Sulfamethoxazole (SMX), which is a commonly used antibiotic, poses persistent risks to aquatic environments owing to its recalcitrance. Adsorption mediated by sludge-derived biochar is a beneficial strategy as an emergency sorbent for antibiotic pollution control. However, its application is limited by the low pore volume and small specific surface area (SSA) of the sorbent owing to the high ash content of sludge. In this study, CaCl2-modified sewage sludge-derived biochar (CaSBC) was prepared via impregnation–pyrolysis followed by acid washing. The treatment increased the pore volume and SSA to 0.3015 cm3/g and 129.50 m2/g, respectively, providing additional accessible pores for adsorption. Furthermore, the modification induced changes in the surface charge and functional groups, which improved electrostatic attraction over a wide pH range and enhanced π–π electron donor–acceptor and hydrogen bonding interactions between CaSBC and SMX. Consequently, CaSBC exhibited an adsorption capacity of 22.30 ± 0.74 mg/g, which was 2.3 and 2.9 times higher than that of unmodified biochar and commercial activated carbon (AC), respectively. Furthermore, CaSBC exhibited stable adsorption in the pH range of 2–8 and in the presence of competing ions, and its estimated production cost was lower than that of AC by 27%. This study presents a practical and cost-effective method for the reusage of sludge as a value-added resource and the concurrent enhancement of SMX removal from wastewater.
Polycyclic aromatic hydrocarbons (PAHs) and mineral dusts are the key toxic and reactive components of atmospheric particulate matter (PM2.5). Their synergistic conversion poses significant adverse environmental concerns but remains underexplored, especially for photoactive particles. Here, we conduct an in-depth study of the photochemical transformation mechanism of acenaphthylene (ACY), a common atmospheric PAH, on the surface of typical mineral dusts. Notably, TiO2 induces the formation of environmentally persistent free radical (EPFR) upon the “cation-π” interaction with ACY, thereby promoting the generation of atmospheric oxidants and significantly enhancing the photochemical conversion of ACY. In contrast, Fe2O3 and SiO2 primarily serve as inert carriers with minimal effect. EPFR-mediated hydroxyl radical (·OH) is identified to be the dominant reactive species in the photochemical transformation of ACY, driving nearly 100% conversion. Oxygenated PAHs (OPAHs), which likely aggravate the formation of secondary organic aerosols (SOA), are the main products. In addition, the enhanced ACY transformation has also been verified on the natural kaolinite, underscoring the universality of this mechanism in atmospheric chemistry. This work proposes a new pathway for the photochemical transformation of PAH on the surface of photoactive mineral particles mediated by EPFR, providing unique perspectives and deep insights into the enhanced atmospheric oxidizing capacity and the photochemical transformation from organic carbon (OC) into SOA.
Both Ozone (O3) and volatile organic compounds (VOCs) pose substantial risks to human health and ecosystems. Catalytic decomposition of O3 and catalytic ozonation of VOCs are effective degradation strategies. This review elucidates the mechanisms underlying catalytic O3 decomposition and catalytic ozonation of VOCs, while simultaneously establishing the interconnections between these two processes. This review comprehensively delineates the catalysts and control methodologies pertinent to both catalytic O3 decomposition and catalytic ozonation of VOCs, endeavoring to draw parallels between the catalysts employed in these processes. Transition metals, with their versatile valence states and rich electronic structures, exhibit remarkable efficacy in catalytic O3 decomposition and catalytic ozonation of VOCs. Modulating surface structure and concentration of oxygen vacancies emerges as the powerful regulatory strategies. Although the approach to enhancing catalytic ozonation of VOCs parallels that of catalytic O3 decomposition, the intricate environmental context of VOCs necessitates increased focuses on selective adsorption during the initial adsorption phase of the catalyst. Furthermore, a meticulous examination of catalyst stability, especially in relation to resistance against water, sulfur, and chlorine, is imperative. Reactive oxygen species act as pivotal active agents in the catalytic ozonation of VOCs, highlighting the strategic importance of screening catalysts that can generate reactive oxygen species from catalytic O3 decomposition to expedite the degradation of VOCs.
Microplastic pollution is threatening planetary health and sustainable development. The microbiota colonizing microplastic surfaces, termed the plastisphere, has emerged as artificial niches that harbor both microbial risks and novel biodegradation potential. However, these two aspects of the plastisphere have often been investigated in isolation. In this review, we first elaborate on how microplastics act as vectors in facilitating the enrichment and dissemination of pathogens, antibiotic resistance genes (ARGs), and even virus, thereby causing serious microbial and ecological risks, and eventually impacting human health. To address the potential risks, the key plastic-degrading resources, the underlying mechanisms, and recent advances in biodegradation technologies are synthesized. Given the dual roles of plastisphere microbes, we therefore propose a two-dimensional screening framework to identify safer and more efficient degraders. This review aims to guide the selection or synthesis of safe and highly efficient degrading microbial consortia, thereby providing sustainable and eco-friendly strategies for mitigating plastic pollution.
Co-formulated antibiotics may exert more complex effects on sludge anaerobic digestion (AD) due to their synergistic mechanisms. However, studies on the transformation and effects of antibiotic combinations in AD systems remain limited. This study investigates the impacts of the representative co-formulated antibiotics sulfamethoxazole and trimethoprim (SMX/TMP) on sludge AD. Results demonstrated that both antibiotics interfered with key metabolic pathways, resulting in marked suppression of methane generation. Bliss Independence Model (BIM) analysis demonstrated that their joint effects were concentration-dependent, with synergistic inhibition occurred at lower doses and higher levels produced antagonistic interactions, likely reflecting metabolic saturation. Further experiments revealed co-exposure triggered excessive reactive oxygen species (ROS) accumulation, decreased key enzyme activity, cell activities. While partial biotransformation of SMX/TMP was observed, transformation products did not serve as carbon sources for methane enhancement. Partitioning assessment showed that both compounds were predominantly retained within extracellular polymeric substances (EPS), with notable fractions remaining in soluble EPS, indicating restricted cellular penetration and potential antibiotic residues in effluent. Microbial community analysis showed severe inhibition of hydrolytic and acidogenic microorganisms such as Syntrophomonas and Romboutsia, but significantly enhanced the abundance of antibiotic degrading functional microorganisms such as norank_f_Anaerolineaceae, which mean a potential degradation in AD system. Moreover, conventional methanogens decreased severely but Candidatus Methanofastidiosum displayed notable resilience, indicating a methane production feasibility in antibiotics stress AD system. These findings provide a comprehensive understanding of the concentration-dependent interaction, transformation, and partitioning behavior of co-occurring SMX/TMP, offering new mechanistic insights into their ecological risks and persistence in AD systems.
Organophosphate esters (OPEs) are widely used synthetic chemicals associated with increased plasma glucose in the general populations; however, evidence regarding their associations among pregnant women remains limited. In the Shanghai-Minhang Birth Cohort Study, urinary concentrations of eight OPE metabolites were measured at 12−16 weeks of gestation. Data on fasting plasma glucose (FPG) and 1 h-plasma glucose (1 h-PG) were obtained from medical records. Women were classified as having elevated glucose levels based on abnormal FPG, 1 h-PG, or a diagnosis of gestational diabetes mellitus (GDM). Multiple linear regression and Bayesian Kernel Machine Regression (BKMR) were employed to estimate associations between individual OPE metabolites or OPE mixtures and plasma glucose levels. Modified Poisson regression assessed the associations of OPE metabolites with the risk of elevated glucose levels. Compared with the lowest exposure group, the highest exposure to bis(1,3-dichloro-2-propyl) phosphate, dibutyl phosphate, and diphenyl phosphate was significantly associated with lower FPG levels. However, 1 h-PG levels tended to increase in the moderate exposure group, with ∑Cl-OPEs showing a marginally significant association. Poisson regression results similarly indicated that pregnant women with moderate exposure had an increased risk of elevated glucose levels, though without statistical significance. The BKMR model produced similar findings, indicating that chlorinated-OPE primarily contributed to altered FPG and 1 h-PG, with bis(1,3-dichloro-2-propyl) phosphate and bis(1-chloro-2-propyl) phosphate being the major contributors, respectively. Additionally, associations between OPE exposure and decreased FPG levels were predominantly observed among pregnant women with daily fruit and vegetable intake. The present study observed different association patterns between OPE exposure and FPG or 1 h-PG levels, suggesting potential disruptive effects of OPEs on glucose homeostasis during pregnancy.
The anaerobic oxidation of methane linked to metal oxide reduction (metal-dependent AOM) plays a crucial role in regulating methane fluxes within deep-sea sedimentary environments. While metal-dependent AOM has been reported, current understanding is primarily derived from in situ investigations and enrichment experiments conducted under atmospheric pressure, leaving its applicability to the high-pressure, low-temperature deep-sea environment uncertain. In this study, we established long-term enrichment cultures of microbial communities from South China Sea cold seep sediments (1392 m) with manganese/iron oxides as electron acceptors under simulated in situ pressure-temperature conditions (12 MPa, 4 °C). Our results demonstrate significant methane consumption (approximately 30%) accompanied by the accumulation of Mn (II) and Fe (II) over 150 d. Microbial community analysis revealed that anaerobic methanotrophic archaea (ANME-1) dominated the archaeal community. Their predicted extracellularly secreted multi-heme cytochromes (MHCs) may facilitate direct electron transfer under high pressure. Metagenomic analysis further revealed a diversity of methane metabolic pathways within the community. Horizontal gene transfer may have facilitated microbial electron exchange, while ANME archaea engaged in cross-feeding with bacterial groups via metabolites such as acetate and amino acids. This study underscores the critical role of microbial community synergy and adaptive evolution in regulating methane oxidation under simulated deep-sea conditions, providing new insights into the marine carbon cycle.
This study systematically examined SO2 and NOx removal via wet oxidation using H2O2 and O3 augmented by ultraviolet (UV) irradiation and microbubbles (MBs), combining experimental, spectroscopic, and modelling approaches. The presence of UV irradiation and MBs enhanced •OH radical generation and facilitated the conversion of NO into water-soluble NO2 and HNO3. Using 5,5-dimethyl-1-pyrroline N-oxide as a spin-trapping agent, electron spin resonance spectroscopy was used to quantify the •OH radicals generated across the six experimental setups. In millibubble systems, the radicals produced by O3 + UV, H2O2 + UV, and O3 + H2O2+ UV were rapidly depleted within 2–5 min. In contrast, the MB systems maintained a steady supply of radicals. The O3 + H2O2 + MB combination produced the highest radical concentration, comparable to that of O3 alone, which allowed continuous oxidation. Two-film modelling, incorporating experimentally measured radical yields, accurately predicted gas-phase removal, whereas neglecting radicals led to an underestimation of NO and SO2 removal. A system-specific mass-transfer correlation for O3 + MB, which increases the interfacial area, provides a reliable basis for scale-up. MB-based advanced oxidation processes also exhibited low energy consumption (0.46 kWh/m3 with H2O2) while efficiently removing pollutants under optimal conditions (298 K, pH 6, 0.2 mol/L H2O2, and 0.06 L/min). These findings highlight the critical role of •OH radicals, the advantages of MB stability in radical-mediated reactions, and the potential of MB-assisted wet oxidation as an energy-efficient and high-performance method for simultaneous SO2 and NOx reduction.
Microplastic (MP) pollution in the Arctic has recently attracted increasing attention; however, only a few studies have reported on this topic. Herein, we review the distribution, transport mechanisms, and major sources of MPs in the Arctic aquatic environment. We found that microfibers are the dominant MPs in the Arctic, and their main sources are atmospheric transport, ocean currents, and local human activities. Furthermore, MPs are widespread in the Arctic and have infiltrated the food web, posing risks to ecosystem stability. In addition, MPs may affect the climate system through several pathways, such as reducing the albedo of ice and snow, releasing greenhouse gases, disrupting the carbon pump, and altering atmospheric processes. Given the unique environmental conditions of the Arctic, we summarize suitable monitoring methods for multiple media and highlight key quality-control measures. We also evaluate the applicability and limitations of existing regulations and policies. This study calls for enhanced scientific monitoring, policy development, and international collaboration to curb the growing MP pollution in the Arctic. There is an urgent need for a systematic governance framework for MP pollution in the Arctic to address the associated environmental and climate risks.
Development of innovative strategies for detoxification of pesticides accumulated in ecosystems is of crucial importance for the global agricultural intensification and reducing their environmental footprint. One of the most promising approaches to the problem is the creation of synthetic microbial consortia possessing high catabolic activity and the ability to efficiently degrade persistent environmental pollutants. This review analyzes recent advancements in metagenomics that enable a detailed examination of the genetic diversity and functional potential of natural microbiomes. Special attention is given to the engineered modification of key genetic elements responsible for pesticide degradation, as well as synthetic biology methodologies aimed at the targeted construction of microbial consortia with predefined biodegradative properties. Additionally, the review discusses critical aspects of biosafety, biostability, and regulatory constraints associated with the introduction of genetically modified microbial systems into natural and agricultural ecosystems. The significance of an interdisciplinary approach is emphasized for the development of environmentally safe, adaptive, and highly effective biotechnological solutions. The implementation of such innovative strategies has the potential not only to minimize pesticide-related environmental burdens but also ensure the long-term sustainability of agricultural ecosystems. Furthermore, this review proposes conceptual models of semi-synthetic and synthetic microbial consortia designed for the sequential degradation of chlorpyrifos and methyl parathion. These models are based on recent experimental advancements in metagenomics and synthetic biology, underscoring their potential for the development of novel biodegradation systems.
Microplastics (MPs) pose a significant threat to soil and groundwater quality. Yet, investigating their transport in soils has so far been limited to conventional packed column experiments where particles suspended in a stock dispersion are injected from one side of the column. This, however, does not represent the natural condition where buoyant MPs are released on the surface of the soil and storm or irrigation water induces their penetration into the soil depth. To consider such prevailing natural condition, we develop a new column experiment setup and a corresponding modeling approach to study the transport of low-density polyethylene MPs in different farmland soil types and investigate the impact of photodegradation and natural organic matter. Results revealed a substantial penetration of buoyant MPs in the soil due to the irrigation or rainfall scenarios. Mathematical modeling showed that processes such as attachment, detachment, blocking, and straining, previously observed for colloidal particles in direct injection scenarios, occur for buoyant MPs irrigation or rainfall release scenario. MPs transport increased in silt compared to the silt loam and in the presence of natural organic matter. UV-photodegraded MPs transport was greater than pristine MPs because of increased surface charge and electrostatic repulsion, reducing MPs attachment to soil.
Quantifying commercial cooking emissions is non-negligible for mitigating urban PM2.5 and O3 pollution, given their significant and spatiotemporally concentrated releases of PM2.5 and volatile organic compounds (VOCs). However, the accuracy of existing commercial cooking emission inventories remains unsatisfactory because generalized estimation parameters fail to represent the dynamic emission variations of this sector. Here, we develop a unified online-source framework (UOS) that simultaneously refines emission magnitudes and spatiotemporal allocations by integrating sample-based calibrated online oil fumes monitoring and point-of-interest data. Our framework corrected a 5.95- and 2.09-fold underestimation of VOCs and PM2.5 emissions in Guangdong Province in 2023 compared to the legacy version, in which hourly-scale emission factors significantly increased up to 159.13 g/h for VOCs and 52.47 g/h for PM2.5, respectively. Moreover, the spatial distribution was optimized to 70% of emission hotspots captured in the Pearl River Delta (PRD) region relative to the 50% population-based allocation of the legacy inventory. With improved spatiotemporal performance in simulated PM2.5 and O3, the UOS framework demonstrated a substantially greater annual contribution of commercial cooking emissions to PM2.5 (2.93 μg/m3) than to O3 (1.02 μg/m3), as well as more pronounced contributions of both PM2.5 (12.06 μg/m3) and O3 (8.39 μg/m3) in high-emission areas during pollution episodes. This work offers a scalable methodology to develop accurate commercial cooking emission inventories, thereby providing a scientific foundation for making targeted emission-reduction policies in commercial cooking.
Feammox, i.e., anaerobic ammonium oxidation coupled with ferric iron (Fe(III)) reduction, has been considered as a promising option for autotrophic nitrogen removal in wastewater with low carbon/nitrogen ratio. This study proposed a novel technology coupling Feammox and vivianite crystallization for the simultaneous removal of ammonium and phosphate in low-strength wastewater. The results showed that the Feammox process achieved high-level phosphate removal with the selective addition of amorphous ferric oxyhydroxide (amorphous FeOOH) as the iron source, compared to the other iron oxides hematite (α-Fe2O3) and magnetite (Fe3O4). The removal efficiencies of nitrogen and phosphate reached 77.6% and 77.1%, respectively, with the addition of 0.4 g/L amorphous FeOOH (equivalent to 0.3 g Fe/L). Fundamental investigations through a combination of microscopic images, X-ray diffraction, scanning electron microscopy-energy dispersive spectroscopy, Mössbauer spectroscopy and sequential phosphate extraction method revealed potential mechanisms for phosphate removal. With the addition of amorphous FeOOH, phosphate was firstly adsorbed to mineral surface sites, and then formed vivianite crystals along with microbial Fe(III) reduction (i.e., Feammox reaction) for iron availability. As a result, the Fe(II) formed in Feammox served as a phosphate sink through vivianite precipitation. This study improves the understanding of nitrogen and phosphate transformations in the proposed innovative Feammox-based process and supports the development of next-generation wastewater treatment technologies.
The treatment of wastewater characterized by high levels of NH4+-N and a moderate organic strength with a low ratio of chemical oxygen demand (COD) to total nitrogen, poses significant challenges to conventional biological processes. In this study, an energy-harvesting microbial electrolysis cell (MEC)–flue gas–anaerobic ammonium oxidation (anammox) system was proposed to treat manure-free piggery wastewater (707 ± 8 mg/L COD and 321 ± 3 mg/L NH4+-N). The MEC first effectively removed wastewater organics and recovered chemical energy in the form of H2 (with trace CH4 production). Flue gas-derived nitrogen oxides were subsequently absorbed by MEC effluent, providing a sustainable nitrite source for the anammox process. The residual NO3–-N generated from anammox metabolism and flue gas absorption could be further removed through hydrogenotrophic denitrification using in situ MEC-derived H2. The integrated system eliminates the need for energy-intensive aeration (required in aerobic processes) while also addressing the inefficiency of anaerobic treatment in handling moderate-strength wastewater. The system demonstrated an outstanding performance, with effluent concentrations of COD < 40 mg/L, NH4+-N < 0.8 mg/L, NO2–-N < 0.5 mg/L, and NO3–-N < 0.8 mg/L. Moreover, the MEC enabled the continuous production of H2 (0.50–0.91 m3/(m3·d)) and CH4 (0.01–0.14 m3/(m3·d)) with an energy recovery efficiency of ~249% (the ratio of the energy content of the produced H2 and CH4 to the input electrical energy). This study provides an energy-effective strategy for the highly efficient treatment of moderate-strength wastewater.
The application of microbial electrochemical system (MES) is limited by the slow rate of extracellular electron transfer in soil remediation. In this study, we evaluated the effects of shuttles, including anthraquinone-2,6-disulfonic acid disodium salt (AQDS), phenazine (PHE), and L-cysteine (CYS) on electricity generation, petroleum hydrocarbon degradation, and the microbial community in a soil MES. The results demonstrated that PHE and CYS enhanced the electron transfer flux by 30% and 22%, respectively, with 10%–18% higher than AQDS. Notably, CYS treatment resulted in the highest removal of petroleum hydrocarbons with a 152% increase which was 164% more than AQDS treatment, and specific degradation selectivity towards benzo[a]pyrene and long-chain alkanes. The addition of glucose as a cosubstrate universally increased the voltage output, confirming carbon source availability as a key limiting factor for electron transfer. Biological analysis revealed that electron shuttle addition reshaped the soil bacterial community structure and increased network complexity. Essentially, PHE not only functioned as an electron shuttle to promote cytochrome c expression but also stimulated Pseudomonas to overexpress endogenous phenazine compounds via quorum sensing. CYS served as both a sulphur source and a redox mediator, significantly increasing NAD(H) levels, and enriching electroactive bacteria with hydrocarbon degradation capability, such as Marinobacter and Clostridium. These findings clarify the potential of quinone- and cysteine-shuttles in pollutant degradation, providing an enhancement strategy for soil remediation.