An equitable and efficient carbon emission responsibility allocation is key to climate change negotiations. This paper proposes a new Human-Development-Index (HDI)-based Accounting (HBA) framework that addresses countries’ historical responsibility for carbon emissions and their mitigation capacity. HBA mandates sharing trade-related carbon emissions: import-oriented emissions are allocated to consumers in proportion to their HDI, with producers bearing the remainder. Crucially, HBA ensures that developed countries bear the majority of trade-related carbon emissions when relocating energy-intensive production to emerging economies. Our empirical study shows that the economies with higher HDI and per capita carbon emissions are assigned significantly higher carbon emission responsibilities under HBA than under production-based accounting (PBA), such as the USA and major European economies. In 2014, HBA increased the USA and EU responsibilities by 1713 and 257 Mt, respectively, over PBA, while reducing them by 50 and 32 Mt, respectively, relative to consumption-based accounting (CBA). Moreover, from 2005 to 2014, an increasing HDI lowered HBA burdens in developed countries (e.g., the USA \downarrow8%). Despite higher carbon intensity of the GDP, emission responsibilities under HBA in emerging economies will increase with HDI growth (e.g., China \uparrow 15%). However, HBA can incentivize cleaner supply-chain investments, alleviate development pressures on emerging economies, and promote global sustainable development. As a result, HBA provided a more equitable, efficient, and sustainable carbon accounting framework.

Traffic-related particles significantly contribute to urban air pollution, impacting global climate, air quality, and human health. Such impacts are dependent on their microstructure and physicochemical properties. While single-particle analysis has improved our understanding of these particles, such studies often focus on specific particle types, limiting a comprehensive view of their sources, aging mechanisms, and environmental behavior. In this review, we reviewed current research on the characterization of traffic-related particles using both online and offline single-particle techniques. Exhaust particles primarily consist of soot, organic matter, sulfates, and mixed particles. Non-exhaust particles are classified into tire wear particles (TWPs), brake wear particles (BWPs), road wear particles (RWPs), and road resuspended dust (RRD), which are rich in metals and minerals. These particles display pronounced physicochemical heterogeneity and complex mixing states, providing valuable insights into emission sources and atmospheric aging processes. Exhaust emissions are significantly influenced by engine types, fuel compositions, and operating conditions. This review deepens scientific knowledge of the physicochemical properties and aging processes of traffic-related particles, providing a valuable foundation for the development of targeted emission control strategies for traffic-related sources.

Ammonia-oxidizing bacteria (AOB) are slow-growing autotrophs prone to washout. Biofilm carriers improve retention; however, conventional types suffer from low roughness, poor hydrophilicity, and unfavorable surface charge, limiting biofilm formation. In this study, a composite carrier was fabricated by loading chitosan (CS) and layered double hydroxide (LDH) onto a polyurethane (PU) sponge, which introduced hydroxyl (–OH) and amino (–NH₂) functional groups as well as Mg²⁺ and Al³⁺ ions onto the surface, increased surface roughness, and enhanced the carrier hydrophilicity by 29.2%. During a 55-d nitritation biofilm cultivation experiment, the carrier modified with 0.8 wt% LDH and 0.8 wt% chitosan exhibited significantly enhanced performance. Compared to the unmodified carrier, the sludge adsorption capacity increased by 80.3%, the biofilm biomass increased by 46.8%, and the biofilm growth rate increased by 198.3%, reaching 333.4 ± 9.5 mg/carrier, 2023.2 ± 31.5 mg/carrier, and 103.2 mg/(carrier·d) respectively. In addition, the biofilm stability on the carrier was significantly enhanced, with a 54.1% reduction in sludge detachment under ultrasound treatment compared with the unmodified carrier. The nitritation reactor with the CS/LDH-PU carrier maintained stable nitritation performance under high ammonia loading (1.0 g/(L·d)) and a higher sludge concentration (5.5 g/L), while the reactor without the carrier collapsed at a lower sludge concentration (4.6 g/L). These findings suggest that the CS/LDH-PU carrier provides an effective strategy for optimizing conventional nitritation carriers and enhancing the resilience of nitritation systems under high ammonia load conditions.

Disposable plastic cups used to hold beverages can release microplastics (MPs) that pose a potential risk to human health. In this study, the release of MPs from polypropylene (PP), polyethylene terephthalate (PET), and polystyrene (PS) cups was systematically investigated under simulated real-world conditions by varying the temperature (20, 40, and 70 °C), contact time (30, 60, and 120 min), and food simulants (4% acetic acid, 10% ethanol, 50% ethanol). The experimental results demonstrate that the highest temperature (70 °C) and longest exposure (120 min) caused a significant increase in MPs release, with PS cups showing the highest level (1281.33 ± 27.23 particles/L), particularly in 50% ethanol food simulant. Scanning electron microscopy(SEM) revealed the formation of surface cracks and protuberances after thermal treatment, while attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR) indicates that the most pronounced chemical alterations in PS. Based on typical consumer behavior, we estimate that adults could ingest up to 6916–66612 MPs particles annually from disposable cups. These results indicating the interplay between cup material, usage conditions, and MPs release mechanisms suggest avoiding prolonged storage of hot liquids in PS containers to mitigate health risks.

Fly ash (FA) is rich in SiO₂ and Al₂O₃, exhibiting potential as a catalyst support for selective catalytic reduction (SCR) reactions. However, its practical application is restricted due to inert oxygen species and insufficient acidic sites. Herein, a series of fly ash-based catalysts were prepared via a sequential method combining acid pretreatment and wet impregnation. The synthesized Mn-Ce/AFA catalyst exhibited outstanding low-temperature denitration performance, reaching a NO_x conversion rate of 100% at 150 °C. Additionally, the Mn-Ce/AFA catalyst showed satisfactory H₂O vapor tolerance, with the NO_x conversion rate maintaining approximately 95% when exposed to 5 vol% water vapor. Compared with the Mn-Ce/Ti catalysts, the Mn-Ce/AFA catalyst exhibited elevated levels of Mn⁴⁺ and Ce³⁺, indicating enhanced electron transfer in the Mn³⁺ + Ce⁴⁺ ⇌ Mn⁴⁺ + Ce³⁺ cycle. Results from H₂-temperature-programmed reduction (H₂-TPR) and NH₃-temperature-programmed desorption (NH₃-TPD) suggested that Ce-Mn co-doping enhanced the catalyst’s reducibility and the adsorption strength of NH₃ on Lewis acid sites. In-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) results and NO oxidation tests revealed that the enhanced NO oxidation capacity promoted the generation of key monodentate nitrite species, while the strengthened Lewis acidity facilitated the NH₃ activation process. This work introduces an innovative approach to convert fly ash into efficient catalysts for environmental remediation, demonstrating waste valorization in green chemistry.

17α-ethinylestradiol (EE2) is a persistent endocrine-disrupting chemical that threatens aquatic ecosystems. Algal extracellular organic matter (EOM), widespread manganese oxides (MnO_x) and their photochemical interactions can drive the natural degradation of EE2. However, these processes can be regulated by the unique surrounding conditions in eutrophic plateau lakes, including elevated levels of dissolved organic carbon, high pH, and abundant anions. Here, we investigated the enhancement of EE2 photodegradation mediated by EOM and MnO_x, with emphasis on the effects of above unique surrounding conditions. Results showed that higher EOM concentrations proceed faster EE2 photodegradation rate by providing sufficient binding sites and more superoxide radicals for Mn(III) generation. In contrast, elevated pH inhibited EE2 degradation due to pH-dependent surface modifications of MnO_x, which suppressed Mn(III) formation. Nitrate can enhance EE2 photodegradation without influencing Mn(III) generation. Product identification and density functional theory calculations suggest that EE2 degradation proceeds via free radical attack and Mn(III/IV)-mediated electron transfer, producing both small oxidized products and oligomers such as dimers and trimers. This study clarifies the environmental drivers of organic micropollutants’ degradation in eutrophic lakes, highlighting the environmental significance of surrounding conditions.

Municipal solid waste incineration fly ash (MSWI-FA) is an urgently treatable hazardous waste in China. High-temperature melting is a promising resource utilization technology for global solid waste. This study examines physicochemical properties of grate furnace incineration fly ash from northern and southern China, finding Cd, Pb, and Zn leaching toxicity exceeds national standards by 9.14, 8.59, and 1.09 times for northern samples, and 17.58, 7.13, and 1.25 times for southern samples, respectively. Clinker ignition loss during melting reaches approximately 40% for both fly ash types. Heavy metal migration (Pb, Zn, Cd, Cr, Cu, Ni) was analyzed across 200–1600 °C. Cr and Ni, predominantly in the slag phase, exhibited low volatility (~20% at 1600 °C). Fe and Cu showed moderate volatility, exceeding 70% at 1600 °C. Pb, Cd, and Zn demonstrated high volatility, surpassing 90% at 1200 °C. The volatilization sequence is Cd > Pb > Zn > Cu > Ni > Cr. XRD, SEM, TGA analyses revealed melting behavior and vitrification mechanisms. Heavy metals accumulate in secondary fly ash mainly as chlorides (PbCl₂, ZnCl₂, ZnCdCl₄). Slag minerals transition from low-temperature CaCl₂, CaClOH, NaCl, KCl to high-temperature chlorinated (Ca₅Al₂SiO₈Cl₄) and non-chlorinated (Ca₅Al₂SiO₁₀) calcium aluminum silicates. However, no glass peaks were observed in XRD spectra of both fly ashes at 1600 °C. Thermodynamic analysis points to high CaO content as the main cause of elevated melting points. To achieve vitrification below 1500 °C, the optimal SiO₂:CaO:Al₂O₃ ratio should be approximately (3.5–9.0):(0–4.0):(0–3.5).

Constructed wetlands (CWs) are gaining recognition as important carbon sinks, subject to factors such as system design and vegetation. However, the effect of configuration on carbon emissions in CWs remains inadequately understood. We constructed three configurations of CWs, free-water surface flow (FWS), horizontal subsurface flow (HSSF), and vertical subsurface flow (VSSF), to assess contaminant removal performance and carbon emissions. Higher removal efficiencies for NH₄⁺-N, NO₃⁻-N and COD were observed in HSSF (72.06%, 60.90%, and 70.01%) and VSSF (75.18%, 48.94%, and 69.47%) compared to FWS (64.89%, 35.50%, and 58.83%). FWS exhibited the highest CH₄ emissions (1.59 mg/(m²·h)) and lowest CO₂ emissions (−176.26 mg/(m²·h)) due to a greater abundance of Methanobacterium and plant biomass. Higher N₂O emissions were observed in VSSF (0.33 mg/(m²·h)) compared to FWS (0.18 mg/(m²·h)) and HSSF (0.12 mg/(m²·h)). In general, the majority of carbon was buried in substrate (55.53%–64.50%), followed by plants (24.90%–40.84%) and wastewater (4.05%–14.08%). Carbon budget estimation showed that all CWs exhibited characteristics of carbon sinks. FWS exhibited the highest annual net carbon sink capacity at 4.78 kg CO₂-eq/(m²·yr), followed by VSSF and HSSF at 2.81 and 2.54 kg CO₂-eq/(m²·yr), respectively.

The growing demand for lithium-ion batteries has intensified the need for efficient, scalable, and sustainable lithium recovery technologies. In this study a fluidized bed homogeneous crystallization recovery (FBHC) system for the selective recovery of lithium from cathode manufacturing wastewater was developed. The recovered pellets were in the form of high-purity lithium phosphate. A comprehensive parametric investigation was conducted to identify the optimal operating conditions of initial lithium concentration, effluent pH, surface loading rate, temperature, and phosphate-to-lithium molar ratio. Packing the bed with homogenous lithium phosphate seeds reduced the time to equilibrium from hundreds of hours to minutes. The optimal conditions of bed height and particle size of the seeds were also surveyed. Under the optimized conditions, the FBHC process achieved a total lithium recovery of ~92%, a crystallization ratio of ~90%, and a product purity of ~98%. The obtained recovered Li₃PO₄ was composed of dense, spherical granules with mechanically stable structures. Compared with other recovery technologies, the FBHC system provides superior control over nucleation and growth kinetics with no formation of hazardous sludge, and requires no use of organic solvents or membranes. The FBHC process demonstrates profitability for the recovery of lithium from real industrial wastewater in a robust and environmentally benign manner, which aligns well with the principles of a circular economy.

Partial denitrification granules (PDG) offer a novel approach to supplying nitrite (NO₂⁻) for anammox. Shear stress (τ) induced by mechanical stirring has been recognized as an effective operational strategy for enhancing mass transfer in continuous-flow PDG systems with minimal gas production. However, the effects of shear stress intensity on nitrite (NO₂⁻) accumulation, granular structure, and microbial succession remains unclear. This study established two continuously up-flow PDG systems to assess the influence of low-strength τ (0.2–0.5 Pa) and high-strength τ (1.2–1.4 Pa) on PDG performance under dynamic nitrate (NO₃⁻) loading rates (NLR). Results indicated that low-strength τ promoted the formation of 1–2 mm granules, mitigating the washout of flocs and smaller granules, and sustaining a stable nitrite production rate (NPR) of 7.7 kg N/(m³·d) at an NLR as high as 11.7 kg N/(m³·d). In contrast, high-strength τ caused particle fragmentation and reaggregation, accompanied by the washout of sludge containing PD bacteria, leading to a lower NPR of 0.2 kg N/(m³·d). Metagenomic analysis revealed that low-strength τ enhanced nitrogen-carbon metabolism, with Thauera.sp. and Thauera_phenylacetica synergistically driving NO₂⁻ accumulation. Although high-strength τ promoted the enrichment of Thauera (~70%), Thauera.sp. decreased its contribution to napA and improved to nirK, whereas Thauera_phenylacetica reduced its contribution to napA, thereby constraining NO₂⁻ accumulation. These findings provide critical insights into optimizing shear conditions for PDG and enhance the understanding of the metagenomic mechanisms of PD.

As an alternative to perfluorooctanoic acid, hexafluoropropylene oxide trimer acid (HFPO-TA) has become a widespread environmental contaminant, posing potential risks to aquatic organisms. However, its intergenerational reproductive toxicity in fish remains poorly understood. In this study, following a 90-d exposure of four-month-old zebrafish to HFPO-TA (0.5, 5, and 50 μg/L), subsequent generation was reared in clean water until adulthood to assess intergenerational reproductive effects. Results revealed that parental HFPO-TA exposure inhibited gonadal development in both generations and affected F1 offspring development. A female-skewed sex ratio was observed in unexposed F1 offspring, accompanied by the dysregulation of genes involved in sex differentiation and maintenance. Furthermore, transcriptions of key genes along the hypothalamus-pituitary-gonad-liver axis were dysregulated across two generations, leading to disorders of sex hormone and vitellogenin levels, and ultimately resulting in intergenerational reproductive dysfunction. It was found that the HFPO-TA exposure also induced DNA hypermethylation in gonads across two generations, which could contribute to the observed reproductive toxicity. Overall, this study provides evidence for the intergenerational reproductive toxicity of HFPO-TA in zebrafish, with potential adverse implications for the sustainability of fish populations.

Fossil fuel combustion-derived CO₂ has a lower ratio of ¹³C than the CO₂ naturally existing in the atmosphere and dilutes the overall level of ¹³C at a global scale. However, the effects of CO₂ with low ¹³C/¹²C on algae and the relevant underlying mechanisms remain elusive. In this study, the effects of ¹³C-depletion and high concentration of carbon sources (LA-HC) on carbon and nitrogen metabolism in Nannochloropsis oceanica (N. oceanica) were investigated using stable isotope techniques and transcriptomics. Results showed that LA-HC increased the growth, carbon fixation, and nitrogen fixation rates of N. oceanica by 21.83%, 19.35%, and 14.71%, respectively. Stable isotope analysis indicated that LA-HC significantly decreased the δ¹³C values of N. oceanica, and the algae preferentially fixed CO₂ containing ¹²C. Furthermore, LA-HC limited nitrogen isotope fractionation, and the algae were enriched in the heavier isotope ¹⁵N, indicative of higher nitrogen fixation. Fatty acid analysis indicated that LA-HC induced polyunsaturated fatty acids accumulation, especially C20:5n-3, which plays a key role in promoting photosynthetic membrane activity. In terms of amino acid content, the increase in phenylalanine, glutamine, and proline levels promoted nitrogen storage in N. oceanica. Transcriptomics revealed that LA-HC upregulated the genes involved in glycolysis, the tricarboxylic acid cycle (TCA cycle), and nitrogen metabolism, which increased energy metabolism and promoted fatty acid and amino acid synthesis, thereby enhancing carbon and nitrogen metabolism in N. oceanica. This study provides new insights into the mechanism of carbon and nitrogen metabolism in algae and is meaningful for studying the marine carbon and nitrogen cycle.

Permanganate (Mn(VII)) is a commonly used oxidant for water treatment. However, manganese dioxide (MnO₂) produced in situ during permanganate oxidation reactions significantly interferes with the spectrophotometric measurement of Mn(VII) when using the previously reported spectrophotometry. In this study, a convenient, low-cost, and reliable spectrophotometry method was firstly established for measuring trace Mn(VII) (μmol/L−level) during the permanganate oxidation reactions without the need to filter out MnO₂. The method was based on the oxidation of 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) by Mn(VII) to produce a stable green radical (ABTS^•+) under mildly alkaline conditions (pH ≥ 8), with detection at long wavelengths (i.e., 732 nm and 820 nm). The strong resistance to interference from MnO₂ of the modified ABTS method was attributed to the inertness of MnO₂ toward ABTS under mildly alkaline conditions and the relatively low molar absorptivity of MnO₂ at long wavelengths compared to ABTS^•+. Using the characteristic peak at 732 nm as the detection wavelength, the sensitivity of the modified ABTS method for the Mn(VII) measurement was determined to be 4.84 × 10⁴ L/(mol·cm). Additionally, the modified ABTS method exhibited high tolerance towards common environmental background matrices and was reliable in measuring the Mn(VII) concentration in natural water samples. The accuracy of the modified ABTS method for the measurement of Mn(VII) in the presence of MnO₂ was also validated by comparing different detection methods. Furthermore, the modified ABTS method was successfully applied to detect the variation of Mn(VII) concentration during diclofenac removal with the humic acid-enhanced Mn(VII) process.

The rupture of electrolysis bubbles at the gas-liquid interface generates electrolytic particulate matter (EPM). EPM poses a threat to both occupational health and ambient air quality. Understanding EPM pollution characteristics and developing effective control strategies are therefore critical for the green development of the electrolysis industry. This review summarizes research on EPM regarding workplace contamination, atmospheric emissions, formation mechanisms, and control technologies. Findings reveal severe contamination of electrolysis facilities by EPM, acid mist, and heavy metals, which collectively pose high cancer and non-cancer risks—even when individual component concentrations fall below exposure limits. However, industrial EPM emission levels remain poorly quantified, partly due to a lack of convenient and accurate measurement methods. Bubble characteristics, electrolyte properties, and electrode materials along with their physical characteristics significantly affect EPM formation. Based on the formation process and influencing factors, we summarize theoretical source reduction pathways, including: inhibiting electrochemical gas generation, reducing detached bubble size, and deploying physical barriers. Existing source control methods, while demonstrating high removal efficiency, often adversely affect energy consumption, product quality, or productivity. Finally, we identify key research gaps and propose future directions for characterizing EPM and developing targeted source reduction technologies.

While multi-wall carbon nanotube (MWCNT)-reinforced nanocomposites offer improved wear resistance, the health implications of released nanoparticle aerosols are a concern. This research aimed to understand the influence of matrix material on the tribological properties, microstructure, and triboemission of MWCNT-functionalized polymer and cement composites. Key findings reveal that aerosol emission cannot be predicted solely based on porosity and mechanical properties. The observed variations in MWCNT effects across different matrix materials are attributed to the distinct dominant wear mechanisms in each.