• Portugal recycles 34% of the 40 kg/hab year of plastic packaging waste.

As a European Union (EU) member, Portugal must comply with reductions in plastic waste. In Portugal, the 330 items/100 m of beach litter, comprising up to 3.9 million pieces and of which 88% is plastic, is higher than the EU median (149 items/100 m) and must be reduced to 20 items/100 m (94%). Integrative measures are needed to reduce littering and improve plastics’ use and disposal under the circular economy. Of this 414 kt of plastic packaging waste, 163 kt were declared plastic packaging, 140 kt subjected to recycling, and 94 kt to energy recovery. The current recycling rate of plastic packaging (34%) should be improved to reach EU recycling averages (42%) and goals and to provide widespread benefits, considering revenues of 167 €/t. As a net importer of waste, Portugal could benefit from the valorization of imported waste. Besides increased recycling, pyrolysis and gasification could provide short-term alternatives for producing value-added substances from plastic waste, such as hydrogen, consistent with the National Plan of Hydrogen and improving ongoing regulations on single-use plastics. This manuscript provides an integrative view of plastics in Portugal, from use to disposal, providing specific recommendations under the circular economy.

▪ Overviewed evolution and environmental applications of stabilized nanoparticles.

Due to improved soil deliverability and high reactivity, stabilized nanoparticles have been studied for nearly two decades for in situ remediation of soil and groundwater contaminated with organic pollutants. While large amounts of bench- and field-scale experimental data have demonstrated the potential of the innovative technology, extensive research results have also unveiled various merits and constraints associated different soil characteristics, types of nanoparticles and particle stabilization techniques. Overall, this work aims to critically overview the fundamental principles on particle stabilization, and the evolution and some recent developments of stabilized nanoparticles for degradation of organic contaminants in soil and groundwater. The specific objectives are to: 1) overview fundamental mechanisms in nanoparticle stabilization; 2) summarize key applications of stabilized nanoparticles for in situ remediation of soil and groundwater contaminated by legacy and emerging organic chemicals; 3) update the latest knowledge on the transport and fate of stabilized nanoparticles; 4) examine the merits and constraints of stabilized nanoparticles in environmental remediation applications; and 5) identify the knowledge gaps and future research needs pertaining to stabilized nanoparticles for remediation of contaminated soil and groundwater. Per instructions of this invited special issue, this review is focused on contributions from our group (one of the pioneers in the subject field), which, however, is supplemented by important relevant works by others. The knowledge gained is expected to further advance the science and technology in the environmental applications of stabilized nanoparticles.

● The safety and health of soil face global threats from widespread contamination.

Soil is a non-renewable resource, providing a majority of the world’s food and fiber while serving as a vital carbon reservoir. However, the health of soil faces global threats from human activities, particularly widespread contamination by industrial chemicals. Existing physical, chemical, and biological remediation approaches encounter challenges in preserving soil structure and function throughout the remediation process, as well as addressing the complexities of soil contamination on a regional scale. Viable solutions encompass monitoring and simulating soil processes, with a focus on utilizing big data to bridge micro-scale and macro-scale processes. Additionally, reducing pollutant emissions to soil is paramount due to the significant challenges associated with removing contaminants once they have entered the soil, coupled with the high economic costs of remediation. Further, it is imperative to implement advanced remediation technologies, such as monitored natural attenuation, and embrace holistic soil management approaches that involve regulatory frameworks, soil health indicators, and soil safety monitoring platforms. Safeguarding the enduring health and resilience of soils necessitates a blend of interdisciplinary research, technological innovation, and collaborative initiatives.

• Recent progress of As-contaminated soil remediation technologies is presented.

Arsenic (As) is a top human carcinogen widely distributed in the environment. As-contaminated soil exists worldwide and poses a threat on human health through water/food consumption, inhalation, or skin contact. More than 200 million people are exposed to excessive As concentration through direct or indirect exposure to contaminated soil. Therefore, affordable and efficient technologies that control risks caused by excess As in soil must be developed. The presently available methods can be classified as chemical, physical, and biological. Combined utilization of multiple technologies is also common to improve remediation efficiency. This review presents the research progress on different remediation technologies for As-contaminated soil. For chemical methods, common soil washing or immobilization agents were summarized. Physical technologies were mainly discussed from the field scale. Phytoextraction, the most widely used technology for As-contaminated soil in China, was the main focus for bioremediation. Method development for evaluating soil remediation efficiency was also summarized. Further research directions were proposed based on literature analysis.

● Reduce the quantifying MPs time by using Nile red staining.

Microplastics (MPs) and plasticizers, such as phthalate esters (PAEs), were frequently detected in municipal wastewater treatment plants (MWTP). Previous research mainly studied the removal of MPs and PAEs in wastewater. However, the occurrence of MPs and PAEs in the sludge was generally ignored. To comprehensively investigate the occurrence and the migration behaviors of MPs and PAEs in MWTP, a series of representative parameters including the number, size, color, shape of MPs, and the concentrations of PAEs in wastewater and sludge were systematically investigated. In this study, the concentrations of MPs in the influent and effluent were 15.46±0.37 and 0.30±0.14 particles/L. The MP removal efficiency of 98.1% was achieved and about 73.8% of MPs were accumulated in the sludge in the MWTP. The numbers of MPs in the sludge before and after digestion were 4.40±0.14 and 0.31±0.01 particles/g (dry sludge), respectively. Fourier Transform Infrared Spectroscopy (ATR FT-IR) analysis showed that the main types of MPs were polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), and polystyrene (PS). Six PAEs, including phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DIBP), ortho dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), and bis(2-ethyl) hexyl phthalate (DEHP), were detected in the MWTP. The concentrations of total PAEs (ΣPAEs) in the influent and effluent were 76.66 and 6.28 µg/L, respectively. The concentrations of ΣPAEs in the sludge before and after digestion were 152.64 and 31.70 µg/g, respectively. In the process of thermal hydrolysis, the number and size of MPs decreased accompanied by the increase of the plasticizer concentration.

● Wastewater treatment targets and processes change with demands.

The “dual-carbon” strategy promotes the development of the wastewater treatment sector and is an important tool for leading science and technology innovations. Based on the global climate change and the new policies introduced by China, this paper described the new needs for the development of wastewater treatment science and technology. It offered a retrospective analysis of the historical trajectory of scientific and technological advancements in this field. Utilizing bibliometrics, it delineated the research hotspots within wastewater treatment, notably highlighting materials genomics, artificial intelligence, and synthetic biology. Furthermore, it posited that, in the future, the field of wastewater treatment should follow the paths of technological innovations with multi-dimensional needs, such as carbon reduction, pollution reduction, health, standardisation, and intellectualisation. The purpose of this paper was to provide references and suggestions for scientific and technological innovations in the field of wastewater treatment, and to contribute to the common endeavor of moving toward a Pollution-Free Planet.

•The history of biological and artificial water channels is reviewed.

Bioinspired and biomimetic membranes that contain biological transport channels or attain their structural designs from biological systems have been through a remarkable development over the last two decades. They take advantage of the exceptional transport properties of those channels, thus possess both high permeability and selectivity, and have emerged as a promising solution to existing membranes. Since the discovery of biological water channel proteins aquaporins (AQPs), extensive efforts have been made to utilize them to make separation membranes–AQP-based membranes, which have been commercialized. The exploration of AQPs’ unique structures and transport properties has resulted in the evolution of biomimetic separation materials from protein-based to artificial channel-based membranes. However, large-scale, defect-free biomimetic membranes are not available yet. This paper reviews the state-of-the-art biomimetic membranes and summarizes the latest research progress, platform, and methodology. Then it critically discusses the potential routes of this emerging area toward scalable applications. We conclude that an appropriate combination of bioinspired concepts and molecular engineering with mature polymer industry may lead to scalable polymeric membranes with intrinsic selective channels, which will gain the merit of both desired selectivity and scalability.

• Dual-reaction-center (DRC) system breaks through bottleneck of Fenton reaction.

Triggered by global water quality safety issues, the research on wastewater treatment and water purification technology has been greatly developed in recent years. The Fenton technology is particularly powerful due to the rapid attack on pollutants by the generated hydroxyl radicals (•OH). However, both heterogeneous and homogeneous Fenton/Fenton-like technologies follow the classical reaction mechanism, which depends on the oxidation and reduction of the transition metal ions at single sites. So even after a century of development, this reaction still suffers from its inherent bottlenecks in practical application. In recent years, our group has been focusing on studying a novel heterogeneous Fenton catalytic process, and we developed the dual-reaction-center (DRC) system for the first time. In the DRC system, H₂O₂ and O₂ can be efficiently reduced to reactive oxygen species (ROS) in electron-rich centers, while pollutants are captured and oxidized by the electron-deficient centers. The obtained electrons from pollutants are diverted to the electron-rich centers through bonding bridges. This process breaks through the classic Fenton mechanism, and improves the performance and efficiency of pollutant removal in a wide pH range. Here, we provide a brief overview of Fenton’s story and focus on combing the discovery and development of the DRC technology and mechanism in recent years. The construction of the DRC and its performance in the pollutant degradation and interfacial reaction process are described in detail. We look forward to bringing a new perspective to continue Fenton’s story through research and development of DRC technology.

• Long amplicon is more effective to test DNA damage induced by UV.

The efficacy of ultraviolet (UV) disinfection has been validated in numerous studies by using culture-based methods. However, the discovery of viable but non-culturable bacteria has necessitated the investigation of UV disinfection based on bacterial viability parameters. We used quantitative polymerase chain reaction (qPCR) to investigate DNA damage and evaluated adenosine triphosphate (ATP) to indicate bacterial viability. The results of qPCR effectively showed the DNA damage induced by UV when using longer gene amplicons, in that sufficiently long amplicons of both 16S and gadA indicated that the UV induced DNA damages. The copy concentrations of the long amplicons of 16S and gadA decreased by 2.38 log/mL and 1.88 log/mL, respectively, after exposure to 40 mJ/cm² low-pressure UV. After UV exposure, the ATP level in the bacteria did not decrease instantly. Instead it decreased gradually at a rate that was positively related to the UV fluence. For low-pressure UV, this rate of decrease was slow, but for medium pressure UV, this rate of decrease was relatively high when the UV fluence reached 40 mJ/cm². At the same UV fluence, the ATP level in the bacteria decreased at a faster rate after exposure to medium-pressure UV.

• Simultaneous C & N removal in Methammox occurs at wide C:N ratio.

High C:N ratio in the wastewater limits biological nitrogen removal (BNR), especially in anammox based technologies. The present study attempts to improve the COD tolerance of the BNR process by associating methanogens with nitrogen removing bacterial (NRB) populations. The new microbial system coined as ‘Methammox’, was investigated for simultaneous removal of COD (C) and ammonia (N) at C:N ratio 1.5:1 to 14:1. The ammonia removal rate (11.5 mg N/g VSS/d) and the COD removal rates (70.6 mg O/g VSS/d) of Methammox was close to that of the NRB (11.1 mg N/g VSS/d) and the methanogenic populations (77.9 mg O/g VSS/d), respectively. The activities established that these two populations existed simultaneously and independently in ‘Methammox’. Further studies in biofilm reactor fetched a balanced COD and ammonia removal (55%–60%) at a low C:N ratio (≤2:1) and high C:N ratio (≥9:1). The population abundance of methanogens was reasonably constant, but the nitrogen removal shifted from mixotrophy to heterotrophy as the C:N ratio shifted from low (C:N≤2:1) to high (C:N≥9:1). The reduced autotrophic NRB (ammonia- and nitrite-oxidizing bacteria and Anammox) population at a high C:N ratio was compensated by the fermentative group that could carry out denitrification heterotrophically. The functional plasticity of the Methammox system to adjust to a broad C:N ratio opens new frontiers in biological nitrogen removal of high COD containing wastewaters.

• Hg bioaccumulation by phytoplankton varies among aquatic ecosystems.

The bioaccumulation of mercury (Hg) in aquatic ecosystem poses a potential health risk to human being and aquatic organism. Bioaccumulations by plankton represent a crucial process of Hg transfer from water to aquatic food chain. However, the current understanding of major factors affecting Hg accumulation by plankton is inadequate. In this study, a data set of 89 aquatic ecosystems worldwide, including inland water, nearshore water and open sea, was established. Key factors influencing plankton Hg bioaccumulation (i.e., plankton species, cell sizes and biomasses) were discussed. The results indicated that total Hg (THg) and methylmercury (MeHg) concentrations in plankton in inland waters were significantly higher than those in nearshore waters and open seas. Bioaccumulation factors for the logarithm of THg and MeHg of phytoplankton were 2.4–6.0 and 2.6–6.7 L/kg, respectively, in all aquatic ecosystems. They could be further biomagnified by a factor of 2.1–15.1 and 5.3–28.2 from phytoplankton to zooplankton. Higher MeHg concentrations were observed with the increases of cell size for both phyto- and zooplankton. A contrasting trend was observed between the plankton biomasses and BAF_MeHg, with a positive relationship for zooplankton and a negative relationship for phytoplankton. Plankton physiologic traits impose constraints on the rates of nutrients and contaminants obtaining process from water. Nowadays, many aquatic ecosystems are facing rapid shifts in nutrient compositions. We suggested that these potential influences on the growth and composition of plankton should be incorporated in future aquatic Hg modeling and ecological risk assessments.

• CWF is a sustainable POU water treatment method for developing areas.

Drinking water source contamination poses a great threat to human health in developing countries. Point-of-use (POU) water treatment techniques, which improve drinking water quality at the household level, offer an affordable and convenient way to obtain safe drinking water and thus can reduce the outbreaks of waterborne diseases. Ceramic water filters (CWFs), fabricated from locally sourced materials and manufactured by local labor, are one of the most socially acceptable POU water treatment technologies because of their effectiveness, low-cost and ease of use. This review concisely summarizes the critical factors that influence the performance of CWFs, including (1) CWF manufacturing process (raw material selection, firing process, silver impregnation), and (2) source water quality. Then, an in-depth discussion is presented with emphasis on key research efforts to address two major challenges of conventional CWFs, including (1) simultaneous increase of filter flow rate and bacterial removal efficiency, and (2) removal of various concerning pollutants, such as viruses and metal(loid)s. To promote the application of CWFs, future research directions can focus on: (1) investigation of pore size distribution and pore structure to achieve higher flow rates and effective pathogen removal by elucidating pathogen transport in porous ceramic and adjusting manufacture parameters; and (2) exploration of new surface modification approaches with enhanced interaction between a variety of contaminants and ceramic surfaces.

�?Recent advances in promising CCUS technologies are assessed.

Carbon capture, utilization and storage (CCUS) technologies play an essential role in achieving Net Zero Emissions targets. Considering the lack of timely reviews on the recent advancements in promising CCUS technologies, it is crucial to provide a prompt review of the CCUS advances to understand the current research gaps pertained to its industrial application. To that end, this review first summarized the developmental history of CCUS technologies and the current large-scale demonstrations. Then, based on a visually bibliometric analysis, the carbon capture remains a hotspot in the CCUS development. Noting that the materials applied in the carbon capture process determines its performance. As a result, the state-of-the-art carbon capture materials and emerging capture technologies were comprehensively summarized and discussed. Gaps between state-of-art carbon capture process and its ideal counterpart are analyzed, and insights into the research needs such as material design, process optimization, environmental impact, and technical and economic assessments are provided.

• Published data was used to analyze the fate of ARGs in water treatment.

The bacterial antibiotic resistome (BAR) is one of the most serious contemporary medical challenges. The BAR problem in drinking water is receiving growing attention. In this study, we focused on the distribution, changes, and health risks of the BAR throughout the drinking water treatment system. We extracted the antibiotic resistance gene (ARG) data from recent publications and analyzed ARG profiles based on diversity, absolute abundance, and relative abundance. The absolute abundance of ARG was found to decrease with water treatment processes and was positively correlated with the abundance of 16S rRNA (r² = 0.963, p<0.001), indicating that the reduction of ARG concentration was accompanied by decreasing biomass. Among treatment processes, biofiltration and chlorination were discovered to play important roles in shaping the bacterial antibiotic resistome. Chlorination exhibited positive effects in controlling the diversity of ARG, while biofiltration, especially granular activated carbon filtration, increased the diversity of ARG. Both biofiltration and chlorination altered the structure of the resistome by affecting relative ARG abundance. In addition, we analyzed the mechanism behind the impact of biofiltration and chlorination on the bacterial antibiotic resistome. By intercepting influent ARG-carrying bacteria, biofilters can enrich various ARGs and maintain ARGs in biofilm. Chlorination further selects bacteria co-resistant to chlorine and antibiotics. Finally, we proposed the BAR health risks caused by biofiltration and chlorination in water treatment. To reduce potential BAR risk in drinking water, membrane filtration technology and water boiling are recommended at the point of use.

• Principles and methods for fluorescence EEM are systematically outlined.

The membrane bioreactor (MBR) technology is a rising star for wastewater treatment. The pollutant elimination and membrane fouling performances of MBRs are essentially related to the dissolved organic matter (DOM) in the system. Three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectroscopy, a powerful tool for the rapid and sensitive characterization of DOM, has been extensively applied in MBR studies; however, only a limited portion of the EEM fingerprinting information was utilized. This paper revisits the principles and methods of fluorescence EEM, and reviews the recent progress in applying EEM to characterize DOM in MBR studies. We systematically introduced the information extracted from EEM by considering the fluorescence peak location/intensity, wavelength regional distribution, and spectral deconvolution (giving fluorescent component loadings/scores), and discussed how to use the information to interpret the chemical compositions, physiochemical properties, biological activities, membrane retention/fouling behaviors, and migration/transformation fates of DOM in MBR systems. In addition to conventional EEM indicators, novel fluorescent parameters are summarized for potential use, including quantum yield, Stokes shift, excited energy state, and fluorescence lifetime. The current limitations of EEM-based DOM characterization are also discussed, with possible measures proposed to improve applications in MBR monitoring.

• Antibiotic azithromycin employed in graphite electrode for EAB biosensor.

Extensive research has been carried out for improved sensitivity of electroactive biofilm-based sensor (EAB-sensor), which is recognized as a useful tool in water quality early-warning. Antibiotic that is employed widely to treat infection has been proved feasible in this study to regulate the EAB and to increase the EAB-biosensor’s sensitivity. A novel composite electrode was prepared using azithromycin (AZM) and graphite powder (GP), namely AZM@GP electrode, and was employed as the anode in EAB-biosensor. Different dosages of AZM, i.e., 2 mg, 4 mg, and 8 mg, referred to as 0.25%, 0.5% and 1% AZM@GP were under examination. Results showed that EAB-biosensor was greatly benefited from appropriate dosage of AZM (0.5% AZM@GP) with reduced start-up time period, comparatively higher voltage output, more readable electrical signal and increased inhibition rate (30%-65% higher than control sensor with GP electrode) when exposing to toxic formaldehyde. This may be attributed to the fact that AZM inhibited the growth of non-EAM without much influence on the physiologic or metabolism activities of EAM under proper dosage. Further investigation of the biofilm morphology and microbial community analysis suggested that the biofilm formation was optimized with reduced thickness and enriched Geobacter with 0.5% AZM@GP dosage. This novel electrode is easily fabricated and equipped, and therefore would be a promising way to facilitate the practical application of EAB-sensors.

• Byproduct formation mechanisms during electrochemical oxidation water treatment.

Electrochemical oxidation (EO) is a promising technique for decentralized wastewater treatment, owing to its modular design, high efficiency, and ease of automation and transportation. The catalytic destruction of recalcitrant, non-biodegradable pollutants (per- and poly-fluoroalkyl substances (PFAS), pharmaceuticals, and personal care products (PPCPs), pesticides, etc.) is an appropriate niche for EO. EO can be more effective than homogeneous advanced oxidation processes for the degradation of recalcitrant chemicals inert to radical-mediated oxidation, because the potential of the anode can be made much higher than that of hydroxyl radicals (E_OH = 2.7 V vs. NHE), forcing the direct transfer of electrons from pollutants to electrodes. Unfortunately, at such high anodic potential, chloride ions, which are ubiquitous in natural water systems, will be readily oxidized to chlorine and perchlorate. Perchlorate is a to-be-regulated byproduct, and chlorine can react with matrix organics to produce organic halogen compounds. In the past ten years, novel electrode materials and processes have been developed. However, spotlights were rarely focused on the control of byproduct formation during EO processes in a real-world context. When we use EO techniques to eliminate target contaminants with concentrations at μg/L-levels, byproducts at mg/L-levels might be produced. Is it a good trade-off? Is it possible to inhibit byproduct formation without compromising the performance of EO? In this mini-review, we will summarize the recent advances and provide perspectives to address the above questions.

• Quorum sensing enhancement and inhibition methods are summarized.

Quorum sensing (QS) plays an important role in microbial aggregation control. Recently, the optimization of biological waste treatment systems by QS regulation gained an increasing attention. The effects of QS regulation on treatment performances and biofilm were frequently investigated. To understand the state of art of QS regulation, this review summarizes the methods of QS enhancement and QS inhibition in biological waste treatment systems. Typical QS enhancement methods include adding exogenous QS molecules, adding QS accelerants and cultivating QS bacteria, while typical QS inhibition methods include additions of quorum quenching (QQ) bacteria, QS-degrading enzymes, QS-degrading oxidants, and QS inhibitors. The specific improvements after applying these QS regulation methods in different treatment systems are concluded. In addition, the effects of QS regulation methods on biofilm in biological waste treatment systems are reviewed in terms of biofilm formation, extracellular polymeric substances production, microbial viability, and microbial community. In the end, the knowledge gaps in current researches are analyzed, and the requirements for future study are suggested.

● Methanol effectively reduces CO, HC, CO₂, PM, and PN emissions of gasoline vehicles.

The transport sector is a significant energy consumer and a major contributor to urban air pollution. At present, the substitution of cleaner fuel is one feasible way to deal with the growing energy demand and environmental pollution. Methanol has been recognized as a good alternative to gasoline due to its good combustion performance. In the past decades, many studies have investigated exhaust emissions using methanol-gasoline blends. However, the conclusions derived from different studies vary significantly, and the explanations for the effects of methanol blending on exhaust emissions are also inconsistent. This review summarizes the characteristics of CO, HC, NO_x, CO₂, and particulate emissions from methanol-gasoline blended fuels and pure methanol fuel. CO, HC, CO₂, particle mass (PM), and particle number (PN) emissions decrease when methanol-blended fuel is used in place of gasoline fuel. NO_x emission either decreases or increases depending on the test conditions, i.e., methanol content. Furthermore, this review synthesizes the mechanisms by which methanol-blended fuel influences pollutant emissions. This review provides insight into the pollutant emissions from methanol-blended fuel, which will aid policymakers in making energy strategy decisions that take urban air pollution, climate change, and energy security into account.

Less than 50 mg/L nitrobenzene brought little effect on anaerobic sulfate reduction.

Nitrobenzene (NB) is frequently found in wastewaters containing sulfate and may affect biological sulfate reduction process, but information is limited on the responses of sulfate reduction efficiency and microbial community to the increased NB contents. In this study, a laboratory-scale expanded granular sludge bed reactor was operated continuously to treat high-sulfate organic wastewater with increased NB contents. Results successfully demonstrated that the presence of more than 50 mg/L NB depressed sulfate reduction and such inhibition was partly reversible. Bath experiments showed that the maximum specific desulfuration activity (SDA) decreased from 135.80 mg SO₄^2?/gVSS/d to 30.78 mg SO₄^2?/gVSS/d when the NB contents increased from none to 400 mg/L. High-throughput sequencing showed that NB also greatly affected bacterial community structure. Bacteroidetes dominated in the bioreactor. The abundance of Proteobacteria increased with NB addition while Firmicutes presented an opposite trend. Proteobacteria gradually replaced Firmicutes for the dominance in response to the increase of influent NB concentrations. The genus Desulfovibrio was the dominant sulfate-reducing bacteria (SRB) with absence or presence of NB, but was inhibited under high content of NB. The results provided better understanding for the biological sulfate reduction under NB stress.

• Mechanisms of redox reactions of Fe- and Mn-oxides were discussed.

Conspectus Redox reactions of Fe- and Mn-oxides play important roles in the fate and transformation of many contaminants in natural environments. Due to experimental and analytical challenges associated with complex environments, there has been a limited understanding of the reaction kinetics and mechanisms in actual environmental systems, and most of the studies so far have only focused on simple model systems. To bridge the gap between simple model systems and complex environmental systems, it is necessary to increase the complexity of model systems and examine both the involved interaction mechanisms and how the interactions affected contaminant transformation. In this Account, we primarily focused on (1) the oxidative reactivity of Mn- and Fe-oxides and (2) the reductive reactivity of Fe(II)/iron oxides in complex model systems toward contaminant degradation. The effects of common metal ions such as Mn²⁺ , Ca²⁺, Ni²⁺, Cr³⁺ and Cu²⁺, ligands such as small anionic ligands and natural organic matter (NOM), and second metal oxides such as Al, Si and Ti oxides on the redox reactivity of the systems are briefly summarized.

● We find air pollution distracts attention and reveal the neurocognitive mechanisms.

Awareness of the adverse impact of air pollution on attention-related performance such as learning and driving is rapidly growing. However, there is still little known about the underlying neurocognitive mechanisms. Using an adapted dot-probe task paradigm and event-related potential (ERP) technique, we investigated how visual stimuli of air pollution influence the attentional allocation process. Participants were required to make responses to the onset of a target presented at the left or right visual field. The probable location of the target was forewarned by a cue (pollution or clean air images), appearing at either the target location (attention-holding trials) or the opposite location (attention-shifting trials). Behavioral measures showed that when cued by pollution images, subjects had higher response accuracy in attention-shifting trials. ERP analysis results revealed that after the cue onset, pollution images evoked lower N300 amplitudes, indicating less attention-capturing effects of dirty air. After the target onset, pollution cues were correlated with the higher P300 amplitudes in attention-holding trials but lower amplitudes in attention-shifting trials. It indicates that after visual exposure to air pollution, people need more neurocognitive resources to maintain attention but less effort to shift attention away. The findings provide the first neuroscientific evidence for the distracting effect of air pollution. We conclude with several practical implications and suggest the ERP technique as a promising tool to understand human responses to environmental stressors.

● A novel hybrid fuel cell (F-HFC) was fabricated.

The development of highly efficient energy conversion technologies to extract energy from wastewater is urgently needed, especially in facing of increasing energy and environment burdens. Here, we successfully fabricated a novel hybrid fuel cell with BiOCl-NH₄PTA as photocatalyst. The polyoxometalate (NH₄PTA) act as the acceptor of photoelectrons and could retard the recombination of photogenerated electrons and holes, which lead to superior photocatalytic degradation. By utilizing BiOCl-NH₄PTA as photocatalysts and Pt/C air-cathode, we successfully constructed an electron and mass transfer enhanced photocatalytic hybrid fuel cell with flow-through field (F-HFC). In this novel fuel cell, dyes and biomass could be directly degraded and stable power output could be obtained. About 87 % of dyes could be degraded in 30 min irradiation and nearly 100 % removed within 90 min. The current density could reach up to ~267.1 μA/cm²; with maximum power density (P_max) of ~16.2 μW/cm² with Rhodamine B as organic pollutant in F-HFC. The power densities were 9.0 μW/cm², 12.2 μW/cm², and 13.9 μW/cm² when using methyl orange (MO), glucose and starch as substrates, respectively. This hybrid fuel cell with BiOCl-NH₄PTA composite fulfills the purpose of decontamination of aqueous organic pollutants and synchronous electricity generation. Moreover, the novel design cell with separated photodegradation unit and the electricity generation unit could bring potential practical application in water purification and energy recovery from wastewater.

● The historical development of free nitrous acid (FNA) technologies is reviewed.

The biocidal effects of free nitrous acid (FNA) have found applications in multiple units in an urban wastewater system, including sewer networks, wastewater treatment processes, and sludge treatment processes. However, these applications are associated with chemical costs as both nitrite and acid are needed to produce FNA at the required levels. The recent discovery of novel acid-tolerant ammonia oxidizers offers the possibility to produce FNA from domestic wastewater, enabling the development of next-generation FNA-based technologies capable of achieving self-sustaining FNA production. In this study, we focus on the concept of in situ FNA generation facilitated by acid-tolerant ammonia oxidizers and highlight the multiple benefits it creates, after a brief review of the historical development of FNA-based technologies. We will discuss how wastewater systems can be made more energy-efficient and sustainable by leveraging the potential of acid-tolerant ammonia oxidizers.

● The airborne bacteria in landfills were 4–50 times higher than fungi.

Landfills are widely complained about due to the long-term odor and landfill gas emissions for local residents, while the bioaerosols are always neglected as another threat to on-site workers. In this study, bioaerosols samples were collected from the typical operation scenes in the large-scale modern landfill, and the emission levels of airborne bacteria, pathogenic species, and fungi were quantified and co-related. The corresponding exposure risks were assessed based on the average daily dose via inhalation and skin contact. It was found that the levels of culturable bacteria and fungi in all landfill samples were around 33–22778 CFU/m³ and 8–450 CFU/m³, and the active-working landfill area and the covered area were the maximum and minimum emission sources, respectively, meaning that the bioaerosols were mainly released from the areas related with the fresh waste operation. Acinetobacter sp., Massilia sp., Methylobacterium-Methylorubrum sp. and Noviherbaspirillum sp. were the main bacterial populations, with a percentage of 42.56%, 89.82%, 70.24% and 30.20% respectively in total bioaerosols measured. With regards to the health risk, the health risks via inhalation were the main potential risks, with four orders of magnitude higher than that of skin contact. Active-working area showed the critical point for non-carcinogenic risks, with a hazard quotient of 1.68, where 80 m protection distance is recommended for on-site worker protection, plus more careful protection measures.

• Explaintheadsorption, uptake and transmembrane transport of PAHs by bacteria.

In recent years, increasing research has been conducted on transmembrane transport processes and the mechanisms behind the microbial breakdown of polycyclic aromatic hydrocarbons (PAHs), including the role of membrane proteins in transmembrane transport and the mode of transmission. This article explains the adsorption, uptake and transmembrane transport of PAHs by bacteria, the regulation of membrane protein function during the transmembrane transport. There are three different regulation mechanisms for uptake, depending on the state and size of the oil droplets relative to the size of the microbial cells, which are (i) direct adhesion, (ii) emulsification and pseudosolubilization, and (iii) interfacial uptake. Furthermore, two main transmembrane transport modes are introduced, which are (i) active transport and (ii) passive uptake and active efflux mechanism. Meanwhile, introduce the proteomics and single cell analysis technology used to address these areas of research, such as Isobaric tags for relative and absolute quantitation (iTRAQ) technology and Nano Secondary ion mass spectrometry (Nano-SIMS). Additionally, analyze the changes in morphology and structure and the characteristics of microbial cell membranes in the process of transmembrane transport. Finally, recognize the microscopic mechanism of PAHs biodegradation in terms of cell and membrane proteins are of great theoretical and practical significance for understanding the factors that influence the efficient degradation of PAHs contaminants in soil and for remediating the PAHs contamination in this area with biotechnology.

Considering the significant roles of the policies in developing environmental finance, an overview is conducted on the environmental finance policies (EFPs) in China. This paper analyzed the definition, scope, evolution and main instruments of EFPs. The implementation progress of financial activities on each instrument are investigated respectively. Then the experiences learned from and failures discovered in the development of the EFPs are discussed well recommendations for further improvement of the EFPs and their implementation are provided. Our study found that the EFPs have been established in China after a four-phase evolution since the early 1980s. The policies have played a critical role in leading to a rapid development in environmental finance by involving more financial instruments to accomplish the objective-led environmental plans. Driven by the policies, the new green credit (GC), green security (GS), and green insurance (GI) instruments have been phased in as supplements to the conventional command and control approaches to improve the environmental governance of financial activities and pollution sources. However, the market mechanism of financial institution is limited due to their defensive and incapable performance on implementation some of EFP instruments. To further strengthen the effectiveness of EFPs in facilitating environmental management, recommendations are made mainly on the aspects including developing more specific policy guidelines, enhancing information sharing and disclosure, providing sufficient economic incentives, establishing environmental liabilities with financial activities, and involving issues related to climate change, and biodiversity and ecosystem service.

• Sub-inhibitory levels of nC₆₀ promote conjugative transfer of ARGs.

The spread and development of antibiotic resistance globally have led to severe public health problems. It has been shown that some non-antibiotic substances can also promote the diffusion and spread of antibiotic resistance genes (ARGs). Nanofullerene (nC₆₀) is a type of nanomaterial widely used around the world, and some studies have discovered both the biological toxicity and environmental toxicity of nC₆₀. In this study, cellular and molecular biology techniques were employed to investigate the influences of nC₆₀ at sub-minimum inhibitory concentrations (sub-MICs) on the conjugation of ARGs between the E. coli strains. Compared with the control group, nC₆₀ significantly increased the conjugation rates of ARGs by 1.32‒10.82 folds within the concentration range of 7.03‒1800 mg/L. This study further explored the mechanism of this phenomenon, finding that sub-MICs of nC₆₀ could induce the production of reactive oxygen species (ROS), trigger SOS-response and oxidative stress, affect the expression of outer membrane proteins (OMPs) genes, increase membrane permeability, and thus promote the occurrence of conjugation. This research enriches our understanding of the environmental toxicity of nC₆₀, raises our risk awareness toward nC₆₀, and may promote the more rational employment of nC₆₀ materials.

● nZVI, S-nZVI, and nFeS were systematically compared for Cd(II) removal.

Cadmium (Cd) is a common toxic heavy metal in the environment. Taking Cd(II) as a target contaminant, we systematically compared the performances of three Fe-based nanomaterials (nano zero valent iron, nZVI; sulfidated nZVI, S-nZVI; and nano FeS, nFeS) for Cd immobilization under anaerobic conditions. Effects of nanomaterials doses, initial pH, co-existing ions, and humic acid (HA) were examined. Under identical conditions, at varied doses or initial pH, Cd(II) removal by three materials followed the order of S-nZVI > nFeS > nZVI. At pH 6, the Cd(II) removal within 24 hours for S-nZVI, nFeS, and nZVI (dose of 20 mg/L) were 93.50%, 89.12% and 4.10%, respectively. The fast initial reaction rate of nZVI did not lead to a high removal capacity. The Cd removal was slightly impacted or even improved with co-existing ions (at 50 mg/L or 200 mg/L) or HA (at 2 mg/L or 20 mg/L). Characterization results revealed that nZVI immobilized Cd through coprecipitation, surface complexation, and reduction, whereas the mechanisms for sulfidated materials involved replacement, coprecipitation, and surface complexation, with replacement as the predominant reaction. A strong linear correlation between Cd(II) removal and Fe(II) dissolution was observed, and we proposed a novel pseudo-second-order kinetic model to simulate Fe(II) dissolution.

Various anaerobic processes have been explored for the energy-efficient treatment of municipal wastewater. However, dissolved methane in anaerobic effluent appears to be a barrier towards the energy and carbon neutrality of wastewater treatment. Although several dissolved methane recovery methods have been developed, their engineering feasibility and economic viability have not yet been assessed in a holistic manner. In this perspective, we thus intend to offer additional insights into the cost-benefit of dissolved methane recovery against its emission.

• Framework of indicators was established based on energy efficiency and recovery.

Wastewater treatment plants (WWTPs) consume large amounts of energy and emit greenhouse gases to remove pollutants. This study proposes a framework for evaluating the energy neutrality potential (ENP) of WWTPs from an integrated perspective. Operational data of 970 WWTPs in the Yangtze River Economic Belt (YREB) were extracted from the China Urban Drainage Yearbook 2018. The potential chemical and thermal energies were estimated using combined heat and power (CHP) and water source heat pump, respectively. Two key performance indicators (KPIs) were then established: the energy self-sufficiency (ESS) indicator, which reflects the offset degree of energy recovery, and the comprehensive water–energy efficiency (CWEE) indicator, which characterizes the efficiency of water–energy conversion. For the qualitative results, 98 WWTPs became the benchmark (i.e., CWEE= 1.000), while 112 WWTPs were fully self-sufficient (i.e., ESS≥100%). Subsequently, four types of ENP were classified by setting the median values of the two KPIs as the critical value. The WWTPs with high ENP had high net thermal energy values and relatively loose discharge limits. The explanatory factor analysis of water quantity and quality verified the existence of scale economies. Sufficient carbon source and biodegradability condition were also significant factors. As the CWEE indicator was mostly sensitive to the input of CHP, future optimization shall focus on the moisture and organic content of sludge. This study proposes a novel framework for evaluating the ENP of WWTPs. The results can provide guidance for optimizing the energy efficiency and recovery of WWTPs.

● Magnetic Co- γ -Fe₂O₃/MoS₂ were prepared via facile hydrothermal methods.

Iron-based catalysts have been widely used to treat refractory organic pollutants in wastewater. In this paper, magnetic Co-γ-Fe₂O₃ was synthesized by a facile tartaric acid-assisted hydrothermal method, and Co-γ-Fe₂O₃/MoS₂ nanocomposite catalyst was obtained via in situ growth of MoS₂ nanosheets on Co-γ-Fe₂O₃ nanoparticles. The nanocomposite catalysts were used to decompose bisphenol A (BPA) by activating peroxymonosulfate (PMS). It was shown that only 0.15 g/L catalyst and 0.5 mmol/L PMS degraded 10 mg/L of BPA (99.3% within 10 min) in the pH range of 3–9. PMS was activated due to redox cycling among the pairs Co(III)/Co(II), Fe(III)/Fe(II), and Mo(VI)/Mo(IV). Quenching experiments and electron paramagnetic resonance spectroscopy demonstrated that both radical and non-radical pathways were involved in BPA degradation, in which active radical sulfate radical and non-radical singlet oxygen were the main reactive oxygen species. Ten intermediates were identified by liquid chromatography-coupled mass spectrometry, and three possible BPA degradation pathways were proposed. The toxicity of several degradation intermediates was lower, and Co-γ-Fe₂O₃/MoS₂ exhibited excellent reusability and could be magnetically recovered.

•Addition of hindered amine increased thermal stability and viscosity of TTTM.

Is it possible to improve CO₂ solubility in potassium carbonate (K₂CO₃)-based transition temperature mixtures (TTMs)? To assess this possibility, a ternary transition-temperature mixture (TTTM) was prepared by using a hindered amine, 2-amino-2-methyl-1,3-propanediol (AMPD). Fourier transform infrared spectroscopy (FT-IR) was employed to detect the functional groups including hydroxyl, amine, carbonate ion, and aliphatic functional groups in the prepared solvents. From thermogravimetric analysis (TGA), it was found that the addition of AMPD to the binary mixture can increase the thermal stability of TTTM. The viscosity findings showed that TTTM has a higher viscosity than TTM while their difference was decreased by increasing temperature. In addition, Eyring’s absolute rate theory was used to compute the activation parameters (ΔG*, ΔH*, and ΔS*). The CO₂ solubility in liquids was measured at a temperature of 303.15 K and pressures up to 1.8 MPa. The results disclosed that the CO₂ solubility of TTTM was improved by the addition of AMPD. At the pressure of about 1.8 MPa, the CO₂ mole fractions of TTM and TTTM were 0.1697 and 0.2022, respectively. To confirm the experimental data, density functional theory (DFT) was employed. From the DFT analysis, it was found that the TTTM+ CO₂ system has higher interaction energy (|ΔE |) than the TTM+ CO₂ system indicating the higher CO₂ affinity of the former system. This study might help scientists to better understand and to improve CO₂ solubility in these types of solvents by choosing a suitable amine as HBD and finding the best combination of HBA and HBD.

• 5R (Recover, Reduce, Recycle, Resource and Reuse) approaches to manage urban water.

Demand for water is expanding with increases in population, particularly in urban areas in developing countries. Additionally, urban water system needs a novel perspective for upgradation with urbanization. This perspective presents a novel 5R approach for managing urban water resources: Recover (storm water), Reduce (toilet flushing water), Recycle (gray water), Resource (black water), and Reuse (advanced-treated wastewater). The 5R generation incorporates the latest ideas for harvesting storm water, gray water, and black water in its several forms. This paper has briefly demonstrated each R of 5R generation for water treatment and reuse. China has the chance to upgrade its urban water systems according to 5R principles. Already, a demonstration project of 5R generation has been installed in Qingdao International Horticultural Exposition, and Dalian International Convention Center (China) has applied 5R, achieving over 70% water saving. The 5R offers promise for moving solutions for urban water scarcity from “hoped for in the future” to “realistic today”.

● Reducing environmental impacts through socioeconomic structural transitions.

Rapid socioeconomic development has caused numerous environmental impacts. Human production and consumption activities are the underlying drivers of resource uses, environmental emissions, and associated environmental impacts (e.g., ecosystem quality and human health). Reducing environmental impacts requires an understanding of the complex interactions between socioeconomic system and environmental system. Existing studies have explored the relationships among human society, economic system, and environmental system. However, it is unclear about the research progress in the effects of socioeconomic activities on environmental impacts and the potential directions of future research. This critical review finds that existing studies have identified critical regions, sectors, and transmission pathways for resource uses, environmental emissions, and environmental impacts from supply chain perspectives. Moreover, scholars have characterized the impacts of socioeconomic transitions on resource uses and environmental emissions. However, existing studies overlook the dynamic nature of the interconnections among human society, economic system, and environmental system. In addition, the effects of socioeconomic structural transitions on environmental impacts remain unknown. This review proposes four prospects and possible solutions that will contribute to a better understanding of the complex interactions among human society, economic system, and environmental system. They can help identify more effective solutions to reduce environmental impacts through socioeconomic transitions.

• Municipal solid waste (MSW) was fermented, screened, gasified, then co-processed.

Cement kiln co-processing techniques have been developed in the past 20 years in China, and more than 60 factories now use fermentation, screening, and gasification pre-treatment techniques to co-process municipal solid waste (MSW). There three complete MSW pre-treatment techniques, co-processing procedures, and environmental risk assessments have been described in few publications. In this study, we assessed the effectiveness of each technique. The results suggested that the pollutant content released by each pre-treatment technology was lower than the emission standard. To reveal the mechanisms of pollutant migration and enrichment, the substances in the kiln and kiln products are investigated. The input of co-processing materials (Co-M) produced by fermentation caused formation of polychlorinated dibenzo-p-dioxins and dibenzofuran (PCDD/Fs) in the bypass flue gas (By-gas) in excess of the regulatory standard. The Co-M input produced by the screening and gasifier technologies caused the total organic carbon (TOC) concentration to exceed the standard. In addition, the NO_x, TOC, and PCDD/Fs in the By-gas exceeded the regulatory standard. Raw meal was the primary chlorine and heavy metals input stream, and clinker (CK) and cement kiln dust (CKD) accounted for>90% of the total chlorine output stream. Flue gas and CKD were the primary volatile heavy metal (Hg) output streams. Greater than 70% of the semi-volatile heavy metals (Cd, Pb, Tl and Se) distributed in hot raw meal and bypass cement kiln dust. The low-volatility heavy metals were concentrated in the CK. These results indicated that co-processing techniques used in China still require improvement.

● A spindle-shaped influent chamber was designed and equipped in FCDI system.

Flow-electrode capacitive deionization (FCDI) is an innovative technology in which an intermediate chamber plays an important role in the desalination process. However, relatively few studies have been conducted on the structures of these intermediate chambers. In this study, we propose a novel flow-electrode capacitive deionization device with a spindle-shaped inlet chamber (S-FCDI). The desalination rate of the S-FCDI under optimal operating conditions was 36% higher than that of the FCDI device with a conventional rectangular chamber (R-FCDI). The spindle-shaped chamber transferred 1.2 μmol more ions than the rectangular chamber, based on energy per joule. Additionally, we performed a detailed analysis of different inlet chamber shapes using computational fluid dynamics software. We concluded that S-FCDI has a relatively low flow resistance and almost no stagnation zone. This provides unique insights into the development of intermediate chambers. This study may contribute to the improvement of the desalination performance in industrial applications of FCDI.

● Coupling merits of SEE and ERH were explored by a laboratory-scale device.

In situ thermal desorption (ISTD) technology effectively remediates soil contaminated by dense nonaqueous phase liquids (DNAPLs). However, more efforts are required to minimize the energy consumption of ISTD technology. This study developed a laboratory-scale experimental device to explore the coupling merits of two traditional desorption technologies: steam-enhanced extraction (SEE) and electrical resistance heating (ERH). The results showed that injecting high-density steam (> 1 g/min) into loam or clay with relatively high moisture content (> 13.3%) could fracture the soil matrix and lead to the occurrence of the preferential flow of steam. For ERH alone, the electrical resistance and soil moisture loss were critical factors influencing heating power. When ERH and SEE were combined, preheating soil by ERH could increase soil permeability, effectively alleviating the problem of preferential flow of SEE. Meanwhile, steam injection heated the soil and provided moisture for maintaining soil electrical conductivity, thereby ensuring power stability in the ERH process. Compared with ERH alone (8 V/cm) and SEE alone (1 g/min steam), the energy consumption of combined method in remediating perchloroethylene-contaminated soil was reduced by 39.3% and 52.9%, respectively. These findings indicate that the combined method is more favorable than ERH or SEE alone for remediating DNAPL-contaminated subsurfaces when considering ISTD technology.

• ARGs were detected in livestock manure, sludge, food waste and fermentation dregs.

Antibiotic resistance genes (ARGs) have been diffusely detected in several kinds of organic solid waste, such as livestock manure, sludge, antibiotic fermentation residues, and food waste, thus attracting great attention. Aerobic composting, which is an effective, harmless treatment method for organic solid waste to promote recycling, has been identified to also aid in ARG reduction. However, the effect of composting in removing ARGs from organic solid waste has recently become controversial. Thus, this article summarizes and reviews the research on ARGs in relation to composting in the past 5 years. ARGs in organic solid waste could spread in different environmental media, including soil and the atmosphere, which could widen environmental risks. However, the conventional composting technology had limited effect on ARGs removal from organic solid waste. Improved composting processes, such as hyperthermophilic temperature composting, could effectively remove ARGs, and the HGT of ARGs and the microbial communities are identified as vital influencing factors. Currently, during the composting process, ARGs were mainly affected by three response pathways, (I) “Microenvironment-ARGs”; (II) “Microenvironment-microorganisms-ARGs”; (III) “Microorganisms-horizontal gene transfer-ARGs”, respectively. Response pathway II had been studied the most which was believed that microbial community was an important factor affecting ARGs. In response pathway III, mainly believed that MGEs played an important role and paid less attention to eARGs. Further research on the role and impact of eARGs in ARGs may be considered in the future. It aims to provide support for further research on environmental risk control of ARGs in organic solid waste.

• A high-efficiency N-doped porous carbon adsorbent for Cr(VI) was synthesized.

To develop highly effective adsorbents for chromium removal, a nitrogen-doped biomass-derived carbon (NHPC) was synthesized via direct carbonation of loofah sponge followed by alkali activation and doping modification. NHPC possessed a hierarchical micro-/mesoporous lamellar structure with nitrogen-containing functional groups (1.33 at%), specific surface area (1792.47 m²/g), and pore volume (1.18 cm³/g). NHPC exhibited a higher Cr(VI) adsorption affinity than the HPC (without nitrogen doping) or the pristine loofah sponge carbon (LSC) did. The influence of process parameters, including pH, dosage, time, temperature, and Cr(VI) concentration, on Cr(VI) adsorption by NHPC were evaluated. The Cr(VI) adsorption kinetics matched with the pseudo-second-order model (R²≥0.9983). The Cr(VI) adsorption isotherm was fitted with the Langmuir isotherm model, which indicated the maximum Cr(VI) adsorption capacities: 227.27, 238.10, and 285.71 mg/g at 298K, 308K, and 318K, respectively. The model analysis also indicated that adsorption of Cr(VI) on NHPC was a spontaneous, endothermal, and entropy-increasing process. The Cr(VI) adsorption process potentially involved mixed reductive and adsorbed mechanism. Furthermore, computational chemistry calculations revealed that the adsorption energy between NHPC and Cr(VI) (−0.84 eV) was lower than that of HPC (−0.51 eV), suggesting that nitrogen doping could greatly enhance the interaction between NHPC and Cr(VI).

The history of China’s municipal wastewater management is revisited.

China has the world’s largest and still growing wastewater sector and water market, thus its future development will have profound influence on the world. The high-speed development of China’s wastewater sector over the past 40 years has forged its global leading treatment capacity and innovation ability. However, many problems were left behind, including underdeveloped sewers and sludge disposal facilities, low sustainability of the treatment processes, questionable wastewater treatment plant (WWTP) effluent discharge standards, and lacking global thinking on harmonious development between wastewater management, human society and the nature. Addressing these challenges calls for fundamental changes in target design, policy and technologies. In this mini-review, we revisit the development history of China’s municipal wastewater management and identify the remaining challenges. Also, we highlight the future needs of sustainable development and exploring China’s own wastewater management path, and outlook the future from several aspects including targets of wastewater management, policies and technologies, especially the new concept WWTP. Furthermore, we envisage the establishment of new-generation WWTPs with the vision of turning WWTP from a site of pollutant removal into a plant of energy, water and fertilizer recovery and an integrated part urban ecology in China.

● A novel nonpolar super-aligned carbon nanotube (SACNT) membrane was prepared.

Membrane separation technology has made great progress in various practical applications, but the unsatisfactory separation performance of prevailing membrane materials hampers its further sustainable growth. This study proposed a novel nonpolar super-aligned carbon nanotube (SACNT) membrane, which was prepared with a layer-by-layer cross-stacking method. Through controlling the number of stacked SACNT layers, three kinds of SACNT membranes (SACNT_200, SACNT_300, and SACNT_400) were prepared. Systematic characterizations and filtration tests were performed to investigate their physico-chemical properties, surface wetting behavior, and filtration performance. Compared with two commercial membranes (Com_0.22 and Com_0.45), all the SACNT membranes achieved smoother and more uniform structures. Due to the hexagonal graphene structure of CNTs, the surface chemistry of the SACNT membranes is simple and inert, thereby potentially eliminating the covalent-bonding-induced membrane fouling. Besides, the SACNT membranes exhibited a typical nonpolar wetting behavior, with high contact angles for polar liquids (water: ~124.9°–126.5°; formamide: ~80.0°–83.9°) but low contact angles for nonpolar diiodomethane (~18.8°–20.9°). This unique nonpolar feature potentially leads to weak interactions with polar substances. Furthermore, compared with the commercial membranes, the SACNT membranes obtained a significantly higher selectivity while achieving a comparable or higher permeability (depending on the number of stacked layers). Moreover, the SACNT membranes exhibited superior separation performance in various application scenarios, including municipal wastewater treatment (> 2.3 times higher cleaning efficiency), electro-assistant fouling inhibition (or even self-cleaning), and oil/water separation (> 99.2 % of separation efficiency), suggesting promising application prospects in various fields.

• K⁺ hinder the structural degradation of Cu/SAPO-34 under humid condition<100°C.

K ions were introduced onto Cu/SAPO-34 catalysts via the ion-exchange process in order to improve their stability under low-temperature hydrothermal aging. The changes in structure and copper-species contents of these catalysts upon hydrothermal aging were probed in order to investigate their effects on selective catalytic reduction (SCR) activity. For the fresh Cu/SAPO-34 catalysts, K ions had little influence on the chabazite framework but effected their acidities by exchanging with acid sites. After hydrothermal aging, the structural integrity and amount of active sites decreased on pure Cu/SAPO-34. While the K-loaded catalysts showed improved chabazite structure, acidity, and active site conservation with increasing K loading. However, although the 0.7 wt% K catalyst maintained the same crystallinity, active site abundance, and low-temperature SCR activity as the fresh catalyst upon aging, an apparent decrease in SCR activity at high temperature was observed because of the inevitable decrease in the number of Brönsted acid sites. To compensate for the activity disadvantage of K-loaded Cu/SAPO-34 at high temperature, Fe/Beta catalysts were co-employed with K-loaded Cu/SAPO-34, and a wide active temperature window of SCR activity was obtained. Thus, our study reveals that a combined system comprising Fe/Beta and K-loaded Cu/SAPO-34 catalysts shows promise for the elimination of NO_x in real-world applications.