ACS Central Science最新文献

In recent years, multifarious new materials have been developed for environmental governance. Thereinto, metal organic framework (MOF)-based catalysts have been widely employed for heterogeneous catalysis because of their high porosity to confine noble metal particles faraway from aggregation. However, the potential reactions between residual species from the material synthesis process and target pollutants, which could form highly toxic byproducts, are often neglected. Herein, we took the widely used Zr-MOF, UiO-66, with highly thermal stability supported Pd catalysts as the example to investigate how the residual species in catalysts are involved in aromatic volatile organic compounds (VOCs) degradation reaction. The results showed that residual Cl species originated from the ZrCl₄ metal precursor participated in the VOC degradation reaction, leading to the production of various chlorine-containing byproducts, even the hypertoxicity dioxin precursor, dichlorobenzene. Meanwhile, the chlorination mechanism for the formation of chlorine-containing byproducts was revealed by density functional theory calculation. Furthermore, the highly efficient residual Cl removal approaches are proposed. Importantly, the migration and transformation of residual Cl during the degradation of five benzene series VOCs are comprehensively studied and elucidated. We anticipate that these findings will raise alarm about the neglected issue of residual species in MOF-based catalysts for heterogeneous catalysis, especially environmentally friendly catalysis.

Enhanced weathering of (ultra)mafic rocks has been proposed as a promising approach to sequester atmospheric CO₂ and mitigate climate change. However, these silicate rocks contain varying amounts of trace metals, which are essential cofactors of metallaenzymes in methanogens. We found that weathering of crushed peridotite and basalt significantly promoted the growth and methanogenesis of a model methanogen─Methanosarcina acetivorans C2A under the condition of excess substrate. The released trace metals from peridotite and basalt, especially Fe, Ni, and Co, accounted for the promotion effect. Observation at different spatial scales showed a close association between the rocks and cells. Proteomic analysis revealed that rock amendment significantly enhanced the expression of core metalloenzymes in the methylotrophic methanogenesis pathway. Our study uncovers a previously unrecognized but important negative effect of enhanced rock weathering on methane production, which may counteract the carbon sequestration effort.

The accuracy of life cycle assessment (LCA) studies is often questioned due to the two grand challenges of life cycle inventory (LCI) modeling: (1) missing foreground flow data and (2) inconsistency in background data matching. Traditional mechanistic methods (e.g., process simulation) and existing machine learning (ML) methods (e.g., similarity-based selection methods) are inadequate due to their limitations in scalability and generalizability. The large language models (LLMs) are well-positioned to address these challenges, given the massive and diverse knowledge learned through the pretraining step. Incorporating LLMs into LCI modeling can lead to the automation of inventory data curation from diverse data sources and to the implementation of a multimodal analytical capacity. In this article, we delineated the mechanisms and advantages of LLMs to addressing these two grand challenges. We also discussed the future research to enhance the use of LLMs for LCI modeling, which includes the key areas such as improving retrieval augmented generation (RAG), integration with knowledge graphs, developing prompt engineering strategies, and fine-tuning pretrained LLMs for LCI-specific tasks. The findings from our study serve as a foundation for future research on scalable and automated LCI modeling methods that can provide more appropriate data for LCA calculations.

Biomass energy recovery from sewage sludge through anaerobic treatment is vital for environmental sustainability and a circular economy. However, large amounts of pharmaceutical and personal care products (PPCPs) remain in sludge, and their interactions with microbes and enzymes would affect resource recovery. This article reviews the effects and mechanisms of PPCPs on anaerobic sludge treatment. Most PPCPs posed adverse impacts on methane production, while certain low-toxicity PPCPs could stimulate volatile fatty acids and biohydrogen accumulation. Changes in the microbial community structure and functional enzyme bioactivities were also summarized with PPCPs exposure. Notably, PPCPs such as carbamazepine could bind with the active sites of the enzyme and induce microbial stress responses. The fate of various PPCPs during anaerobic sludge treatment indicated that PPCPs featuring electron-donating groups (e.g., ·–NH₂ and ·–OH), hydrophilicity, and low molecular weight were more susceptible to microbial utilization. Key biodegrading enzymes (e.g., cytochrome P450 and amidase) were crucial for PPCP degradation, although several PPCPs remain refractory to biotransformation. Therefore, remediation technologies including physical pretreatment, chemicals, bioaugmentation, and their combinations for enhancing PPCPs degradation were outlined. Among these strategies, advanced oxidation processes and combined strategies effectively removed complex and refractory PPCPs mainly by generating free radicals, providing recommendations for improving sludge detoxification.

Heterogeneous electro-Fenton degradation with ¹O₂ and ^•OH generated from O₂ reduction is cost-effective for the removal of refractory organic pollutants from wastewater. As ¹O₂ is more tolerant to background constituents such as salt ions and a high pH value than ^•OH, tuning the production of ¹O₂ and ^•OH is important for efficient electro-Fenton degradation. However, it remains a great challenge to selectively produce ¹O₂ and improve the species yield. Herein, the electronic structure of atomically dispersed Cu–N₄ sites was regulated by doping electron-deficient B into porous hollow carbon microspheres (CuBN-HCMs), which improved *O₂ adsorption and significantly enhanced ¹O₂ selectivity in electro-Fenton degradation. Its ¹O₂ yield was 2.3 times higher than that of a Cu single-atom catalyst without B doping. Meanwhile, ^•OH was simultaneously generated as a minor species. The CuBN-HCMs were efficient for the electro-Fenton degradation of phenol, sulfamethoxazole, and bisphenol A with a high mineralization efficiency. Its kinetic constants showed insignificant changes under various anions and a wide pH range of 1–9. More importantly, it was energy-efficient for treating actual coking wastewater with a low energy consumption of 19.0 kWh kg_COD^–1. The superior performance of the CuBN-HCMs was contributed from ¹O₂ and ^•OH and its high ¹O₂ selectivity.

Airborne microorganisms impact cloud formation and are involved in disease spreading. The ability of airborne cells to survive and express genes may be limited by reduced water availability in the atmosphere and depend on the ability of the cells to attract water vapor at subsaturated conditions, i.e., their hygroscopicity. We assessed hygroscopic properties of the plant pathogen Pseudomonas syringae, known to participate in cloud formation. We used a hygroscopicity tandem differential mobility analyzer to examine both hydration and dehydration behavior in the relative humidity (RH) range 5–90%. The cells were aerosolized either from Milli-Q water or from a 35 g L^–1 NaCl solution, resulting in pure cells or cells associated with NaCl. Pure cells exhibited no deliquescence/efflorescence and a small gradual water uptake reaching a maximum growth factor (GF) of 1.09 ± 0.01 at 90% RH. For cells associated with NaCl, we observed deliquescence and a much larger maximum GF of 1.74 ± 0.03 at 90% RH. Deliquescence RH was comparable to that of pure NaCl, highlighting the major role of the salt associated with the cells. It remains to be investigated how the observed hygroscopic properties relate to survival, metabolic, and ice-nucleation activities of airborne P. syringae.

The adoption of zero-emission vehicles (ZEVs) offers multiple benefits for the climate, air quality, and public health by reducing tailpipe emissions. However, the environmental justice implications of the nonexhaust emissions from future ZEV fleets for near-roadway communities remain unclear. Here, we model the on-road fine particulate matter (PM_2.5) emissions across all California counties and assess the near-roadway exposure disparities at the census block group level in the Los Angeles County in 2050, when almost all passenger vehicles are projected to be ZEVs. We found that promoting zero-emission heavy-duty trucks generates more air quality benefits for disadvantaged communities than light-duty passenger vehicles. Persistent disparities in near-roadway PM_2.5 levels, however, exist due to the remaining brake and tire wear emissions and increased truck traffic in disadvantaged communities. We recommend implementing fleet-specific ZEV policies to address brake and tire wear emissions and optimizing freight structures to address these persistent environmental justice issues in California.

Minimal research exists on the remaining nonexhaust emissions from future ZEV fleets. This study emphasizes that addressing both nonexhaust emissions and the increasing truck traffic is crucial for reducing disparities in near-roadway PM_2.5 levels.

The selective photoreduction of nitrate to nontoxic nitrogen gas has emerged as an energy-efficient and environmentally friendly route for nitrate removal. However, the coexisting high-concentration chloride ions in wastewater can exert a significant influence on nitrate reduction due to the competitive adsorption and corrosion of Cl^– on photocatalysts. Herein, we prepared ethylene glycol-Cu/TiO_2–x (EG-Cu/TiO_2–x) through a solvothermal reaction of Cu-doped TiO₂ in an EG solution. The photodegradation of nitrate using EG-Cu/TiO_2–x without adding sacrificial agents can efficiently occur in near-neutral pH solutions containing 50 mM Cl^– with 95.26% of NO₃^– removal and 76.52% of N₂ selectivity. Moreover, the photocatalyst performance remained at a high level after 8 cycles. In this work, NO₃^– was first converted to NH₄⁺ by Cu⁰ and Ti³⁺, followed by the NH₄⁺-to-N₂ conversion by photogenerated chlorine free radicals. Compared to HO^•, Cl^•, and Cl₂^•–, ClO^• is proved to play the predominant role in transforming NH₄⁺ to N₂. The EG radicals produced by UV light impede Cl^– adsorption on Cu, protecting Cu⁰ from being corroded. What’s more, photoelectrons can reduce Ti⁴⁺ to Ti³⁺ and protect Cu⁰ from being oxidized, enabling the stability of reactive sites. This work provides novel insights and understanding on designing photocatalysts for NO₃^– removal in solutions containing chloride ions, highlighting the significance of eliminating Cl^– by EG radicals and adjusting the conversion process of NO₃^– for the efficient removal of NO₃^–.

Antiscalant disposal in reverse osmosis concentrate (ROC) treatment is a significant obstacle in desalination. This study investigated the adsorption performance of LDHs for removing 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP). CaFe-LDH presented a specific adsorption behavior and ultrahigh adsorption capacity for HEDP, with a maximum adsorption capacity of 335.7 mg P/g (1116.5 mg HEDP/g) at pH 7.0. X-ray diffraction (XRD) demonstrated that HEDP adsorption induced a structural transformation of CaFe-LDH from a layered configuration to a highly ordered structure, leading to a noticeable phase transition. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and Raman spectroscopy further confirmed that two distinct binding modes of HEDP, relating to chelation with Ca²⁺ and adsorption on Fe³⁺ simultaneously, are connected by phosphonic acid groups (−C–PO(OH)₂), forming the CaFe-HEDP complex. X-ray fluorescence (XRF) and X-ray photoelectron spectroscopy (XPS) analyses revealed that the CaFe-HEDP ternary complex exhibits a highly ordered arrangement in an oxygen-bridged framework. The construction of an oxygen-coordinated framework contributes to the incorporation of more HEDP into CaFe-LDH, leading to a well-aligned lattice in the new phase. These findings provide valuable insights into developing novel LDH-based adsorbents for removing phosphorus-containing antiscalants, establishing a sustainable approach to ROC management, and potential environmental risk reduction.

A comprehensive assessment of chemical alternatives (ACA) is necessary to avoid regrettable substitution. In a preceding study, an analysis of six hazard assessment methods found that none of them are fully aligned with the hazard assessment criteria of Article 57 of the European REACH regulation, indicating a need for a method better reflecting hazard assessment schemes in European chemical regulations. This paper presents a multiple-criteria decision analysis (MCDA) method for the ACA that takes the criteria of Article 57 of REACH into account. Investigated and presented are objective hierarchies, the aggregation of objectives, the curvature of the value functions, weights, and the introduction of a classification threshold. The MCDA-ACA method allows for the aggregation of hazards in such a way that poor performance in one hazard cannot be compensated for by good performance in another hazard. The method parameters were developed and tested using two data sets with the aim to classify chemical alternatives into acceptable (nonregrettable) and unacceptable (regrettable) alternatives according to the regulations set in Europe. The flexibility of the general method was explored by adapting the method to align with two hazard assessment schemes, Article 57 of REACH and GreenScreen. The results show that MCDA-ACA is so flexible and transparent that it can easily be adapted to various hazard assessment schemes.

We propose parameters for a multiple-criteria decision analysis method to comprehensively assess chemical alternatives and present a practical policy tool necessary to prevent regrettable substitutions.