Abstract:As a critical material for the rapidly expanding photovoltaic(PV)industry,PV glass is facing increasingly rigorous environmental scrutiny.A thorough investigation into its decarbonization potential is of paramount importance,not only for advancing the long-term sustainability of the entire PV sector from a life-cycle perspective but also for effectively navigating the complexities of emerging global green trade policies.This study employed a comprehensive Life Cycle Assessment(LCA)methodology to evaluate the carbon footprint associated with the manufacturing of typical PV glass in China.We developed a robust,process-based life cycle carbon emission accounting model that focuses on the two pivotal stages of production:raw glass sheet formation and subsequent deep-processing treatments.To ensure a high degree of accuracy,we developed a hybrid allocation methodology grounded in the physical relationships of mass and area,tailored for activity-level data.Our quantitative analysis of a 2 mm thick,1 m2PV glass panel elucidates that the primary carbon emission hotspots are the combustion of fossil fuels(heavy oil and natural gas),raw material acquisition,and electricity consumption,which contribute 26.74％,24.84％,and 20.62％to the total carbon footprint,respectively.In contrast,ancillary activities such as the procurement of packaging materials,water resource consumption,and waste disposal have a negligible impact,collectively constituting less than 1％of the total emissions.A sensitivity analysis further identifies the consumption volumes of heavy oil and soda ash,along with the carbon emission factor of the electricity mix,as the most influential parameters affecting the product's overall carbon footprint.To chart a path toward a low-carbon future,a scenario analysis was conducted to quantify the technically feasible carbon mitigation potential.Five standalone low-carbon scenarios were modeled:(1)substituting fossil fuels with green hydrogen,(2)replacing them with green methanol,(3)increasing the proportion of natural gas,(4)optimizing the soda ash production process,and(5)powering operations with PV-generated electricity.These strategies were found to yield carbon reductions of 2.40 kg CO2-eq(30.14％),0.82 kg CO2-eq(10.21％),0.50 kg CO2-eq(6.31％),0.64 kg CO2 eq(8.07％),and 0.22 kg CO2-eq(2.77％)per panel,respectively.More significantly,a synergistic optimization scenario that integrates the use of hydrogen fuel,a decarbonized electricity grid,and an optimized soda ash supply chain demonstrated a substantial cumulative reduction potential of 41.11％.The findings underscore that the deep decarbonization of the PV glass sector is contingent upon the establishment of a coordinated,synergistic mechanism across the entire value chain.This requires concerted efforts and the implementation of systemic carbon reduction strategies through close collaboration between upstream raw material suppliers and downstream manufacturers.

Abstract:Fly ash from municipal solid waste incineration(MSWI)is a hazardous waste that contains various toxic heavy metals,posing significant environmental risks if not properly treated.The leaching of these heavy metals restricts the resource utilization of fly ash and threatens the environment.This study investigates the influence of the slaked lime pre-addition during flue gas purification on the subsequent chelation and solidification treatment of MSWI fly ash.It focuses on the impact of slaked lime dosage and purity on the stabilization efficiency of heavy metals.Additionally,the mechanism of heavy metal solidification is elucidated by analyzing the micro-structure,mineral composition,and the distribution of heavy metal speciation.The experimental results indicated that the optimal solidification efficiency for most heavy metals was achieved when the slaked lime dosage reached 8％;specifically,the solidification efficiencies of Zn,Se,and Cr(Ⅵ)were 97.6％,82.9％,and 53.3％,respectively.Moreover,the solidification efficiencies of Cu,Pb,Cd,and Ni reached 100％.The addition of slaked lime increased the leaching concentrations of Ba and As;however,these concentrations did not exceed the regulatory limts for landfill disposal.Notably,using high-purity slaked lime significantly reduced the leaching concentrations of heavy metals,highlighting the crucial role of lime purity in stabilization.Microstructural analysis revealed that the addition of slaked lime densified the internal structure of fly ash,promoting the solidification of heavy metals.Mineral composition analysis showed that the presence of alkaline substances enhanced heavy metal stabilization.Heavy metal speciation distribution analysis indicated that the distribution of heavy metals shifted to more stable forms,further demonstrating the benefits of slaked lime addition.This study emphasizes the importance of pre-addition of slaked lime during flue gas purification in enhancing the subsequent chelation and solidification treatment of MSWI fly ash.The findings provide valuable insights into optimizing lime dosage to improve heavy metal stabilization,contributing to more effective and sustainable waste management practices.

Abstract:Deep eutectic solvents(DESs),distinguished by their low volatility,high thermal stability,structural tunability,and environmental friendliness,have emerged as highly promising novel absorbents for carbon dioxide capture.This review categorizes DESs into four types based on their interaction mechanisms with CO2 and systematically evaluates their capture performance and underlying principles:(1)Physical DESs achieve reversible absorption through van der Waals forces and hydrogen bonding,resulting in low regeneration energy consumption,although they require high-pressure conditions.These DESs can be further integrated with porous supports or membrane technologies to construct high-performance material systems.(2)Amine-functionalized DESs enhance capture capacity at low partial pressures via chemical absorption;however,they are challenged by high viscosity.Strategies such as introducing hydrogen bond regulators,increasing steric hindrance,and modulating reaction product structures can be employed to design low-viscosity systems.(3)Superbase-derived DESs utilize guanidine/amidine superbases to activate hydrogen bond donors(HBDs),thereby generating highly reactive anions for efficient capture.However,they pose toxicity risks,requiring simultaneous evaluation and regulation of biocompatibility to balance performance and safety during optimization.(4)Ionic liquid-type DESs combine the advantages of ionic liquids and DESs to reduce viscosity and improve absorption efficiency.Nevertheless,further optimization of the synthesis pathway and reduction of material costs are still required.The study further elucidates the influence of DES molecular structure,environmental parameters,and water content on CO2 capture performance.Specifically,(1)From a structural perspective,the basicity of the HBA and HBD components,the synergy between HBA and HBD,alkyl chain length,side-chain structure,and the introduction of specific functional groups play critical roles in the CO2 capture performance of DESs.(2)In terms of operational parameters,the CO2 absorption capacity generally increases with pressure under constant temperature and decreases with increasing temperature under constant pressure.However,exceptions to this trend exist.Therefore,specific absorption operating conditions should be determined by comprehensively considering the structural features,physicochemical properties,and absorption mechanisms of DESs.(3)Regarding water content,an optimal range exists for DESs,necessitating a balance among various physicochemical properties during the capture process.Finally,the key challenges associated with DESs,the potential solutions,and the future development directions are discussed.(1)CO2 capture mechanisms remain incompletely understood,thus necessitating the development of models that correlate DES structures with CO2 capture performance.(2)Process development is hindered by a lack of physicochemical data,requiring the creation of a comprehensive DES database.(3)Formulation design suffers from low efficiency,which may be enhanced using machine-learning-assisted methods leveraging key structural parameters of DESs.(4)Engineering risks require systematic evaluation.It is suggested that a multi-dimensional assessment framework be established and that hybrid technologies and process intensification strategies be explored.

Abstract:As the largest organic carbon reservoir in terrestrial ecosystems,soils store approximately 1 500-2 400 Pg of organic C,which is 2-3 times larger than the atmospheric carbon pool.Their carbon sequestration potential and functionality are crucial for regulating the global carbon cycle.Against the backdrop of global warming,soil carbon sequestration represents one of the key pathways for achieving long-term carbon neutrality.Therefore,understanding the fate and stability of soil organic carbon(SOC)has become critically important.In recent years,the mineral-associated carbon sequestration mechanisms in soils have garnered widespread attention due to their pivotal role in long-term carbon storage.Soil minerals constitute a vital component of the soil solid phase and can interact closely with SOC.Consequently,they engage in complex,multi-pathway reactions with SOC during its cycling,either protecting or activating it,thereby influencing the stability of SOC.However,the diversity of soil mineral types and the inherent complexity of SOC composition result in highly intricate and incompletely understood interaction processes between the two.This paper reviews the literature on soil carbon sequestration mechanisms.First,it briefly outlines the instability of soil carbon sequestration under climate warming or land-use change scenarios,highlighting that mineral-associated organic carbon(MAOC)forms a stable carbon pool through physicochemical interactions and constitutes a core pathway for soil carbon retention.Subsequently,the paper focuses on analyzing the differences in carbon sequestration mechanisms arising from the unique surface physicochemical properties(e.g.,specific surface area,charge characteristics,surface functional groups,chemical reactivity)of various soil minerals,such as layered phyllosilicate clay minerals,iron/aluminum oxides,and carbonate minerals.It systematically reviews multiple carbon stabilization mechanisms driven by mineral-organic carbon interfacial reactions,including ligand exchange,electrostatic interactions,hydrogen bonding,occlusion/entrapment,and interlayer intercalation.The influence of organic carbon structural characteristics on mineral-mediated carbon stability is also briefly introduced.Furthermore,based on the properties of clay minerals and metal oxides,the paper elaborates on the synergistic pathways by which interactions at mineral interfaces enhance carbon sequestration.The collective action of these diverse interfacial reaction mechanisms within the mineral-organic carbon system drives SOC stabilization.The paper also summarizes the main challenges and key unresolved questions in current research on the long-term carbon sequestration mechanisms mediated by soil minerals.Finally,to address the limitations and gaps in current studies on mineral-mediated carbon sequestration,this paper proposes that future research should strengthen coupled multi-scale and multi-process observational and modeling approaches.Emphasis should also be placed on exploring the application potential within practical ecosystem management frameworks to support the achievement of China's"carbon neutrality"goals.

Abstract:Nickel(Ni),a heavy metal,poses a significant threat to both the ecological environment and human health.Traditional treatment technologies are limited by high costs and the potential for secondary pollution,which severely restricts their widespread application.Biochar,recognized as a green adsorbent material,has attracted considerable attention in recent years.Its adsorption performance can be effectively enhanced through modification,offering a promising alternative for heavy metal remediation.Against this backdrop,this study used distiller's grains as the biomass feedstock.By combining pyrolysis temperature regulation with the addition of specific substances,Mg/Al layered double hydroxide modified biochar(E-Mg/Al-LDH BC)was successfully synthesized.A systematic study was conducted on its performance and underlying mechanism for the adsorption of Ni(Ⅱ)ions,focusing on factors such as pH,initial concentration,and biochar dosage.The study found that the adsorption efficiency of E-Mg/Al-LDH BC for Ni(Ⅱ)was influenced by multiple factors.The optimal adsorption occurred at pH 6,with a capacity of 78.10 mg/g and a removal rate of 97.62％.Lower pH values resulted in reduced efficiency,reflecting competition between H+and Ni(Ⅱ)ions in solution.When the biochar dosage was 1.25 g/L,it maintained excellent adsorption performance for Ni(Ⅱ)solutions with initial concentrations ranging from 25 to 150 mg/L.Adsorption isotherm and kinetic analyses indicated that the Langmuir model fit the experimental data better than the Freundlich isotherm model,suggesting a monolayer adsorption mechanism.The strong fit with the pseudo-second-order kinetic model further indicated that chemical adsorption was the dominant process.FTIR analysis showed that after E-Mg/Al-LDH BC adsorbed Ni(Ⅱ),—OH groups may participate in surface precipitation or complexation.Enhanced C-O and O-H signals,along with weakened C=O peaks,suggested surface complexation and possible π-Ni(Ⅱ)interactions.SEM-EDS mapping analysis revealed a high surface accumulation of Ni,with elements such as Al,P,O,and Mg potentially playing roles in its removal.In summary,the adsorption of Ni(Ⅱ)by E-Mg/Al-LDH BC is primarily driven by complexation,with ion exchange and π-Ni(Ⅱ)interactions contributing to the overall efficiency.This study elucidates the adsorption characteristics and mechanisms of E-Mg/Al-LDH BC for Ni(Ⅱ)and offers theoretical and technical support for the application of this modified biochar in heavy metal remediation.The findings provide innovative insights for practical environmental remediation and lay the groundwork for developing green and efficient treatment technologies.

Abstract:The Microbial electrosynthesis system(MES)represents a significant interdisciplinary innovation that synergizes microbial reductive metabolism with electrochemical technology.By leveraging the metabolic capabilities of electroactive microorganisms and renewable electricity inputs,MES provides a sustainable platform for converting CO2 into value-added chemicals and mitigating greenhouse gas emissions.Among the various products derived from biological CO2 conversion,acetate has emerged as a key target due to its versatility as a chemical precursor and energy carrier.With applications in food preservation,biopolymer synthesis,and renewable fuel production,acetate holds substantial market value and economic potential,positioning MES as a transformative solution for carbon utilization.At the core of this process lies the reductive acetyl-CoA pathway,commonly known as the Wood-Ljungdahl pathway,a unique metabolic mechanism employed by acetogenic bacteria for efficient CO2 fixation and energy conservation.Unlike conventional CO2 fixation pathways,this pathway allows the direct reduction of CO2 into acetyl-CoA through a series of enzymatic reactions powered by electrons sourced from electrodes or hydrogen.This mechanism achieves high carbon reduction efficiency and offers thermodynamic stability under ambient conditions,making it a cornerstone for scalable CO2-to-acetate conversion.This review examines recent advancements in MES-driven acetate synthesis,with a focus on the optimization of the reductive acetyl-CoA pathway.Optimization strategies are categorized into three areas:(1)Enhancing electron transfer efficiency:The application of nanostructured catalysts has proven effective in accelerating electron transfer to microbial communities,thereby synergistically promoting both indirect and direct electron transfer pathways.(2)Regulating metabolic pathways:Enhancing in situ hydrogen generation and utilization,as well as supplementing with key intermediates such as CO and formate,can significantly improve the conversion of CO2 into value-added products.(3)Integrating CO2 capture and conversion:Coupling MES with advanced adsorbents or gas diffusion electrodes facilitates efficient CO2 mass transfer,addressing solubility limitations in aqueous systems.Finally,future research directions are proposed:(1)Catalyst design driven by machine learning:Integrating experimental data with neural networks could accelerate the identification of optimal electrode materials.(2)Synthetic biology for strain optimization:Applying gene-editing technologies to engineer microbial chassis can significantly enhance electron transfer capacity and improve the efficiency of target product synthesis.(3)System-level sustainability analysis:Life cycle assessments should guide reactor scaling to balance energy inputs with environmental benefits and ensure net-negative carbon emissions.By bridging fundamental insights with engineering innovations,this work provides a comprehensive framework to advance MES from lab-scale prototypes to industrial carbon refineries,ultimately contributing to a circular carbon economy.

Abstract:Antibiotic resistance genes(ARGs)pose a serious threat to public health.Wastewater treatment plants(WWTPs)are hotspots for ARGs,and their operational conditions significantly influence the removal of ARGs from wastewater.However,research on the effects of hydraulic retention time(HRT)in different wastewater treatment units on ARGs remains limited.In this study,two pilot-scale AAO(Anaerobic-Anoxic-Oxic)systems with advanced treatment and disinfection processes were designed with different HRTs to investigate the concentrations and distributions of ARGs at various treatment stages.The correlations among ARGs,water quality parameters,and microbial communities were also analyzed.The results showed that in the long-HRT group,the ARG concentrations in the secondary sedimentation tank effluent were lower than those in the short-HRT group.Regarding the concentrations of ARGs in the activated sludge,the retention of ARGs by sludge was found to be similar in both groups.This suggests that the sludge in the long-HRT group had a longer contact time with the ARGs,potentially promoting their biological degradation.The concentrations of ARGs in the sand filtration effluent of both groups showed no significant decrease compared to those in the secondary sedimentation tank effluent.After disinfection,the concentrations of blaTEM,sul1,tetX,ermB,intIl,and 16S rDNA in the long-HRT group decreased to 4.26×103,2.31×105,7.15×103,7.29×103,4.64×104,and 3.61 ×105 copies/mL,respectively,all of which were lower than those in the short-HRT group.Overall,the removal rates of blaTEM,sul1,tetX,ermB,intIl,and 16S rDNA in the long-HRT group reached 2.55,2.60,3.23,2.99,2.77,and 2.97 log,respectively,indicating that the long-HRT group exhibited higher removal efficiencies of ARGs than the short-HRT group.However,it is worth noting that the ARGs/16S rDNA ratio after disinfection in the long-HRT group was significantly higher than that in the filtration effluent.This indicates that although prolonged disinfection reduces ARG concentration in the effluent,it also significantly increases the ARGs/16S rDNA ratio.This phenomenon may be attributed to horizontal gene transfer of ARGs,as excessive disinfectant dosage damages bacterial cells,increasing the frequency of ARG transfer to non-resistant bacteria.Such changes may impact the microbial community in the receiving water body.In addition,both the biological and disinfection stages reduced the abundance of pathogenic genera such as Aeromonas,Desulfovibrio,and Pseudomonas.However,in both the long-and short-HRT groups,the relative abundance of these genera was higher in the disinfection effluent than in the filtration effluent.Redundancy analysis revealed that genera such as Nitrospira,Dechloromonas,and Ferruginibacter were highly correlated with ARGs,and both 16S rDNA and suspended solids(SS)were highly correlated with ARGs.This study provides theoretical support for better controlling the risks associated with the release of ARGs from WWTPs.

Abstract:The study investigates the optimization of nitrogen removal efficiency in an enhanced anaerobic membrane bioreactor coupled with a partial nitrification/anammox(eAnMBR-PN/A)integrated process.Simulation results demonstrate that the surface oxygen loading rate significantly influences system performance.When maintained between 0.12 and 0.14 g/(m d),the system achieves a peak total nitrogen(TN)removal efficiency of 64.45％,which corresponds to the highest relative abundance of anaerobic ammonium-oxidizing bacteria(AnAOB)in the biofilm.However,at rates exceeding 0.16 g/(m d),elevated dissolved oxygen concentrations inhibit AnAOB activity while promoting the growth of nitrite-oxidizing bacteria(NOB),resulting in nitrate accumulation and reduced TN removal efficiency.The carbon-to-nitrogen(C/N)ratio also plays a crucial role in regulating system performance.At low influent NH4-N concentrations(＜35 g/m3),increasing the C/N ratio enhances TN removal by stimulating the denitrification activity of heterotrophic bacteria(HB).In contrast,at high NH+-N concentrations(≥ 35 g/m3),maintaining a low C/N ratio(＜2.0)is essential to prevent HB from competitively competitively inhibiting AnAOB functionality.The findings indicate that the eAnMBR-PN/A process can effectively remove nitrogen from municipal wastewater with low C/N ratios by optimizing oxygen transfer and substrate distribution.This provides valuable theoretical insights and a technical pathway for the low-carbon transformation of wastewater treatment plants.The study highlights the importance of balancing the surface oxygen loading rate to avoid suppression of ammonia-oxidizing bacteria(AOB)activity at low oxygen levels and inhibition of AnAOB at high oxygen levels.Additionally,when the influent NH4+-N concentration is low,increasing the influent chemical oxygen demand(COD)can enhance TN removal,albeit at the cost of higher operational expenses.Conversely,under high NH+4-N concentrations,maintaining a lower influent COD facilitates AnAOB activity,thereby reduce costs.Microbial community analysis reveals that at oxygen loading rate of 0.12 g/(m3·d),a stable symbiotic biofilm community of AnAOB,AOB,and HB is established.As the oxygen loading rate increases to 0.16 g/(m3·d)and above,AnAOB abundance initially increases and subsequently decreases due to high dissolved oxygen inhibition.In conclusion,the eAnMBR-PN/A integrated process offers an effective solution for nitrogen removal from municipal wastewater with low C/N ratios.By optimizing the oxygen loading rate and C/N ratio,the system can achieve high nitrogen removal efficiency while reducing operational costs.This study advances the understanding of nitrogen removal mechanisms and underscores the potential of the eAnMBR-PN/A process in promoting the enrichment of functional microbial communities for efficient treatment.

Abstract:With the rapid development of China's socio-economic landscape,the volume of municipal solid waste(MSW)generated from daily urban life has been increasing steadily.MSW decoupling combustion technology holds significant research value due to its ability to reorganize the combustion stages of volatile components.This staged approach facilitates low-NOx combustion while offering inherent advantages such as system simplicity and robust environmental adaptability.In this study,a two-stage fixed-bed reactor was employed to investigate the combined effects of reaction temperature(T),excess air ratio(α),and gas residence time(t)on the burnout behavior of combustible gases,flue gas pollutant emissions,and particulate matter characteristics during the decoupling combustion of MSW.The pyrolysis stage primarily yielded CH4 and CO as the dominant combustible gaseous components.Results demonstrated that a higher T and a higher α significantly enhanced the burnout efficiency of combustible gases.In contrast,extending t exerted a comparatively weaker positive influence on burnout.Regarding nitrogen oxides,NO formation was found to be strongly dependent on free radical accumulation and high-temperature reaction pathways,while NO2 generation was primarily governed by the NO oxidation rate and remained largely unaffected by variations in t.PM generation displayed a complex,non-monotonic response under different decoupling combustion conditions.Crucially,the operational condition yielding the minimum PM production rate closely coincided with the condition achieving optimal burnout of combustible gasest.This strong correlation suggests a synergistic relationship between PM suppression and efficient burnout control.However,adverse effects were observed under a high α combined with a short t,where conditions favored the enrichment of highly active polycyclic aromatic hydrocarbons(PAHs),consequently elevating the potential risk of dioxin formation.Although a higher T can promote PAH cracking,effective dioxin suppression necessitates complementary measures such as rapid cooling and efficient adsorption techniques downstream.Comprehensive analysis identified the parameter set of 850 ℃,α=1.5,and t=2.5 s as offering a well-balanced performance profile at this temperature.This condition achieved satisfactory burnout of combustible gases,effective PM suppression,and significant NOx reduction,demonstrating considerable promise for practical engineering applications.While the condition of 1 000 ℃,α=1.5,and t=2.5 s delivered superior burnout and overall pollutant suppression,the substantially higher energy input required at this elevated temperature presents a significant trade-off,potentially diminishing its net energy efficiency and economic viability.This study provides essential data and insights for optimizing MSW decoupling combustion systems towards cleaner and more efficient waste-to-energy conversion.

Abstract:Coal-to-methanol remains the dominant industrial pathway for methanol production;however,its significant carbon emissions pose major challenges to the chemical industry's transition to green and low-carbon development.As global methanol demand continues to grow,addressing the environmental burden of coal-based production has become increasingly critical.Carbon capture,utilization,and storage(CCUS)is widely recognized as a promising solution for large-scale emission reduction.However,its high energy consumption,process complexity,and potential leakage risks can offset some of the net climate benefits.Therefore,a comprehensive and scientifically robust carbon emission accounting framework is essential for accurately evaluating the mitigation potential of CCUS across the entire coal-to-methanol value chain.Integrating CCUS into coal-to-methanol systems introduces a range of challenges due to complex inter-unit interactions and the nonlinear behavior of material and energy flows.Existing carbon accounting standards are often difficult to apply directly,as they fail to capture internal carbon transfers among subsystems and overlook feedback mechanisms induced by CCUS.To address these limitations,this study develops a whole-process carbon emission accounting framework tailored for coal-to-methanol systems with integrated CCUS.The framework aims to fill current methodological gaps,enhance transparency and comparability of emission data,and support scientific evaluation of emission reduction performance at both process and system levels.The framework defines system boundaries encompassing raw material input,syngas generation,methanol synthesis,purification,CCUS operation,and product delivery.Layered and categorized accounting methods are applied to systematically trace carbon sources,flows,and sinks throughout each stage.To improve accuracy and represent process dynamics,the framework is coupled with Aspen Plus process simulations,allowing simultaneous tracking of carbon flows under various operational scenarios.This coupling overcomes limitations of static accounting approaches and enables quantitative assessment of the impact of process integration on the carbon balance.Sensitivity analysis is conducted to evaluate the influence of uncertain parameters on the accounting results,thereby assessing the robustness of the proposed method.A case study of an industrial-scale coal-to-methanol plant with an annual capacity of 1.2 million tons validates the framework.Results indicate that the baseline carbon emission intensity of the conventional process is 3.00 tons of CO2 per ton of methanol,which decreases to 1.88 tons after CCUS integration.Despite an 83.1％CO2 capture rate,the net emission reduction rate is only 37.8％due to energy penalty-associated emissions from CCUS operations.Further analysis reveals that maximizing mitigation potential requires coordinated optimization of both the gasification and acid gas removal units.Overall,the proposed framework provides a rigorous and generalizable approach for carbon emission assessment in coal-to-methanol and other carbon-intensive industries.

Abstract:The rapid urbanization and industrialization have led to the massive generation and accumulation of municipal sludge,posing significant challenges to waste management and environmental sustainability.To address this issue,it is imperative to develop innovative methods for the safe,efficient,and resource-oriented utilization of sludge,in alignment with the principles of waste reduction,harmless treatment,and resource recovery.In this context,this study explores the application of chemical looping gasification(CLG)for hydrogen production from municipal sludge generated in highway service areas.This approach is crucial for advancing a circular economy and facilitating the transition to sustainable energy systems,as it enables the conversion of sludge into high-purity hydrogen,a vital energy carrier.Compared to conventional sludge treatment methods,CLG offers several advantages,including reduced energy losses,the generation of high-value-added products,and suppressed pollutant formation.To evaluate the feasibility and optimize the CLG process,a thermodynamic calculation platform was employed to develop an iron-based oxygen carrier-enabled sludge CLG system.The study conducted a comprehensive computational analysis of the reaction pathways and thermodynamic behaviors of key sludge components,as well as the interaction mechanisms of the iron-based oxygen carriers.The results indicate that increasing the oxygen supply within the fuel reactor(FR)effectively shifts the CLG equilibrium in the forward direction,enhancing the overall gasification efficiency.Additionally,the introduction of water molecules into the system facilitated the depolymerization and conversion of carbon species,thereby increasing the equilibrium concentration of hydrogen(H2)in the produced syngas.Under optimal conditions,specifically,an oxygen carrier-to-municipal sludge ratio(OC/MS)of 0.25 and a steam-to-municipal sludge ratio(S/MS)of 0.5 at a temperature of 900℃,the CLG process produced syngas with a high H2 content.Notably,this configuration ensured the complete conversion of nitrogen oxide(NOx)precursors into environmentally benign nitrogen gas(N2),thereby mitigating potential pollutant emissions.Further optimization in the steam reactor(SR)was conducted by considering the solid-phase residues under optimal CLG conditions.The analysis determined that a hydrogen production temperature of 600 ℃,combined with a steam addition of 1 kmol per kilogram of sludge,resulted in a hydrogen purity of 95.45％,demonstrating the process's effectiveness in producing high-purity hydrogen suitable for various applications.In the air reactor(AR),the optimal oxygen supply condition for regenerating the oxygen carrier was identified as 0.125 kmol of the sludge model compound.The sequential restoration of lattice oxygen in the iron-based carrier(Fe→FeO→Fe3O4→Fe2O3)during regeneration in the air reactor ensured the sustained functionality and longevity of the oxygen carrier.

Abstract:Gas extraction drilling and sealing technologies are essential measures for controlling mine gas and ensuring safe production.However,the high demand for sealing materials in mines necessitates more cost-effective alternatives to existing materials.Coal gangue,the most abundant solid waste in coal production,can be used as an admixture to modify gas sealing materials,thereby promoting their large-scale utilization and reducing grouting costs.Therefore,this study systematically investigates the effects of coal gangue content,particle size,and water-to-cement(w/c)ratio on the working performance of gas sealing materials,as well as the composition and structure of their hydration products.The results show that the addition of coal gangue affects the material's hydration process.Specifically,it inhibits the transformation of ettringite(AFt)to monosulfoaluminate(AFm),thereby promoting the net generation of AFt.This results in an increased expansion rate and compressive strength of the material.However,increasing the coal gangue content raises the silica concentration and reduces the amount of hydration products in the modified material system,leading to higher porosity and lower compressive strength.Changing the w/c ratio significantly impacts the properties of the coal gangue-modified materials.A higher w/c ratio leads to increased structural porosity and decreased compressive strength.It also improves fluidity and extends the setting time,which is beneficial for engineering applications,albeit at the expense of reduced material strength.When the w/c ratio reaches 1.2,the material experiences severe water bleeding.The particle size of the coal gangue has a relatively minor impact on the properties of the modified materials.At low w/c ratios(0.8 and 1.0),increasing the coal gangue particle size reduces the material's fluidity and shortens its setting time.However,changes in particle size do not significantly affect the material's expansion rate or mechanical properties.At a given w/c ratio,materials with coal gangue particle sizes between 100-300 mesh exhibit the shortest setting time and lowest porosity,resulting in the highest compressive strength.Overall,the performance of the modified gas sealing material is optimal when the w/c ratio is 0.8,the coal gangue content is 40％,and the particle size ranges from 100 to 300 mesh.Under these conditions,the material demonstrates good fluidity,a setting time of 30 minutes,and a 4-hour compressive strength of nearly 4 MPa.This formulation can significantly increase economic benefits while ensuring effective gas control.

Abstract:Organic solvent waste,a common by-product of industrial production processes,exhibits dual characteristics of high resource value and significant environmental risk,making it a priority in urban solid waste management.To enhance precise control over the full life cycle of organic solvent waste,this study focuses on Chengdu in Sichuan Province as a case study.By integrating statistical data with web-based data,it systematically maps the metabolic pathways throughout the entire life cycle and identifies key challenges in the current management practices.Building upon these findings and in response to practical management needs,this study integrates Geographic Information System(GIS)with Multi-Criteria Decision Analysis(MCDA)to develop a comprehensive evaluation framework comprising nine indicators across environmental,economic,and social dimensions.This framework enables the scientific identification of potential sites for new centralized collection and storage facilities.The metabolic path analysis reveals that the volume of organic solvent waste generated is substantial,while local treatment capacity remains limited,resulting in a substantial gap between supply and demand for disposal services.In particular,the inter-provincial and inter-municipal transfer network is complex,involving Shaanxi Province,Chongqing Municipality,and Anhui Province.Transferred organic solvent waste accounts for over 35％of the total volume generated.The study area contains numerous organic solvent waste sources that are highly dispersed spatially,with over 95％being small and micro enterprises producing less than 100 tons annually.Although their combined output accounts for only 11.78％of the total volume,the absence of a unified and standardized collection and transportation system leads to widespread difficulties in securing reliable disposal pathways.Specifically,54.98％of the waste-generating enterprises have not established consignment treatment relationships with downstream receiving enterprises,and 16.91％of waste is temporarily stored onsite,posing significant risks of environmental hazard accumulation.These findings suggest that enhancing centralized collection and storage capacity is essential for improving the overall management system for organic solvent waste and mitigating associated environmental risks.Suitability analysis results indicate that,across the study area,11.76％,42.23％,41.22％,and 4.79％of the regions are classified as highly suitable,moderately suitable,generally suitable,and unsuitable,respectively,for siting centralized collection and storage facilities.The highly suitable areas are primarily located in Jianyang City,Jintang County,Pengzhou City,and Shuangliu District.Based on a comprehensive analysis of waste generation trends,Jianyang City and Longquanyi District have been identified as priority areas for constructing new centralized collection and storage centers.Overall,the findings provide a scientific basis for urban hazardous waste management and support the advancement of waste-free city initiatives.

Abstract:The flash vapor emissions generated during the production process at tight gas field stations are typically rich in water and non-methane hydrocarbons.When these emissions are burned for disposal,a common problem is the generation of"black smoke".This issue is often encountered due to incomplete combustion and the formation of particulate matter.In this study,a Venturi-structured burner that facilitates partial-premixed combustion by a jet of combustible waste gases entraining air was designed.The primary objective was to reduce soot formation while ensuring stable combustion.To understand the effects of various structural parameters on combustion performance and soot formation behavior,computational fluid dynamics(CFD)simulations were conducted.The simulation investigated the influence of several key burner parameters,including the sleeve angle,sleeve diameter,and the presence of swirl vanes in the fuel jet.Based on these findings,the optimal burner structure was determined,a prototype burner was fabricated,and field trials were conducted to validate the design.The results from CFD simulations and experimental verification revealed several important trends.First,increasing the sleeve angle in the intake section of the burner proved to be the most effective optimization strategy.By increasing the angle from 30° to 60°,the entrained air volume increased by 64％,and soot formation was reduced by 73％.This improvement can be attributed to the enhanced air-fuel mixing,which improves combustion efficiency and reduces particulate matter formation.In contrast,enlarging the diameter of the mixing sleeve created low-velocity zones within the burner.This reduction in air velocity decreased the cooling effect of the sleeve and caused early ignition of the fuel.As a result,regions of the burner exceeded 1 500 K,creating high-temperature zones that could jeopardize the safe long-term operation of the burner.This finding emphasizes the importance of maintaining an optimal balance in the burner's structural design to avoid excessively high temperatures.The addition of swirl vanes at the fuel nozzle proved beneficial in creating a swirling jet inside the combustion chamber.This approach successfully reduced soot formation and flame size.Importantly,it achieved these improvements without significantly altering the external dimensions of the burner,contributing to a more compact and efficient design.Finally,the burner designed based on the simulation results showed stable flame behavior in field tests,with no visible black smoke.The newly designed burner,which incorporates multi-point jet entrainment,swirl-stabilized combustion,and partial-premixed features,effectively reduced soot formation during the combustion of flash vapor emissions from tight gas field stations.This demonstrates the potential of this burner design to achieve clean combustion and reduce the environmental impact of gas field emissions.

Abstract:Low-carbon treatment and resource utilization of urban sludge are important pathways for sewage treatment to achieve"zero-carbon"or even"negative-carbon"goals.With increasing global attention to climate change and the announcement of China's dual-carbon goals,the exploration and application of new technologies for urban sludge treatment and resource utilization have become a critical challenge in the current sewage treatment industry.In this study,we systematically review the current research and development directions of technologies for enhancing the anaerobic digestion of sewage sludge,focusing on three aspects:high solid content,treatment in cold regions,and operational stability.Due to the low efficiency of anaerobic digestion of sewage sludge in cold regions,mainly caused by geographic and climatic factors,we discuss the effects of various pretreatment methods.These include microwave and ultrasonic treatment,acid-alkali and oxidative pretreatment,the addition of conductive materials such as biochar,and heat preservation methods,particularly the use of ground-source heat pump systems.We emphasize the impacts of calcium peroxide-coupled freeze-thaw pretreatment and the addition of biochar derived from magnetic oil sludge on the anaerobic digestion of sewage sludge in cold regions.We summarize the optimization of operating conditions,such as stirring intensity,organic loading,temperature,and C/N ratio,as well as the design of a high-efficiency,heat and mass transfer-enhanced anaerobic reactor using computational fluid dynamics(CFD)simulation to enhance the anaerobic digestion of sewage sludge with high solid content.Furthermore,we conduct an in-depth analysis of the mechanisms of anaerobic co-digestion of sewage sludge and other substrates,including food waste and agricultural residues(such as pig manure,wheat straw,and cow dung),as well as molecular weight substrate compounding technology to alleviate system inhibition caused by intermediate products(volatile fatty acids and free ammonia),thereby maintaining high stability in anaerobic digestion systems.We outline applicable technologies and index systems for different directions and clarify the mechanisms of heat and mass transfer involved in methane production within anaerobic digestion systems from multiple perspectives.Additionally,we propose future optimization directions for anaerobic digestion technology from the perspectives of microbial ecology,innovative reactor design,intelligent control systems,and integrated multi-energy systems.Finally,we discuss the prospects for the development and application of anaerobic digestion technology for sewage sludge in China,based on its specific characteristics.This study aims to serve as a reference for the future development of high-efficiency anaerobic digestion in cold regions,with a focus on high solid content and operational stability.

Abstract:In alignment with the global net-zero emissions target by 2050,the International Maritime Organization(IMO)and its member states are advancing regulatory frameworks such as the Carbon Intensity Indicator(CII)and Energy Efficiency Existing Ship Index(EEXI)to reduce greenhouse gas emissions in maritime operations.These frameworks mandate a 40％reduction in carbon intensity by 2030 compared to 2008 levels,a crucial step toward the sector's long-term decarbonization goals.Current research focuses on retrofitting existing fleets with energy-efficient propulsion systems,including waste-heat recovery technologies and hull optimization designs,which can reduce fuel consumption by 15％-20％.Simultaneously,the adoption of low-carbon fuels like liquefied natural gas(LNG)and green methanol is accelerating.This study evaluates the efficacy of maritime decarbonization policies and technologies,tracking the sector's transition from high-carbon practices to zero-carbon operations.Key innovations include closed-loop carbon management systems achieving up to 80％onboard carbon capture,demonstrated in pilot projects integrating exhaust gas treatment with renewable energy sources.Sustainable decarbonization further depends on hybrid solutions that combine low-emission fossil fuels,renewable energy systems,and resilient carbon capture infrastructure,including port-based carbon dioxide storage hubs.Recent advancements have focused on optimizing vessel operations through propulsion upgrades and fuel flexibility,supported by compliance with the CII and EEXI frameworks.These policies incentivize energy efficiency and emissions transparency,seen in the widespread adoption of dual-fuel engines capable of switching between LNG and methanol.Lifecycle management of carbon sequestration infrastructure ensures long-term emissions reductions across the supply chain,from fuel production to end-use.By integrating energy-efficient retrofits such as air lubrication systems,fuel transition roadmaps blending LNG and methanol,and carbon capture solutions,the industry achieves cost-effective emission reductions while moving from fragmented measures to unified strategies.For example,digital twin modeling for hull design enables real-time vessel performance optimization,reducing drag by up to 10％in simulated environments.Additionally,ammonia-fueled engines offer promising zero-carbon propulsion for deep-sea vessels,though challenges related to fuel storage and safety protocols still need further standardization.Looking ahead,future advancements will prioritize holistic vessel optimization through renewable energy integration,such as wind-assisted propulsion.Resilient supply chains for alternative fuels,along with standardized carbon accounting frameworks,will guide the shipbuilding industry toward achieving IMO's 2050 net-zero targets.For example,the EU's inclusion of maritime emissions in its carbon market from 2024 incentivizes investment in green fuel production and carbon capture infrastructure.This integrated approach aligns with global decarbonization strategies,emphasizing the synergy between regulatory mandates-such as IMO's revised GHG strategy-and technological breakthroughs in fuel flexibility,energy efficiency,and carbon management.

Abstract:Mercury,as a widespread heavy metal pollutant,poses a serious threat to both human health and the ecosystem.It is of great significance to develop efficient mercury removal technologies for reducing elemental mercury(Hg0)emissions from flue gas and controlling atmospheric mercury pollution.Adsorption has emerged as a simple,practical,and promising method for mercury removal,and various types of adsorbents have been developed for the efficient capture and recovery of Hg0 from flue gas.In this work,we systematically classified adsorbents based on their effective components and provided an in-depth examination of their characteristics,preparation methods,Hg0 removal performance,and adsorption mechanisms.Furthermore,we conducted a thorough comparative analysis of these materials from multiple perspectives,examining their performance and characteristics.Adsorbents for mercury removal can broadly be classified into four main categories:carbon-based and modified materials,metal oxides,metal sulfides,and other innovative materials.Carbon-based and modified materials are particularly effective in removing Hg0 due to their large specific surface area and the presence of various functional groups,such as C-O,C—S,C—Cl.However,these adsorbents suffer from limitations such as poor heat resistance and insufficient functional groups.As a result,they exhibit low adsorption capacities,poor stability,and limited recyclability.Metal oxide adsorbents are primarily composed of iron and manganese oxides,forming various crystal structures.These adsorbents are notable for their operational stability across a broad temperature range,from room temperature up to 250 ℃,as well as their large adsorption capacities.Moreover,they benefit from thermal stability and maintain their effectiveness over multiple cycles.Metal sulfide adsorbents primarily rely on the abundant unsaturated S-sites to achieve efficient adsorption of Hg0.Their advantages include high activity,a wide operational temperature range,and large adsorption capacities.However,the high temperatures required for thermal regeneration can easily degrade their activity,posing challenges for recyclability.Based on the above analysis and the current advances in adsorbent research,we illustrate the respective advantages and disadvantages of different types of adsorbents and propose targeted suggestions for their further development.This work provides novel insights and useful references for the development of new materials and their potential applications in mercury removal technologies based on adsorption.

Abstract:Direct interspecies electron transfer(DIET)offers a faster electron transfer rate and a reduced dependence on diffusive mass transfer,potentially becoming a primary mechanism for the anaerobic digestion of urban organic solid wastes,such as food waste and excess sludge.However,digestate,the byproduct of anaerobic digestion,poses environmental hazards and hinders the achievement of a waste-free city.This study investigates the morphological and structural characteristics of iron-containing digestate-based biochar(Fe-BC)produced at various carbonization temperatures,and its impact on the anaerobic digestion of urban organic solid wastes,with the goal of achieving"waste-to-value-added products".The results showed that increasing the carbonization temperature led to a more developed pore structure in the Fe-BC,but reduced the complexity of its functional group composition.Fe-BC prepared at 800 ℃ exhibited the most developed pore structure and the highest iron content,with more uniform iron distribution throughout the biochar.In anaerobic digestion experiments,the group with biochar prepared at 800 ℃ demonstrated a cumulative methane yield of 184.24 mL/g volatile solids(VS),a 19.78％increase compared to the control group(without biochar).The VS removal rate reached 45.75％,a 6.73％increase over the control group.The group with biochar prepared at 500 ℃ showed a 15.66％increase in cumulative methane yield and a 5.79％increase in the VS removal rate,while the other experimental groups showed no significant improvement.The effect of Fe-BC on promoting methane production was most pronounced in the middle of the experiment,peaking on the ninth day.Furthermore,Fe-BC prepared at 800 ℃ improved both the methane content and the quality of the biogas produced.Electrochemical analysis indicated that the sludge in the Fe-BC group prepared at 800 ℃ exhibited greater capacitance and lower electrical resistance,suggesting enhanced interspecies electron transfer,microbial electron exchange,and electrical conductivity.Additionally,Fe-BC increased the relative abundance of Methanosaeta and Fastidiosipila.In conclusion,Fe-BC derived from digestate possesses a well-developed pore structure,with Fe-BC prepared at 800℃ exhibiting the most developed porosity.The addition of Fe-BC prepared at 800 ℃ was the most effective in promoting the anaerobic digestion of urban organic solid wastes.Moreover,Fe-BC enriched specific microorganisms,thereby promoting DIET and enhancing the anaerobic digestion of urban organic solid wastes.

Abstract:Under the"dual-carbon"strategic goal,ammonia,as a carbon-free fuel,is one of the most promising options for the industrial and transportation sectors.The use of ammonia fuel in automotive engines can effectively reduce carbon emissions in transportation.This study investigated the combustion and emission characteristics of a gasoline/ammonia dual-fuel engine under different intake valve opening(IVO)conditions using a modified engine test bench and three-dimensional combustion simulation software.The IVO was adjusted within the range from-30℃A to 10℃A,with IVO=-356 ℃A ATDC as the reference point.The results show that as IVO advances,the peak in-cylinder pressure and heat release rate gradually decrease,and the corresponding combustion phases are progressively delayed.This is due to the increase in residual gas in the cylinder as the valve overlap angle increases,which suppresses in-cylinder combustion.As IVO advances,the combustion phases CA10,CA50,and CA90 are initially delayed and subsequently advanced,due to the combined effect of valve overlap angle and the intake-exhaust pressure difference.The advance of IVO affects the intake valve closing angle,resulting in a gradual decrease in pumping mean effective pressure,which reaches its minimum value at IVO=-30℃A.Notably,the effect of IVO on thermal efficiency is small.Meanwhile,the emissions of unburned hydrocarbons,carbon monoxide,and nitrogen oxides increase gradually with the advancement of IVO,while the change in IVO has little effect on the emission rate of unburned ammonia.This is because the lower cylinder temperature reduces the oxidation of hydrocarbons and carbon monoxide,while the increased valve overlap raises the concentration of nitrogen oxides in the residual gas.Meanwhile,the decrease in pumping mean effective pressure(PMEP),which indicates reduced pumping losses,leads to a slight increase in the overall combustion temperature,thereby promoting the generation of nitrogen oxides.IVO influences the performance and emissions of a gasoline/ammonia dual-fuel engine.To improve emission characteristics under fixed exhaust valve timing,the IVO should be set to 10℃A.At this point,total hydrocarbons,nitrogen oxides,and carbon monoxide all reach their minimum values,but the brake thermal efficiency(BTE)is relatively low,at only 32.1％.To improve combustion characteristics,IVO should be adjusted to-30℃A.At this point,the BTE reaches 32.7％,but total hydrocarbons,nitrogen oxides,and carbon monoxide all reach their maximum values,leading to worsened emission characteristics.By using multivariate optimization methods to find the optimal valve timing combination,overall optimization of engine performance and emissions can be achieved.

Abstract:This study is based on an experimental platform for coaxial laminar diffusion flames,employing thermophoresis probe sampling and high-resolution transmission electron microscopy.It investigates the micro-and nano-morphology of carbonaceous particles in ethylene/methanol coaxial diffusion flames under varying methanol substitution rates.The micro-morphology focuses primarily on analyzing the size and number of carbonaceous particles,while the nano-morphology examines changes in the oxidative properties of these particles through the analysis of carbon layer length,interlayer spacing,and carbon layer curvature.The results reveal that with increasing height above the burner(HAB),the ethylene flames mixed with different proportions of methanol exhibit trends in which the number,size,fractal dimension,carbon layer curvature,and interlayer spacing of carbonaceous primary particles initially increase and then decrease,while carbon layer length continues to rise.Compared to pure ethylene flames,in flames at a methanol substitution rate of 60％,the growth rate of soot particle size at the flame front is lower,and the particle size decreases faster towards the flame end.As the methanol substitution rate increases,particles collected at a flame height of 15 mm gradually shift from aggregated carbonaceous particles to isolated primary soot particles,with pure methanol or high methanol ratio diffusion flames producing almost no soot.In terms of micro-morphology,as the methanol substitution rate increases,laminar diffusion flames show a gradual decrease in the number,size,and fractal dimension of primary particles produced.This trend is primarily due to the higher methanol substitution rate,which enhances the total oxygen content in the fuel,leading to more complete combustion and thereby inhibiting the formation of soot precursors,as well as the nucleation and growth processes of carbonaceous particles.In terms of nano-morphology,under pure ethylene conditions,soot particles exhibit a nearly spherical shape with a shell-like structure composed of a graphitic outer shell and an amorphous inner core.Conversely,under high methanol substitution rates,the internal carbon layers of soot extracted from the flame appear more loosely packed and exhibit greater curvature.Increasing methanol substitution rates result in a continuous decrease in carbon layer length and an increase in carbon layer curvature and interlayer spacing,indicating heightened oxidative properties of soot.In conclusion,this study provides detailed insights into how varying methanol substitution rates affect the formation and structure of carbonaceous particles in ethylene/methanol coaxial diffusion flames,at both the micro-and nano-scales.The findings underscore the complex interplay between fuel composition,combustion dynamics,and soot morphology,contributing to our understanding of particulate emissions in alternative fuel combustion systems.