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Developing efficient technologies to eliminate or degrade contaminants is paramount for environmental protection. Biocatalytic decontamination offers distinct advantages in terms of selectivity and efficiency; however, it still remains challenging when applied in complex environmental matrices. The main challenge originates from the instability and difficult-to-separate attributes of fragile enzymes, which also results in issues of compromised activity, poor reusability, low cost-effectiveness, etc. One viable solution to harness biocatalysis in complex environments is known as enzyme immobilization, where a flexible enzyme is tightly fixed in a solid carrier. In the case where a reticular crystal is utilized as the support, it is feasible to engineer next-generation biohybrid catalysts functional in complicated environmental media. This can be interpreted by three aspects: (1) the highly crystalline skeleton can shield the immobilized enzyme against external stressors. (2) The porous network ensures the high accessibility of the interior enzyme for catalytic decontamination. And (3) the adjustable and unambiguous structure of the reticular framework favors in-depth understanding of the interfacial interaction between the framework and enzyme, which can in turn guide us in designing highly active biocomposites. This Review aims to introduce this emerging biocatalysis technology for environmental decontamination involving pollutant degradation and greenhouse gas (carbon dioxide) conversion, with emphasis on the enzyme immobilization protocols and diverse catalysis principles including single enzyme catalysis, catalysis involving enzyme cascades, and photoenzyme-coupled catalysis. Additionally, the remaining challenges and forward-looking directions in this field are discussed. We believe that this Review may offer a useful biocatalytic technology to contribute to environmental decontamination in a green and sustainable manner and will inspire more researchers at the intersection of the environment science, biochemistry, and materials science communities to co-solve environmental problems.

The tanning, textile, and dye industries consume a large amount of water during production, leading to a large quantity of wastewater. This study aims to provide insight into the phycoremediation of the tannery, textile, and dye wastewater microalgae biofilm. Microalgae biofilm was grown in a photobioreactor with BG-11 as the culture medium, used to treat tannery, textile, and dye wastewater. The antioxidant response of the microalgae biofilm before and after treatment of the wastewater was determined. The results obtained show the microalgae biofilm best reduced biochemical oxygen demand (BOD) (68%), chemical oxygen demand (COD) (83%), chloride (52%), phenol (39%), and alkalinity (47%), from textile wastewater, Total dissolve solids (TDS) (88%), total suspended solids (TSS) (94%), sulfate (56%), phosphate (45%), total nitrogen (63%), oil and grease (42%), and total chromium (64%) were all reduced in dyeing wastewater, while electrical conductivity (EC) (64%) and total chromium were reduced the best in tannery wastewater. The result also shows an increase in peroxidase activity, catalase activity, superoxide dismutase activity (SOD), and glutathione reductase activity, indicating the role of enzymatic antioxidants in pollutant degradation and counteracting the effect of reactive oxygen species (ROS). The decrease in flavonoid, anthocyanin, and carotenoid indicates non-enzymatic antioxidants involvement in the degradation and role of the pollutant in osmoregulatory balance maintenance. Simultaneously, the increase in TOC and lipid content signifies the strong role of antioxidants in radical scavenging. The increase in phosphomolybdate capacity, hydrogen peroxide scavenging, and DPPH scavenging ability is also a strong indication of high ROS production and prevention of its effect. The microalgae biofilm's ability to remove pollutants from wastewater is by the activities of enzyme release by the microalgae or adsorption of the pollutants to the wall of the participant microalgae in the biofilm. [ABSTRACT FROM AUTHOR]

This research explores reduced graphene oxide-Fe 3 O 4 nanocomposites synthesis, characterization, and it's ability to degrade methylene blue dye using sodium lamp as the visible white light source. The modified co-precipitation method was employed for the synthesis of the photocatalyst. The photocatalyst was further characterized by various characterization techniques. Moreover, photocatalytic activity was performed by varying performance conditions, and analyzed the results. It was found that photocatalyst has highly active performance at the working conditions of pH 12 with 50 mg catalyst for 10 ppm methylene blue dye solutions and produced 98.3% degradation of the dye within 80 min. It was also observed that minor positive performance was observed on varying temperature and catalyst concentration. The photocatalytic activity was found highly dependent on the pH of the solution and increased with an increase in pH. Additional studies were also performed by adding some amount of hydrogen peroxide in the solution without changing its pH. It was also noted that as the amount of hydrogen peroxide was increased in the solution, there was an increment in the degradation of the dye. A maximum of 98.8% degradation was recorded with the 9 ml addition of hydrogen peroxide-containing 25 mg catalyst, pH 8, and at 40 °C reaction temperature within 70 min of irradiation. [ABSTRACT FROM AUTHOR]

The plant extract has been used extensively for biosynthesis of noble metallic nanoparticles due to cost efficiency and simple technology. However, influence of plant growth condition can induce changes in composition and content of bioactive compounds, leading to difficulty in reproducing the metallic nanoparticles. In this work, we first utilized the plant embryos (Panax vietnamensis embryos—PVE) cultured under laboratory condition as a biosource for the synthesis of silver nanoparticles (AgNPs). This method can reduce unwanted changes of bioactive composition in the plant. The formation of AgNPs was optimized to afford the best colloidal solution. The physicochemical properties were characterized using analysis techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), Fourier transform infrared spectroscopy (FTIR) and thermal properties. Size of crystalline AgNPs was determined in the range of 3–20 nm with a mean size of 10 nm. The applications were investigated for antibacterial and catalytic effect. The biosynthesized AgNPs exhibited high antibacterial activity against Bacillus subtilis, Staphylococcus aureus and Escherichia coli. The excellent catalysis behavior of PVE-AgNPs has been investigated for the reduction of o-, m-, p-nitrophenols and toxic organic dyes including methyl orange, rhodamine 6G and rhodamine B. The effect of catalyst amount on the reaction performance was studied via kinetic investigation. This work unfolds a potential method for scalable reproduction of metallic nanoparticles. [ABSTRACT FROM AUTHOR]

A new copper phenylacetylide of PhC2Cu2.5 was prepared and compared with PhC2Cu, a copper‐based metal–organic coordination polymer we reported previously. Based on the characterizations on the structures of the two prepared samples, they possessed significantly different crystal structures and similar micro and band structures. Interestingly, they also showed different preferences for the photocatalytic degradation of methyl orange (MO) and 2,4‐diclorophenol (2,4‐DCP). The active species trap experimental results show that different active species were required for the degradation of MO and 2,4‐DCP, resulting to different degradation pathways and mechanism. At last, different preferentially production of active species by PhC2Cu2.5 and PhC2Cu were studied by electrochemical measurements and fluorescence spectra, as well as the photocatalytic productions of reactive oxygen species by PhC2Cu and PhC2Cu2.5, which further demonstrated the obtained conclusions by active species trap experimental results. This work developed a new copper phenylacetylide of PhC2Cu2.5 as a photocatalyst and demonstrated the different degradation pathways of MO and 2,4‐DCP. [ABSTRACT FROM AUTHOR]

In this study,a Ti02/CuS heterojunction photocatalyst was prepared by a combination of in-situ precipitation and hydrothermal methods. This heterojunction improves the defects of a single Ti02 semiconductor photocatalyst and significantly improves the efficiency of photocatalytic degradation of methyl orange under suniight. The heterojunction structure and suitable band structure formed between Ti02 and CuS can extend the response range of the material to the solar spectrum,and can also collect and transmit light induced carreers well,thereby improving the carreer separation effidency. The photocatalyic activtty of the semiconductor ss significantly enhanced. After 25 minutes of suniight exposure, compared wth Ti02/MnS,Ti02/CdS and Ti02/ZnS heterojunciions,the Ti02/CuS heterojunciion(the moaar ratio of Ti02 and CuS is 3 thas the best degradation effect on methyl orange,and the degradation effidency can achieved 97. 3%. It provided a feasib!e way to improve the photocatalyic acidity of semiconductor. [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.

We integrate a potential conjugated donor-acceptor (DA) co-monomer such as 2, 6-dimethylmarpholine (MP) within the structure of polymeric carbon nitride (PCN) by a facile one-pot co-polymerization process. The hydrogen evolution rate (HER) for pure CNU with 115.2 μmol/h while for CN-MP 0.1 it was estimated at 641.2 μmol/h which remarkably fueled almost six times more than blank sample. In particular, the pseudo-order kinetic constant of CN-MP 0.1 for photodegradation of RhB was two times higher as compared with pure CNU. [Display omitted] • A facile ionothermal co-polymerization method was used to introduce MP, an organic monomer into PCN. • The integration of MP by DFT and TD-DFT shows a change in its surface area, electronic structure and band gap. • An six-time improved HER was observed for CN-MP 0.1 (641.2 μmol/h) than pure PCN (115.2 μmol/h). • Pseudo-order kinetic constant of CN-MP 0.1 for photodegradation of RhB was two times higher as compared with pure PCN. The development of superior heterogeneous catalyst for hydrogen (H 2) evolution is a significant feature and challenging for determining the energy and environmental crises. However, the dumping of numerous lethal colorants (dye) as of textile manufacturing has fascinated widespread devotion-aimed water pollution anticipation and treatment. In this regard, a photocatalytic H 2 evolution by visible light using low-dimensional semiconducting materials having pollutant degradable capacity for Rhodamine B dyes (RhB) has been anticipated as a route towards environmental aspect. Here we fabricated the incorporation of organic electron-rich heterocyclic monomer 2,6-dimethylmorpholine (MP), inside electron-poor graphitic carbon nitride (g-CN) semiconductor by solid-state co-polymerization. The supremacy of copolymerization process was successfully examined via absorbent, calculated band gap, and migration of electrons on the photocatalytic performance of as-constructed CN-MP copolymer. The density functional theory (DFT) calculation provides extra support as evident for the successful integration of MP into the g-CN framework by this means-reduced band gap upon co-polymerization. The hydrogen evolution rate (HER) for g-CN was found as 115.2 μmol/h, whereas for CN-PM 0.1 was estimated at 641.2 μmol/h (six times higher). In particular, the pseudo-order kinetic constant of CN-MP 0.1 for photodegradation of RhB was two times higher than that of g-CN. Results show an important step toward tailor-designed and explain the vital role of the D-A system for the rational motifs of productive photocatalysts with effective pollutant degradable capability for future demand. [ABSTRACT FROM AUTHOR]

The development and investigation of materials that leverage unique interfacial effects on electronic structure and redox chemistry are likely to play an outstanding role in advanced technologies for wastewater treatment. Here, the use of surface functionalization of metal oxides with a RuIIpoly(pyridyl) complex was reported as a way to create hybrid assemblies with optimized electrochemical performance for water remediation, superior to those that could be achieved with the molecular catalyst or metal‐oxide electrodes used individually. Mechanistic analysis demonstrated that the molecularly functionalized electrodes could suppress the formation of hydroxyl radicals (i. e. the dominant remediation pathway for bare metal‐oxide electrodes), allowing the water remediation to proceed through the highly oxidizing Ru3+ ions in the surface‐bound complexes. Furthermore, the underlying metal‐oxide substrates played a crucial role in altering the electronic structure and electrochemical properties of the surface‐bound catalyst, such that the competing side reaction (i. e. water splitting) was largely inhibited. [ABSTRACT FROM AUTHOR]

Natural waters, water droplets in the air at coastal regions and wastewaters usually contain chloride ions (Cl-) in relatively high concentrations in the milimolar range. In the reactions of highly oxidizing radicals (e.g., •OH, •NO3, or SO4•-) in the nature or during wastewater treatment in advanced oxidation processes the chloride ions easily transform to chlorine containing radicals, such as Cl•, Cl2•-, and ClO•. This transformation basically affects the degradation of organic molecules. In this review about 400 rate constants of the dichloride radical anion (Cl2•-) with about 300 organic molecules is discussed together with the reaction mechanisms. The reactions with phenols, anilines, sulfur compounds (with sulfur atom in lower oxidation state), and molecules with conjugated electron systems are suggested to take place with electron transfer mechanism. The rate constant is high (107–109 M-1 s-1) when the reduction potential the one-electron oxidized species/molecule couple is well below that of the Cl2•-/2Cl- couple. [ABSTRACT FROM AUTHOR]

Wastewater treatment, especially for those containing insoluble oils and soluble chemical pollutants, has been a major concern in the field of environmental protection. Materials integrating both hydrophobicity and photocatalytic activity are good candidates in terms of separating insoluble oils from water and photodegrading soluble chemical pollutants. However, the wide application of such materials is curtailed by their susceptible photodecomposition issue. In this paper, we report the design of a durable yet efficient hydrophobic photocatalyst by immobilizing photocatalytic titanium dioxide (TiO2) on a carbonized melamine foam (CMF) for a three‐dimensional (3D) porous structure, and subsequently coating a hydrophobic polydimethylsiloxane (PDMS) layer on TiO2 surface (CMF‐TiO2‐PDMS). The key feature of the design is that the PDMS layer could re‐graft on the TiO2 surface via forming chemical bonds with TiO2 under UV illumination, granting the resulting CMF‐TiO2‐PDMS stable hydrophobicity to durably resist photocatalytic oxidation. As expected, the as‐designed CMF‐TiO2‐PDMS photocatalyst shows excellent durability in removing insoluble organic solvents and photodegrading soluble chemical pollutants under UV illumination. This study is interesting not only because it provides a paradigm in designing durable yet efficient hydrophobic photocatalyst for wastewater treatment, but also shed lights on the design of other multifunctional materials. [ABSTRACT FROM AUTHOR]

Calcium titanate (CaTiO 3) a multi-metal oxide has received extensive attention in recent years, due to its unique structural features, high chemical stability, optimum band edge positions, strong catalytic activity, inexpensiveness, low toxicity and easy synthesis. The current review summarizes various synthesis methods that have been carried out for the preparation of CaTiO 3 nanomaterials, their structural properties, their modification strategies including elemental doping, noble metal deposition, heterostructure formation, hybridization with carbonaceous materials like graphene, graphitic‑carbon nitride and photocatalytic applications related to environmental and energy fields such as photodegradation of organic pollutants, carbon-dioxide reduction, and production of green currency of energy (hydrogen). Besides, efforts are also made to provide a perspective for future research. Overall this review aims to provide useful information for specialists dealings with calcium titanate. [Display omitted] • Summary of the significant advances achieved in the past few years on CaTiO 3. • Review of the synthesis methods and its different morphologies • Strategies that enhance the photocatalytic activity of CaTiO 3 are focused. • Great potential of CaTiO 3 photocatalysts in energy and environmental applications • Future works for the highly efficient CaTiO 3 based photocatalysis are suggested. [ABSTRACT FROM AUTHOR]

The presence of non-reactive phosphorus (NRP) in environmental waters presents a potential risk of eutrophication and poses challenges for the removal of all phosphorus (P) fractions. This study presents the first investigation on the removal performance and mechanism of three model NRP compounds, sodium tripolyphosphate (STPP), adenosine 5′-monophosphate (AMP) and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), in the sediment microbial fuel cell-floating treatment wetland (SMFC-FTW). Coupling SMFC with plants proved to be effective at removing NRP via electrochemical oxidation and plant uptake, particularly the challenging-to-degrade phosphonates that contain C–P bonds. Compared with the control group, the removal efficiencies of the model NRP in SMFC were observed to increase by 11.9%–20.8%. SMFC promoted the conversion of NRP to soluble reactive phosphorus (sRP) and the transfer of P to sediment. Furthermore, the electrochemical process enhanced both plant growth and P uptake, and increased P assimilation by 72.6%. The presence of plants in the bioelectrochemical system influenced the occurrence and fate of P by efficiently assimilating sRP and supporting microbial transformation of NRP. Consequently, plants enhanced the removal efficiencies of all P fractions in the overlying water. This study demonstrated that SMFC-FTW is a promising technology to remove various NRP species in environmental waters. [Display omitted] • Coupling SMFC with plants can effectively degrade various NRP species. • SMFC facilitated the NRP conversion to RP in the overlying water and sediments. • Electrochemical treatment enhanced plant growth and P uptake. • Plants improved the removal efficiencies of all P fractions. [ABSTRACT FROM AUTHOR]

Methods to produce WO 3 nanostructures have become important due to the possibility of using this material in a wide range of technological applications. In this context, a hydrated WO 3. 2 H 2 O structure was produced by the electrochemical dissolution of welding electrode scraps in an alkali aqueous solution, followed by acid precipitation. The thermal treatment of this precursor structure at 550, 700, 850, and 1000 °C was able to produce γ phase WO 3 materials with a monoclinic crystalline structure at all the temperatures used, as demonstrated by XRD and RAMAN characterization. However, different treatment temperatures can yield materials with diverse morphologies and optoelectronic properties. For example, the material produced at 1000 °C presented an elongated nanorod shape, with dimensions, from the base, ranging between 50 and 500 nm, a length of about 4 μm, and the lowest E g value. The spectroscopic characterization also demonstrated that above 700 °C, the thermal treatment could eliminate the crystallization water and create oxygen vacancies, mainly at 850 and 1000 °C; explaining the decrease in the E g values with increased temperature. As proof of concept, photocatalytic degradation of the Reactive Black 5 dye demonstrated that the material produced at 1000 °C was able to discolor ca. 50% of the initial color. Broad DFT analyses were performed, carefully describing the surface properties and the influence of morphology on the material properties. Therefore, we demonstrated that a simple, fast and low-cost two-step process was successfully developed aiming at a noble reuse of residues of this important material. WO 3 nanostructures were produced from a WO 3. 2 H 2 O hydrate precursor. The precursor was obtained by electrochemical dissolution of welding electrode scraps. The WO 3 nanostructures were produced by thermal treatment of the precursor at 550, 700, 850, and 1000 °C. All temperatures yielded materials with monoclinic γ-WO 3 crystalline structure, but with diverse morphologies and optoelectronic properties. The materials produced at 850 and 1000 °C were tested in the photocatalytic discoloration of Reactive Black 5 textile dye, and the latter demonstrated a discoloration efficiency of ca. 50%. [Display omitted] • WO 3 nanostructures were prepared using TIG tungsten welding electrodes scraps. • Precursor compound was obtained by a green and low-cost anodic dissolution process. • Variety in crystallinity/morphology was achieved, widening possible applications. • Reuse of tungsten scraps is relevant because it is a strategic material. [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of novel CTF-1/AgI heterojunction catalysts was designed and prepared simply. • Coordination adsorption and in-situ growth yield a high-quality heterojunction interface. • The heterojunction catalysts exhibited superior catalytic activity for CIP removal. • A type II charge transfer pathway of the heterojunction photocatalysts was proposed. In this paper, a multitude of novel CTF-1/AgI (CTFA- x) type-Ⅱ heterojunction were fabricated by in-situ growth approach based on the stable covalent triazine-based framework CTFs. 2D CTF-1 with sufficient nitrogen sites anchored AgI to its matrix, supporting ample active sites for CTFA to degrade ciprofloxacin (CIP) in aqueous solution. The structural and physicochemical characteristic of the CTFA products were explored by TEM, XRD, XPS, FT-IR, BET and PL characterization. The respective roles and synergistic effects of AgI and CTF-1 are discussed. Benefiting from this unique structure, the CTF-1/AgI with the mass ratio of 1:1 (CTFA-50) demonstrated the highest photocatalytic capacity and showed a degradation efficiency of more than 90 % against CIP after 120 min under simulated sunshine irradiation. Compared to pure AgI and CTF-1, the apparent rate constant for the CIP photodegradation of CTFA-50 (0.0153 min−1) was found to be 6.7 and 8.5 times greater. The CTFA-50 catalyst possessed good structural stability and broad-spectrum applicability, and had the ability to efficiently degrade various stubborn organic matters including tetracycline (87.97 %), 2- sec -butyl-4,6-dinitrophenol (63.42 %), bisphenol A (68.22 %), rhodamine B (98.62 %), methyl orange (70.25 %), methylene blue (63.27 %). As demonstrated by the results of the radical trapping tests and EPR analysis, the photodegradation process of CIP was mostly mediated by •O 2 – and h+. In view of the LC/MS findings, all reaction intermediates could be determined and a reasonable photocatalytic mechanism was proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fundamental knowledge on SSPFR are detailed illustrated. • Catalytic mechanism of each step and development of SSPFR are reviewed. • Various strategies aimed at improving the reaction rate are discussed and summarized. • Applications are introduced. • Prospects for the future development of SSPFR are presented. Fenton reaction has gained tremendous attention in the field of non-selective pollutant degradation, as •OH with powerful oxidizing capacity can be produced via H 2 O 2 activation. However, the widespread application is limited by the continuous consumption of commercial H 2 O 2 with high price. As an alternative strategy, self-sufficient photo-Fenton reaction (SSPFR) has been explored, where oxidant H 2 O 2 was in-situ produced inside the system for subsequent Fenton reactions, rather than external addition. Benefiting from the low cost, high H 2 O 2 utilization efficiency, and low risk in H 2 O 2 storage and transportation, SSPFR became a hotpot in scientific research, and developed rapidly in recent years. Herein, we critically reviewed the state-of-the-art development of SSPFR, in which the fundamental mechanism and catalytic process were firstly introduced. Then, SSPFR reaction was divided into three cascade steps: in-situ H 2 O 2 production, H 2 O 2 activation, and reactive oxygen species utilization. This paper reviewed the research progress in every step, and proposes corresponding potential strategies to accelerate the reaction rate. Finally, conclusions and prospects of SSPFR for the removal of organic pollutants were proposed. This study provides a valuable resource for researchers to construct novel and efficient SSPFR systems. [ABSTRACT FROM AUTHOR]

Photocatalytic technology is one of the ideal approaches for clean energy production and environmental pollution control in the future. However, the rapid recombination of photo-generated charge carriers is a bottleneck problem of low solar energy conversion efficiency. Herein, a magnetic ZnFe 2 O 4 /Pt/polymeric carbon nitride (PCN) semiconductor catalyst is designed and prepared for high-performance photocatalytic hydrogen production reaction and photocatalytic degradation rate of RhB. It exhibits 339.31 μmol · g−1 · h−1 hydrogen production rate and 96.08 % photocatalytic degradation rate of RhB within 120 min under visible light. The introduction of Pt, constructing an electronic bridge, accelerated the transfer of photo-generated carriers, meanwhile, the smaller band gap of the ternary composites enabled the generation of more photo-generated electrons. The internal electric field accelerated the accumulation of electrons and holes in the conduction band of ZnFe 2 O 4 and valence band of PCN, thus photocatalytic activity is greatly enhanced. The electron-hole separation is also improved and the transport of photo-generated electrons is facilitated by the special structure of the heterojunction and the unique morphology of PCN. In addition, the used catalyst can be recovered through magnetic fields, and this magnetic catalytic system has great application prospects in the fields of photocatalytic hydrogen production and pollutant degradation. [Display omitted] • PCN/Pt/ZnFe 2 O 4 semiconductor catalyst was designed and successfully synthesized. • The introduction of Pt, constructing an electronic bridge, accelerated the transfer of photo-generated carriers. • PCN/Pt/ZnFe 2 O 4 exhibits the highest hydrogen production rate and degradation rate of RhB due the role of electronic bridge. [ABSTRACT FROM AUTHOR]

Photocatalysis has shown great potential in solving environmental and energy problems. Perylene diimide (PDI) has received significant attention as a semiconductor photocatalyst. However, pure PDI photocatalysts still face challenges because of their low photogenerated carrier separation efficiency, leading to suboptimal photocatalytic activity. In recent years, PDI-based heterostructures have become a hot research topic because of their greatly improved carrier separation efficiency and photocatalytic performance. According to the different transfer mechanisms of photogenerated carriers between PDI and coupling components, PDI-based heterostructured photocatalysts can be classified into conventional type-II, Z-scheme, and S-scheme heterojunctions. This paper reviews the recent research progress in the design of PDI-based heterojunction photocatalysts and their photogenerated carrier transfer mechanisms. Subsequently, the enhanced photocatalytic activity of PDI-based heterojunctions with respect to environmental remediation and energy conversion in terms of pollutant degradation, CO 2 reduction, and photocatalytic H 2 evolution have been thoroughly reviewed. Moreover, the typical mechanism of the photocatalytic reaction of PDI-based composites is described in detail. Lastly, the unresolved challenges and potential applications of PDI-based heterojunction photocatalysts are presented to guide the future development direction. [Display omitted] • The charge transfer mechanism and design of PDI-based heterojunction are deeply discussed. • Various methods for the preparation of PDI-based heterojunction photocatalysts are presented. • The applications of PDI-based heterojunction photocatalysts in energy production and environmental remediation are reviewed. • Prospects and challenges for the development of PDI-based photocatalytic systems are pointed. [ABSTRACT FROM AUTHOR]

• BiOBr/BTO heterojunction catalysts were prepared by chemical precipitation method. • The catalyst exhibits highly efficient piezo-photocatalysis for degrading multi-pollutant. • Synergistic piezo-photocatalysis was realized under light illumination and ultrasound. • The catalyst shows favorable cycling stability and applicability for multi-pollutant. Piezo-catalysis is a green and effective method for degrading rich and obstinate molecules in wastewater. Yet, the piezo-catalytic performance of frequently-used barium titanate (BTO) is still limited for practical applications, thus it is crucial to construct high-efficiency BTO-based catalysts. Herein, BiOBr/BTO heterojunction-based piezo-photocatalysts were successfully prepared using the chemical precipitation method, and an internal electric field was established via ultrasound to promote the separation of photogenerated electron-hole pairs through the synergistic effect of piezocatalysis and photocatalysis. Transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy were utilized to characterize the heterojunction. The degradation performance of Rhodamine B (RhB) by BiOBr/BTO is the best among various pollutants, giving a reaction rate constant up to 20.839 × 10−2 min−1, exceeding numerous previously reported catalysts. In addition, the piezo-photocatalytic reaction rate of BiOBr/BTO for Methyl Orange was 9.298 × 10−2 min−1, ≈ 3.3 times than those of pure BTO (2.806 × 10−2 min−1), and also ≈ 15.9 times and 3.3 times than those of single photocatalysis (0.585 × 10−2 min−1) or piezocatalysis (2.848 × 10−2 min−1). Importantly, the BiOBr/BTO heterojunction demonstrates excellent catalytic degradation performance for a broad range of pollutants (e.g., dyes and antibiotics) and their mixtures, as well as favorable cycling stability and repeatability with changed environmental conditions, displaying applicability in actual wastewater treatment. The possible degradation pathways of RhB were analyzed by liquid chromatography-mass spectrometry. The present work supplies a feasible strategy for the preparation of high-efficiency piezo-photocatalytic BTO-based heterojunctions, which can guide other composites for environmental remediation. [ABSTRACT FROM AUTHOR]

Photocatalytic technology having the advantages of low-cost, environmental friendliness, is important in removing organic pollutants. To enhance the catalytic efficacy of well-established TiO 2 photocatalyst, TiO 2 -conjugated/coordination polymer heterojunction photocatalysts have been rapidly developed in the area of environmental remediation. However, a comprehensive summary and description of these advancements are lacking. To fill this gap, the research progress of TiO 2 -conjugated/coordination polymer heterojunction photocatalysts for organic pollutants degradation is reviewed. Firstly, classifications, working principles, and photodegradation pathways of TiO 2 -based heterostructures are introduced. Subsequently, the synthesis strategies, photocatalytic performance, and mechanisms of TiO 2 -conjugated/coordination polymer photocatalysts are comprehensively summarized. The effects of operational parameters on photodegradation are discussed. Lastly, promising prospects of TiO 2 -based heterojunction photocatalysts systems and urgent issues to be solved are foreseen. It is hoped that this review sets the trajectory for providing references in preparation and catalytic capacities of TiO 2 -based heterojunction photocatalysts, providing new ideas for resourceful wastewater remediation. [Display omitted] • First review of photodegradation pollutants by TiO 2 -conjugated/coordination polymer. • The detailed degradation pathways of common organic pollutants are discussed. • Properties and mechanisms of TiO 2 -conjugated/coordination polymer are elaborated. • The influence of operating parameters on photodegradation efficiency is recalled. • Challenges and prospects of TiO 2 -conjugated/coordination polymer are presented. [ABSTRACT FROM AUTHOR]

This study delves into the untapped potential of BCN (boron carbon nitride) as a photocatalyst, highlighting its remarkable porosity and bandgap adjustability. In pursuit of enhancing BCN's photocatalytic capabilities, we introduce an innovative approach to incorporate Bi 2 O 3 nanoparticles onto BCN's surface through a thermal condensation process. The assessment of photocatalytic activity involved the degradation of both non-dye and dye compounds (acetaminophen, malachite green, and reactive blue) under UV–visible light irradiation. Our findings reveal that the Bi 2 O 3 /BCN (BiBCN) composites exhibit significantly improved photocatalytic activity compared to individual BCN or Bi 2 O 3. Notably, the 5%BiBCN photocatalyst excels, achieving removal rates of 80.88 % for ACE, 98.6 % for MG, and 97.7 % for RB within 120 min under UV–Vis light exposure. Characterization unveils that the composite photocatalysts enhance the separation of photogenerated carriers, primarily attributed to the formation of heterojunctions. Our proposed mechanism underscores the synergy of increased specific surface area and the heterojunction formed by the interaction between Bi 2 O 3 and TCN in enhancing photocatalytic performance. Altogether, this study sheds light on the promising potential of BCN-based heterojunction photocatalysts for efficient water depollution. [Display omitted] [ABSTRACT FROM AUTHOR]

Global water demand and environmental concerns related to climate change require industries to develop high-efficiency wastewater treatment methods to remove pollutants. Likewise, toxic pollutants present in wastewater negatively affect the environment and human health, requiring effective treatment. Although conventional treatment processes remove carbon and nutrients, they are insufficient to remove pharmaceuticals, pesticides, and plasticizers. Electrochemical processes effectively remove pollutants from wastewater through the mineralization of non-biodegradable pollutants with consequent conversion into biodegradable compounds. Its advantages include easy operation, versatility, and short reaction time. In this way, this review initially provides a global water scenario with a view to the future. It comprises global demand, treatment methods, and pollution of water resources, addressing various contaminants such as heavy metals, nutrients, organic compounds, and emerging contaminants. Subsequently, the fundamentals of electrochemical treatments are presented as well as electrochemical treatments, highlighting the latest studies involving electrocoagulation, electroflocculation, electroflotation, capacitive deionization and its derivatives, eletrodeionization, and electrochemical advanced oxidation process. Finally, the challenges and perspectives were discussed. In this context, electrochemical processes have proven promising and effective for the treatment of water and wastewater, allowing safe reuse practices and purification with high contaminant removal. [Display omitted] • The latest studies involving electrochemical treatments were discussed. • Inclusive explanations of electrochemical processes were highlighted. • Electrochemical treatments can produce chemicals and simultaneously degrade pollutants. • Electrocoagulation/flocculation removes efficiently macromolecular organic compounds. • Capacitive deionization and its derivatives have stood out in the removal of heavy metals. [ABSTRACT FROM AUTHOR]

Iron-based materials are difficult to produce single oxygen (1O 2) efficiently from H 2 O 2. Herein, we demonstrate that 1O 2 production from H 2 O 2 can be manipulated by regulating the lattice distortion degrees of spinel ferrite through controlling the contents of Co and Ni in Co 1−x Ni x Fe 2 O 4. Typically, NiFe 2 O 4 , which owns the lowest lattice distortion degree, can produce 1O 2 as the dominated reactive oxygen species with·O 2 - as the intermediate. Due to the production of 1O 2 , the NiFe 2 O 4 /H 2 O 2 system removes bisphenol A (BPA) completely within 180 min but removes only ∼ 4% of benzoic acid. In addition, the system demonstrates significant resistance to water matrix interference, as 50 mM of Cl-, NO 3 -, H 2 PO 4 -, and humic acid inhibited the BPA degradation by only ∼0%, ∼2%, ∼40%, and ∼3%, respectively. Our work may shed light for regulating the formation of 1O 2 from H 2 O 2 through the rational design of iron-based catalysts for Fenton-like reactions. [Display omitted] • Activating H 2 O 2 to produce 1O 2 by adjusting the lattice distortion of spinel ferrite. • The degree of lattice distortion and the yield of 1O 2 showed a negative correlation. • NiFe 2 O 4 /H 2 O 2 system has selectivity, anti-interference and high H 2 O 2 utilization rate. [ABSTRACT FROM AUTHOR]

Abstract Fabrication of the heterojunction composites photocatalyst has attained much attention for solar energy conversion due to their high optimization of reduction-oxidation potential as a result of effective separation of photogenerated electrons-holes pairs. In this review, the background of photocatalysis, mechanism of photocatalysis, and the several researches on the heterostructure graphitic carbon nitride (g-C3N4) semiconductor are discussed. The advantages of the heterostructure g-C3N4 over their precursors are also discussed. The conclusion and future perspectives on this emerging research direction are given. This paper gives a useful knowledge on the heterostructure g-C3N4 and their photocatalytic mechanisms and applications. Impact Statements The paper on g-C3N4 Nano-based photocatalysts is expected to enlighten scientists on precise management and evaluating the environment, which may merit prospect research into developing suitable mechanism for energy, wastewater treatment and environmental purification.

Theoretically, lanthanum can bond with surface oxygens of ZnTiO3 to form La-O-Ti bonds, resulting in the change of both the band structure and the electron state of the surface. To verify this statement, DFT calculations were performed using a model with a dispersed lanthanum atom on the surface (101) of ZnTiO3. The negative heat segmentation values obtained suggest that the incorporation of La on the surface of ZnTiO3 is thermodynamically stable. The bandgap energy value of La/ZnTiO3 (2.92 eV) was lower than that of ZnTiO3 (3.16 eV). TDOS showed that the conduction band (CB) and the valence band (VB) energy levels of La/ZnTiO3 are denser than those of ZnTiO3 due to the participation of hybrid levels composed mainly of O2p and La5d orbitals. From the PDOSs, Bader’s charge analysis, and ELF function, it was established that the La-O bond is polar covalent. MB adsorption on La/ZnTiO3 (−200 kJ/mol) was more favorable than on ZnTiO3 (−85 kJ/mol). From the evidence of this study, it is proposed that the MB molecule first is adsorbed on the surface of La/ZnTiO3, and then the electrons in the VB of La/ZnTiO3 are photoexcited to hybrid levels, and finally, the MB molecule oxidizes into smaller molecules.

In recent decades, the destructive impact of active pharmaceutical ingredients (API) present in surface and drinking water on aquatic and terrestrial life forms becomes a major concern of researchers. API like diclofenac (DCF), carbamazepine (CBZ), tetracycline (TC), and sulfamethoxazole (SME) found in water bodies cause antimicrobial resistance and are potent carcinogens and endocrine disruptors. Conventional wastewater treatment methods possess some drawbacks and were found to be insufficient for the effective removal of APIs. Visible light-assisted semiconductor photocatalysis has become an alternative choice for tackling this worse scenario. Graphitic carbon nitride, a metal-free visible light active semiconductor photocatalyst is an emerging hotspot nanomaterial whose practical utility in water purification is widely recognized. This review comes up with an insightful outlook on the panorama of recent progress in the field of g-C3N4-assisted photocatalytic systems for the eradication of APIs. In addition, the review summarizes various strategies adopted for the broad-spectrum utilization of visible light and the enhancement of charge separation of pristine g-C3N4. The mechanistic pathways followed by different pharmaceuticals during their photocatalytic degradation process were also briefly discussed. [ABSTRACT FROM AUTHOR]

In the process of exploration, exploitation, and transportation of offshore oil, it is easy to cause leakage accidents due to bad environment, aging facilities, and violent collision. The existence of a large number of offshore oil spills has seriously affected the marine ecological environment; the treatment of crude oil pollutants not only has a very long treatment cycle, but also its treatment cost is immeasurable. In order to clarify the cost allocation of marine crude oil pollutants, this study constructs the cost allocation model of offshore crude oil based on game theory. Based on the characteristics of crude oil diffusion and the tidal current field model of the leakage sea area, the influence area of crude oil diffusion is analyzed, and the crude oil leakage diffusion model is constructed. Based on the Shapley value method, this paper constructs the cost allocation model of the tripartite game subject, and analyzes its stability and fairness. The results show that the fair index of Shapley method is 0.507, and the split index of the three subjects is 0.688, 0785, and 0.011.This model can ensure the fairness of cost allocation on the premise of ensuring the stability of the cooperative alliance. The crude oil diffusion model and cost allocation model constructed in this study will have certain guiding significance for compensation allocation in crude oil leakage. [ABSTRACT FROM AUTHOR]

Solar illumination is a promising source of primary energy to reduce global warming and to clean polluted waters, thus fostering research of the design of efficient photocatalysts for hydrogen production by water splitting and for contaminant degradation. In particular, photocatalysis by indium sulfide (In2S3) is drawing attention due to its suitable narrow bandgap of 2.0–2.3 eV for visible light harnessing, yet large-scale application of unmodified In2S3 is limited. Here we review the photocatalyst criteria for water splitting, the synthesis and morphological manipulations of In2S3, the synthesis of heterojunctions by coupling semiconductors to increase performance, and doping In2S3. In2S3-based heterojunctions, i.e., traditional type II, all-solid-state, and direct Z-scheme photocatalytic systems show benefits such as larger charge separation, broad solar spectrum absorption, and amended conduction band and valence band edge potentials for maximum pollutant removal and H2 production. The effect of dopant incorporation on electronic modulations of In2S3 is explained by the density functional theory. [ABSTRACT FROM AUTHOR]

The semiconductor photocatalyst is crucial for dealing with the current environmental and energy crises. However, the large-scale applications of the reported semiconductor materials are hampered by the recombination of electrons and holes, low kinetic properties, and slow reaction rates. Herein, a three-dimensional structured kaolin/hydrothermally treated red phosphorus (K/HRP) composite photocatalyst was synthesized. The composition ratio was optimized, and the K 7 /HRP composites (contained 7%) exhibited the highest photocatalytic activity. The rhodamine B photodegradation rate constant and the hydrogen production rate were 0.25 min−1 and 252 μmol h−1 g−1, which were higher than those of HRP by 12.4 and 7.2 times, respectively. The enhancement of the HRP photocatalytic activity was attributed to the presence of K, which inhibited the overgrowth and the agglomeration of HRP and shortened the carrier migration distance. The electrostatic interaction between the K and the HRP effectively promoted the separation of photogenerated charge carriers. In addition, the three-dimensional structure of the K and the HRP construct enhanced the light absorption and provided a pollution-free and large-area transport interface for carriers. This work has paramount guiding importance in the preparation of high-efficiency, cheap, and recyclable nanocomposite photocatalyst materials. [ABSTRACT FROM AUTHOR]

Today's rapid industrialization and globalization have provoked the sustainable chain of diversity. Photocatalytic nano-materials are emerging to combat two major problems like environmental pollution and energy crisis. In this regard, incredible experimental as well as theoretical studies have been done to realize the characteristic properties of g-C 3 N 4 , as a metal free polymeric photocatalytic nano-material. However, because of some important limitations, like low-surface area, limited light absorption, quantum confinement effect and low-dimensionality, diversified modification like band structure engineering, doping, defecting and designing of heterojunction/composites etc. were introduced to broaden its prospective applications. Amongst, band gap engineering through elemental doping is considered as a successful approach to modify its optical as well as electronic properties. In this review, we have highlighted synthesis methods, distinct doping mode of the dopants, complexity due to the dopants, benefits of co-doping, mechanism involved in the photo catalytic performance of various anion doped g-C 3 N 4 based photo catalyst. Incorporation of non-metallic elements plays an unique role in enhancing light absorption and tuning the band potentials to bring about targeted redox reactions. It can pave a novel avenue for the advances of element doped g-C 3 N 4 systems towards visible-light driven photo catalysis. Although we have critically discussed the mono/bi/tri-anion doped g-C 3 N 4 systems, our aim is to showcase the broader version to develop these systems in a sustainable manner. Schematic representation of the highlights of anion doped g-C 3 N 4 based photocatalyst. Image 1 • The study highlights efficient anion doped g-C 3 N 4 systems towards energy and environment. • Easy synthesis procedure through simple one step calcinations, abundant availability makes the process sustainable. • The nature of dopant, doping sites and modifications of mono/bi/tri-doped g-C 3 N 4 -based photocatalysts are enlightened. • By tuning the band edge potential through insertion of impurity levels helps to bring about targeted redox reactions. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) is, due to its widespread use including the production of plastic materials, an ubiquitous pollutant in the aquatic environment. Due to evidence of adverse BPA effects on the environment and human health, its use has been restricted and replaced by analogues such as bisphenol F (BPF). This study examined the toxicity of BPA, BPF and their mixture towards primary producers, the eukaryotic green alga Pseudokirchneriella subcapitata and the prokaryotic cyanobacterium Synechococcus leopoliensis. The results demonstrated that S. leopoliensis is more sensitive than P. subcapitata, whereas toxic potential of the two BPs is comparable and represents comparable hazard for phytoplankton. The toxicity of the binary mixture was predicted by different models (concentration addition, independent action, combination index and the isobologram method) and compared to experimental data. Additive effect was observed in P. subcapitata over the whole effect concentration range (EC5–EC90), whereas in S. leopoliensis, no pronounced combined effect was observed. The environmental risk characterisation based on the comparison of reported concentrations of BPA and BPF in surface waters to the predicted no-effect concentration values obtained in this study showed that at certain industrial areas, BPA represents environmental risk, whereas BPF does not. However, BPF concentrations in aquatic environment are expected to increase in the future. To enable environmental risk assessment of BP analogues, more data on the toxicity to aquatic species, including combined effect, as well as data on their occurrence in the aquatic environment are needed. Graphical abstract [ABSTRACT FROM AUTHOR]

ZnO is an exciting material for photocatalysis applications due to its high activity, easy accessibility of raw materials, low production costs, and nontoxic. Several ZnO nano and microstructures can be obtained, such as nanoparticles, nanorods, micro flowers, microspheres, among others, depending on the preparation method and conditions. ZnO is a wide bandgap semiconductor presenting massive recombination of the generated charge carriers, limiting its photocatalytic efficiency and stability. It is common to mix it with metal, metal oxide, sulfides, polymers, and nanocarbon-based materials to improve its photocatalytic behavior. Therefore, ZnO–nanocarbon composites formation has been a viable alternative that leads to new, more active, and stable photocatalytic systems. Mainly, graphene is a well-known two-dimensional material, which could be an excellent candidate to hybridize with ZnO due to its excellent physical and chemical properties (e.g., high specific surface area, optical transmittance, and thermal conductivity, among others). This review analyses ZnO–graphene nanocomposites’ recent advances, addressing the synthesis methods and the resulting structural, morphological, optical, and electronic properties. Moreover, we examine the ZnO–graphene composites’ role in the photocatalytic degradation of organic/inorganic pollutants. [ABSTRACT FROM AUTHOR]

Iron minerals are widespread in earth's surface water and soil. Recent studies have revealed that under sunlight irradiation, iron minerals are photoactive on producing reactive oxygen species (ROS), a group of key species in regulating elemental cycling, microbe inactivation, and pollutant degradation. In nature, iron minerals exhibit varying crystallinity under different hydrogeological conditions. While crystallinity is a known key parameter determining the overall activity of iron minerals, the impact of iron mineral crystallinity on photochemical ROS production remains unknown. Here, we assessed the photochemical ROS production from ferrihydrites with different degrees of crystallinity. All examined ferrihydrites demonstrated photoactivity under irradiation, resulting in the generation of hydrogen peroxide (H 2 O 2 ) and hydroxyl radical ( • OH). The photochemical ROS production from ferrihydrites increased with decreasing ferrihydrite crystallinity. The crystallinity-dependent photochemical • OH production was primarily attributed to conduction band reduction reactions, with the reduction of O 2 by conduction band electrons being the rate-limiting key process. Conversely, the crystallinity of iron minerals had a negligible influence on photon-to-electron conversion efficiency or surface Fenton-like activity. The difference in ROS productions led to a discrepant degradation efficiency of organic pollutants on iron mineral surfaces. Our study provides valuable insights into the crystallinity-dependent ROS productions from iron minerals in natural systems, emphasizing the significance of iron mineral photochemistry in natural sites with abundant lower-crystallinity iron minerals such as wetland water and surface soils.

We developed a novel method to fabricate copper nanorods in situ in a poly(ether sulfone) (15 wt %) casting solution by a sonochemical reduction of Cu 2+ ions with NaBH 4 . The main twist is the addition of ethanol to remove excess NaBH 4 through Cu(0) catalyzed ethanolysis. This enabled the direct use of the resulting copper-containing casting dispersions for membrane preparation by liquid nonsolvent-induced phase separation and led to full utilization of the copper source, generating zero metal waste. We characterized the copper nanorods as presented in the membranes via scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and UV/vis spectroscopy. We could demonstrate that the rapid immobilization from reducing conditions led to the membrane incorporation of copper nanorods in a state of high reactivity, which also promoted the complete oxidation to CuO after fabrication. We further observed a large aspect ratio and crystal straining of the nanorods, likely resulting from growth around the matrix polymer. The entanglement with poly(ether sulfone) further facilitated a selective presentation at the pore surface of the final CuO-decorated membranes. The membranes also exhibit high water permeances of up to 2800 L/m 2 hbar. Our catalytic membranes achieved exceptionally high activities in the aqueous flow-through reduction of p -nitrophenol ( p -NP), with turnover frequencies of up to 115 h -1 , even surpassing those of other state-of-the-art catalytic membranes that incorporate Pd or Ag. Additionally, we demonstrated that catalytic hydrolysis of the reducing agent in water can lead to hydrogen gas formation and blocking of active sites during continuous catalytic p -NP hydrogenation. We illustrated that the accompanying conversion loss can be mitigated by facilitated gas transport in the water-filled pores, which is dependent on the orientation of the pore size gradient and the flow direction.

In this paper, first-principle calculations were performed to investigate the effects of oxygen (O) vacancies (Ovac) on the crystal structure, electronic distribution, adsorption energies of O2 and H2O and the density of states (DOS) of monoclinic bismuth vanadate (m-BiVO4). Ovac were stable when incorporated into m-BiVO4(001) and increased the adsorption energy of O2. Ovac changed the V3d orbitals of m-BiVO4(001) by adding a new band gap level, causing the redundant electrons of V atoms to become carriers and promoting the separation efficiency of electrons and holes. To verify the first-principle calculations, m-BiVO4 with different Ovac levels was prepared via hydrothermal synthesis. X-ray diffraction (XRD) patterns confirmed the existence of the (001) crystal surface of m-BiVO4. In addition, X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) spectroscopy of m-BiVO4 confirmed the presence of Ovac and demonstrated that, as the Ovac level increased, the number of superoxide radicals (O2-·) and hydroxyl radicals (·OH) produced increased. In addition, m-BiVO4 with a higher Ovac level possessed superior photocatalytic properties to and degraded rhodamine B (RhB) dye nearly 2-fold faster than m-BiVO4 with a lower Ovac level. Finally, the removal rate of RhB increased from 23 to 44%. All experimental results were in good agreement with the first-principle calculated results.

Abstract Due to the fact that traditional heavy metal‐based catalysts toward wastewater treatment could cause the problem of secondary contamination, it is imperative to seek for more eco‐friendly catalysts to address this tricky issue. Recently, numerous novel metal‐based heterogeneous catalysts, especially perovskite oxides, have been widely investigated for the activation of peroxymonosulfate (PMS), which is significant in the removal of organic pollutants. Here, we report a novel perovskite oxide (La0.7Sr0.3)CoO3‐δ (LSC)‐based 3D ceramic hollow fiber catalyst for aqueous‐phase advanced oxidation. Through it cooperating with PMS, the methylene blue (20 ppm) can be completely degraded only about 30 minutes. The mechanism of advanced oxidation process is explored via the electron paramagnetic resonance test on the active species. In addition, it also displays high activity for the degradation of other pollutes, such as tetrabromobisphenol A and rhodamine B. This study provides a new strategy to effectively degrade contaminant via introducing 3D ceramic catalysts.

Porous recycled glass beds were produced for the potential use in water remediation. The present work discusses the structural and mechanical characteristics of filters made of commercially available powdered recycled glass. The study measured the porosity and percolation performance of the sintered glass beds as a function of the sintering parameters and the particle size of the original powdered glass. Moreover, because TiO2 can serve as a photocatalyst to degrade organic pollutants, a TiO2/recycled glass composite was also studied. Optical microscopy helped measure the resulting porosity by quantitative image analysis. Finally, a performance map that specified the composite porosity, percolation, and compression characteristics was obtained as a function of sintering time, sintering temperature, glass particle size, and the percentage of TiO2 added.

A novel graphitic carbon nitride (g-C3N4)–CaTiO3 (CTCN) organic–inorganic heterojunction photocatalyst was synthesized by a facile mixing method, resulting in the deposition of CaTiO3 (CT) nanoflakes onto the surface of g-C3N4 nanosheets. The photocatalytic activity of the as-synthesized heterojunction (along with the controls) was evaluated by studying the degradation of an aqueous solution of rhodamine B (RhB) under UV, visible and natural sunlight irradiation. The CTCN heterojunction with 1:1 ratio of g-C3N4/CT showed the highest photocatalytic activity under sunlight irradiation and was also demonstrated to be effective for the degradation of a colorless, non-photosensitizing pollutant, bisphenol A (BPA). The superior photocatalytic performance of the CTCN heterojunction could be attributed to the appropriate band positions, close interfacial contact between the constituents and extended light absorption (both UV and visible region), all of which greatly facilitate the transfer of photogenerated charges across the heterojunction and inhibit their fast recombination. In addition, the two-dimensional (2D) morphology of g-C3N4nanosheets and CT nanoflakes provides enough reaction sites due to their larger surface area and enhances the overall photocatalytic activity. Furthermore, the active species trapping experiments validate the major role played by superoxide radicals (O2−•) in the degradation of pollutants. Based on scavenger studies and theoretically calculated band positions, a plausible mechanism for the photocatalytic degradation of pollutants has been proposed and discussed.

Semiconductor–semiconductor binary photocatalysts with complementary band gaps and desirable conduction band (CB)/valence band (VB) potentials are considered as attractive photocatalysts. In this study, binary exfoliated MoS2 sheet–Cu2O nanocrystal (e‐MoS2sheet–Cu2ONC) hybrids have been synthesized through direct growth of Cu2O nanocrystals on e‐MoS2 sheets. Under visible light irradiation, electrons and holes are efficiently generated in the binary e‐MoS2sheet–Cu2ONC hybrids. In addition, migration of electrons and holes is also accelerated into opposite e‐MoS2 sheets and Cu2O nanocrystals, respectively. The efficient charge carrier formation and transfer in the e‐MoS2sheet–Cu2ONC hybrids are attributed to their morphological and compositional features, which boost their photocatalytic performance toward methyl orange degradation. [ABSTRACT FROM AUTHOR]

Schematic of pollutants degradation in PFC. Wastewater contains organic compounds (fatty acids, amino acids, and carbohydrates) that have a significant amount of chemical energy. In this regard, the use of wastewater for recovering energy by some appropriate energy conversion technologies can be considered as an appropriate approach to simultaneously achieve the reduction of environmental contamination and increasing supply of energy. The Photocatalytic Fuel Cell (PFC) can provide a new approach in developing technology for simultaneous organic pollutants removal from wastewaters and power generation, but it also has disadvantages, such as requires higher voltage, more cost and complexity. To present a comprehensive vision of the current state of the art, and progress the treatment efficiency and agitate new studies in these fields, this review discussed the study covering PFC aspects, with a focus on the comparison of pollutant degradation, power generation, different photoanode and photocathode materials as well as the application of the Fenton process in PFCs. [ABSTRACT FROM AUTHOR]

Nowadays, increasing extortions regarding environmental problems and energy scarcity have stuck the development and endurance of human society. The issue of inorganic and organic pollutants that exist in water from agricultural, domestic, and industrial activities has directed the development of advanced technologies to address the challenges of water scarcity efficiently. To solve this major issue, various scientists and researchers are looking for novel and effective technologies that can efficiently remove pollutants from wastewater. Nanoscale metal oxide materials have been proposed due to their distinctive size, physical and chemical properties along with promising applications. Cupric Oxide (CuO) is one of the most commonly used benchmark photocatalysts in photodegradation owing to the fact that they are cost-effective, non-toxic, and more efficient in absorption across a significant fraction of solar spectrum. In this review, we have summarized synthetic strategies of CuO fabrication, modification methods with applications for water treatment purposes. Moreover, an elaborative discussion on feasible strategies includes; binary and ternary heterojunction formation, Z-scheme based photocatalytic system, incorporation of rare earth/transition metal ions as dopants, and carbonaceous materials serving as a support system. The mechanistic insight inferring photo-induced charge separation and transfer, the functional reactive radical species involved in a photocatalytic reaction, have been successfully featured and examined. Finally, a conclusive remark regarding current studies and unresolved challenges related to CuO are put forth for future perspectives. [ABSTRACT FROM AUTHOR]

Development of superior heterogeneous photocatalyst for hydrogen (H 2) evolution with promising pollutant degradable capacity is a significant feature but then again thought-provoking for shaping the energy and environmental issues. In this regard, a photocatalytic H 2 evolution using nano diamond (ND) semiconducting materials having pollutant degradable capacity for Rhodamine B dye (RhB) has been rarely reported and hence predicted to the sustainable energy. Productive characteristics such good chemical stability, super hardness, nanometer size, biocompatibility and thermal conductivity, ND is a capable and highly valuable powder physical material. Non-uniform and agglomeration dispersion spread of ND in different solvents are the main problems preventing ND from the wide-use in commercial applications. Upon 535 nm solar light excitation, the fabricated ND sample exhibit remarkable photocatalytic H2 production with a HER of about 400 μmol h−1 than pristine ND (197 μmol h−1). Additionally, this H2 generation dramatically enhances the quantum yield, indicating the H2 terminated sites work as electron reservoirs. Precisely, the kinetic constant pseudo-order of FND for photodegradation of RhB was higher as compared with pristine ND. As such, the results show an important step toward tailor-designed and explain the vital role of FND composites for the rational motifs of fruitful photocatalyst with effective pollutant degradable capability for future demand. • A ball milling Functionalization of ND. • An twice improved HER was observed for FND (400 μmol/h) than pure ND (197 μmol/h). • Pseudo-order kinetic constant of FND for RhB was higher as compared with ND. [ABSTRACT FROM AUTHOR]

Pyrogenic Carbonaceous Matter (PCM; e.g., black carbon, biochar, and activated carbon) are solid residues from incomplete combustion of fossil fuel or biomass. They are traditionally viewed as inert adsorbents for sequestering contaminants from the aqueous phase or providing surfaces for microbes to grow. In this account, we reviewed the recently discovered reactivity of PCM in promoting both chemical and microbial synergies that are important in pollutant transformation, biogeochemical processes of redox-active elements, and climate change mitigation with respect to the interaction between biochar and nitrous oxide (N2O). Moreover, we focused on our group’s work in the PCM-enhanced abiotic transformation of nitrogenous and halogenated pollutants and conducted in-depth analysis of the reaction pathways. To understand what properties of PCM confer its reactivity, our group pioneered the use of PCM-like polymers, namely conjugated microporous polymers (CMPs), to mimic the performance of PCM. This approach allows for the controlled incorporation of specific surface properties (e.g., quinones) into the polymer network during the polymer synthesis. As a result, the relationship between specific characteristics of PCM and its reactivity in facilitating the decay of a model pollutant was systematically studied in our group’s work. The findings summarized in this account help us to better understand an overlooked environmental process where PCM synergistically interacts with various environmental reagents such as hydrogen sulfide and water. Moreover, the knowledge gained in these studies could inform the design of a new generation of reactive carbonaceous materials with tailored properties that are highly efficient in contaminant removal. [ABSTRACT FROM AUTHOR]

An acid, 2,2-dichloropropionic acid (2,2-DCP) is an active ingredient in herbicide (Dalapon®). Using 2,2-DCP as a model substrate, an alkalotolerant bacterium was successfully isolated from the Blue Lake, Turkey. This bacterium is a potential bioremediation agent of recalcitrant xenobiotic halogenated compounds. This study aimed to prove the efficacy of the alkalotolerance Bacillus megaterium BHS1 in degrading 2,2-DCP as the sole source of carbon. Biolog GEN III system and 16S rRNA analysis were used for the identification of the bacterium. It was discovered that the strain BHS1 is Bacillus megaterium, and the bacterium that was observed to thrive in alkaline conditions (pH 7.0-14.0), supplemented with varying concentrations of 2,2-DCP (from 20 to 60 mM). Growth of strain BHS1 was exceptional in 40 mM of 2,2-DCP at pH 9, corresponding to a cell doubling time of 17.7 hour, whereas was fully inhibited at 50 mM 2,2-DCP. Since halogenated pollutants can make their way into highly alkaline environments, therefore, identifying threshold levels of strain BHS1 with respect to alkaline-tolerance and maximum level of 2,2-DCP may prove pertinent. This is to ensure that an optimal environment is created for the bacteria to degrade 2,2-DCP-contaminated water. In addition, this is the first study exploring a Bacillus species isolated from an alkaline environment adept in utilizing 2,2-DCP as a sole source of carbon. Hence, the ability of this strain to degrade other types of haloalkanoic acids constitutes a worthy future study. [ABSTRACT FROM AUTHOR]

Shewanella oneidensis MR‐1, a model strain of exoelectrogenic bacteria (EEB), plays a key role in environmental bioremediation and bioelectrochemical systems because of its unique respiration capacity. However, only a narrow range of substrates can be utilized by S. oneidensis MR‐1 as carbon sources, resulting in its limited applications. In this study, a rapid, highly efficient, and easily manipulated base‐editing system pCBEso was developed by fusing a Cas9 nickase (Cas9n (D10A)) with the cytidine deaminase rAPOBEC1 in S. oneidensis MR‐1. The C‐to‐T conversion of suitable C within the base‐editing window could be readily and efficiently achieved by the pCBEso system without requiring double‐strand break or repair templates. Moreover, double‐locus simultaneous editing was successfully accomplished with an efficiency of 87.5%. With this tool, the key genes involving in N‐acetylglucosamine (GlcNAc) or glucose metabolism in S. oneidensis MR‐1 were identified. Furthermore, an engineered strain with expanded carbon source utilization spectra was constructed and exhibited a higher degradation rate for multiple organic pollutants (i.e., azo dyes and organoarsenic compounds) than the wild‐type when glucose or GlcNAc was used as the sole carbon source. Such a base‐editing system could be readily applied to other EEB. This study not only enhances the substrate utilization and pollutant degradation capacities of S. oneidensis MR‐1 but also accelerates the robust construction of engineered strains for environmental bioremediation. [ABSTRACT FROM AUTHOR]

Low‐dimensional materials and heterostructure photocatalysts are distinct research topics in artificial photocatalysis. The rational design of photocatalysts considering both aspects has established significant importance due to the fascinating advantages of superior charge carrier transport/transfer and photocatalytic performances. Graphitic carbon nitride (g‐C3N4), a captivating metal‐free and visible light‐active photocatalyst, has drawn interdisciplinary attention in the field of solar energy conversion and pollutant degradation because of its appropriate electronic band structure, excellent physicochemical stability, facile synthesis, and unique layered structure. The g‐C3N4‐based low‐dimensional heterostructures demonstrate various mechanisms for photogenerated charge carrier transfer including type I heterojunction, type II heterojunction, p–n heterojunction, Z‐scheme heterojunction, Schottky junction, and surface plasmon resonance (SPR) effect. Herein, the state‐of‐the‐art g‐C3N4‐based low‐dimensional heterostructure photocatalysts are analyzed to provide an insightful outlook with respect to doping and defect engineering, band structures tuning, and charged carrier dynamics to realize enhanced visible light absorption, improved photoinduced charge carrier transport/transfer, and spatially separated electron–hole pairs for improved photocatalytic performances. Furthermore, the potential application of g‐C3N4‐based low‐dimensional heterostructures for water splitting, CO2 reduction, and pollutant degradation is also presented. Finally, conclusion and invigorating perspective about challenges and opportunities for advanced design of g‐C3N4‐based low‐dimensional heterostructures are briefed. [ABSTRACT FROM AUTHOR]

Designing and constructing one-dimensional (1D) discrete heterojunctions comprise an ideal strategy to improve the charge-separation efficiency and enhance the photocatalytic activities of semiconductor materials. Here, a novel architecture of discrete heterojunction nanofibers (DH-NFs) was obtained by growing Bi 2 WO 6 nanosheets (NSs) on electrospun BiFeO 3 nanofibers (NFs) via solvothermal technology. The charge-separation efficiency of BiFeO 3 /Bi 2 WO 6 DH-NFs was approximately 2 times higher than that of BiFeO 3 NFs and Bi 2 WO 6 NSs. As expected, the BiFeO 3 /Bi 2 WO 6 DH-NFs exhibited enhanced photocatalytic activities for oxygen evolution and RhB degradation. The reaction rates of BiFeO 3 /Bi 2 WO 6 DH-NFs for oxygen evolution and RhB degradation were 18.3 and 36.7 times higher, respectively, than those of BiFeO 3 NFs, and 31.9 and 8.7 times higher than those of Bi 2 WO 6 NSs, respectively. The improved charge-separation efficiency and enhanced photocatalytic activities of BiFeO 3 /Bi 2 WO 6 DH-NFs could be attributed to the following three points. The 1D heterojunctions could realize the separation and axial transport of photogenerated charges. The discrete structure could facilitate the spatial separation of redox reaction sites as well as photogenerated charges. The high surface area of BiFeO 3 /Bi 2 WO 6 DH-NFs might provide more active sites for photocatalytic reaction. Moreover, the BiFeO 3 /Bi 2 WO 6 DH-NFs possessed good recycling performance owing to the magnetic-separable property derived from the ferromagnetic behavior of BiFeO 3. [ABSTRACT FROM AUTHOR]