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Photoreforming hydrogen evolution (Pr‐HE) of a water‐pollutant system could simultaneously achieve efficient hydrogen production and pollutant degradation. It provides a new way to solve energy and environmental issues, but the poor internal charge separation still limits its performance. This work designed hetero‐Janus nanofibers (HJNFs) with ordered electric field distribution and separated redox surfaces to promote Pr‐HE of the water‐pollutant system. Taking ZnO/NiO heterojunction as an example, the hetero‐Janus structures were prepared via "Dual‐channel" electrospinning and further confirmed by the element morphology analysis and asymmetric distribution of the XPS spectra. The theoretical simulation showed that Janus structures could effectively inhibit the electron trap and hole trap generation, then accelerate the directional carrier migration to the surface. Experimental investigations also confirmed that Janus structures could effectively suppress internal exciton luminescence and accelerate surface charge transfer. The Pr‐HE amount and the corresponding propranolol (PRO) degradation rate of HJNFs were 7.9 and 1.5 times higher than hetero‐mixed nanofibers (HMNFs). The enhancement factor of Pr‐HE in water‐PRO to pure water was about 3.1, but nearly zero for HMNFs. This prominent synergistic effect was due to the enhancement of charge separation and the inhibition of cascade side reaction from hetero‐Janus structures. Furthermore, the synchronous Pr‐HE and degradation reactions were significantly promoted by selective introducing Ag nanoparticles in one side of the HJNFs for enlarging the interfacial Fermi energy level difference. The hetero‐Janus strategy offers a new perspective on designing efficient photoreforming photocatalysts for energy and environment applications. [ABSTRACT FROM AUTHOR]

Herein, we successfully fabricated porous nanocomposite membranes decorated with high loadings of nickel nanoparticles (25–45 wt %) by using chelating additives (sodium dodecyl sulfate (SDS) and Fumion) for the film casting cum phase separation approach. These additives decreased the nickel agglomeration and promoted the presentation of particles at the pore surface of the final membranes, leading to increased water permeances (450 to 1200–2400 L/m2 hbar) and porosities (56% to 70–78%) in comparison to a nanocomposite membrane made without additives. The hydrophobic ionomer Fumion, incorporated into the polyethersulfone matrix during solidification, further allowed us to tune the membrane hydrophobicity. We discovered that the same nickel nanoparticles exhibited a 5× increased H2 generation rate during the catalytic hydrogen formation from ammonia borane when presented in a membrane with a higher water contact angle (85° compared to 60°). We could attribute this improvement to the lower capillary pressure in more hydrophobic pores, which facilitates the release of H2 bubbles. The nanocomposite membranes were further employed as flow-through reactors for the catalytic hydrogenation of p-nitrophenol (p-NP) in the presence of ammonia borane. Membranes with an additive-directed nickel nanoparticle presentation at the pore surface demonstrated 6 to 7× higher p-NP turnover frequencies (TOFs). We also observed that the formation of hydrogen gas from ammonia borane results in a permeance decrease during the flow-through p-NP conversion. However, this effect was mitigated in more hydrophilic membranes with an anisotropic pore structure. [ABSTRACT FROM AUTHOR]

A composite CC/Fe−MoS2@Au composed of gold nanoparticles in‐situ grown on Fe‐doped MoS2 anchored on carbon cloth (CC) was prepared for SERS detection and photo/photo‐Fenton degradation of fungi pesticides. Flower‐like MoS2 grown on CC provides large surface area for in‐situ reduction and immobilization of AuNPs, generating high SERS enhancement effect. Fe‐doping improves MoS2's SERS activity and photocatalysis and endows the composite with Fenton degradation ability due to the coexistence of Fe3+/Fe2+ confirmed by XPS. Owing to their synergy, the CC/Fe−MoS2@Au can achieve the SERS detection of fungicide crystal violet (CV) and malachite green (MG) with detection limits of 0.1 nM and 10 nM, respectively. The CC endows it flexibility for fungicide sensing on irregular surface, such as fish skin with a LOD of 10−7 M for MG. The composite displayed multimode degradation ability for fungicides: 70 % of 10−5 M CV could be degraded after 75 min photocatalytic degradation by CC/Fe−MoS2@Au under natural light, while it increases to 85 % in the presence of H2O2 through a photo‐Fenton reaction. The synergy mechanism of these components for fungicide degradation were discussed. Such flexible multifunctional composite has great value in SERS analysis, environmental monitoring and remediation. [ABSTRACT FROM AUTHOR]

In this study, we demonstrated a Step‐scheme (S‐scheme) based S‐C3N4/Ce2Zr2O7 (SCN/CZ) organic‐inorganic heterostructure, which was synthesized by a facile wet chemical route. The photocatalyst was highly efficient for the remediation of organic pollutants (POPs), namely 2,4‐dichlorophenol (2,4‐DCP, 20 ppm), 4‐chlorophenol (4‐CP, 20 ppm), and phenol (20 ppm) via dehalogenation under visible light (λ≥420 nm). Our finding reveals that a 20 wt.% S‐C3N4 on the surface of the SCN/CZ hybrid is an optimum requirement for potential catalytic activity. We achieve excellent photocatalytic performances i. e. 94 % for 2,4‐DCP, 92 % for 4‐CP, and 90 % for phenol removal, respectively. It was identified that superoxide and hydroxyl radicals (O2⋅− and ⋅OH) are diligently participating in the reaction medium. However, the content of O2⋅− species is more, which we have quantified as ∼66 μM when 20 % SCN/CZ is used. Furthermore, we have established the reaction pathways via an S‐scheme mechanism, which has great importance for photocatalysis. The prepared catalyst is highly stable and reusable for more than five cycles. The work presented here can contribute to the new perspective for pollutant removal via the dehalogenation route over the S‐C3N4/Ce2Zr2O7 surface. [ABSTRACT FROM AUTHOR]

Through the current research status of plasma degradation pollutants at home and abroad, taking the generation of plasma to how to play a role as the main line, this paper explores the generation process and influencing factors of plasma, summarizes the common plasma generation devices, discusses and compares the degradation efficiency of organic, inorganic and solid pollutants, and the degradation principle and mechanism of different types of pollutants. It also discusses the current problems of plasma, and the future development direction of plasma degradation is prospected. [ABSTRACT FROM AUTHOR]

In this work, an eco-friendly sol-gel synthesis of pure and doped TiO2, previously developed at lab-scale, is applied in three different environmental applications at lab-scale and then, upscaled towards industrial applications. For each application, the TiO2 is used as a coating deposited mainly on steel substrates. The three applications are: (i) the development of a photocatalytic reactor made of a UV lamp, an ozonation part and a TiO2 photocatalytic coating to treat water from swimming pools, (ii) the development of a new generation of low energy sterilizers by an advanced oxidation process using a photocatalytic coating illuminated by a blue LED, and (iii) an easy-to-clean coating for outdoor steel. In each application, the up-scale results were similar to those obtained in the laboratory with respect to the crystallinity, the visual aspect, the hydrophilicity, and the photocatalytic properties of the produced coatings. These developments showed the possibility to bring sol-gel TiO2 products outside the laboratory towards pilot and industrial applications, and opens the way for many possible up-scaled sol-gel based environmental applications. Highlights: Eco-friendly sol-gel synthesis of pure and doped TiO2 developed for industrial applications. TiO2 is deposited on steel substrates for three applications. TiO2 coatings used for decontamination of swimming pool and fountain waters. TiO2 layer also used as easy-to-clean coating for outdoor pre-painted steel. The efficiency of the layers is successfully up-scaled from laboratory to industrial applications. [ABSTRACT FROM AUTHOR]

Metal organic frameworks (MOFs) could greatly improve the power generation and degradation performance of microbial fuel cells (MFCs). MOFs and their compound derivatives played key role in cathode, anode and proton exchange membrane of MFCs, which greatly promoted the power generation of MFC and the degradation efficiency of various pollutants. However, MOFs were still possessed some defects, such as complex synthesis process, difficult regulation, instability, etc. Moreover, the application of MFC was limited in low power density, system internal resistance, microbial consumption, etc. Which further limited the degradation of pollutants by MFC. The existing problems and various improvement schemes of MOFs for MFCs were further summarized, which would provide references for promoting the application of MOFs materials in MFC system. It was expected to enhance the application of MOFs materials and promote the performance of MFC. • The types, design and synthesis methods of MOFs and their complex were summarized. • The research progress of MOFs compound in MFC degradation was reviewed. • The research trend of MOFs composites in MFC degradation was prospected. [ABSTRACT FROM AUTHOR]

The global energy shortage and environmental degradation are two major issues of concern in today's society. The production of renewable energy and the treatment of pollutants are currently the mainstream research directions in the field of photocatalysis. In addition, over the last decade or so, graphene (GR) has been widely used in photocatalysis due to its unique physical and chemical properties, such as its large light-absorption range, high adsorption capacity, large specific surface area, and excellent electronic conductivity. Here, we first introduce the unique properties of graphene, such as its high specific surface area, chemical stability, etc. Then, the basic principles of photocatalytic hydrolysis, pollutant degradation, and the photocatalytic reduction of CO2 are summarized. We then give an overview of the optimization strategies for graphene-based photocatalysis and the latest advances in its application. Finally, we present challenges and perspectives for graphene-based applications in this field in light of recent developments. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) is an important green oxidant in the field of sewage treatment, and how to improve its activation efficiency and generate free radicals with stronger oxidation performance is a key issue in current research. Herein, we synthesized a Cu-doped α-Fe2O3 catalyst (7% Cu-Fe2O3) for activation of H2O2 under visible light for degradation of organic pollutants. The introduction of a Cu dopant changed the d-band center of Fe closer to the Fermi level, which enhanced the adsorption and activation of the Fe site for H2O2, and the cleavage pathway of H2O2 changed from heterolytic cleavage to homolytic cleavage, thereby improving the selectivity of ⋅OH generation. In addition, Cu doping also promoted the light absorption ability of α-Fe2O3 and the separation of hole-electron pairs, which enhanced its photocatalytic activities. Benefiting from the high selectivity of ⋅OH, 7% Cu-Fe2O3 exhibited efficient degradation activities against ciprofloxacin, the degradation rate was 3.6 times as much as that of α-Fe2O3, and it had good degradation efficiency for a variety of organic pollutants. [ABSTRACT FROM AUTHOR]

Phase engineering is an emerging strategy for tuning the electronic states and catalytic functions of nanomaterials. Great interest has recently been captured by phase-engineered photocatalysts, including the unconventional phase, amorphous phase, and heterophase. Phase engineering of photocatalytic materials (including semiconductors and cocatalysts) can effectively affect the light absorption range, charge separation efficiency, or surface redox reactivity, resulting in different catalytic behavior. The applications for phase-engineered photocatalysts are widely reported, for example, hydrogen evolution, oxygen evolution, CO2 reduction, and organic pollutant removal. This review will firstly provide a critical insight into the classification of phase engineering for photocatalysis. Then, the state-of-the-art development of phase engineering toward photocatalytic reactions will be presented, focusing on the synthesis and characterization methodologies for unique phase structure and the correlation between phase structure and photocatalytic performance. Finally, personal understanding of the current opportunities and challenges of phase engineering for photocatalysis will also be provided. [ABSTRACT FROM AUTHOR]

Solar energy harvesting using semiconductor photocatalysis offers an enticing solution to two of the biggest societal challenges, energy scarcity and environmental pollution. After decades of effort, no photocatalyst exists which can simultaneously meet the demand for excellent absorption, high quantum efficiency and photochemical resilience/durability. While CdS is an excellent photocatalyst for hydrogen evolution, pollutant degradation and organic synthesis, photocorrosion of CdS leads to the deactivation of the catalyst. Surface passivation of CdS with 2D graphitic carbon nitrides (CN) such as g-C3N4 and C3N5 has been shown to mitigate the photocorrosion problem but the poor oxidizing power of photogenerated holes in CN limits the utility of this approach for photooxidation reactions. We report the synthesis of exfoliated 2D nanosheets of a modified carbon nitride constituted of tris-s-triazine (C6N7) linked pyromellitic dianhydride polydiimide (CN:PDI) with a deep oxidative highest occupied molecular orbital (HOMO) position, which ensures sufficient oxidizing power for photogenerated holes in CN. The heterojunction formed by the wrapping of mono-/few layered CN:PDI on CdS nanorods (CdS/CN:PDI) was determined to be an excellent photocatalyst for oxidation reactions including photoelectrochemical water splitting, dye decolorization and the photocatalytic conversion of benzyl alcohol to benzaldehyde. Extensive structural characterization using HR-TEM, Raman, XPS, etc., confirmed wrapping of few-layered CN:PDI on CdS nanorods. The increased photoactivity in CdS/CN:PDI catalyst was ascribed to facile electron transfer from CdS to CN:PDI in comparison to CdS/g-C3N4, leading to an increased electron density on the surface of the photocatalyst to drive chemical reactions. [ABSTRACT FROM AUTHOR]

Photonic crystals (PCs) with slow photon effect and multiple scattering for its three-dimensional ordered structure have been applied to improve light utilization and enhance photocatalytic activity. A ternary-structured photocatalyst was prepared. Bi2MoO6 was first sensitized by graphite-carbon nitride quantum dots (g-CNQDs) by in situ coupling via a hydrothermal method. The best performance of Bi2MoO6/g-CNQDs was 3.56 times higher than that of Bi2MoO6. The introduction of g-CNQDs improved both the light absorption range and charge transfer efficiency for Bi2MoO6/g-CNQDs composites. Furthermore, because of the combination of the g-CNQDs with the Bi2MoO6 nanosheets, the separation efficiency of photogenerated carriers was improved and the recombination rate was greatly reduced. To further improve light utilization, SiO2 PCs were composited to the above Bi2MoO6/g-CNQDs by spin coating to obtain ternary-structured Bi2MoO6/g-CNQDs/SiO2 PCs. The effect of the photonic band gap (PBG) of PCs on photocatalytic activity was investigated, and the photocatalytic activity was highest when the PBG was located near the absorption peak of g-CNQDs at 464 nm, which was 5.56 times higher than that of pure Bi2MoO6. The farther the photonic PBG is away from the absorption edge of g-CNQDs, the lower the photocatalytic activity of the composite membranes. This work provides a way to construct multiple-structured photocatalysts with high photocatalytic activity and confirms that PCs with precisely tuned band gap will substantially enhance the activity of photocatalysts. Highlights: A ternary-structured photocatalyst Bi2MoO6/g-CNQDs/SiO2 PCs was synthesized. Light harvesting is enhanced and the separation efficiency of photogenerated carriers is improved. The optimized Bi2MoO6/g-CNQDs/SiO2 PCs exhibit excellent photodegradation efficiency. As-prepared composite film photocatalyst has excellent reproducibility and stability. [ABSTRACT FROM AUTHOR]

Modern‐day society requires advanced technologies based on renewable and sustainable energy resources to face the challenges regarding environmental remediation. Solar‐inspired photocatalytic applications for water purification, hydrogen and oxygen evolution, carbon dioxide reduction, nitrogen fixation, and removal of bacterial species seem to be unique solutions based on green and efficient technologies. Considering the unique electronic features and larger surface area, 2D photocatalysts have been broadly explored for the above‐mentioned applications in the past few years. However, their photocatalytic potential has not been optimized yet to the adequate level of practical and commercial applications. Among many strategies available, surface and interface engineering and the hybridization of different materials have revealed pronounced potential to boost the photocatalytic potential of 2D materials. This feature review recapitulates recent advancements in engineered materials that are 2D for various photocatalysis applications for environmental remediation. Various surface and interface engineering technologies are briefly discussed, like anion–cation vacancies, pits, distortions, associated vacancies, etc., along with rules and parameters. In addition, several hybridization approaches, like 0D/2D, 1D/2D, 2D/2D, and 3D/2D hybridization, etc., are also deeply investigated. Lastly, the application of these engineered 2D materials for various photocatalytic applications, challenges, and future perspectives is extensively explored. [ABSTRACT FROM AUTHOR]

Water scarcity is becoming a major issue worldwide due to water pollution and population growth, calling for advanced techniques for water reclamation. For instance, advanced oxidation processes using semiconductor photocatalysts appear promising, yet the light-harvesting capacity of semiconductors must be optimized to ensure complete degradation of contaminants. For this, semiconductors have been modified using electrochemical, sol–gel, hydrothermal, co-precipitation, and microwave-assisted methods. Here, we review electro-fabrication strategies for generating photocatalytic systems for wastewater remediation. We found that the photophysical properties of electrogenerated photocatalysts can be optimized by modulating electrochemical parameters, customizing the electrolyte component, integration of other synthetic routes, innovative technology in the electrochemical setup, and optimization at the final crystallization stages. We focus on anodic dissolution, anodization, metal electrodeposition, current and potential, electrolyte agitation and formulation, additives, electrosynthesis temperature, solvents, crystallization and unconventional electrochemical setup. [ABSTRACT FROM AUTHOR]

The growing world population is closely associated with the increased demand of safe drinking water and sustainable energy production. This drives the focus of the scientific community to work toward water remediation and clean energy generation. The combination of photoelectrooxidation of pollutants at the anode with simultaneous hydrogen gas production at the cathode is a smart strategy to address these problems. Herein, we have designed a bifunctional photoelectrocatalytic system consisting of a self-standing photoanode to degrade the water pollutant molecules with simultaneous production of molecular hydrogen at the cathode. The photoanode was prepared by coating Bi2O3 over the surface of self-standing TiO2 nanorods. Thus, prepared photoelectrodes show high degradation efficiency for rhodamine molecules, where direct oxidation of rhodamine by the holes generated under solar light illumination was detrimental for its activity. During simultaneous pollutant removal and energy production experiments, the anode shows 100% degradation of pollutant molecules while the cathode shows high hydrogen gas production (128 mM cm–2 h–1). The prepared composite showed higher efficiency of visible-light absorbance, high charge generation capability, and low charge transfer resistance at the interface as determined via several characterizations, compared to the bare titania. The catalyst is easy to prepare and robust in activity for several kinds of pollutant molecules tested. Its robust activity, high stability, and durability open up an avenue for the wastewater treatment with simultaneous renewable energy production technologies. [ABSTRACT FROM AUTHOR]

The preparation of visible-light-driven photocatalysts has become highly appealing for environmental remediation through simple, fast and green chemical methods. The current study reports the synthesis and characterization of graphitic carbon nitride/titanium dioxide (g-C3N4/TiO2) heterostructures through a fast (1 h) and simple microwave-assisted approach. Different g-C3N4 amounts mixed with TiO2 (15, 30 and 45 wt. %) were investigated for the photocatalytic degradation of a recalcitrant azo dye (methyl orange (MO)) under solar simulating light. X-ray diffraction (XRD) revealed the anatase TiO2 phase for the pure material and all heterostructures produced. Scanning electron microscopy (SEM) showed that by increasing the amount of g-C3N4 in the synthesis, large TiO2 aggregates composed of irregularly shaped particles were disintegrated and resulted in smaller ones, composing a film that covered the g-C3N4 nanosheets. Scanning transmission electron microscopy (STEM) analyses confirmed the existence of an effective interface between a g-C3N4 nanosheet and a TiO2 nanocrystal. X-ray photoelectron spectroscopy (XPS) evidenced no chemical alterations to both g-C3N4 and TiO2 at the heterostructure. The visible-light absorption shift was indicated by the red shift in the absorption onset through the ultraviolet-visible (UV-VIS) absorption spectra. The 30 wt. % of g-C3N4/TiO2 heterostructure showed the best photocatalytic performance, with a MO dye degradation of 85% in 4 h, corresponding to an enhanced efficiency of almost 2 and 10 times greater than that of pure TiO2 and g-C3N4 nanosheets, respectively. Superoxide radical species were found to be the most active radical species in the MO photodegradation process. The creation of a type-II heterostructure is highly suggested due to the negligible participation of hydroxyl radical species in the photodegradation process. The superior photocatalytic activity was attributed to the synergy of g-C3N4 and TiO2 materials. [ABSTRACT FROM AUTHOR]

In recent years, polydopamine (PDA) has attracted extensive attention of researchers due to its unique chemical structure and functional groups. However, a comprehensive review of PDA-based materials in electrocatalysis and photocatalysis is still lacking. The aim of this review is to summarize recent progress and development of PDA-assisted electrocatalytic and photocatalytic reactions. Owing to its unique advantages in surface modification, it has been a good platform for the construction of electrocatalytic and photocatalytic materials. With the development of biological sources, PDA has been increasingly applied in the field of materials science. However, it is still lacking of a comprehensive review which focuses on PDA surface modification strategies and its derivative function for electrocatalysis and photocatalysis applications. Here in this article the preparation and polymerization mechanism of PDA and its derivatives has been firstly reviewed. Then their physical and chemical properties have been introduced, including chemical reactivity, optical property, conductivity, and cohesiveness. Thirdly, the electrocatalytic and photocatalytic activities of PDA and its derivatives have been demonstrated. Finally, the advances of their electrocatalytic and photocatalytic applications have been summarized including hydrogen production, pollutant degradation, and CO 2 reduction. We believe this synthetic study can provide critical information for mussel-inspired chemistry, which will be of great interest for researchers from chemistry, materials, biology, medicine, and interdisciplinary. This paper can provide readers with a general framework of PDA and its derivatives in the field of photocatalysis and electrocatalysis including hydrogen production, pollutant degradation, and CO 2 reduction. [Display omitted] • Bioinspired polydopamine for electrocatalysis and photocatalysis are overviewed. • The mechanism of polydopamine derivatives assisted electrocatalytic hydrogen evolution reaction is classified and discussed. • The design and fabrication of polydopamine and photoresponsive semiconductor for photocatalytic reaction. • This review bodes well for the development of electrocatalysis and photocatalysis field founded on multifunctional polydopamine. • The advances of electrocatalytic and photocatalytic applications of polydopamine have been summarized. [ABSTRACT FROM AUTHOR]

Piezocatalytic reactions are generally excited by ultrasonication and, as such, should occur simultaneously with other catalytic reactions caused by different mechanisms such as sonocatalysis or tribocatalysis. One of the main challenges is how to discriminate between these effects in a catalysis experiment and quantify each contribution. In order to distinguish these effects, we use nano- and micro-particles of piezoelectric barium titanate (BaTiO3) and then compare their catalytic properties below and close to the piezoelectric to non-piezoelectric phase transition temperature at which the crystalline structure changes from the low-temperature tetragonal, piezoelectric phase to the higher-temperature cubic, non-piezoelectric phase. All other parameters, such as particle size, surface termination, etc., remain unaltered. The phase transition in bulk occurs at about 120 °C, but the transition temperature decreases as a function of particle size and reaches room temperature for particle sizes of about 20 nm. Transmission electron microscopy and X-ray diffraction were used to characterize the morphology and crystalline phase of the nanoparticles, respectively. Since the piezoelectric properties and the lattice dynamics are closely related, temperature-dependent Raman spectroscopy provides an even better insight into the nano- and micro-structural properties, allowing the ferroelectric phase transition temperature to be estimated. The catalytic activities of the BaTiO3 nanoparticles were determined by monitoring the optical absorption of a solution containing the model pollutant methyl orange, after ultrasonication of the solution to which were added the dispersed piezoelectric BaTiO3 particles as catalysts. An exponential-like correlation has been found between the catalytic reaction rates and the tetragonal distortion of the crystal structure of the BaTiO3 particles. Our study has also established that while 10% of the catalytic reaction of BaTiO3 is related to either sonocatalysis or tribocatalysis, the remaining 90% of the overall catalytic activity is ascribed to the piezocatalytic contribution. [ABSTRACT FROM AUTHOR]

Three-dimensionally printed materials show great performance and reliable stability in the removal of refractory organic pollutants in Fenton-like reactions. In this work, hierarchically porous zero-valent copper (3DHP-ZVC) was designed and fabricated via 3D printing and applied as a catalyst for the degradation of tetracycline (TC) through heterogeneous Fenton-like processes. It was found that the 3DHP-ZVC/H2O2 system could decompose over 93.2% of TC within 60 min, which is much superior to the homogeneous Cu2+/H2O2 system under similar conditions. The leaching concentration of Cu2+ ions in the 3DHP-ZVC/H2O2 system is 2.14 times lower than that in the Cu powder/H2O2 system in a neutral environment, which could be ascribed to the unique hierarchically porous structure of 3DHP-ZVC. Furthermore, 3DHP-ZVC exhibited compelling stability in 20 consecutive cycles. The effects of co-existing inorganic anions, adaptability, and pH resistance on the degradation of TC were also investigated. A series of experiments and characterizations revealed that Cu0 and superoxide radicals as reducing agents could facilitate the cycling of Cu(II)/Cu(I), thus enhancing the generation of hydroxyl radicals to degrade TC. This study provides new insights into employing promising 3D printing technology to develop high-reactivity, stable, and recycling-friendly components for wastewater treatment. [ABSTRACT FROM AUTHOR]

In recent times, green chemistry or "green world" is a new and effective approach for sustainable environmental remediation. Among all biomaterials, cellulose is a vital material in research and green chemistry. Cellulose is the most commonly used natural biopolymer because of its distinctive and exceptional properties such as reproducibility, cost-effectiveness, biocompatibility, biodegradability, and universality. Generally, coupling cellulose with other nanocomposite materials enhances the properties like porosity and specific surface area. The polymer is environment-friendly, bioresorbable, and sustainable which not only justifies the requirements of a good photocatalyst but boosts the adsorption ability and degradation efficiency of the nanocomposite. Hence, knowing the role of cellulose to enhance photocatalytic activity, the present review is focused on the properties of cellulose and its application in antibiotics, textile dyes, phenol and Cr(VI) reduction, and degradation. The work also highlighted the degradation mechanism of cellulose-based photocatalysts, confirming cellulose's role as a support material to act as a sink and electron mediator, suppressing the charge carrier's recombination rate and enhancing the charge migration ability. The review also covers the latest progressions, leanings, and challenges of cellulose biomaterials-based nanocomposites in the photocatalysis field. [ABSTRACT FROM AUTHOR]

A fuzzy optimization model was implemented in this study as a decision-making approach to optimize pollutant degradation processes in facultative ponds of domestic wastewater treatment plants. The fuzzy parameters are due to uncertain situations, which eliminate the need for managers to collect data, particularly when the data are no longer represent the real situation. The managers formulate the fuzzy parameters in the problem based on their intuition and experience in using the provided decision-making tool. Also, the fuzzy optimization model proposed in this study was solved using the fuzzy-based programming approach with the generalized gradient algorithm performed in LINGO 19.0 optimization software. In addition, the numerical experiment was conducted with secondary and generated data for the certain and fuzzy parameters, respectively. The results showed that optimal decisions were achieved and the manager can then use the proposed model in managing domestic wastewater treatment plants. [ABSTRACT FROM AUTHOR]

In recent years, microwave (MW) photocatalytic treatment was used for the removal of several pollutants from wastewater to overcome the disadvantages of conventional photocatalytic treatment. MW irradiation significantly enhanced the photocatalytic degradation pollutants and is considered an innovative treatment approach. This enhancement in photoactivity was mainly attributed to thermal and non-thermal effects of the MW irradiation. Even though the thermal effects of MW irradiation have been conclusively studied, there are many conflicting results regarding the non-thermal effects in catalysts. In general, it has been verified that the non-thermal effects are due to the electrical and magnetic properties of MW. In this article, a detailed review of the recent advancements in MW-assisted photocatalysis has been done, emphasizing the non-thermal effects of MW radiation on the surface of the catalysts. Also, the evolution of external ultraviolet (UV) sources from the conventional Hg lamp to the latest microwave-driven electrodeless lamps (MDEL) has been discussed. MW photocatalytic treatment using MDELs showed complete removal of lignin, dimethyl phthalate (DMP), and azo dye reactive brilliant red X-3B (BR) and more than 90% removal for cimetidine (CMT), rhodamine B (RB), and methylene blue (MB). A brief comparison regarding the removal efficiencies of pollutants by various AOPs and MW photocatalysis has been made to understand the enhanced photoactivity. In addition, various operating parameters that affect the MW photocatalysis like MW intensity, pH, dissolved oxygen, and catalyst dosage; the degradation pathways of various pollutants; and the cost assessment of MW photocatalysis are discussed in detail. This paper will deliver a scientific and technical overview and useful information to scientists and engineers working in this field. [ABSTRACT FROM AUTHOR]

[Display omitted] • Tightly bound EPS had high aromaticity and molecular weight. • RIs generation efficiency of EPS depended on the attachment degree with biofilm. • 1O 2 had the highest contribution on the photodegradation of SDBS by EPS. • RIs led to benzene ring opening and produced low-molecular breakdown substances. Extracellular polymeric substances (EPS) produced by microorganisms are ubiquitous in natural and engineered aquatic systems, but limited research has been conducted on the photosensitivity of EPS for degrading organic pollutants. The degradation of sodium dodecylbenzene sulfonate (SDBS), a typical organic pollutant in natural aquatic environments, is closely associated with biofilms; however, the indirect photodegradation of SDBS by photosensitized reactive intermediates (RIs) of EPS remains unclear. Here, we extracted three types of EPS (soluble state-SEPS, loosely bound-LB-EPS, and tightly bound-TB-EPS) from biofilms from cultured biofilms to evaluate their photoactivities in generating RIs under irradiation and photodegradation mechanism of SDBS. We found that TB-EPS exhibited higher aromaticity, molecular weight and nitrogenous compound concentration, whereas SEPS and LB-EPS had higher proportion of CHO-like substances than TB-EPS did. The steady-state concentrations of 3DOM*, ·OH, and 1O 2 for EPS solutions varied depending on the degree of attachment to the biofilm; specifically, looser attachment resulted in higher efficiency in generating RIs. EPS effectively facilitated the degradation of SDBS through RIs, with 1O 2 contributing significantly. Products analysis demonstrated that RIs attacked the sulfonic acid groups within SDBS − possessing strong electron-donating ability − leading to benzene ring opening as well as oxidation-induced breakdown into low-molecular-weight substances. This study elucidates the intricate structure and photochemical properties of EPS, while also delving into the mechanistic role of RIs in the degradation of SDBS. These findings hold significant implications for enhancing the efficiency of organic pollutant photodegradation and broadening the application scope of photocatalytic technology. [ABSTRACT FROM AUTHOR]

The presence of tetrachlorobisphenol A(TCBPA) in the environment is continually increasing, which has potential negative effects on human health. Therefore, it is important to develop new materials that can degrade these compounds using various modification techniques. Recently, the photocatalytic degradation of organic pollutants using peroxides has been widely used as the focus of several research studies. This study synthesized Zr-doped NiFe 2 O 4 (Zr-NiFe 2 O 4) metal complex materials using a co-precipitation method and applied them to catalyze the degradation of a typical halogenated bisphenol A pollutant using different phase-catalyzed peroxydisulfate (PS) compounds. The results showed that Zr-NiFe 2 O 4 significantly enhances the nitrogen-active adaptive catalytic action between the reactive species and (NH 4) 2 S 2 O 8 , exhibiting an excellent catalytic performance (99 %). The degradation rate could reach 90 % after 30 mins with the low concentration of TCBPA (20 mg•L–1). Furthermore, the degradation of TCBPA in the Zr-NiFe 2 O 4 /LED/(NH 4) 2 S 2 O 8 system occurred over a wide pH range of 3–11. The results of leaching metals were detected that the concentrations of the leached zirconium, nickel and iron ions declined to 0.018 mg•L−1. In addition, the tri-metal synergistic effect of Zr-NiFe 2 O 4 not only significantly improved the TCBPA removal efficiency, but also enhanced the long-term stability of the composite material. Mechanistic studies revealed that ·OH and SO 4 ·– were involved in the TCBPA degradation process with ·OH being the primary active species, and the possible degradation pathways were deduced using mass spectrometry. The on-line infrared test experiments showed the disappearance of the hydroxyl and double bond within approximately 120 seconds. Moreover, the magnetic properties of Zr-NiFe 2 O 4 met the water recovery requirements, effectively reducing secondary pollution, and aligned with the practical needs for water treatment, providing data for the construction of efficient magnetic catalysts. • NiFe 2 O 4 doped with Zr was fabricated and characterized. • The degradation of a halogenated bisphenol A pollutant using Zr-NiFe 2 O 4 was studied. • The effect of Zr-NiFe 2 O 4 and (NH 4) 2 S 2 O 8 on halogenated bisphenol degradation efficiency is up to 99 %. • TCBPA degradation in real wasterwater was investigated. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel phosphorus heteroatom doped BiOCl (P-BiOCl) catalyst was rationally designed. • P-BiOCl catalyst endowed excellent photo-piezocatalytic activity and stability toward organic pollutant degradation. • The relevant experimental and DFT calculation results were exhibited to clarify enhanced photo-piezocatalytic mechanism. • P-BiOCl catalyst holds significant practical value in environmental remediation applications. A novel phosphorus heteroatom doped bismuth oxychloride (P-BiOCl) catalyst was synthesized and the photo-piezocatalytic degradation of rhodamine B dye performances were explored under the ultrasound vibration and light illumination. The P-BiOCl exhibited excellent photo-piezocatalytic degradation activity, such as an ultra-high reaction kinetic rate constant of 0.3961 min−1, efficient degradation efficiency (94.7 % within 8 min) and excellent stability compared to solely piezocatalysis and photocatalysis. More impressively, these outstanding performances of P-BiOCl exceeded pure BiOCl and most other catalytic materials systems. The relevant experimental and density functional theory (DFT) calculation results were exhibited to clarify enhanced photo-piezocatalytic mechanism. The introduction of P heteroatom could reduce the bandgap of BiOCl, modulate electronic structure and charge redistribution, provide novel electron channel to promote electron transfer and restrain charge carriers recombination. Additionally, P-doped could also enhance the adsorption of oxygen and water molecules, promote intrinsic catalytic activity, leading to the increased production of active free radicals ·O 2 – and ·OH, thus significantly boosting the efficiency of organic pollutant degradation. This work provides a comprehensive understanding of heteroatom doping enhancing photo-piezocatalytic activity and presents a potential new strategy for designing highly efficient catalysts for wastewater treatment. [ABSTRACT FROM AUTHOR]

• Use of CFD modeling to analyze photocatalytic reactors' performance. • The desirability function method used to optimize the reactor geometry configuration. • Box-Benken experimental design to evaluate the effect of different factors. • Heterogeneous photocatalysts as alternative to water treatment of emerging pollutants. • Combining the annular and labyrinth photocatalytic reactor advantages in one device. An annular labyrinth photocatalytic reactor design was optimized to degrade water emerging pollutants by combining CFD modeling and a Box-Benken experimental design with the desirability function method for the optimization. The optimization was performed by minimizing the pollutant degradation time and the reactor operational cost, varying three factors in the experimental design, the fins number in the labyrinth, the thickness of the annular region, and the solution transmittance. The range of variation levels was 5 to 9, 5 mm to 25 mm, and 35 % to 95 % respectively. The intrinsic kinetic model of the salicylic acid degradation used in CFD simulations takes into account the variations of pollutant concentration and light intensity. Results showed that the transmittance was the most significant factor in minimizing both degradation time and energy cost, followed by the annular reactor thickness and the fins number. The desirability method showed that the combination of the optimized reactor levels was 9 fins, thickness of 25 mm, and transmittance of 95 %. To verify the efficiency gain of the optimized reactor, it was compared the degradation time and the energy cost of the optimized reactor with a conventional annular reactor. The efficiency gain was about 53 %. [Display omitted] [ABSTRACT FROM AUTHOR]

Soil ecosystems are complex networks of microorganisms that play pivotal roles in nutrient cycling, stress resilience, and the provision of ecosystem services. Among these microbial communities, soil biofilms, and complex aggregations of microorganisms embedded within extracellular polymeric substances (EPS) exert significant influence on soil health and function. This review delves into the dynamics of soil biofilms, highlighting their structural intricacies and the mechanisms by which they facilitate nutrient cycling, and discusses how biofilms enhance the degradation of pollutants through the action of extracellular enzymes and horizontal gene transfer, contributing to soil detoxification and fertility. Furthermore, the role of soil biofilms in stress resilience is underscored, as they form symbiotic relationships with plants, bolstering their growth and resistance to environmental stressors. The review also explores the ecological functions of biofilms in enhancing soil structure stability by promoting aggregate formation, which is crucial for water retention and aeration. By integrating these insights, we aim to provide a comprehensive understanding of the multifaceted benefits of biofilms in soil ecosystems. This knowledge is essential for developing strategies to manipulate soil biofilms to improve agricultural productivity and ecological sustainability. This review also identifies research gaps and emphasizes the need for practical applications of biofilms in sustainable agriculture. [Display omitted] • Soil microbes communicate via density dependent signaling molecules to form biofilms. • Soil biofilms facilitate nutrient cycle and resistance of environmental stresses. • Cometabolism and crossfeeding are primary modes of bioremediation by soil biofilms. • Biofilms enhanced remediation efficiency of pollutants by horizontal gene transfer. • Microorganisms and plants interact closely through the rhizosphere biofilms in soil. [ABSTRACT FROM AUTHOR]

[Display omitted] • Overview of Titanium and Iron-based Metal-Organic Frameworks (MOFs): This review provides a comprehensive examination of the synthesis methods, structural characteristics, and properties of Ti and Fe-based MOFs, emphasizing their relevance in photocatalysis. • Synthetic Strategies: Various synthetic approaches for the fabrication of Ti and Fe-based MOFs are discussed, including microwave-assisted, and mechanochemical methods, Dry- gel conversion, crystallization method, diffusion method, post-synthetic modification and diffusion method with a focus on optimizing structure and photocatalytic performance. • Photocatalytic Applications: This review explores the diverse range of photocatalytic applications enabled by Ti and Fe-based MOFs, including pollutant degradation, hydrogen evolution, CO 2 reduction, N 2 reduction, oxygen production and organic synthesis, showcasing their versatility and potential for sustainable energy and environmental remediation. Metal-organic frameworks (MOFs) have emerged as promising materials for photocatalytic applications due to their tunable structures and exceptional surface areas. Among various types of MOFs, those based on titanium (Ti) and iron (Fe) have garnered significant attention for their potential in environmental remediation, energy conversion, and organic synthesis. This review paper comprehensively examines the recent advancements in the photocatalytic applications and synthetic strategies of Ti and Fe-based MOFs. In the first part, we provide an in-depth analysis of the synthetic strategies employed for the preparation of Ti and Fe-based MOFs with tailored photocatalytic properties. The second part of the review highlights the diverse photocatalytic applications of Ti and Fe-based MOFs, including environmental remediation through the degradation of organic pollutants, hydrogen evolution reaction (HER) for renewable energy production, carbon dioxide reduction for greenhouse gas mitigation, and catalysis of organic transformations. Overall, this review paper offers valuable insights into the current state-of-the-art in the field of Ti and Fe-based MOFs for photocatalytic applications, providing researchers and practitioners with a comprehensive understanding of the potential and limitations of these materials. The synthesis strategies discussed herein serve as guidelines for the rational design and development of highly efficient photocatalysts for various environmental and energy-related applications. [ABSTRACT FROM AUTHOR]

Photocatalysis has been widely used as one of the most promising approaches to remove various pollutants in liquid or gas phases during the last decade. The main emphasis of the study is on the synergy of vacancy engineering and heterojunction formation, two widely used modifying approaches, to significantly alter photocatalytic performance. The vacancy-induced Ag 2 CO 3 /BiOBr/WO 3-x heterojunction system has been fabricated using a co-precipitation technique to efficiently abate methylene blue (MB) dye and doxycycline (DC) antibiotic. The as-fabricated Ag 2 CO 3 /BiOBr/WO 3-x heterojunction system displayed improved optoelectronic characteristic features because of the rational combination of dual charge transferal route and defect modulation. The Ag 2 CO 3 /BiOBr/WO 3-x system possessed 97% and 74% photodegradation efficacy for MB and DC, respectively, with better charge isolation and migration efficacy. The ternary photocatalyst possessed a multi-fold increase in the reaction rate for both MB and DC, i.e., 0.021 and 0.0078 min−1, respectively, compared to pristine counterparts. Additionally, more insightful deductions about the photodegradation routes were made possible by the structural investigations of MB and DC using density functional theory (DFT) simulations. This study advances the understanding of the mechanisms forming visible light active dual Z-scheme heterojunction for effective environmental remediation. • Vacancy induced Ag 2 CO 3 /BiOBr/WO 3-x was fabricated using co-precipitation method. • O V in WO 3 and dual charge transferal route synergistically boosted the charge isolation efficacy. • •OH, and •O 2 − were the main reactive species responsible for the photodegradation of MB and DC. • The MB and DC degradation pathways are validated by DFT and experimental studies. • 97%, and 74% degradation efficacies were obtained for MB and DC, respectively within 1h 15 min. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Bi/BiOClBr photocatalyst had obtained for the first time by solvothermal method. • The formation of heterostructures facilitated the migration of photogenerated carriers. • Bi metal improves light absorption and promotes electron-hole separation. • The sample exhibits good degradation of RhB (100%), OFX (95.4%) and TC (97.0%), respectively. Exploring cost-effective and highly active photocatalysts is crucial for achieving the thorough breakdown of pollutants and addressing the inherent drawbacks of current photocatalytic technologies. In this research, a chrysanthemum-like Bi/BiOClBr photocatalyst was obtained for the first time using a straightforward solvothermal means. Various analytical methods were utilized to comprehensively analyze the characteristics of the composite materials. The exceptional photocatalytic effectiveness of Bi/BiOClBr was demonstrated by its efficient removal of pollutants such as rhodamine (RhB), tetracycline (TC) and ofloxacin (OFX). The presence of BiOCl and BiOBr heterostructures facilitated the movement of photogenerated carriers. Moreover, by incorporating metallic Bi into the composite, which manifests a surface plasmon resonance (SPR) effect, we not only notably augmented the composite's ability to absorb visible light but also functioned as an "electron trap," thereby enhancing the efficiency of separating and transferring photogenerated electrons and holes. This work offered innovative perspectives in the development and fabrication of noble metal-free, decorated semiconductor photocatalysts with outstanding activity and reusability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Well unified organic–inorganic hybrid membrane for energy and environment systems. • Network-like structure amid β-PVDF and sMOS 2 , nanocellulose in membrane. • High H+ transport and less O 2 permeability leads to higher MFC result. • Stable and efficient sonocatalytic activity with high degradation efficiency. • Viable substitute for PEM ofMFC and sonocatalyst for organic pollutant degradation.. Fostering the creation of clean energy technologies that eliminate gas emissions and positively impact the environment is vital for confronting the dual challenges of escalating energy demands and environmental contaminants. Membrane-based technologies have emerged as effective strategies for harvesting clean energy and practically purifying water from contaminated wastewater. Here, we show that polyvinylidene difluoride (PVDF) with functionalized molybdenum disulfide (sMoS 2) and nanocellulose (NC) is an attractive membrane for single-chamber air cathode microbial fuel cells (MFCs). Compared with conventional proton exchange membranes, our membrane boosts power generation up to 48.5 mW m−2 and efficiently catalyzes sonocatalytic dye degradation with 96 % efficiency when treating wastewater. This performance is due to a relatively high hydrophilicity, ion exchange capacity (0.84 meq. g−1), and proton conductivity (1.03 × 10−2 S cm−1), combined with reduced oxygen permeability (27 × 1012 cm s−1) compared with conventional membranes. The synergy effect of the PVDF matrix and sMoS 2 + NC promotes proton transfer, enhancing electricity generation and pollutant degradation. The membrane shows promising stability and mechanical properties, offering a viable membrane for improved energy recovery from wastewater treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel g-C 3 N 4 /C-dots/ZnIn 2 S 4 heterostructures as photocatalyst of dye degradation were synthesized. • In the presence of C dots, heterostructures with a higher specific surface area are formed. • Doping with C dots results on 1.6-fold increase in adsorption capacity of heterostructures. • Degradation of rhodamine B occurs with the participation of both photoexcited electrons and holes. • In excess oxygen, dye degradation is more efficient due to the formation of OH radicals. This paper reports synthesis and characterization of original photocatalytic materials based on g-C 3 N 4 and ZnIn 2 S 4 compounds and doped with carbon dots. Such materials can be used for degradation of organic contaminants and water splitting. Deposition of the ZnIn 2 S 4 phase on surfaces of g-C 3 N 4 materials resulted in a substantial increase in their specific surface area and adsorption capacity. Synthesis of heterostructures in the presence of carbon dots favored formation of uniform structures with larger surface areas and a narrow size distribution of pores. Photocatalytic properties of the materials produced in this work were tested by performing degradation of rhodamine B. The highest photocatalytic activity was demonstrated by the heterostructures with the 25/75 ratio of the g-C 3 N 4 and ZnIn 2 S 4 components. Doping 2.5 w.% carbon dots into the resulting g-C 3 N 4 /ZnIn 2 S 4 heterostructures provided an additional 1.3-fold increase in their photocatalytic activity. Carbon dots in the heterostructures contributed to accumulating photoexcited electrons and therefore intensifying dye degradation. Photoexcited electrons were found to mostly participate in rhodamine B deethylation via formation of O 2 ·– radicals. Destruction of the dye structure was found to occur via its interactions with photoexcited holes and partially with the OH· radicals generated by O 2 ·– particles. [ABSTRACT FROM AUTHOR]

Fe-based metal-organic frameworks (Fe-MOFs) show great potential as effective Fenton catalysts in practical pollutants degradation. However, the sluggish cycling rate of the Fe(III)/Fe(II) pair severely impedes their catalytic performance, and thus hinders the framework's effectiveness. In this work, by employing a mixed-valent Fe-MOF, we proposed an innovative strategy to address the limitation of Fe(III)/Fe(II) cycle of Fe-MOF in photo-Fenton-like reaction. We pioneered a direct Fe(II) proportional substitution method to synthesize a variety of mixed-valent Fe-MOFs by adjusting the FeIII/FeII ratio in the precursor, utilizing MIL-53(Fe)-NH 2 as the template material. Notably, with superior accelerated Fe(III)/Fe(II) cycle, the constructed Fe-MOF-2 with a distinctive FeIII/FeII ratio of 3:1 displayed exceptional oxytetracycline (OTC) catalytic degradation capabilities, with an impressive degradation rate of 92.6 % within 30 min. The FeIII/FeII mixed-valent structure was proven to expedite the rate-determining step of PMS activation, which involved the reduction process of the Fe(III)/Fe(II) cycle. The production of more iron-unsaturated sites effectively promoted the production of SO 4 •− and •OH, which contributed significantly to the OTC degradation. Additionally, the possible removal intermediates, mechanism and pathways of OTC degradation in the Fe-MOF-2-based system were elucidated. This study provides a pioneering perspective, and demonstrates the potential application of mixed-valent Fe-MOF as a photo-Fenton-like catalyst. [Display omitted] • A novel mixed-valent Fe-MOFs was constructed for Fenton-like oxidation processes. • The structure of Fe-MOFs was rationally regulated by partial Fe(II) substitution. • Accelerated Fe(II)/Fe(III) cycling was achieved under visible light irradiation. • The catalytic sites and diffusion rate was enhanced for antibiotic degradation. • Mixed-valence Fe-MOFs showed excellent photo-Fenton-like degradation for OTC and dyes. [ABSTRACT FROM AUTHOR]

• Enhanced photocatalytic performance achieved through the synthesis of a novel Ag6Si2O7/WSe2 heterojunction. • Effective charge separation and strong redox ability attained. • Semiconductors modified using S-scheme heterojunctions to broaden the absorption spectrum. • Valuable insights provided through a detailed demonstration of the RhB degradation pathway. The implementation of semiconductor photocatalyst engineering offers a promising solution to combat water pollution and energy crises by efficiently converting solar energy into chemical energy for organic dye decomposition. By hydrothermal method nanostructures of Ag 6 Si 2 O 7 /WSe 2 were synthesized and investigated their effectiveness in solar-driven photo-degradation of rhodamine B (RhB) and Methylene Blue (MB) dyes. Ag 6 Si 2 O 7 /WSe 2 nanocomposites were developed by varying the weight percentage of WSe 2 from 0 to 25 % in the Ag 6 Si 2 O 7 matrix. The physicochemical properties of the nanocomposites were analyzed by using various techniques such as XRD, FE-SEM, and TEM/HRTEM. Additionally, the optical properties were investigated using UV–Vis, PL, and EIS. According to the BET study, the AgWS-c composite exhibited the highest BET surface area at 47.56 m2/g and outperformed other composites by achieving degradation rates of 96.24 % for RhB and 97.70 % for MB within 50 min. The rate constant of AgWS-c (0.0513 min−1) was 16.54 times higher than that of Ag 6 Si 2 O 7 and 2.63 times more than WSe 2 pristine, indicating its efficacy in dye degradation. ESR analysis assessed ROS species activity, LC/MS identified degradation intermediates, and a degradation mechanism pathway for RhB was proposed. The findings suggest that AgWS-c is a promising candidate for rapid and efficient wastewater treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

Microbial communities in groundwater ecosystems can develop the capacity to degrade complex mixtures of chemicals resulting from pollution by landfill leachate. Monitoring this natural attenuation requires insight into the metabolic potential and activity of microbial communities. We contrasted the metagenomes and metatranscriptomes from a leachate-polluted aquifer downstream of the Banisveld (the Netherlands) landfill with uncontaminated groundwater, which revealed changes in microbial genomic content and activity. Banisveld landfill leachate contains mono-aromatic hydrocarbons and the assessment of natural attenuation of these compounds in the aquifer had been a focal point of research. In the contaminated groundwater, active microbial functions were the ones involved in degradation of complex carbon substrates and organic pollutants. We found that benzylsuccinate synthase genes-involved in the catabolism of toluene-were highly expressed close to the source of contamination, confirming the ongoing natural attenuation of organic mono-aromatic hydrocarbon pollution in this aquifer. Additionally, metatranscriptomes were indicative of phosphorus limitation that can constrain total microbial activity and agree with the low phosphate concentrations (

Photocatalytic technology could effectively degrade pollutants and release hydrogen. Herein, novel composite materials of Zn0.4Cd0.6S (ZCS) and cobalt antimony oxide (CSO) with different proportions were successfully synthesized through a hydrothermal reaction process. It was proved via various characterization analyses that abundant nano ZCS particles (about 100 nm) were closely coated on the surface of larger CSO particles in the composite photocatalysts, and the heterojunction structure was formed. The synthesized materials could be used as highly efficient photocatalysts to boost the photocatalytic hydrogen evolution and degradation of methylene blue (MB) in visible light. The composite photocatalysts displayed favorable stability, and the optimal proportion was ZCS/1CSO. In addition, the composite materials exhibited a wider absorption range for visible light, and the apparent hydrogen production rate was about 3.087 mmol·g−1·h−1. Meanwhile, compared with single materials, the composite photocatalyst obtained higher photocurrent response and lower electrochemical impedance through conducting photo-electrochemical experiments and analysis. Moreover, all of the photo-generated electrons, superoxide radicals, photo-generated holes, and hydroxyl radicals were proved to contribute the MB photodegradation and hydrogen evolution, and the former two active species played more vital roles. Furthermore, the effective separation of photo-generated electrons and holes through the n-type of ZCS and p-type of CSO heterojunction structure accelerated the improvement of photocatalytic abilities for composite materials. The photo-generated electrons concentrated in the conduction band of ZCS might be helpful for the improvement of hydrogen evolution abilities of composite photocatalysts. This work not only provides a novel strategy towards high-efficiency composite photocatalysts through constructing heterojunction assisted with hydrothermal reaction, but also demonstrates the possibility of utilizing binary composites for enhanced hydrogen evolution reaction and pollutant degradation. [ABSTRACT FROM AUTHOR]

Fe-C 3 N 4 /Ti 3 C 2 /C-TiO 2 Z-scheme heterojunction was prepared via coupling Fe-C 3 N 4 and partially oxidized MXenes-derived C-TiO 2 /Ti 3 C 2. It presented excellent catalytic activity and photothermal performance in photo-Fenton reaction toward tetracycline degradation. [Display omitted] Photo-Fenton reaction combining the photocatalytic reaction and Fenton reaction showed excellent degradation performance. However, it highly demanded the catalysts to display outstanding activity in these two reactions. Herein, Fe-doped carbon nitride/MXenes-derived C-TiO 2 /Ti 3 C 2 (Fe-C 3 N 4 /Ti 3 C 2 /C-TiO 2) was prepared via two steps: Fe-C 3 N 4 and Ti 3 C 2 were assembled via face-to-face attachment, following by in-situ partial oxidation of Ti 3 C 2 to C-TiO 2. DFT predicted a Z-scheme charge transfer routine via metallic Ti 3 C 2 as bridge, which was verified by EPR and radical trapping experiments. Additionally, PDOS calculation revealed the charge density around the doped-Fe atoms was remarkably increased, leading to better H 2 O 2 activation, which was experimentally confirmed by high yield of •OH. Moreover, Fe-C 3 N 4 /Ti 3 C 2 /C-TiO 2 possessed the high photothermal effect to accelerate the surface reaction. By taking advantage of these merits, the degradation rate of Fe-C 3 N 4 /Ti 3 C 2 /C-TiO 2 was at least 4.2 times higher than the reference catalysts. Our work provided an insight toward the g -C 3 N 4 /TiO 2 -based photo-Fenton catalysts with high performance. [ABSTRACT FROM AUTHOR]

Carbon quantum dots (CDs) are a fascinating class of carbon nanomaterials (less than 10 nm in size) with unique optical, electrical, and physicochemical properties. In addition to these properties, CQDs exhibit the desired advantages of aqueous stability, low toxicity, high surface area, economic feasibility, chemical inertness, and highly tunable photoluminescence behaviour. Recently, graphitic carbon nitride (g-C3N4) has appeared as one of the required stable carbon-based polymers due to its varied applications in several fields. In this regard, modification strategies have been made in the g-C3N4 semiconductor using CQDs to enhance the adsorptive and photocatalytic activity. In comparison to other semiconductor quantum dots, g-C3N4 shows strong fluorescent properties, such as wide excitation spectra, photostability, and tunable photo-luminescent emission spectra. The interaction inside this multicomponent photocatalyst further promotes the photocatalytic activity by improving charge transference, which plays a vital role in electrochemistry. Therefore, CQDs are auspicious nanomaterials in the field of photocatalysis, wastewater treatment and water adsorption treatment. This particular article featured the recent progression in the field of CDs/g-C3N4-based photocatalysts focusing on their luminescent mechanism and potential applications in wastewater treatment. [ABSTRACT FROM AUTHOR]

In this research work, a green synthesis method of using a Nigella sativa L. seeds extract as a reductant was adopted for the silver nanoparticles (AgNP) production. The AgNP were produced using a 5 mM silver nitrate mixed with the seeds extract at 25 °C and at 60 °C. It was observed that the AgNP production rate significantly increased at high temperatures. The obtained AgNP were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. SEM depicted an average particle size (42 ± 15 nm) of synthesized AgNP. XRD results further augmented the SEM data and indicated definite crystallinic peaks for synthesized AgNP. The prepared Nigella sativa L. extract assisted AgNP (N.S./AgNP) were further used in the reduction of the MB and 4-nitroaniline dyes as well as in antibacterial studies. It was found that the AgNP successfully transformed the 4-NA and MB to their reductive compounds with high conversion rates of 0.1021 min−1 and 0.4197 min−1, respectively. The antibacterial results showed that the N.S./AgNP have good killing properties against Staphylococcus aureus, Klebsiella pneumonia and Pseudomonas aeruginosa bacteria. [ABSTRACT FROM AUTHOR]

The development of efficient catalysts is a highly necessary but challenging task within the field of environmental water remediation. Single-atom catalysts are promising nanomaterials within this respect, but in-depth studies encompassing this class of catalysts remain elusive. In this work, we systematically study the degradation of gemfibrozil, a persistent pollutant, on a series of carbon nitride photocatalysts, investigating both the effect of (i) catalyst textural properties and (ii) metal single atoms on the contaminant degradation. Tests in the absence of the catalyst result in negligible degradation rates, confirming the stability of the contaminant when dispersed in water. Then, photocatalytic tests at optimal pH, solvent, and wavelength reveal a correlation between the support surface area and the degradation. This points to the role of carbon nitride surface nanostructure on gemfibrozil degradation. In particular, the use of silver on mesoporous carbon nitride single-atom catalyst (Ag@mpgC3N4) leads to an unprecedented degradation of gemfibrozil (>90% within 60 min). The possible degradation intermediates and products were identified by mass spectrometry and were inert by cytotoxicity evaluation. We anticipate that, with further refinement and customization, the carbon nitride catalysts reported herein may find broad applications for light-driven degradation of other contaminants of emerging concern. [ABSTRACT FROM AUTHOR]

[Display omitted] • Green approach to improve charge separation at interfaces through sodium doping. • Willow-shaped Na-doped g-C 3 N 4 material exposed a high degree of crystallinity. • G-C 3 N 4 morphology structure accelerated the electron transport efficiency. • The e−-h+ pairs recombination rate was significantly reduced by Na doping. • The Na-doped g-C 3 N 4 exhibits multi-functional photocatalytic activity. Graphitic carbon nitride (g-C 3 N 4) is considered as a promising low-cost polymeric semiconductor as conjugated photocatalyst for energy and environmental application. This study exhibits a Na-doped g-C 3 N 4 with willow-leaf-shaped structure and high degree of crystallinity, which was synthesized with a convenient thermal polymerization using sodium carbonate (Na 2 CO 3) as the sodium source. The π-conjugated systems of g-C 3 N 4 were improved by doping sodium, which could accelerate the electron transport efficiency resulting in outstanding photocatalytic properties. Furthermore, optimum Na-doped g-C 3 N 4 (CN-0.05) attributed its enhanced irradiation efficiency of light energy to its narrower band gap and significant improvement in charge separation. Consequently, the H 2 evolution rate catalyzed with CN-0.05 can achieve 3559.8 μmol g−1 h−1, which is about 1.9 times higher than that with pristine g-C 3 N 4. The rate of CN-0.05 for reduction of CO 2 to CO (3.66 μmol g−1 h−1) is 6.6 times higher than that of pristine g-C 3 N 4. In experiments of pollutants degradation, the reaction constants of degradation of rhodamine B (RhB) and methyl orange (MO) with CN-0.05 were 0.0271 and 0.0101 min−1, respectively, which are 4.7 and 7.2 times more efficient than pristine g-C 3 N 4 , respectively. This work provides a simple preparation method for tailoring effective photocatalyst for the sustainable solution of environmental issues. [ABSTRACT FROM AUTHOR]

Pr-doped CeO2 with different doping levels was prepared from Ce(NO3)3∙6H2O and Pr(NO3)3∙6H2O by solvothermal method without any additional reagents, in which the mixed solution of ethylene glycol and distilled water was employed as a solvent. The influences of Pr-doping on phase composition, crystal structure and morphology were investigated, as well as Pr valence and oxygen vacancy defects. The Pr cations entered into the CeO2 crystal lattice with normal trivalence and formed a Pr-CeO2 solid solution based on the fluorite structure. The larger trivalent Pr was substituted for tetravalent Ce in the CeO2 crystal and compensated by oxygen vacancy defects, which caused the local lattice expansion of the crystal lattice. Moreover, the Pr-doped CeO2 solid solutions exhibited visible color variation from bright cream via brick red to dark brown with the increasing of Pr contents. The degradation of AO7 dye was also investigated using a domestic medical ultraviolet lamp; the removal efficiency of AO7 by 1% and 2% Pr-doped CeO2 approached 100%, much higher than 66.2% for undoped CeO2. [ABSTRACT FROM AUTHOR]

[Display omitted] • Defective TEB-DBT CMPs with alkynyl defects via the molecular design are constructed. • Combination of the DFT calculations and experimental results, the incorporation of alkynyl defect accelerates the separation of photogenerated charge carriers. • The microstructure, band structure, and photocatalytic performance of CMPs can be regulated by varying the content of alkynyl defect. Defect engineering is a versatile approach to modulate band and electronic structures as well as materials performance. Nowadays, more research has been performed for enhancing catalytic performance of organic photocatalysts via the regulation of structure defect. Herein, we constructed the dibenzo[b,d]thiophene-sulfone-based conjugated microporous polymers (CMPs) with alkynyl defects via the molecular design. The effects of the concentration of alkynyl defects on the optical band gap, energy level structure, charge separation and photoactivity of the as-prepared samples were further explored. Combination of the first-principle density functional theory (DFT) calculations and experimental results, the incorporation of alkynyl defects accelerated the separation of photogenerated charge carriers. Furthermore, the concentration of alkynyl defects in CMPs can be adjusted by the dosage of 1,3-diethynylbenzene (MEB), thereby modulating the electronic structure and charge carrier separation properties. At appropriate alkynyl defect concentration, the prepared Defect-TD-2 shows higher visible-light photocatalytic performance for H 2 production and pollutants degradation. The work therefore shows an efficient self-modification strategy for improving the photoactivity of CMPs. [ABSTRACT FROM AUTHOR]

Environmental and energy crises are a major threat to the sustainable growth of the human society, calling for greener technologies such as photocatalysis. Photocatalysis is a solar-driven approach that converts photon energy into chemical energy, yet the conversion efficacy of classical photocatalysis is usually restricted and controlled by the charge carrier's separation and migration. Enhanced conversion requires suppressed recombination rate and superior redox abilities. From this aspect, the manipulation of heterojunction allows to overcome the drawback of classical photocatalysis. The cascade mechanism follows a dual direct charge migration route, resulting in enhanced redox abilities and efficient mineralization of pollutants. Here, we review photocatalytic material aspects in improving redox ability by cascade charge transfer. We describe the mechanisms and applications of three cascade systems: two type-II cascade systems, mediator-based cascade systems, and dual direct Z-scheme. We highlight the superiority of the direct dual cascade route with a prolonged lifetime of carriers, higher quantum yield, and enhanced redox abilities. Applications to carbon dioxide reduction, hydrogen production by water splitting and pollutant degradation are discussed. [ABSTRACT FROM AUTHOR]

Cobalt-based materials are promising catalysts for activating peroxymonosulfate (PMS) to degrade organic pollutants. Among various cobalt-based catalysts, the alteration in cobalt species and the reactive species produced are not fully understood. Herein, four materials were synthesized by controlling synthesis methods and doping of g-C 3 N 4 to regulate cobalt species. Through two methods, ZIF/Co and Co 3 O 4 , whose main cobalt species are Co-O/Co-N and CoO/O-CoO, were synthesized. On this basis, ZIF/Co-CN and Co 3 O 4 -CN were synthesized by adding g-C 3 N 4 . Then, the four materials were used to activate PMS for carbamazepine (CBZ) degradation, focusing on the correlation between active sites and reactive species. CoO/O-CoO mainly led to the formation of free radicals, while Co-N tended to produce non-free radicals. The addition of g-C 3 N 4 would facilitate non-free radical catalysis by promoting the conversion of Co-O to Co-N and enhancing the catalytic role of C and N. Finally, the systems with a high proportion of non-free radicals showed better degradation performance when multiple pollutants co-existed, and reactive species may be selective to different pollutants. The findings have significance for the synthesis design of cobalt-based catalysts and the regulation of reactive species to degrade different pollutants practically., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Indirect photolysis driven by photochemically produced reactive intermediates (PPRIs) is pivotal for the transformations and fates of pollutants in nature. While well-studied in bulk water, indirect photolysis processes at environmental interfaces remain largely unexplored. This study reveals a significant acceleration of indirect photodegradation of organic pollutants at the soil-water interface of wetlands. Organic pollutants experienced ubiquitously enhanced indirect photodegradation at the soil-water interfaces, with rates 1.41 ± 0.01 to 4.27 ± 0.03-fold higher than those in bulk water. This enhancement was observed across various natural and artificial wetlands, including coastal wetlands and rice paddies. In situ mapping indicated that soil-water interfaces act as hotspots, concentrating both organic pollutants and PPRIs by 9.30- and 4.27-folds, respectively. This synchronized colocation is the primary cause of the accelerated pollutant photolysis. Additionally, the contribution of each PPRI species to pollutant photolysis and a coupled transformation pathway at the soil-water interface significantly differed from those in bulk water. For instance, the contribution of singlet oxygen to metoxuron photolysis increased from 10.1% in bulk water to 44.4% at the soil-water interface. Our study highlights the rapid indirect photolysis of organic pollutants at the soil-water interfaces, offering new insights into the natural purification processes in wetlands as "Earth's kidneys."