themultifaceted recycling of HMs-rich spinel fromES,encompassing its synthesis,metal enrichment,and thermodynamic stability.The pyro-metallurgical and hydrometallurgical processes for spinel synthesis were discussed,with a focus on the critical role of thermodynamic data in predicting the stability and formation of spinel structures.The crystallographic and magnetic properties of spinels,with their applications in environmental remediation and energy storage are highlighted.The article provides a comprehensive reviewon the recycling of HMs-rich spinel fromES,offering a means to recycle HMs,mitigate ecological harm,and contribute to a circular economy through the recovery and application of valuable materials.The selective leaching of metals from ES also faces challenges,which was limited by the separation,purification steps and high energy consumption.This high energy consumption is a significant operational cost and also contributes to environmental concerns related to carbon emissions.It is essential to address the challenges through continued research and development,improved technologies,and supportive regulatory frameworks.展开更多
Drilling operations in carbonate rock heavy oil blocks(e.g.,in the Tahe Oilfield)are challenged by the intrusion of high-viscosity,temperature-sensitive formation heavy oil into the drilling fluid.This phenomenon ofte...Drilling operations in carbonate rock heavy oil blocks(e.g.,in the Tahe Oilfield)are challenged by the intrusion of high-viscosity,temperature-sensitive formation heavy oil into the drilling fluid.This phenomenon often results in wellbore blockage,reduced penetration rates,and compromised well control,thereby significantly limiting drilling efficiency and operational safety.To address this issue,this study conducts a comprehensive investigation into the mechanisms governing heavy oil invasion using a combination of laboratory experiments and field data analysis.Findings indicate that the reservoir exhibits strong heterogeneity and that the heavy oil possesses distinctive physical properties.The intrusion process is governed by multiple interrelated factors,including pressure differentials,pore structure,and the rheological behavior of the heavy oil.Experimental results reveal that the invasion of heavy oil occurs in distinct phases,with temperature playing a critical role in altering its viscosity.Specifically,as temperature increases,the apparent viscosity of the drilling fluid decreases;however,elevated pressures induce a nonlinear increase in viscosity.Furthermore,the compatibility between the drilling fluid and the intruding heavy oil declines markedly with increasing oil concentration,substantially raising the risk of wellbore obstruction.Simulation experiments further confirm that at temperatures exceeding 40℃and injection rates of L/min,the likelihood of wellbore blockage significantly≥0.4increases due to heavy oil infiltration.Based on these insights,a suite of targeted mitigation strategies is proposed.These include the formulation of specialized chemical additives,such as viscosity reducers,dispersants,and plugging removal agents,the real-time adjustment of drilling fluid density,and the implementation of advanced monitoring and early-warning systems.展开更多
This study evaluates the impact of heavy metals(zinc,copper and cadmium)on the development and metabolic responses of the maize(Zea mays)variety“Torro Plus”.Seeds were cultivated on MS medium enriched with progressi...This study evaluates the impact of heavy metals(zinc,copper and cadmium)on the development and metabolic responses of the maize(Zea mays)variety“Torro Plus”.Seeds were cultivated on MS medium enriched with progressively higher concentrations of heavy metals(50,100 and 150μM),and plants were analyzed after 21 days.The results show a significant reduction in morphological parameters,notably an 87.28%decrease in the fresh weight of aerial parts and a 69.93%decrease in the fresh weight of roots under 150μM of Cd.Chlorophyll a,b and total content also decreased drastically,reaching a maximum reduction of 74.31%under Cd(150μM).In contrast,secondary metabolites such as proline and flavonoids increased,with a maximum proline accumulation of 0.71 mg/g under Cu(150μM)and a flavonoid concentration reaching 176.33 mg/g under Cu(100μM).These results show mechanisms of adaptation to stress,notably the accumulation of flavonoids and proline,while highlighting the increased toxicity of cadmium at high doses.These data are promising for applications in phytoremediation and sustainable agriculture.This study provides important data on the physiological and biochemical responses of plants to heavy metals and opens up prospects for phytoremediation applications.展开更多
Surface water provides crucial support to the aquatic ecosystem and humans in numerous ways.However,its quality is paramount in determining its impact on the health of the aquatic ecosystem and humans.Currently,the ma...Surface water provides crucial support to the aquatic ecosystem and humans in numerous ways.However,its quality is paramount in determining its impact on the health of the aquatic ecosystem and humans.Currently,the malady of pollution arising from anthropogenic activities poses a significant threat to the quality of most rivers.The quality of water in the Kapingazi river in Embu County has received limited attention which is a concern that needs to be addressed.This study therefore,sought to investigate the status of water quality in river Kapingazi.The study analyzed 96 samples from four locations in a span of eight months which combined the dry and wet seasons of the year.Parameters measured in-situ included turbidity,pH,total dissolved solids(TDS),temperature,dissolved oxygen(DO)and electrical conductivity(EC)while ex-situ parameters were phosphates,nitrates and concentrations of heavy metals:iron and manganese.Results showed that Water Quality Index(WQI)during the drought period was74.05,suggesting that the water quality is only recommended for agricultural and industrial applications.During wet season,the water quality index was 89.67,reflecting a poor status,as more contaminants were likely introduced through surface runoff.Overall,the WQI averaged to 88.02.This study concludes that water in River Kapingazi is not suitable for human consumption;therefore,appropriate treatment is essential prior to its use.Similarly,the findings indicate that both rainy and drought periods significantly affect water quality,presenting challenges for its use for various purposes.It is recommended that the allocation of resources towards water treatment facilities and regulation of pollution sources should be enforced to ensure the safety of river water for diverse applications.展开更多
基金Supported by the Foundation for Innovative Research Groups of National Natural Science Foundation of China(52421002)General Program of National Natural Science Foundation of China(52474016).
文摘This paper investigates the macroscopic and microscopic characteristics of viscosity reduction and quality improvement of heavy oil in a supercritical water environment through laboratory experiments and testing.The effect of three reaction parameters,i.e.reaction temperature,reaction time and oil-water ratio,is analyzed on the product and their correlation with viscosity.The results show that the flow state of heavy oil is significantly improved with a viscosity reduction of 99.4%in average after the reaction in the supercritical water.Excessively high reaction temperature leads to a higher content of resins and asphaltenes,with significantly increasing production of coke.The optimal temperature ranges in 380–420℃.Prolonged reaction time could continuously increase the yield of light oil,but it will also results in the growth of resins and asphaltenes,with the optimal reaction time of 150 min.Reducing the oil-water ratio helps improve the diffusion environment within the reaction system and reduce the content of resins and asphaltenes,but it will increase the cost of heavy oil treatment.An oil-water ratio of 1︰2 is considered as optimum to balance the quality improvement,viscosity reduction and reaction economics.The correlation of the three reaction parameters relative to the oil sample viscosity is ranked as temperature,time and oil-water ratio.Among the four fractions of heavy oil,the viscosity is dominated by asphaltene content,followed by aromatic content and less affected by resins and saturates contents.
基金the outcome of project conducted at the Vietnam Academy of Science and Technology(VAST.07.05/24-25).
文摘Heavy metal pollution in coastal waters is on the rise,presenting serious threats to both ecosystems and human health.Coastal aquaculture zones,such as those in Quang Ninh province,are especially vulnerable due to the accumulation of heavy metals from multiple sources,including industrial wastewater,land runoff,and maritime activities.This study applies the Heavy Metal Pollution Index(HPI)to assess pollution levels based on the concentrations of nine heavy metals(Cr,Mn,Fe,Cu,Zn,As,Cd,Hg,Pb)found in seawater samples collected from coastal aquaculture areas in Quang Ninh.According to the HPI method,values exceeding 100 indicate polluted water,serving as a benchmark for evaluating heavy metal contamination in the region.A total of 25 seawater samples were collected and analyzed;of these,18 samples(72%)had HPI values above 100,signaling a concerning level of heavy metal pollution,while only 7 samples(28%)fell below the threshold,suggesting no significant contamination.These results underscore the urgent need for enhanced monitoring of water quality and stricter regulation of pollution sources to protect both environmental and public health.
基金supported by the National Natural Science Foundation of China(Nos.52100184,and U22A20617).
文摘Controlling heavy metal pollution in agricultural soil has been a significant challenge.These heavy metals seriously threaten the surrounding ecological environment and human health.The effective assessment and remediation of heavy metals in agricultural soils are crucial.These two aspects support each other,forming a close and complete decisionmaking chain.Therefore,this review systematically summarizes the distribution characteristics of soil heavy metal pollution,the correlation between soil and crop heavy metal contents,the presence pattern and migration and transformation mode of heavy metals in the soil-crop system.The advantages and disadvantages of the risk evaluation tools and models of heavy metal pollution in farmland are further outlined,which provides important guidance for an in-depth understanding of the characteristics of heavymetal pollution in farmland soils and the assessment of the environmental risk.Soil remediation strategies involve multiple physical,chemical,biological and even combined technologies,and this paper compares the potential and effect of the above current remediation technologies in heavy metal polluted farmland soils.Finally,the main problems and possible research directions of future heavy metal risk assessment and remediation technologies in agricultural soils are prospected.This review provides new ideas for effective assessment and selection of remediation technologies based on the characterization of soil heavy metals.
基金supported by the National Natural Science Foundation of China(No.32171615)the National Key R&D Program of China(2019YFC1804102)。
文摘Agricultural soil is related to food security and human health,antibiotics and heavy metals(HMs),as two typical pollutants,possess a high coexistence rate in the environmental medium,which is extremely prone to inducing antibiotic-HMs combined pollution.Recently,frequent human activities have led to more prominent antibiotics-HMs combined contamination in agricultural soils,especially the production and spread of antibiotic resistance genes(ARGs),heavy metal resistance genes(MRGs),antibiotic resistant bacteria(ARB),and antibiotics-HMs complexes(AMCs),which seriously threaten soil ecology and human health.This review describes the main sources(Intrinsic and manmade sources),composite mechanisms(co-selective resistance,oxidative stress,and Joint toxicity mechanism),environmental fate and the potential risks(soil ecological and human health risks)of antibiotics and HMs in agricultural soils.Finally,the current effective source blocking,transmission control,and attenuation strategies are classified for discussion,such as the application of additives and barrier materials,as well as plant and animal remediation and bioremediation,etc.,pointing out that future research should focus on the whole chain process of“source-processterminal”,intending to provide a theoretical basis and decision-making reference for future research.
基金supported by the National Key Research and Development Program of China(No.2019YFC1804501)the National Natural Science Foundation of China(Nos.42122056 and U1901210)+2 种基金Guangdong Basic and Applied Basic Research Foundation(No.2021B1515020063)the Key Research and Development Program of Guangdong Province(No.2021B1111380003)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01Z032).
文摘Coking industry is a potential source of heavy metals(HMs)pollution.However,its impacts to the groundwater of surrounding residential areas have not been well understood.This study investigated the pollution characteristics and health risks of HMs in groundwater nearby a typical coking plant.Nine HMs including Fe,Zn,Mo,As,Cu,Ni,Cr,Pb and Cd were analyzed.The average concentration of total HMswas higher in the nearby area(244.27μg/L)than that of remote area away the coking plant(89.15μg/L).The spatial distribution of pollution indices including heavy metal pollution index(HPI),Nemerow index(NI)and contamination degree(CD),all demonstrated higher values at the nearby residential areas,suggesting coking activity could significantly impact the HMs distribution characteristics.Four sources of HMs were identified by Positive Matrix Factorization(PMF)model,which indicated coal washing and coking emission were the dominant sources,accounted for 40.4%,and 31.0%,respectively.Oral ingestionwas found to be the dominant exposure pathway with higher exposure dose to children than adults.Hazard quotient(HQ)values were below 1.0,suggesting negligible non-carcinogenic health risks,while potential carcinogenic risks were from Pb and Ni with cancer risk(CR)values>10−6.Monte Carlo simulation matched well with the calculated results with HMs concentrations to be the most sensitive parameters.This study provides insights into understanding how the industrial coking activities can impact the HMs pollution characteristics in groundwater,thus facilitating the implement of HMs regulation in coking industries.
基金supported by the National Natural Science Foundation of China(Nos.12035019,62234013,12205350,12075290,12175287)the China National Postdoctoral Program for Innovative Talents(BX20200340)+1 种基金the fund of Innovation Center of Radiation Application(No.KFZC2022020601)the Chinese Academy of Sciences(CAS)“Light of West China"Program hosted by Jian Zeng.
文摘Gallium nitride(GaN)-based devices have significant potential for space applications.However,the mechanisms of radiation damage to the device,particularly from strong ionizing radiation,remains unknown.This study investigates the effects of radiation on p-gate AlGaN/GaN high-electron-mobility transistors(HEMTs).Under a high voltage,the HEMT leakage current increased sharply and was accompanied by a rapid increase in power density that caused"thermal burnout"of the devices.In addition,a burnout signature appeared on the surface of the burned devices,proving that a single-event burnout effect occurred.Additionally,degradation,including an increase in the on-resistance and a decrease in the breakdown voltage,was observed in devices irradiated with high-energy heavy ions and without bias.The latent tracks induced by heavy ions penetrated the heterojunction interface and extended into the GaN layer.Moreover,a new type of N_(2)bubble defect was discovered inside the tracks using Fresnel analysis.The accumulation of N_(2)bubbles in the heterojunction and buffer layers is more likely to cause leakage and failure.This study indicates that electrical stress accelerates the failure rate and that improving heat dissipation is an effective reinforcement method for GaN-based devices.
基金supported by Open Foundation of the State Key Laboratory of Refractories and Metallurgy(No.G201711)the National Natural Science Foundation of China(Nos.52104317 and 51874001).
文摘The impact of heavy reduction on dendritic morphology was explored by combining experimental research and numerical simulation in metallurgy,including a detailed three-dimensional(3D)analysis and reconstruction of dendritic solidification structures.Combining scanning electron microscopy and energy-dispersive scanning analysis and ANSYS simulation,the high-precision image processing software Mimics Research was utilized to conduct the extraction of dendritic morphologies.Reverse engineering software NX Imageware was employed for the 3D reconstruction of two-dimensional dendritic morphologies,restoring the dendritic characteristics in three-dimensional space.The results demonstrate that in a two-dimensional plane,dendrites connect with each other to form irregularly shaped“ring-like”structures.These dendrites have a thickness greater than 0.1 mm along the Z-axis direction,leading to the envelopment of molten steel by dendrites in a 3D space of at least 0.1 mm.This results in obstructed flow,confirming the“bridging”of dendrites in three-dimensional space,resulting in a tendency for central segregation.Dense and dispersed tiny dendrites,under the influence of heat flow direction,interconnect and continuously grow,gradually forming primary and secondary dendrites in three-dimensional space.After the completion of dendritic solidification and growth,these microdendrites appear dense and dispersed on the two-dimensional plane,providing the nuclei for the formation of new dendrites.When reduction occurs at a solid fraction of 0.46,there is a noticeable decrease in dendritic spacing,resulting in improved central segregation.
基金funded by the Project of Yunnan Province’s Xingdian Talents Support Program(yfgrc202437)the Project of the International Cooperation Science Program of National Natural Science Foundation of China(42361144885).
文摘Phosphorus(P)poses a global challenge to the environment and human health due to its natural association with heavy metals.Sustainable use of P is crucial to ensure food security for future generations.An analysis of the 150 phosphate fertilizers stored at the Institute for Crop and Soil Science in Germany has been conducted,supplemented by previously published data.The elements Cd,Bi,U,Cr,Zn,Tl,As,B,Sb,Ni,and Se are found in higher concentrations in sedimentary derived phosphates compared to igneous derived phosphates.Mineral fertilizers contain more than ten times the amount of U,Cd,B,and As compared to farmyard manure.Principal component analyses(PCA)indicate that U,Cd,Be,and Cr are primarily present in sedimentary derived phosphates and their concentrations are 2 to 10 times higher than those in igneous derived phosphates.Regarding heavy metal contamination,over 1000 potential combinations were identified;36% of these were significant but weak(>0.1).It is estimated that approximately 707 t of uranium enter farmland annually through the application of mineral phosphate fertilizers in European countries.This contribution addresses environmental issues related to the utilization of rock phosphate as well as alternative production methods for cleaner and safer phosphate fertilizers while presenting a roadmap with measures for mitigation.
基金supported by the National Key Research and Development Program of China(No.2023YFC3710000)the National Natural Science Foundation of China(Nos.42277078 and 42307118).
文摘Abandoned mines,especially pyrite-rich ones,release acid mine drainage(AMD)with high acidity and excessive amounts of heavy metals,threatening regional ecosystems.Six samples of mine drainage,nine samples of surface water,and twelve samples of sediment were analyzed in this case study of the Dashu pyrite mine in southwest China.A comprehensive analysis of the pollution levels,pollution sources,and potential hazards of eight metals(Ni,Cd,Cu,Zn,Fe,Al,Pb,and Mn)that exceeded regulatory standardswas conducted bymonitoring 24 conventional and characteristic indicators.Ultimately,this research evaluated the environmental hazards associated with abandonedmine water using the"pressure-response"model,thereby providing valuable insights for the effective protection of the environment in mining regions.The primary pollutants in mine water were determined to be SO_(4)^(2−),Fe,and Mn,with concentrations of 7700,1450,and 6.78mg/L,respectively.A clear"source-sink"dynamic was observed between themine water and the surrounding water system.surface water was primarily polluted by Ni and Mn,while water system sediments were primarily polluted by Cu and Hg.Ion ratio and Pearson correlation analyses indicated heavy metals in surface water and sediments originated from the same AMD source.The"pressureresponse"model was used to assess the environmental hazards of water from abandoned mines.Mines W1,W2,W5,and W6 were classified as high-risk,while W3 and W4 were medium-risk.This study offers a novel approach and valuable reference for identifying and classifying environmental risks in abandoned mines and targeting AMD treatment.
基金supported d by the National Key Research and Development Program of China(No.2018YFC1802905).
文摘Two strains of Fe/Mn oxidizing bacteria tolerant to high concentrations of multiple heavy metal(loid)s and efficient decontamination for them were screened.The surface of the bio-Fe/Mn oxides produced by the oxidation of Fe(II)and Mn(II)by Pseudomonas taiwanensis(marked as P4)and Pseudomonas plecoglossicida(marked as G1)contains rich reactive oxygen functional groups,which play critical roles in the removal efficiency and immobilization of heavymetal(loid)s in co-contamination system.The isolated strains P4 and G1 can growwell in the following environments:pH 5-9,NaCl 0-4%,and temperature 20-30℃.The removal efficiencies of Fe,Pb,As,Zn,Cd,Cu,and Mn are effective after inoculation of the strains P4 and G1 in the simulated water system(the initial concentrations of heavy metal(loid)were 1 mg/L),approximately reaching 96%,92%,85%,67%,70%,54%and 15%,respectively.The exchangeable and carbonate bound As,Cd,Pb and Cu are more inclined to convert to the Fe-Mn oxide bound fractions in P4 and G1 treated soil,thereby reducing the phytoavailability and bioaccessible of heavy metal(loid)s.This research provides alternatives method to treat water and soil containing high concentrations of multi-heavy metal(loid)s.
文摘Hydroxyapatite nanoparticles(HAP NPs)were synthesized by a one‐step hydrothermal method.The surface of HAP NPs was grafted-SH and-COOH chelating groups via in situ surface‐modification with iminodiacetic acid(IDA)and 3‐mercaptopropyl trimethoxysilane(MPS)to afford dual surface‐capped nano‐amendment HAPIDA/MPS.The structure of HAP‐IDA/MPS was characterized,and its adsorption performance for Hg^(2+),Cu^(2+),Zn^(2+),Ni^(2+),Co^(2+),and Cd^(2+)was evaluated.The total adsorption capacity of 0.10 g HAP‐IDA/MPS nano‐amendment for Hg^(2+),Cu^(2+),Zn^(2+),Ni^(2+),Co^(2+),and Cd^(2+)with an initial mass concentration of 20 mg·L^(-1) reached 13.7 mg·g^(-1),about 4.3 times as much as that of HAP.Notably,HAP‐IDA/MPS nano‐amendment displayed the highest immobilization rate for Hg^(2+),possibly because of its chemical reaction with-SH to form sulfide,possessing the lowest solubility product constant among a variety of metal sulfides.
基金National Natural Science Foundation of China(52074031)Key Research and Development Program of Shandong Province(ZR2021MB051,ZR2020ME256)。
文摘The traditional techniques for treating wastewater contaminated by heavy metals mostly involve chemical precipitation,solvent extraction and adsorption,ion-exchange,chemical precipitation,and membrane separation.The main shortcomings of traditional procedures are low economic efficiency,lack of environmental friendliness,and poor selectivity.Cyclodextrins are artificial compounds that resemble cages.Through host-vip interaction,pollutants can be adsorbed by its stable inner hydrophobic chamber and exterior hydrophilic surface.It is not only inexpensive and environmentally friendly,but also quite selective.The synthesis and application of materials were reviewed,as well as the primary influencing factors,and the reaction principle of cyclodextrin adsorbent materials for better separation of heavy metal ions.And the future trend of discovery was described.
文摘Industrial activities have contributed so much to the pollution of water bodies and these pollutions have adversely affected the aquatic ecosystem.This study aimed to investigate the ecological risk evaluation of heavy metal accumulation in Aba River bottom sediments:implications for soap and detergent industry wastewater management.Varian AA240 Atomic absorption spectrometer was used to analyse heavy metals.Individual and complex ecological indices were used to evaluate heavy metal contamination in bottom sediments.According to the results,the heavy metal properties of the wastewater indicated that Fe,Pb,Cd,Cr and Cu mean concentration values were higher than the World Health Organization(WHO)and the National Environmental Standards and Regulations Enforcement Agency(NESREA)permissible limits.Heavy metal properties of the surface water in Aba River(dry seasons)showed that Pb,Cd,Cu,Mn,Fe,and Cr,mean concentrations were above the NESREA,WHO and U.S.Environmental Protection Agency(USEPA)permissible limits.Heavy metal properties of the bottom sediments of Aba River(wet and dry season)showed that Pb,Cd,and Fe mean concentrations were significantly higher than the NESREA,WHO and USEPA permissible limits.The heavy metal contamination factor(CF)of sediments obtained from Aba River during the wet and dry season was low and the CFs of each of the assayed heavy metals were less than 1(CD<1).This also signifies the existence of a low contamination in the sediments of the course streams of Aba River during wet and dry season.The pollution load index(PLI)values of Aba River(sediment)indicated that there is no metal pollution at PLI<1 in the sampled sediments.The potential ecological risk index(RI)of Aba River was less than 150(RI<150)indicating a low ecological RI.Abatement of pollutants in the wastewater to permissible concentrations required for natural environment protection is needed.
基金supported by the National Natural Science Foundation of China(21707056)the Natural Science Foundation of Jiangxi Province,China(20192BAB203019)the Jiangxi Province Graduate Innovation Special Fund Project(YC2022-S412)。
文摘The migration/transformation characteristics of heavy metals and polycyclic aromatic hydrocarbons(PAHs) during the co-liquefaction of pig manure and rice straw/wood sawdust were explored in this study.More than 87% of the heavy metals in feedstocks were enriched in hydrochars.The decreased proportion of active heavy metals in the hydrochars suggested partial passivation of the heavy metals.The pollution degree and risk of heavy metals were significantly mitigated from high and considerable levels in pig manure to moderate and low levels in hydrochar,respectively.Compared with commercial diesel,bio-oil products still contained an undesirable amount of heavy metals.PAHs were re-synthesized during liquefaction,with a net synthesis amount of 29.65-73.98 mg·kg^(-1).Moreover,the PAHs mainly existed in bio-oils,with a content of 57.32-132.33 mg·kg^(-1) and a toxicity equivalent of3.25-8.19 mg·kg^(-1).Compared to pig manure,the hydrochars presented a lower content of PAHs(1.76-3.53 mg·kg^(-1) versus 3.73 mg·kg^(-1)) and a smaller toxicity equivalent(0.14-0.22 mg·kg^(-1) versus0.26 mg·kg^(-1)).Interestingly,introducing lignocellulose(especially for rice straw) during the liquefaction of pig manure further mitigated the pollution degree/risk of heavy metals and PAHs.Overall,hydrochar reached a safe utilization level,while bio-oil products needed further clarification.
基金supported by the National Key Research and Development Plan of China(No.2022YFE0197200)the National Natural Science Foundation of China(No.42277055).
文摘Urban rivers are one of the main water sources for local residents.However,the rapid industrialization and urbanization caused serious heavy metals pollution in urban rivers,which posed harmful impact on human health and ecosystem.In this study,134 sediment samples were collected fromurban rivers in a typical Economic and Technological Development Zone(ETDZ)to evaluate the contamination status,ecological risk,biotoxicity,and potential source of 8 heavy metals including arsenic(As),cadmium(Cd),chromium(Cr),copper(Cu),mercury(Hg),nickel(Ni),plumbum(Pb),and zinc(Zn).Results showed that the average concentrations of all 8 metals exceeded their corresponding background values and followed the trend:Cr(248.67 mg/kg)>Pb(123.58 mg/kg)>Zn(67.06 mg/kg)>Ni(47.19 mg/kg)>Cu(27.40 mg/kg)>As(16.15 mg/kg)>Cd(0.62mg/kg)>Hg(0.21mg/kg).A high contamination and accumulation tendency of Cd and Cr were found in the sediments.Moreover,Cd and Hg were the main contributors of ecological risk,and posed moderate to high risk.In terms of biotoxicity,all the sediment samples were harmful to benthic organisms.Two possible pollution sources of heavy metals were identified:one is a combined source of industrial and traffic pollution dominated by Cr and Pd,the other is an industrial pollution source consisting of six heavy metals(Ni,Zn,Cd,Hg,As,and Cu).This study provides insights into heavy metals pollution management and risk control in the ETDZ and similar urban rivers worldwide due to intense industrialization.
基金supported by the Budget Execution(Allotment)Document,National Research and Innovation Agency(BRIN)in 2022(Grant No.SP DIPA-124.01.1.690504/2022)。
文摘Nusantara,the new capital city of Indonesia,and its surrounding areas experienced intense heavy rainfall on 15-16 March 2022,leading to devastating and widespread flooding.However,the factors triggering such intense heavy rainfall and the underlying physical mechanisms are still not fully understood.Using high-resolution GSMaP(Global Satellite Mapping of Precipitation)data,we show that a mesoscale convective system(MCS)was the primary cause of the heavy rainfall event.The rainfall peak occurred during the MCS's mature stage at 1800 UTC 15 March 2022,and diminished as it entered the dissipation stage.To understand the large-scale environmental factors affecting the MCS event,we analyzed contributions from the MJO,equatorial waves,and low-frequency variability to column water vapor and moisture flux convergence.Results indicate a substantial influence of the MJO and equatorial waves on lower-level(boundary layer)meridional moisture flux convergence during the pre-MCS stage and initiation,with their contributions accounting for up to80%during the growth phase.Moreover,while La Nina and the Asian monsoon had negligible impacts on MCS moisture supply,we find a large contribution from the residual term of the water vapour budget during the maturation and decay phases of the MCS.This suggests that local forcing(such as small-scale convection,local evaporation,land-surface feedback,and topography)also contributed to modulation of the intensity and duration of the MCS.The results of this study can help in our understanding of the potential causes of extreme rainfall in Nusantara and could be leveraged to improve rainstorm forecasting and risk management across the region in the future.
基金supported by the National Natural Science Foundation of China(Nos.52370158 and 22006053)Guangzhou Science and Technology Plan Project(No.2024A04J0821)Guangdong Provincial Education Science Planning Project(Higher Education Special Project)(No.2023GXJK108).
文摘Electroplating sludge(ES),a byproduct of the electroplating industry,is a significant environmental concern due to its high content of soluble heavy metals(HMs).The significance of spinel formation from ES lies in its potential for HMs enrichment and environmental remediation,offering a sustainable solution for hazardous waste management.The article delves into themultifaceted recycling of HMs-rich spinel fromES,encompassing its synthesis,metal enrichment,and thermodynamic stability.The pyro-metallurgical and hydrometallurgical processes for spinel synthesis were discussed,with a focus on the critical role of thermodynamic data in predicting the stability and formation of spinel structures.The crystallographic and magnetic properties of spinels,with their applications in environmental remediation and energy storage are highlighted.The article provides a comprehensive reviewon the recycling of HMs-rich spinel fromES,offering a means to recycle HMs,mitigate ecological harm,and contribute to a circular economy through the recovery and application of valuable materials.The selective leaching of metals from ES also faces challenges,which was limited by the separation,purification steps and high energy consumption.This high energy consumption is a significant operational cost and also contributes to environmental concerns related to carbon emissions.It is essential to address the challenges through continued research and development,improved technologies,and supportive regulatory frameworks.
基金Hubei Key Laboratory of Oil and Gas Drilling and Production Engineering(Yangtze University),China(Grant No.YQZC202415)Hubei Province Science and Technology Plan Project(Key R&D Special Project),China(Grant No.2023BCB070)+2 种基金Key R&D Program Project in Xinjiang,China,Grant No.2022B01042Guiding Project of Scientific Research Program of Education Department of Hubei Province,China(Grant No.B2023024)Open Fund of National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University),Grant No.PLN2023-03.
文摘Drilling operations in carbonate rock heavy oil blocks(e.g.,in the Tahe Oilfield)are challenged by the intrusion of high-viscosity,temperature-sensitive formation heavy oil into the drilling fluid.This phenomenon often results in wellbore blockage,reduced penetration rates,and compromised well control,thereby significantly limiting drilling efficiency and operational safety.To address this issue,this study conducts a comprehensive investigation into the mechanisms governing heavy oil invasion using a combination of laboratory experiments and field data analysis.Findings indicate that the reservoir exhibits strong heterogeneity and that the heavy oil possesses distinctive physical properties.The intrusion process is governed by multiple interrelated factors,including pressure differentials,pore structure,and the rheological behavior of the heavy oil.Experimental results reveal that the invasion of heavy oil occurs in distinct phases,with temperature playing a critical role in altering its viscosity.Specifically,as temperature increases,the apparent viscosity of the drilling fluid decreases;however,elevated pressures induce a nonlinear increase in viscosity.Furthermore,the compatibility between the drilling fluid and the intruding heavy oil declines markedly with increasing oil concentration,substantially raising the risk of wellbore obstruction.Simulation experiments further confirm that at temperatures exceeding 40℃and injection rates of L/min,the likelihood of wellbore blockage significantly≥0.4increases due to heavy oil infiltration.Based on these insights,a suite of targeted mitigation strategies is proposed.These include the formulation of specialized chemical additives,such as viscosity reducers,dispersants,and plugging removal agents,the real-time adjustment of drilling fluid density,and the implementation of advanced monitoring and early-warning systems.
文摘This study evaluates the impact of heavy metals(zinc,copper and cadmium)on the development and metabolic responses of the maize(Zea mays)variety“Torro Plus”.Seeds were cultivated on MS medium enriched with progressively higher concentrations of heavy metals(50,100 and 150μM),and plants were analyzed after 21 days.The results show a significant reduction in morphological parameters,notably an 87.28%decrease in the fresh weight of aerial parts and a 69.93%decrease in the fresh weight of roots under 150μM of Cd.Chlorophyll a,b and total content also decreased drastically,reaching a maximum reduction of 74.31%under Cd(150μM).In contrast,secondary metabolites such as proline and flavonoids increased,with a maximum proline accumulation of 0.71 mg/g under Cu(150μM)and a flavonoid concentration reaching 176.33 mg/g under Cu(100μM).These results show mechanisms of adaptation to stress,notably the accumulation of flavonoids and proline,while highlighting the increased toxicity of cadmium at high doses.These data are promising for applications in phytoremediation and sustainable agriculture.This study provides important data on the physiological and biochemical responses of plants to heavy metals and opens up prospects for phytoremediation applications.
文摘Surface water provides crucial support to the aquatic ecosystem and humans in numerous ways.However,its quality is paramount in determining its impact on the health of the aquatic ecosystem and humans.Currently,the malady of pollution arising from anthropogenic activities poses a significant threat to the quality of most rivers.The quality of water in the Kapingazi river in Embu County has received limited attention which is a concern that needs to be addressed.This study therefore,sought to investigate the status of water quality in river Kapingazi.The study analyzed 96 samples from four locations in a span of eight months which combined the dry and wet seasons of the year.Parameters measured in-situ included turbidity,pH,total dissolved solids(TDS),temperature,dissolved oxygen(DO)and electrical conductivity(EC)while ex-situ parameters were phosphates,nitrates and concentrations of heavy metals:iron and manganese.Results showed that Water Quality Index(WQI)during the drought period was74.05,suggesting that the water quality is only recommended for agricultural and industrial applications.During wet season,the water quality index was 89.67,reflecting a poor status,as more contaminants were likely introduced through surface runoff.Overall,the WQI averaged to 88.02.This study concludes that water in River Kapingazi is not suitable for human consumption;therefore,appropriate treatment is essential prior to its use.Similarly,the findings indicate that both rainy and drought periods significantly affect water quality,presenting challenges for its use for various purposes.It is recommended that the allocation of resources towards water treatment facilities and regulation of pollution sources should be enforced to ensure the safety of river water for diverse applications.
