A Hydrogel-coated Wood Membrane with Intelligent Oil Pollution Detection for Emulsion Separation.

Considering the potential threats posed by oily wastewater to the ecosystem, it is urgently in demand to develop efficient, eco-friendly, and intelligent oil/water separation materials to enhance the safety of the water environment. Herein, an intelligent hydrogel-coated wood (PPT/PPy@DW) membrane with self-healing, self-cleaning, and oil pollution detection performances is fabricated for the controllable separation of oil-in-water (O/W) emulsions and water-in-oil (W/O) emulsions. The PPT/PPy@DW is prepared by loading polypyrrole (PPy) particles on the delignified wood (DW) membranes, further modifying the hydrogel layer as an oil-repellent barrier. The layered porous structure and selective wettability endow PPT/PPy@DW with great separation performance for various O/W emulsions (≥98.69% for separation efficiency and ≈1000 L m-2 h-1 bar-1 for permeance). Notably, the oil pollution degree of PPT/PPy@DW can be monitored in real-time based on the changed voltage generated during O/W emulsion separation, and the oil-polluted PPT/PPy@DW can be self-cleaned by soaking in water to recover its separation performance. The high affinity of PPT/PPy@DW for water makes it effective in trapping water from the mixed surfactant-stabilized W/O emulsions. The prepared eco-friendly and low-cost multifunctional hydrogel wood membrane shows promising potential in on-demand oil/water separation and provides new ideas for the functional improvement of new biomass oil/water separation membrane materials.

Distribution, sources and ecological risks of PAHs and n-alkanes in water and sediments of typically polluted estuaries: Insights from the Xiaoqing River.

Seasonal water and sediment samples were collected from the Xiaoqing River estuary and the neighboring sea to study the spatial and temporal distributions, sources and ecological risks of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes. The results showed significant spatial and temporal differences in the concentrations of PAHs and n-alkanes under the influence of precipitation, temperature, and human activities. The concentrations of PAHs in water were lower in the wet season than in the dry season, and those in sediments were higher in the wet season than in the dry season. The concentrations of n-alkanes were higher in the rainy season than in the dry season for both water and sediments. The spatial distributions of PAHs and n-alkanes were estuarine > offshore. The concentration ranges of ∑PAHs in water and sediments were 230.66-599.86 ng/L and 84.51-5548.62 ng/g, respectively, in the wet season and 192.46-8649.55 ng/L and 23.39-1208.92 ng/g, respectively, in the dry season. The proportion of three-ring PAHs in water (57.03% and 78.27% in the wet and dry seasons, respectively) was high, followed by two-ring PAHs (27.31% and 13.59% in the wet and dry seasons, respectively). The proportion of four-ring PAHs was higher in sediments (24.79% and 32.20% in the wet and dry seasons, respectively). The ecological risk of PAHs assessed using the toxicity equivalent quotient and risk quotient was at moderate to moderately high risk levels. The high concentration of n-alkane fraction C16 (611.65-75594.58 ng/L) in the water is indicative of petroleum or other fossil fuel inputs. The main peaks of n-alkanes in river sediments were C27, C29 and C31, indicating higher inputs of plant sources. The sediments in the estuary showed dominance of both short-chain C16 and long-chain C25-C31, indicating a combined input of higher plants and petroleum. The diagnostic ratios of PAHs and n-alkanes indicated that their sources were mainly oil/coal/biomass combustion and petroleum spills attributed to frequent vehicular, vessel and mariculture activities. Given the potential ecological risks of PAHs and n-alkanes in water and sediments, future studies should focus on their bioaccumulation and biotoxicity.

Assessment of spilled oil dispersion affected by dispersant: Characteristic, stability, and related mechanism.

Oil dispersion, a crucial process in oil transport, involves the detachment of oil droplets from slicks and their introduction into the water column, influencing subsequent oil migration and transformation. This study examines oil dispersion, considering characteristics, stability, and mechanisms, while evaluating the impact of dispersants and salinity. Results show the significant role of surfactant type in dispersants on oil dispersion characteristics, with anionic surfactants exhibiting higher sensitivity to salinity changes compared to nonionic surfactants. The dispersion efficiency varies with salinity, with anionic surfactants performing better in low salinity (<20‰) and nonionic surfactants showing superior performance at 30-35‰ salinities. Rheological analysis illustrates the breakup and coalescence of oil droplets within the shear rates of breaking waves. An increase in interfacial film rigidity impedes the coalescence of oil droplets, contributing to the dynamic stability of the oil-water hybrid system. The use of GM-2, a nonionic dispersant, results in the formation of a solid-like interface, characterized by increased elastic modulus, notably at 20‰ salinity. However, stable droplet size distribution (DSD) at 35‰ salinity for 60 h suggests droplets can remain dispersed in seawater. The enhancement of stability of oil dispersion is interpreted as the result of two mechanisms: stabilizing DSD and developing the strength of viscoelastic interfacial film. These findings offer insights into oil dispersion dynamics, highlighting the importance of surfactant selection and salinity in governing dispersion behavior, and elucidating mechanisms underlying dispersion stability.

The Role of Bacteria in the Formation and Migration of Oil-Particle Aggregates (OPAs) after Marine Oil Spills and the Associated Mechanism.

Oil spills interact with mineral particles to form oil-particle aggregates (OPAs), which promotes the oil's natural diffusion and biodegradation. We investigated the effect of bacteria on the formation and vertical migration of OPAs under different concentrations and types of particles and proposed and elucidated an oil-particle-bacteria coupling mechanism. The depth of particle penetration into oil droplets (13-17 µm) was more than twice that of the nonbacterial group. Oil that remained in the water column and deposited to the bottom decreased from 87% to 49% and increased from 14% to 15% at high/low concentration, respectively. Interestingly, the median droplet diameter showed a negative correlation (R2 = 0.83) and positive correlation (R2 = 0.60) at high/low concentration, respectively, with the relative penetration depth first proposed. We further demonstrated that bacteria increased the penetrating depth by a combination of reducing/increasing the interfacial tension, reducing the oil amount (C17-C38) in the OPAs, and increasing the particle width. These effects reduced the droplet size and ultimately changed the vertical migration of OPAs. Finally, we provided a simple assessment of the vertical distribution of OPAs in nearshore environments based on experimental data and suggested that the role of bacteria in increasing the depth of particles penetrating into the oil droplets should not be ignored. These findings will broaden the research perspective of marine oil spill migration.

A step closer to real practice: Integrated tandem photocatalysis-biofilm process towards degradation of crude oil.

Intimately coupled photocatalysis and biodegradation (ICPB) systems represent a promising wastewater treatment technology. The implementation of ICPB systems for oil spill treatment is a pressing concern. In this study, we developed an ICPB system comprising BiOBr/modified g-C3N4 (M-CN) and biofilms for the treatment of oil spills. The results demonstrate that the ICPB system achieved the rapid degradation of crude oil, outperforming the single photocatalysis and biodegradation methods by degrading 89.08 ± 5.36% within 48 h. The combination of BiOBr and M-CN formed a Z-scheme heterojunction structure, enhancing the redox capacity. The interaction between the holes (h+) and the negative charge on the biofilm surface promoted the separation of electrons (e-) and h+, thereby accelerating the degradation process of crude oil. Moreover, ICPB system maintained an excellent degradation ratio after three cycles and its biofilms progressively adapted to the adverse effects of crude oil and light. The microbial community structure remained stable throughout the degradation of crude oil, with Acinetobacter and Sphingobium identified as the dominant genera in biofilms. The proliferation of the Acinetobacter genus appeared to be the main factor contributing to the promotion of crude oil degradation. Our work demonstrates that the integrated tandem strategies perhaps represent a feasible pathway toward practical crude oil degradation.

Effect of fermentation pH on the structure, rheological properties, and antioxidant activities of exopolysaccharides produced by Alteromonas australica QD.

The pH value was essential for the growth and metabolism of microorganisms. Acidic pH exopolysaccharide (AC-EPS) and alkaline pH exopolysaccharide (AL-EPS) secreted by A. australica QD mediated by pH were studied in this paper. The total carbohydrate content and molecular weight of AC-EPS (79.59% ± 2.24% (w/w), 8.374 × 105 Da) and AL-EPS (82.48% ± 1.46% (w/w), 6.182 × 105 Da) were estimated and compared. In AC-EPS, mannose (3.78%) and galactose (3.24%) content was more, while the proportion of glucuronic acid was less in comparison to AL-EPS. The scanning electron microscopy revealed the structural differences among the AC-EPS and AL-EPS. Thermogravimetric analysis showed degradation temperatures of 272.8 °C and 244.9 °C for AC-EPS and AL-EPS, respectively. AC-EPS was found to exhibit better rheological properties and emulsifying capabilities, while AL-EPS had superior antioxidant activities. Overall, both AC-EPS and AL-EPS have the potential to be used as emulsifiers and biological antioxidants.

Construction of a Superhydrophobic Sodium Alginate Aerogel for Efficient Oil Absorption and Emulsion Separation.

Bio-based aerogels serve as potential materials in separation of oil/water mixtures. Nevertheless, there remain some key challenges, including expensive/toxic organic cross-linkers, unpromising reusability, and poor performance in emulsion separation. Hereby, a novel, robust, and superhydrophobic sodium alginate/graphene oxide/silicon oxide aerogel (SA/GO/SiO2-M) was fabricated by simple calcium ion cross-linking self-assembly, freeze-drying, and chemical vapor deposition methods based on the renewable and abundant raw materials. The as-prepared SA-based aerogel possesses high absorbency for varieties of organic solvents and oils. Importantly, it shows high efficiency in the separation of surfactant-stabilized water-in-oil emulsions. SA/GO/SiO2-M aerogels display excellent reusability in both absorption and separation because of their good mechanical properties in the air and oil phase, and the mechanism in emulsion separation is discussed. This study shows that SA/GO/SiO2-M aerogels are a promising material in treating oil contaminants from different fields.

Simultaneous nitrification and denitrification in an aerobic biofilm biosystem with loofah sponges as carriers for biodegrading hydrolyzed polyacrylamide-containing wastewater.

Simultaneous nitrification and denitrification (SND) during treating hydrolyzed polyacrylamide (HPAM) containing wastewater were explored in an aerobic biofilm reactor biosystem. Here, loofah sponges as the environment-friendly and low-cost material were applied as the carriers in this biosystem. The removal efficiencies of HPAM and total nitrogen (TN) reached 43.6% and 54.3%, respectively, after 120 days stabilized running periods. Moreover, the structure of loofah sponges affected anaerobic microenvironment significantly which was indispensable for realizing a high-performance of SND. Key microorganisms in this biosystem included nitrobacteria, denitrobacteria and HPAM-biodegrading bacteria. The abundance of nitrobacteria and denitrobacteria on the biofilm was increased by 17.2% and 15.3%, respectively, through cultivation. Meanwhile, the biotransformation mechanisms of HPAM and diverse valence of nitrogen under different chemical oxygen demand (COD)/N and dissolved oxygen (DO) conditions were investigated. When COD/N and DO were 8:1 and 2 mg/L, HPAM biodegradation, SND efficiency and TN removal achieved their maximum, and the values were 54.3%, 92.3% and 60.1%, respectively. Key enzyme activities also reached their maximum in this condition. The optimal COD/N and DO was pivotal to achieve the high-performance of SND, and it was closely correlated with HPAM biodegradation. Meanwhile, SND could facilitate the biotransformation of HPAM.

Hydrolyzed polyacrylamide biotransformation in an up-flow anaerobic sludge blanket reactor system: key enzymes, functional microorganisms, and biodegradation mechanisms.

Hydrolyzed polyacrylamide (HPAM) biotransformation in an up-flow anaerobic sludge blanket reactor including biodegradation performances, biodegradation mechanisms, key enzymes, and functional microorganisms was explored. Response surface methodology was applied to further improve HPAM degradation. The predicted degradation ratios of HPAM and CODCr were 46.2% and 83.4% under the optimal conditions. HPAM biodegradation ratio and total organic carbon removal ratio reached 40.5% and 38.9%. Total nitrogen concentration was dramatically decreased with the increasing fermentation time during the fermentation, while low ammonia nitrogen (NH4+-N) and nitrite nitrogen (NO2--N) were generated. NH4+-N and NO2--N increased slightly on the whole. Enzyme activity change was correlated with HPAM biodegradation. Dehydrogenase activity had a decline of 21.3-41.0%, and the minimum value occurred at 300 mg/L of HPAM. Urease activity was varied from 28.7 to 78.7% and the maximal inhibition ratio occurred at 200 mg/L of HPAM. Mechanisms for the biodegradation of HPAM were also explored by FT-IR, HPLC, and SEM. The results indicated that long-chain HPAM was broken into micromolecule compounds and the amide groups of HPAM were transformed into carboxyl groups. Based on the sequencing results on an Illumina MiSeq platform, Proteobacterias, Bacteroidetes, and Chloroflexi were turned out to be the critical microorganisms involved in HPAM degradation. This work lays a basis for HPAM-containing wastewater treatment and offers a support for water saving and emission reduction. It is of great significance to the sustainable development of oilfield.

Regulation of different electron acceptors on petroleum hydrocarbon biotransformation to final products in activated sludge biosystems.

The types and concentrations of electron acceptor are the significant factors influencing the oxidation and biotransformation of organic matter in the process of pollutant biodegradation. Regulation of O2, SO42- and NO3- as electron acceptors on petroleum hydrocarbon biotransformation to final products was studied using the multiple methods including mesoscale biodegradation experiments, thermodynamic theoretical calculations and stoichiometric analyses. Petroleum hydrocarbon biodegradation ratio (PHBR) rose from 64.7 to 82.4% with dissolved oxygen (DO) (3-5 mg L- 1). PHBR increased from 57.4 to 66.1% in SO42--reducing biosystems and rose from 65.0 to 77.9% in NO3--reducing biosystems. Carbon balance was verified in different cultures. The shared functional microorganisms in different biosystems included Candida, Rhodococcus, Pseudomonas, Ochrobactrum, Marinobacter, Bacillus, Azoarcus, Alcanivorax, Acinetobacter. Pandoraea, Enterobacter and Burkholderia in anaerobic biosystems preferred to use NO3- and SO42- as electron acceptors for metabolism, and order of availability followed: NO3- > SO42-. Thermodynamic constraint showed that potentials of alkanes biotransformation to methane through hydrogenotrophic and acetoclastic methanogenesis in NO3--reducing biosystems were 7.27-7.73 and 7.25-7.70 times larger than those of SO42--reducing biosystems, respectively. Metabolism equations of microorganisms proved that anabolism and catabolism on alkanes were feasible. This work provides a support for studying the biochemical process of petroleum hydrocarbon biotransformation and lays a foundation for the realization of oil-containing wastewater bioremediation.

Facile Fabrication of Cyclodextrin-Modified Magnetic Particles for Effective Demulsification from Various Types of Emulsions.

Effective oil-water phase separation from various emulsions, especially those stabilized by surfactant, is of great importance. Although superhydrophobic and superoleophilic materials have attracted considerable attention in recent years, they are incapable of directly separating all types of oil-water mixtures. To separate various types of emulsions, one of the most important features of particles is that they can be dispersed in the continuous phase for delivery and target dispersed phases. In this study, cyclodextrin-modified magnetic composite particles (M-CDs) have been fabricated for this goal, based on their special interfacial activity and response to an external magnetic field. Though M-CDs are hydrophilic, the intelligent M-CDs can switch from hydrophilicity to hydrophobicity spontaneously, due to the formation of CD-oil inclusion complexes (ICs) at the oil-water interface. Physicochemical characterization reveals that M-CDs can adsorb at the oil-water interface and locate at the droplet surface as an effective Pickering emulsifier. By applying an external magnetic field, M-CDs are removed from the droplet surface and a rapid oil-water phase separation occurs. Our M-CDs can demulsify, for the first time, surfactant-free or surfactant-stabilized oil-in-water (O/W) and water-in-oil (W/O) emulsions directly, with high separation efficiency. Furthermore, the recycled MNPs still show high demulsification efficiency. In view of the sustainability of cyclodextrin and effective recycling ability of MNPs, M-CDs provides a new opportunity to develop an environmentally friendly interfacial material for practical applications in wastewater treatment.

Mechanism of nearshore sediment-facilitated oil transport: New insights from causal inference analysis.

A quantitative understanding of spilled oil transport in a nearshore environment is challenging due to the complex physicochemical processes in aqueous conditions. The physicochemical processes involved in oil sinking mainly include oil dispersion, sediment settling, and oil-sediment interaction. For the first time, this work attempts to address the sinking mechanism in petroleum contaminant transport using structural causal models based on observed data. The effects of nearshore salinity distribution from the estuary to the ocean on those three processes are examined. The causal inference reveals sediment settling is the crucial process for oil sinking. Salinity indirectly affects oil sinking by promoting sediment settling rather than directly affecting oil-sediment interaction. The increase of salinity from 0‰ to 35‰ provides a natural enhancement for sediment settling. Notably, unbiased causal effect estimates demonstrate the strongest positive causal effect on the settling efficiency of sediments is posed by increasing oil dispersion effectiveness, with a normalized value of 1.023. The highest strength of the causal relationship between oil dispersion and sediment settling highlights the importance of the dispersing characteristics of spilled oil to sediment-facilitated oil transport. The employed logic, a data-driven method, will shed light on adopting advanced causal inference tools to unravel the complicated contaminants' transport.

Joule Heating-Assisted Crude Oil Purification by a Poly(pyrrole)-Modified Microfibril Cellulose Membrane.

Using membrane materials to purify viscous watery oil from industrial production processes and accidental oil spills is of great importance but still challenging. Based on the excellent electrical conductivity and electric-thermal conversion of poly(pyrrole) (PPy), a hydrophobic PPy-modified micro-fibrillated cellulose membrane (P-CP) was successfully prepared. The size of the P-CP membrane can be customized to meet specific requirements. In this research, the membrane diameter is capable of reaching 24 cm. By applying a voltage ranging from 0 to 12 V, the surface temperature of the P-CP membrane can be elevated to roughly 120 °C. After 10 cycles of heating and cooling under 12 V voltage, the electric-thermal curves, surface hydrophobicity, and pore structure of P-CP membrane can remain stable, which suggests remarkable electric-thermal stability and reliability despite prolonged operation. The P-CP membrane shows good linearity between voltage and current (R2 = 0.997) and easy temperature control from room temperature to ∼120 °C at low supply voltage (0-12 V). Under the condition of 12 V power supply and self-gravity, the separation flux of the P-CP membrane for water-in-oil (W/O) emulsions (kerosene, diesel) is 2-3 times higher than that at room temperature, and the separation efficiency is also improved. Importantly, the P-CP membrane shows excellent separation performance for high viscosity water-in-crude oil emulsions, with a separation flux of 40 L m-2 h-1 by gravity. Compared to the situation without electricity, the separation flux of water-in-crude oil emulsion has increased four-fold. The joule heating of the P-CP membrane expands its service time and application scenarios, demonstrating its great application prospects in actual viscous oil-water emulsion separation.

Co-pollution risk of petroleum hydrocarbons and heavy metals in typically polluted estuarine wetlands: Insights from the Xiaoqing River.

Excessive accumulation of total petroleum hydrocarbons (TPH) and heavy metals (HMs) in sediments poses a significant threat to the estuarine ecosystem. In this study, the spatial and temporal distribution, ecological risks, sources, and their impacts on the microbial communities of TPH and nine HMs in the estuarine sediments of the Xiaoqing River were determined. Results showed that the spatial distribution of TPH and HMs were similar but opposite in temporal. Ni, Cr, Pb, and Co concentrations were similar to the reference values (RVs). However, the other five HMs (Cu, Zn, Cd, As, and Hg) and TPH concentrations were 2.00-763.44 times higher than RVs; hence, this deserves attention, particularly for Hg. Owing to the water content of the sediments, Hg was mainly concentrated on the surface during the wet season and on the bottom during the dry season. Moreover, because of weak hydrodynamics and upstream pollutant sinks, TPH-HMs in the river were higher than those in the estuary. TPH and HM concentrations were negatively correlated with microbial diversity. Structural equation modeling showed that HMs (path coefficient = -0.50, p < 0.001) had a negative direct effect on microbial community structure and a positive indirect effect on TPH. The microbial community (path coefficient = 0.31, 0.01 < p < 0.05) was significantly correlated with TPH. In summary, this study explores both the chemical analysis of pollutants and their interaction with microbial communities, providing a better understanding of the co-pollution of TPH and HMs in estuarine sediments.

Unveiling the long-term dynamic effects: Biochar mediates bacterial communities to modulate the petroleum hydrocarbon degradation in oil-contaminated sediments.

Sediment, as the destination of marine pollutants, often bears much more serious petroleum pollution than water. Biochar is increasingly utilized for remediating organic pollutant-laden sediments, yet its long-term impacts on oil-contaminated sediment remain poorly understood. In this study, simulation experiments adding 2.5 wt% biochars (corn straw and wood chips biochar at different pyrolysis temperatures) were conducted. The effects on petroleum hydrocarbon attenuation, enzyme activities, and microbial community structure were systematically investigated. Results showed enhanced degradation of long-chain alkanes in certain biochar-treated groups. Biochar species and PAH characteristics together lead to the PAHs' attenuation, with low-temperature corn straw biochar facilitating the degradation of phenanthrene, fluorene, and chrysene. Initially, biochars reduced polyphenol oxidase activity but increased urease and dehydrogenase activities. However, there was a noticeable rise in polyphenol oxidase activity for a long time. Biochars influenced bacterial community succession and abundance, likely due to nutrient release stimulating microbial activity. The structural equations model (SEM) reveals that DON affected the enzyme activity by changing the microbial community and thus regulated the degradation of PAHs. These findings shed light on biochar's role in bacterial communities and petroleum hydrocarbon degradation over extended periods, potentially enhancing biochar-based remediation for petroleum-contaminated sediments.

N-alkane shape distinctive microbial patterns in Kuroshio Extension.

Marine microorganisms are primary drivers of the elemental cycling. The interaction between heterotrophic prokaryotes and biomarker (n-alkane) in Kuroshio Extension (KE) remains unclear. Here, we categorize KE into three characteristic areas based on ocean temperatures and nutrient conditions: Cold Water Area (CWA), Mixed Area (MA), and Warm Water Area (WWA). A total of 49 samples were collected during two-year voyage to identify the source of n-alkane and associated degrading microorganisms. Total n-alkane concentrations (Σn-Alk) in surface water (SW) spanned from 1,308 ng L-1 to 1,890 ng L-1, it was significantly higher (Tukey-Kramer test, p < 0.05) in MA than CWA and WWA. The Σn-Alk in surface sediments (SS) gradually increased from north to south, ranging from 5,982 ng g-1 to 37,857 ng g-1. Bacteria and algae were the primary sources of n-alkane in both SW and SS. Proteobacteria was the most widely distributed among three areas. The presence of Rhodobacteraceae with alkB was the primary reason affecting n-alkane concentrations in SW. The Gammaproteobacteria with alkB and alkR chiefly affected n-alkane concentrations in SS. In summary, n-alkane s serve as an energy source for particular microorganisms, shaping the unique oceanographic patterns.

Quantitative analysis of biosurfactants in water samples by a modified oil spreading technique.

The oil spreading technique relies on biosurfactant to reduce the surface tension of an oil film and form an oil spreading ring in the center, and then judges the content of biosurfactant according to the diameter of the spreading ring. However, the instability and large errors of the traditional oil spreading technique limit its further application. In this paper, we modified the traditional oil spreading technique by optimizing the oily material, image acquisition and calculation method, which improves the accuracy and stability of the quantification of biosurfactant. We screened lipopeptides and glycolipid biosurfactants for rapid and quantitative analysis of biosurfactant concentrations. By selecting areas by color done by the software to modify image acquisition, the results showed that the modified oil spreading technique has a good quantitative effect, reflected in the concentration of biosurfactant being proportional to the diameter of the sample droplet. More importantly, using the pixel ratio method instead of the diameter measurement method to optimize the calculation method, the region selection was more exact, and the accuracy of the data results was high, and the calculation efficiency was improved significantly. Finally, the contents of rhamnolipid and lipopeptide in oilfield water samples were judged by the modified oil spreading technique, the relative errors were analyzed according to the different substances as the standard, and the quantitative measurement and analysis of oilfield water samples (the produced water of Zhan 3-X24 and the injected water of the estuary oil production plant) were realized. The study provides a new perspective on the accuracy and stability of the method in the quantification of biosurfactant, and provided some theoretical and data support for the study of the microbial oil displacement technology mechanism.

An S-scheme NH2-MIL-101(Fe)@MCN/Bi2O3 heterojunction photocatalyst for the degradation of tetracycline and production of H2O2.

Effective and durable photocatalysts are essential for the decomposition of persistent contaminants and the generation of hydrogen peroxide. In this study, we successfully constructed an S-type heterojunction by in situ growing Bi2O3 nanocrystals and NH2-MIL-101(Fe) onto surface-modified g-C3N4. The process of charge transfer in the S-type heterojunction was confirmed using ISI-XPS, DFT calculations, capture experiments, and EPR signals. The combined influence of the heterojunction and MOF demonstrated remarkable photocatalytic performance in the breakdown of tetracycline (TC) and the generation of hydrogen peroxide (H2O2). In the enhanced setup (10%-NH2-MIL-101(Fe)@MCN/Bi2O3), full degradation of TC was accomplished within 50 min under visible light exposure. Additionally, a notable H2O2 yield of 655.63 µmol/g was attained, all achieved without the necessity of sacrificial agents or supplementary oxygen. Based on the outcomes of the dual functionality, the exceptional performance of the ternary composite material can be ascribed to the collaborative influence of the heterojunction and MOF. This collaborative effect expands the light absorption range in the visible region, suppresses the recombination of electron-hole pairs, and enhances the photocatalytic redox ability. The system demonstrates significant potential in the efficient in situ production of H2O2 and removal of recalcitrant organic pollutants in pure water.

Preparation of MOF/polypyrrole and flower-like MnO2 electrodes by electrodeposition: High-performance materials for hybrid capacitive deionization defluorination.

Fluorine pollution has become a global public health problem due to its adverse health effects. Adsorption is the primary method for removing fluoride from drinking water. However, the adsorption method has disadvantages such as difficulty in recovering the adsorbent, and the need to add additional chemicals for regeneration, thereby causing secondary pollution, which limits further industrial applications. Capacitive deionization (CDI), as an emerging water treatment technology, has attracted widespread attention due to its advantages of simple operation, low energy consumption and less environmental impact. In this study, a polypyrrole (PPy) film was prepared on a graphite substrate by electrodeposition, and then metal-organic framework Ce/Zn-BDC-NH2 (CZBN) was deposited on the PPy film by electrophoretic deposition to obtain CZBN/PPy electrode was obtained. The CZBN/PPy anode was then coupled with the MnO2 cathode for capacitive removal of fluoride in a CDI cell. Both CZBN/PPy and MnO2 electrodes exhibit pseudocapacitive behavior, which can selectively and reversibly intercalate F- (CZBN/PPy) and Na+ (MnO2) ions. As expected, the CZBN/PPy-MnO2 system exhibits excellent fluorine removal performance. In 1.2 V, 100 mg/L F- solution, the F- removal capacity can reach 55.12 mg/g. It has high F- selectivity in the presence of some common anions, and can maintain high F- removal ability even after five adsorption regeneration processes. The mechanism of F- removal was studied by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). F- was mainly removed by electrostatic interaction and ion exchange with hydroxyl. The excellent defluorination performance of the CZBN/PPy-MnO2 system makes it have good practical application prospects.

MXene/Graphene modified cellulose aerogel for photo-electro-assisted all-weather cleanup of high-viscous crude oil from spill.

The frequent occurrence of oil spills has led to serious environmental pollution and ecological issues. Given the high-viscosity of crude oil, it is essential to develop sorbents with efficient viscosity reduction and sorption capacity in various environmental conditions. Herein, a superhydrophobic carboxymethyl cellulose (CMC) aerogel co-modified by MXene and graphene jointly (M-Mxene/Gr CA) with aligned channels structure was prepared. The aligned channels structure can effectively improve the longitudinal thermal conductivity and reduce the sorption resistance. Through the modification of MXene and graphene, the aerogel realized efficient photo/electro-thermal conversion, thus ensuring its adaption to various working environments. The rapid heat generation can significantly reduce the viscosity of crude oil, achieving rapid recovery. Under one sun illumination (1.0 kW/m2), the surface temperature of M-Mxene/Gr CA can reach 72.6 °C and its sorption capability for high-viscous crude oil reaches 18 g/g. Combining photo-thermal and electro-thermal (0.5 kW/m2 and 23 V), the average sorption rate of crude oil can reach 1.3 × 107 g m-3 s-1. Finally, we present a continuous sorption system to recover offshore oil spills under the assistance of a pump. This work provides a new option for tackling high-viscous offshore oil spills due to its environmental friendliness and fast sorption capacity.