Comparison of O3, UV/O3, and UV/O3/PS processes for marine oily wastewater treatment: Degradation performance, toxicity evaluation, and flocs analysis

Machine Learning-Assisted Molecular Structure Embedding for Accurate Prediction of Emerging Contaminant Removal by Ozonation Oxidation

Ozone has demonstrated high efficacy in depredating emerging contaminants (ECs) during drinking water treatment. However, traditional quantitative structure-activation relationship (QSAR) models often fall short in effectively normalizing and characterizing diverse molecular structures, thereby limiting their predictive accuracy for the removal of various ECs. This study uses embedded molecular structure vectors generated by a graph neural network (GNN), combined with functional group prompts, as inputs to a feedforward neural network. A data set of 28 ECs and 542 data points, representing diverse molecular structures and physiochemical properties, was built to predict the residual rate of ECs (REC) in ozonation oxidation. Compared to traditional QSAR models, the GNN-based molecular structure embedded methods significantly improve prediction accuracy. The resulting KANO-EC model achieved an R2 of 0.97 for REC, demonstrating its ability to capture complex structural features. Moreover, KANO-EC maintains exceptional interpretability, elucidating key functional groups (e.g., carbonyls, hydroxyls, aromatic rings, and amines) involved in the oxidation mechanism. This study presents the KANO-EC model as a novel approach for predicting the ozonation removal efficiency of current and potential ECs. The model also provides valuable insights for developing efficient control strategies for ensuring the long-term safety and sustainability of drinking water supplies.

Advanced oxidation processes for the degradation of tralomethrin: Impacts on zebrafish embryonic development

Tralomethrin (TRA), a synthetic pyrethroid insecticide, has long-term adverse effects on aquatic organisms, highlighting the necessity for effective methods to mitigate its toxicity. This study investigated the degradation efficiency of TRA using ultraviolet (UV) irradiation, ozone (O3) oxidation, and a combined O3/UV process. Unlike previous studies that primarily focused on degradation efficiency, this research not only compares the performance of UV, O3, and O3/UV processes but also evaluates the detoxification effects of their degradation products using zebrafish embryos. The results showed that the UV irradiation alone exhibited a low UV254 removal rate (20.69 %) but achieved the highest debromination efficiency (40.51 %), leading to the formation of less toxic degradation products. In contrast, both O3 and the combined O3/UV processes attained higher removal rates but exhibited lower debromination efficiencies compared to UV irradiation alone. Acute toxicity assessment demonstrated a significant decrease in the toxicity of TRA to zebrafish post-treatment. Specifically, the UV irradiation and O3/UV treatments resulted in enhanced detoxification compared to the parent compound TRA, as evidenced by normal hatching rates and lower rates of malformation, as well as improved gene expression profiles and normal movement patterns in zebrafish embryos. The zebrafish toxicity assay further revealed that UV irradiation and the combined O3/UV process fully restored the normal expression of neural markers (slc6a3 and th), suggesting its superior safety as a detoxification strategy. The optimal processing time for UV irradiation to achieve efficient TRA degradation was identified as 10 min, and the photodegradation pathways were identified. These findings underscore the practical applicability of UV-based processes in wastewater treatment, providing a promising strategy for reducing TRA contamination risks to aquatic ecosystems.

Treatment of synthetic slaughterhouse wastewater using integrated UV/H2O2/TiO2 photocatalytic advanced oxidation process enhanced by yeast-assisted dissolved air floatation

In treating slaughterhouse wastewater (SWW), conventional treatment processes (CTPs) such as anaerobic processes, membrane processes, and electrocoagulation have various weaknesses, including limited effectiveness, fouling issues, and high energy consumption. Conversely, photocatalytic advanced oxidation processes (PAOPs) have demonstrated superiority over CTPs. However, the treatment effectiveness of PAOPs significantly diminishes when SWW contains high levels of suspended solids (SS). This research explores the feasibility of pre-treating synthetic slaughterhouse wastewater (SSWW) using a novel yeast-assisted dissolved air flotation (YADAF) process to reduce the SS level. This process utilizes H2O2 and catalase enzymes from inexpensive yeast, readily available in local markets. Under optimized conditions, this combination generates O2 bubbles to uplift particles as flocs, which can then be removed via a mechanical scraper before undergoing treatment with UV/H2O2/TiO2 PAOP under optimized conditions. The enhanced process yielded a 93.75%, 83.23%, and 94.35% reduction in chemical oxygen demand (COD), 5-day carbonaceous biochemical oxygen demand (CBOD5), total suspended solids (TSS), signifying increments of 41.15%, 56.59%, and 2867% in COD, CBOD5, and TSS, respectively, compared to when using the UV/H2O2/TiO2 PAOP alone, unenhanced. This demonstrates that YADAF significantly amplifies the effectiveness of conventional UV/H2O2/TiO2 PAOP, making it a viable pre-treatment option that complements the latter in treating SSWW. PRACTITIONER POINTS: Yeast-assisted dissolved air floatation (YADAF) is a novel variant of dissolved air floatation (DAF) capable of removing 94.35% of TSS in 15 min. On top of that, when combined with advanced oxidation processes (AOP), the combined process can deliver 93.75%, 83.23%, and 94.35% reduction in COD, CBOD5, and TSS, respectively, when used to treat synthetic slaughterhouse wastewater (SSWW). This novel process has never been used in the field of SWW treatment and can prove to be a valuable addition ready to be implemented into current treatment technologies.

MnO2/porous spontaneously polarized ceramic with self-powered electric field and superior charge transfer to catalyze ozonation for efficient demulsification

Ozone (O3) demulsification shows great potential in emulsion wastewater treatment due to its strong oxidative properties. However, the low mass transfer efficiency and oxidation selectivity of O3 cannot be ignored. Herein, a MnO2/porous spontaneously polarized ceramic (MnO2/PSPC) composite with strong interfacial interactions and self-powered electric field was prepared for heterogeneous catalytic ozonation (HCO) to achieve efficient demulsification. Excellent remanent polarization (0.00858 μC/cm2) together with systematic electrochemical characterizations of MnO2/PSPC demonstrated its significant charge transfer capability, which is essential for the subsequent reduction of Mn4+ in the HCO demulsification process. O3- MnO2/PSPC exhibited excellent demulsification performance with 99 % demulsification rate of cetyltrimethylammonium bromide-stabilized emulsion within 30 min, outperforming O3 (130 min), O3-MnO2 (60 min), and O3-PSPC (90 min). O3-MnO2/PSPC showed effective demulsification of non-/anionic surfactant stabilized emulsions and excellent stability after 5 cycles. Density functional theory calculations together with characterizations illustrate that potential difference-induced rapid electron transfer and water flow-induced self-powered electric field were the fundamental motivation for the fast Mn3+/Mn4+ cycle and O3 adsorption/decomposition to generate reactive oxygen species (ROS). Notably, the oxidation of surfactants by ROS led to the coalescence of the oil droplets. This study provides an efficient, sustainable, and energy-efficient method to improve the O3 demulsification performance.

Unique effect of bromide ion on intensification of advanced oxidation processes for pollutants removal: A systematic review

Advanced oxidation processes (AOPs) have been developed to decompose toxic pollutants to protect the aquatic environment. AOP has been considered an alternative treatment method for wastewater treatment. Bromine is present in natural waters posing toxic effects on human health and hence, its removal from drinking water sources is necessary. Of the many techniques advanced oxidation is covered in this review. This review systematically examines literature published from 1997 to April 2024, sourced from Scopus, PubMed, Science Direct, and Web of Science databases, focusing on the efficacy of AOPs for pollutant removal from aqueous solutions containing bromide ions to investigate the impact of bromide ions on AOPs. Data and information extracted from each article eligible for inclusion in the review include the type of AOP, type of pollutants, and removal efficiency of AOP under the presence and absence of bromide ion. Of the 1784 documents screened, 90 studies met inclusion criteria, providing insights into various AOPs, including UV/chlorine, UV/PS, UV/H2O2, UV/catalyst, and visible light/catalyst processes. The observed impact of bromide ion presence on the efficacy of AOP processes, alongside the AOP method under scrutiny, is contingent upon various factors such as the nature of the target pollutant, catalyst type, and bromide ion concentration. These considerations are crucial in selecting the best method for removing specific pollutants under defined conditions. Challenges were encountered during result analysis included variations in experimental setups, disparities in pollutant types and concentrations, and inconsistencies in reporting AOP performance metrics. Addressing these parameters in research reports will enhance the coherence and utility of subsequent systematic reviews.

Polyhydroxybutyrate Plastics Show Rapid Disintegration and More Straightforward Biogeochemical Impacts than Polyethylene under Marine Biofragmentation

Although massive studies have investigated the spatiotemporally occurring marine plastisphere, a new microbial ecosystem colonizing the surfaces of plastics, the resulting biofragmentation process and impacts of plastics on biogeochemical cycles remain largely unknown. Here, we leverage synchrotron-based Fourier transform infrared spectromicroscopy (FTIR mapping) and metagenomic sequencing to explore independent marine microcosms amended with petroleum-based polyethylene (PE) and biobased polyhydroxybutyrate (PHB) plastic films. FTIR mapping results demonstrate unequal fragmentation scenarios by which the PE plastic rarely releases oxidized fragments while PHB disintegrates quickly, gradually forming fragments composed of extracellular polymeric substances resembling plastic films. Metagenomic analysis shows the critical role of hydrocarbonoclastic lineages in the biodegradation of the two plastics by the fatty acid degradation pathway, where the PE plastics host different microbial trajectories between the plastisphere (dominated by Alcanivorax) and surrounding seawater. In contrast, the PHB addition demonstrates decreased microbial richness and diversity, consistent community composition (dominated by Phaeobacter and Marinobacter), and apparently stimulated sulfur cycle and denitrification pathways in both the plastisphere and surrounding seawater. Our study gives scientific evidence on the marine biotic processes distinguishing petroleum- and biobased plastics, highlighting marine PHB input exerting straightforward impacts on the water phase and deserving critical management practices.

Intertwisted superhydrophilic and superhydrophobic collagen fibers enabled anti-fouling high-performance separation of emulsion wastewater

Oil-contaminated wastewater has been one of the most concerned environmental issues. Superwetting materials-enabled remediation of oil contamination in wastewater faces the critical challenge of fouling problems due to the formation of intercepted phase. Herein, high-performance separation of emulsions wastewater was accomplished by developing collagen fibers (CFs)-derived water-oil dual-channels that were comprised of intertwisted superhydrophilic and superhydrophobic CFs. The dual-channels relied on the superhydrophilic CFs to accomplish efficient demulsifying, which played the role as water-channel to enable fast transportation of water, while the superhydrophobic CFs served as the oil-transport channel to permit oil transportation. The mutual repellency between water-channel and oil-channel was essential to guarantee the stability of established dual-channels. The unique dual-channel separation mechanism fundamentally resolved the intercepted phase-caused fouling problem frequently engaged by the superwetting materials that provided single-channel separation capability. Long-lasting (1440 min) anti-fouling separations were achieved by the superwetting CFs-derived dual-channels with separation efficiency high up to 99.99%, and more than 4-fold of stable separation flux as compared with that of superhydrophilic CFs with single-channel separation capability. Our investigations demonstrated a novel strategy by using superwetting CFs to develop water-oil dual-channels for achieving high-performance anti-fouling separation of emulsions wastewater. ENVIRONMENTAL IMPLICATION: Industrial processes discard a large amount of emulsion wastewater, which seriously imperils the aquatic ecosystem. This work demonstrated a conceptual-new strategy to achieve effective remediation of emulsion wastewater via the water-oil dual-channels established by the intertwisted superhydrophilic and superhydrophobic collagen fibers (CFs). The superhydrophilic CFs enabled efficient demulsification of emulsions and played the role of water-channel for the rapid transportation of water, while the superhydrophobic CFs worked as oil-channel to permit the efficient transportation of oil pollutants. Consequently, the long-term (1440 min) anti-fouling high-performance separation of emulsion wastewater was achieved.

Suppressing Organic Bromine but Promoting Bromate: Is the Ultraviolet/Ozone Process a Double-Edged Sword for the Toxicity of Wastewater to Mammalian Cells?

Brominated byproducts and toxicity generation are critical issues for ozone application to wastewater containing bromide. This study demonstrated that ultraviolet/ozone (UV/O3, 100 mJ/cm2, 1 mg-O3/mg-DOC) reduced the cytotoxicity of wastewater from 14.2 mg of pentol/L produced by ozonation to 4.3 mg of pentol/L (1 mg/L bromide, pH 7.0). The genotoxicity was also reduced from 1.65 to 0.17 μg-4-NQO/L by UV/O3. Compared with that of O3 alone, adsorbable organic bromine was reduced from 25.8 to 5.3 μg/L by UV/O3, but bromate increased from 32.9 to 71.4 μg/L. The UV/O3 process enhanced the removal of pre-existing precursors (highly unsaturated and phenolic compounds and poly aromatic hydrocarbons), while new precursors were generated, yet the combined effect of UV/O3 on precursors did not result in a significant change in toxicity. Instead, UV radiation inhibited HOBr concentration through both rapid O3 decomposition to reduce HOBr production and decomposition of the formed HOBr, thus suppressing the AOBr formation. However, the hydroxyl radical-dominated pathway in UV/O3 led to a significant increase of bromate. Considering both organic bromine and bromate, the UV/O3 process effectively controlled both cytotoxicity and genotoxicity of wastewater to mammalian cells, even though an emphasis should be also placed on managing elevated bromate. Futhermore, other end points are needed to evaluate the toxicity outcomes of the UV/O3 process.

Chlorination of antiviral drug ribavirin: Kinetics, nontargeted identification, and concomitant toxicity evolution

Residual antiviral drugs in wastewater may increase the risk of generating transformation products (TPs) during wastewater treatment. Therefore, chlorination behavior and toxicity evolution are essential to understand the secondary ecological risk associated with their TPs. Herein, chlorination kinetics, transformation pathways, and secondary risks of ribavirin (RBV), one of the most commonly used broad-spectrum antivirals, were investigated. The pH-dependent second-order rate constants k increased from 0.18 M-1·s-1 (pH 5.8) to 1.53 M-1·s-1 (pH 8.0) due to neutral RBV and ClO- as dominant species. 12 TPs were identified using high-resolution mass spectrometry in a nontargeted approach, of which 6 TPs were reported for the first time, and their chlorination pathways were elucidated. The luminescence inhibition rate of Vibrio fischeri exposed to chlorinated RBV solution was positively correlated with initial free active chlorine, probably due to the accumulation of toxic TPs. Quantitative structure-activity relationship prediction identified 7 TPs with elevated toxicity, concentrating on developmental toxicity and bioconcentration factors, which explained the increased toxicity of chlorinated RBV. Overall, this study highlights the urgent need to minimize the discharge of toxic chlorinated TPs into aquatic environments and contributes to environmental risk control in future pandemics and regions with high consumption of antivirals.

Marine biodegradation of plastic films by Alcanivorax under various ambient temperatures: Bacterial enrichment, morphology alteration, and release of degradation products

The global ocean has been receiving massive amounts of plastic wastes. Marine biodegradation, influenced by global climate, naturally breaks down these wastes. In this study, we systematically compared the biodegradation performance of petroleum- and bio-based plastic films, i.e., low-density polyethylene (LDPE), polylactic acid (PLA), and polyhydroxyalkanoates (PHAs) under three ambient temperatures (4, 15, and 22 °C). We deployed the our previously isolated cold-tolerant plastic-degrading Alcanivorax to simulate the accelerated marine biodegradation process and evaluated the alteration of bacterial growth, plastic films, and released degradation products. Notably, we found that marine biodegradation of PHA films enriched more bacterial amounts, induced more conspicuous morphological damage, and released more microplastics (MPs) and dissolved organic carbon (DOC) under all temperatures compared to LDPE and PLA. Particularly, MPs were released from film edges and cracks with a mean size of 2.8 μm under all temperatures. In addition, the degradation products released by biodegradation of PHA under 22 °C induced the highest acute toxicity to Vibrio fischeri. Our results highlighted that: (1) marine biodegradation of plastics would release millions of MPs per cm2 exposed surface area even in cold environments within 60 days; (2) different marine biodegradation scenarios of these plastics may raise disparate impacts and mitigation-related studies.

Novel vacuum UV/ozone/peroxymonosulfate process for efficient degradation of levofloxacin: Performance evaluation and mechanism insight

Vacuum UV (VUV) irradiation has advantage in coupling oxidants for organics removal because VUV can dissociate water to produce reactive oxygen species (ROS) in situ and decompose oxidants rapidly. In this study, the synergistic activation of peroxymonosulfate (PMS) by VUV and ozone (O3) was explored via developing a novel integrated VUV/O3/PMS process, and the performance and mechanisms of VUV/O3/PMS for levofloxacin (LEV) degradation were investigated systematically. Results indicated that VUV/O3/PMS could effectively degrade LEV, and the degradation rate was 1.67-18.79 times of its sub-processes. Effects of PMS dosage, O3 dosage, solution pH, anions, and natural organic matter on LEV removal by VUV/O3/PMS were also studied. Besides, hydroxyl radical and sulfate radical were main ROS with contributions of 49.7% and 17.4%, respectively. Moreover, the degradation pathways of LEV in VUV/O3/PMS process were speculated based on density functional theory calculation and by-products detection. Furthermore, synergistic reaction mechanisms in VUV/O3/PMS process were proposed. The energy consumption of VUV/O3/PMS decreased by 22.6%- 88.1% compared to its sub-processes. Finally, the integrated VUV/O3/PMS process showed satisfactory results in removing LEV in actual waters, manifesting VUV/O3/PMS had great application potential and feasibility in removing organics in wastewater reuse.

Effective and low-toxicity: A membrane cleaning method using peroxymonosulfate catalytic chlorination

In chemical membrane cleaning, the challenge is to efficiently remove irreversible fouling while minimizing the impact on membrane materials. Particularly, traditional hypochlorite cleaning will further lead to the generation of toxic halogenated by-products. To address these issues, a combined system composed of peroxymonosulfate and chloride (PMS/Cl-) was applied to clean irreversible-humic-acid-fouled polyethersulfone (PES) membranes. After fouled membranes were soaked for 1 h in a PMS/Cl- solution (10 mM/15 mM) at 25 °C under neutral conditions, 94% flux recovery and 96% resistance removal were realized. Surface properties of virgin and cleaned membranes were very similar, confirming the effectiveness of the PMS/Cl- solution in removing irreversible foulants. The stability of membrane separation performance during multiple fouling and cleaning cycles further confirmed the minimal impact on membrane materials. Rapid diminution of the peaks centered in the region of fulvic-like and humic-like components, monitored under 3D-fluorescence for the cleaning solution, was attributed to PMS-catalyzed chlorination, thereby revealing the primary foulant detachment mechanism. Crucially, the approach exhibited lower toxicity than hypochlorite, as evidenced by reduced halogenated by-products and lower acute toxicity to Photobacterium phosphoreum T3. Overall, this novel cleaning system is promising for the efficient and environmentally friendly removal of irreversible organic foulants in practical water-treatment.

Superhydrophilic and oleophobic sponges prepared based on Mussel-Inspired chemistry for efficient oil-water separation

Superhydrophilic/oleophobic materials are considered to be the best materials for achieving oil-water separation, but their preparation is difficult and the existing methods are not universal. In this paper, a two-step modification strategy was used to prepare superhydrophilic/oleophobic sponges by adjusting the polar and nonpolar components of the materials using mussel-inspired chemistry. While remaining superhydrophilic, the modified sponge surface has a maximum contact angle of 135° with different oils in air. The modified sponge exhibited superoleophobicity in water, and the contact angle of oil could reach more than 150°. In addition, the modified sponges were also reusable, chemically stable, and mechanically durable. Its oil-water separation flux was up to 24900 Lm-2  h-1  bar-1 , and the separation efficiency was above 97 %. We believe that this method will provide an environmentally friendly and efficient way to prepare the superhydrophilic/oleophobic materials.

The utility of ultraviolet beam in advanced oxidation-reduction processes: a review on the mechanism of processes and possible production free radicals

Advanced oxidation processes (AOPs) and advanced reduction processes (ARPs) are a set of chemical treatment procedures designed to eliminate organic (sometimes inorganic) contamination in water and wastewater by producing free reactive radicals (FRR). UV irradiation is one of the factors that are effectively used in oxidation-reduction processes. Not only does the UV beam cause the photolysis of contamination, but it also leads to the product of FRR by affecting oxidants-reductant, and the pollutant decomposition occurs by FRR. UV rays produce active radical species indirectly in an advanced redox process by affecting an oxidant (O3, H2O2), persulfate (PS), or reducer (dithionite, sulfite, sulfide, iodide, ferrous). Produced FRR with high redox potential (including oxidized or reduced radicals) causes detoxification and degradation of target contaminants by attacking them. In this review, it was found that ultraviolet radiation is one of the important and practical parameters in redox processes, which can be used to control a wide range of impurities.

Insight into typical photo-assisted AOPs for the degradation of antibiotic micropollutants: Mechanisms and research gaps

Due to the incomplete elimination by traditional wastewater treatment, antibiotics are becoming emerging contaminants, which are proved to be ubiquitous and promote bacterial resistance in the aquatic systems. Antibiotic pollution has raised particular concerns, calling for improved methods to clean wastewater and water. Photo-assisted advanced oxidation processes (AOPs) have attracted increasing attention because of the fast reaction rate, high oxidation capacity and low selectivity to remove antibiotics from wastewater. On the basis of latest literature, we found some new breakthroughs in the degradation mechanisms of antibiotic micropollutants with respect to the AOPs. Therefore, this paper summarizes and highlights the degradation kinetics, pathways and mechanisms of antibiotics degraded by the photo-assisted AOPs, including the UV/O3 process, photo-Fenton technology, and photocatalysis. In the processes, functional groups are attacked by hydroxyl radicals, and major structures are destroyed subsequently, which depends on the classes of antibiotics. Meanwhile, their basic principles, current applications and influencing factors are briefly discussed. The main challenges, prospects, and recommendations for the improvement of photo-assisted AOPs are proposed to better remove antibiotics from wastewater.

A solar-driven degradation-evaporation strategy for membrane self-cleaning in the efficient separation of viscous crude oil/water emulsions

Membrane separation techniques are promising methods for effectively treating hazardous emulsified oily wastewater, but membrane fouling remains a serious challenge because the high viscosity and complex composition of crude oil make it easy to adhere to membranes and difficult to be removed by conventional physical or chemical cleaning means. Herein, a two-stage solar-driven (photo-Fenton degradation/evaporation) strategy was proposed to realize the self-cleaning of membranes fouled by viscous crude oil (>60,000 mPa s), wherein the photo-Fenton process helped to degrade the heavy components into light components, and all light components removed during the solar-driven evaporation process. A 1D/2D heterostructure membrane with photo-Fenton activity and anti-crude-oil-fouling performance was prepared via a facile self-assembly vacuum-assist method. The addition of rod-like g-C₃N₄ (RCN) increased the interlayer distance of α-FeOOH/porous g-C₃N₄ (FPCN) nanosheets, resulting in a high permeation flux. The FPCN-RCN membrane exhibited both high permeation flux of 779 ± 19 L m^-2h^-1bar^-1 and a separation efficiency of 99.4% for highly viscous crude oil-in-water emulsion. Importantly, the viscous crude oil fouled on the membrane was completely removed by the photo-Fenton degradation/solar-driven evaporation strategy, and the flux recovery rate of the membrane was ∼100%. Therefore, the FPCN-RCN membrane combined with the novel self-cleaning strategy exhibits great potential for practical emulsified oily wastewater treatment.

Water-oil dual-channels enabled exceptional anti-fouling performances for separation of emulsified oil pollutant

Oil contamination has been an increasingly concerned environmental issue due to the large quantity of oily wastewater discharged by the industry. The extreme wettability-enabled single-channel separation strategy guarantees efficient separation of oil pollutant from wastewater. However, the ultra-high selective permeability forces the intercepted oil pollutant to form a blocking layer, which weakens the separation capability and slows the kinetics of permeable phase. As a consequence, the single-channel separation strategy fails to maintain a stable flux for a long-term separation process. Herein, we reported a brand-new water-oil dual-channels strategy for accomplishing an ultra-stable long-term separation of emulsified oil pollutant from oil-in-water nano-emulsion by engineering two drastically opposite extreme wettabilities (i.e. superhydrophilicity and superhydrophobicity) to build the water-oil dual-channels. The strategy established the superwetting transport channels to permit water and oil pollutant to permeate through their own channel. In this way, the generation of intercepted oil pollutant was prevented, which guaranteed an exceptional long-lasting (20 h) anti-fouling performance for successful achievement of an ultra-stable separation of oil contamination from oil-in-water nano-emulsion with high flux retention and high separation efficiency. Therefore, our investigations provided a new route for realizing ultra-stable long-term separation of emulsified oil pollutant from wastewater.

Constructing a highly tough, durable, and renewable flexible filter by epitaxial growth of a glass fiber fabric for high flux and superefficient oil-water separation

The separation and purification of complex and stable stubborn oily sewage is extremely challenging. To respond to this challenge, we developed a powerful flexible filter with ultrahigh strength, durability, flux, separation efficiency, and a multiobjective separation function based on a universal epitaxial growth process of glass fiber fabric (Gf). The underwater oil contact angle (UOCA) of the silicate@Gf (MgSi@Gf) filter is 156.3°, so it can achieve both an ultrahigh permeation flux (5632.7 L·m^-2·h^-1) and oil-water separation efficiency (99.5%) under gravity (≈ 1 kPa) in purifying surfactant-stabilized emulsions, actual industrial oily sewage and mechanical cold rolling emulsions. The filter with a high tensile strength (66.5 MPa) and oil invasion pressure (4626 Pa) can withstand the impact of much sewage or intense water flow. The filter can tolerate extreme conditions and can maintain high separation performance in acid or alkaline (pH 1-13), high or low temperature (100 °C, 200 °C, -18 °C) conditions or natural salty waters such as seawater. The filter can remove methylene blue (MB) dye (99.8%) by filtration, and can be repeatedly and easily reconstructed (renewable advantage). The filter shows great potential for efficiently eliminating the hazards of contaminants in actual oily sewage and thus protect human health.

Subtle tuning of nanodefects actuates highly efficient electrocatalytic oxidation

Achieving controllable fine-tuning of defects in catalysts at the atomic level has become a zealous pursuit in catalysis-related fields. However, the generation of defects is quite random, and their flexible manipulation lacks theoretical basis. Herein, we present a facile and highly controllable thermal tuning strategy that enables fine control of nanodefects via subtle manipulation of atomic/lattice arrangements in electrocatalysts. Such thermal tuning endows common carbon materials with record high efficiency in electrocatalytic degradation of pollutants. Systematic characterization and calculations demonstrate that an optimal thermal tuning can bring about enhanced electrocatalytic efficiency by manipulating the N-centered annulation-volatilization reactions and C-based sp³/sp² configuration alteration. Benefiting from this tuning strategy, the optimized electrocatalytic anodic membrane successfully achieves >99% pollutant (propranolol) degradation during a flow-through (~2.5 s for contact time), high-flux (424.5 L m^-2 h^-1), and long-term (>720 min) electrocatalytic filtration test at a very low energy consumption (0.029 ± 0.010 kWh m^-3 order^-1). Our findings highlight a controllable preparation approach of catalysts while also elucidating the molecular level mechanisms involved.