Photocatalytic Process Research Articles

Efficient Photocatalytic Water Purification Through Novel Janus-Nanomicelles with Long-Lived Charge Separation Properties.

Although the design of photocatalysts incorporating donor-acceptor units has garnered significant attention for its potential to enhance the efficiency of the photocatalysis process, the primary bottleneck lies in the challenge of generating long-lived charge separation states during exciton separation. Therefore, a novel Janus-nanomicelles photocatalyst is developed using carbazole (Cz) as the donor unit, perylene-3,4,9,10-tetracarboxydiimide (PDI) with long-excited state as the acceptor unit and polyethylene glycol (PEG) as the hydrophilic segment through ROMP polymerization. After optimizing the ratio, Cz19-PDI18-PEG10 rapidly adsorbs bisphenol A (BPA) within 10 s through π-π interaction, hydrogen-bonding interaction, and hydrophobic interaction between BPA and hydrophobic blocks when exposed to aqueous humor and efficiently photodegrades BPA (50ppm) within 120min for water purification purposes due to its long-lived charge separation state and achieving the highest reported efficiency so far. Mechanistic studies have shown that this excellent performance of Cz19-PDI18-PEG10 can be attributed to synergistic interactions between highly efficient adsorption capacity and long-lived charge separation states during photocatalysis. This novel Janus-nanomicelles design strategy holds promise as an effective candidate for water purification.

Self-Assembly Strategy for Synthesis of WO3@TCN Heterojunction: Efficient for Photocatalytic Degradation and Hydrogen Production via Water Splitting

Herein, a WO3@TCN photocatalyst was successfully synthesized using a self-assembly method, which demonstrated effectiveness in degrading organic dyestuffs and photocatalytic evolution of H2. The synergistic effect between WO3 and TCN, along with the porous structure of TCN, facilitated the formation of a heterojunction that promoted the absorption of visible light, accelerated the interfacial charge transfer, and inhibited the recombination of photogenerated electron–hole pairs. This led to excellent photocatalytic performance of 3%WO3@TCN in degrading TC and catalyzing H2 evolution from water splitting under visible-light irradiation. After modulation, the optimal 3%WO3@TCN exhibited a maximal degradation rate constant that was twofold higher than that of TCN alone and showed continuous H2 generation in the photocatalytic hydrogen evolution. Mechanistic studies revealed that •O2− constituted the major active species for the photocatalytic degradation of tetracycline. Experimental and DFT results verified the electronic transmission direction of WO3@TCN heterojunction. Overall, this study facilitates the structural design of green TCN-based heterojunction photocatalysts and expands the application of TCN in the diverse photocatalytic processes. Additionally, this study offers valuable insights into strategically employing acid regulation modulation to enhance the performance of carbon nitride-based photocatalysts by altering the topography of WO3@TCN composite material dramatically.

Electron Push-Pull Effect of Benzotrithiophene-Based Covalent Organic Frameworks on the Photocatalytic Degradation of Pharmaceuticals and Personal Care Products

A covalent organic framework (COF) has emerged as a promising photocatalyst for the removal of pharmaceutical and personal care product (PPCP) contaminants; however, high-performance COF photocatalysts are still scarce. In this study, three COF photocatalysts were successfully synthesized by the condensation of benzo[1,2-b:3,4-b′:5,6-b′′]trithiophene-2,5,8-tricarbaldehyde (BTT) with 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)trianiline (TAPT), 1,3,5-Tris(4-aminophenyl)benzene (TAPB), and 4,4′,4′′-nitrilotris(benzenamine) (TAPA), namely, BTT-TAPA, BTT-TAPB, and BTT-TAPT, respectively. The surface areas of BTT-TAPA, BTT-TAPB, and BTT-TAPT were found to be 800.46, 1203.60, and 1413.58 cm2∙g−1, respectively, providing abundant active sites for photocatalytic reactions. Under visible-light irradiation, BTT-TAPT exhibited the highest removal rate of tetracycline (TC), reaching 82.7% after 240 min. The superior photocatalytic performance of BTT-TAPT was attributed to its large specific surface area and the strong electron-acceptor properties of the triazine group. Electron paramagnetic resonance capture experiments and liquid chromatograph mass spectrometer analysis confirmed that superoxide radicals played a pivotal role in the degradation of TC and ciprofloxacin. Moreover, BTT-TAPT exhibited high stability and reproducibility during the photocatalytic degradation process. This study confirms that BTT-based COFs are a class of promising photocatalysts for the degradation of PPCPs in water, and their performance can be further optimized by tuning the structure and composition of the frameworks.

Two Novel Viologen/Polyoxometalate‐Based Compounds for the Efficient Photocatalytic Reduction of Cr (VI) Under Visible Light Irradiation

ABSTRACTDesigning efficient photocatalyst has attracted extensive attention for treating polluted wastewater containing Cr (VI). In this work, two viologen/polyoxometalate (POM)‐based compounds were synthesized, [Ni (mimb)2(H2O)4(β‐Mo8O26)]·4H2O (1) and [Zn (mimb)2(H2O)4(β‐Mo8O26)]·4H2O (2) (mimb = 1‐((3,5‐dimethylisoxazol‐4‐yl)methyl)‐[4,4′‐bipyridin]‐1‐ium), through a hydrothermal method and investigated their ability of photocatalytic reduction of Cr (VI). The structures of compounds 1–2 were characterized by single‐crystal X‐ray diffraction, revealing that both possess a zero‐dimensional (0D) structure and can form one‐dimensional (1D) chain structures through hydrogen bondings. Photocatalytic experiments demonstrate that compound 1 has superior photocatalytic performance compared to compound 2. Under optimal conditions (pH = 2, 15 mg catalysts, and 10 mg L−1 Cr (VI) concentration), compound 1 can completely reduce Cr (VI) within 20 min, while compound 2 requires 30 min. Compounds 1–2 also show good stability after photocatalytic reaction, and maintain high photocatalytic activity after five reaction cycles. Additionally, the photocatalytic reaction mechanism of compounds 1–2 was studied, and the free radical scavenging experiments show that its main active species are e−, h+, and ˙O2−. The nitroblue tetrazolium (NBT) experiments further confirm the crucial role of ˙O2− in the photocatalytic process. The good photocatalytic activity, stability, and recyclability of the viologen/POM‐based compounds suggest their potential application in the treatment of wastewater containing Cr (VI).

The use of green synthesized TiO2/MnO2 nanoparticles in solar power membranes for pulp and paper industry wastewater treatment

The pulp and paper manufacturing wastewater is as complicated as any other industrial effluent. A promising approach to treating water is to combine photocatalysis and membrane processes. This paper demonstrates a novel photocatalytic membrane technique for solar-powered water filtration. The method is based on creating green-prepared TiO2, and MnO2 nanoparticles (NPs) using Pomegranate peels and Seder leaf extracts and incorporation into polyvinylidene chloride to produce a novel water purification system that combines semiconductor photocatalysis with membrane filtration. The prepared heterostructure of the TiO2/MnO2 nanocomposite membrane provides photogenerated charge separation. To ensure chemical bonding at the membrane surface, Raman and Fourier transform infrared spectroscopy (FT-IR) were employed. The modified membrane’s hydrophilicity and roughness increased significantly. Additionally, the modified nanocomposite membrane’s porosity was measured. The integrated process demonstrated much higher removal of humic acid and high efficiency of wastewater treatment for pulp and paper. In sunlight, humic acid removal was 98% from synthetic wastewater. While using the produced membrane on pulp and paper effluent, these studies indicate that: in the dark, the removal was 50%, while in the sunlight, the removal increased to 70%, with a reduction in the COD from 1500 mg/L to 247 mg/L. Additionally, the TDS decreased from 1630 to 452 ppt in the sunlight. This research sheds light on how solar energy can clean wastewater from the pulp and paper industry while improving membrane separation. Also, an alternative source to sunlight was used to manufacture a photocatalytic membrane with high efficiency for wastewater treatment and an inexpensive price.

Mesoporous NiFe2O4@g-C3N4-Based p-n Heterostructures for Boosting Solar-Driven Photocatalytic Dye Degradation and Hydrogen Evolution.

Mass-fraction-optimized heterojunction composites featuring precisely engineered interfaces and mesoporous structures are crucial for improving light absorption, minimizing electron-hole recombination, and boosting overall catalytic efficiency. Herein, highly efficient mesoporous-NiFe2O4@g-C3N4 heterojunctions were developed by embedding p-type NiFe2O4 nanoparticles (NPs) within n-type porous ultrathin g-C3N4 (p-uCN) nanosheets. The optimized NiFe2O4@g-C3N4, loaded with 20 wt % magnetic counterparts, exhibits exceptional photocatalytic methylene blue (MB) degradation, achieving the highest performance in both photocatalytic and photo-Fenton processes with rate constants of 0.062 min-1 and 0.161 min-1, respectively. These performance metrics are 1.3 and 2.55 fold higher than p-uCN (0.048 min-1 and 0.063 min-1) and 51.6 and 17.4 fold higher than NiFO (0.0012 min-1 and 0.009 min-1). Notably, mp-NiF@uCN-20 % with 1.0 wt % of Pt loading achieves the highest H2 evolution rate of 2294 μmolg-1h-1, which is 3.72, 1.52, and 13.49 times higher than that of pure CN, p-uCN, and NiFO, respectively. The enhanced performance is corroborated by increased surface area, improved separation of charge carriers, and effective charge transfer, which enables simultaneous reduction and oxidation processes. Further, the magnetic nanocomposite exhibits remarkable stability even after multiple runs, indicating their reusability. The experimental findings emphasize the importance of p-n heterojunctions, interfacial band alignment, and mesoporous architecture in enhancing the photocatalytic efficiency of NiFe2O4@g-C3N4 nanocomposites.

Enhancing the Built-in Electric Field in Oxygen Vacancies-Enriched I-Doped Bi3O4Cl for Visible Light-Driven Photocatalytic Oxidation.

In semiconductor catalysts, rational doping of nonmetallic elements holds significant scientific and technological importance for enhancing photocatalytic performance. Here, using a one-step hydrothermal technique, we synthesized iodine-doped Bi3O4Cl composite and evaluated the impact of iodine doping on its photocatalytic capability for organic dye degradation under visible light irradiation. In this study, we demonstrate that the introduction of iodide ions not only provides an ideal built-in electric field (BIEF) for Bi3O4Cl but also induces the generation of additional oxygen vacancies (OVs). The significantly enhanced BIEF, along with the collaborative effect of the OVs-induced narrow bandgap in Bi3O4Cl, effectively promotes the separation and transfer efficiency of photogenerated charges while suppressing recombination. Under this driving force, photogenerated electrons transfer to the surface OVs, facilitating the activation of surface oxygen, thereby forming highly active superoxide radicals (•O2). Simultaneously, oxygen vacancy engineering can reduce the reaction energy barrier, thereby facilitating the formation of singlet oxygen (1O2), which contributes significantly to photocatalytic processes. The results indicate that under visible light, the prepared iodine-doped Bi3O4Cl exhibits a 6.5-fold increase in the degradation rate constant for rhodamine B and demonstrates enhanced photocatalytic activity toward methyl orange and methylene blue. This study not only provides strong references for optimizing structural design to enhance photocatalytic performance but also offers profound insights into the synergistic effects of BIEF and OVs on charge transfer mechanisms in photocatalytic systems.

Isomer-Effects of Aminophenol Decorated Gold Nanoclusters for H2O2 Photoproduction via Two-Step One-Electron Oxygen Reduction Reaction.

Gold (Au) nanoclustersare promising photocatalysts for biomedicine, sensing, and environmental remediation. However, the short carrier lifetime, inherent instability, and unclear charge transfer mechanism hinder their application. Herein, the Au nanoclusters decorated with three different isomers of o-Aminophenol, m-Aminophenol, and p-Aminophenol are synthesized, namely o-Au, m-Au, and p-Au, which achieve efficient hydrogen peroxide (H2O2) photoproduction through two-step one-electron oxygen reduction reaction (ORR). The interfacial kinetics for the photocatalytic process in this system are investigated in detail, in which, the isomer-effects of aminophenol decorated in Au nanoclusters are definitely elucidated by combining transient photovoltage (TPV), transient potential scanning (TPS), and photo-induced current (TPC) tests. The reaction pathway of o-Au, m-Au, and p-Au is confirmed to be the same through TPC. Although the conduction band values of o-Au, m-Au, and p-Au are essentially the same under working conditions, the values of surface effective charges (ne) for both m-Au and p-Au are higher than that of o-Au. In addition, m-Au has a stronger adsorption capacity for O2 and a faster ORR rate. Thus, the m-Au manifests the highest photocatalytic activity for the H2O2 photoproduction. This work shows a new way for the in-situ study on charge distribution and transfer on photocatalysts.

Photocatalytic Oxygen Evolution with Prussain Blue Coated ZnO Origami Core-Shell Nanostructures.

The design and development of particulate photocatalysts has been an attractive strategy to incorporate earth-abundant metal ions to water splitting devices. Herein, we synthesized CoFe-Prussian blue (PB) coated ZnO origami core-shell nanostructures (PB@ZnO) with different mass ratio of PB components and investigated their photocatalytic water oxidation activities in the presence of an electron scavenger. Photocatalytic experiments reveal that the integration of PB on ZnO boosts the oxygen evolution rate by a factor of ~2.4 compared to bare ZnO origami. We ascribe this increased photocatalytic rate to an improved charge carrier separation and transfer due to the formation of heterojunction at the interface between PB and ZnO. Long-term photocatalytic experiments indicate that the activity and stability of the catalyst was preserved up to 9 h. Our results indicate that the core-shell PB@ZnO particles possess a proper band energy alignment for the photocatalytic water oxidation process.

Photoinduced Pd-Catalyzed 1,4-Dicarbofunctionalization of 1,3-Butadienes via Aliphatic C-H Bond Elaboration.

A three-component coupling strategy for 1,4-dicarbofunctionalization of 1,3-butadiene with C-H bearing substrates has been developed using photoinduced Pd catalysis, with aryl bromide serving as the hydrogen atom transfer (HAT) reagent. This photocatalytic coupling process achieves functionalized oxindole motifs in good yield and regioselectivity under mild reaction conditions. The versatility and synthetic utility of this method are demonstrated through the addition of a variety of C-H-bearing partners and various oxindole substrates to both substituted and unsubstituted butadiene.

Degradation of ciprofloxacin using CoFe2O4@three-dimensional TiO2@graphene aerogels composite: kinetic, reusability, mineralization, degradation pathway, and toxicity assessment.

An investigation into the degradation of ciprofloxacin (CIP) under visible light was carried out using an efficient photocatalyst, i.e., CoFe2O4@3D-TiO2@GA, synthesized by doping CoFe2O4@three-dimensional-TiO2 into a hierarchical porous graphene aerogel. Optimal conditions for achieving complete removal of CIP involved a reaction time of 60 min, a catalyst dose of 0.6 g/L, an initial CIP concentration of 25 mg/L, and a solution pH range of 3-5. The reusability of CoFe2O4@3D-TiO2@GA was observed to remain high even after four consecutive cycles, as the CIP degradation only slightly decreased from 94.3 to 87.1%. Following a 2-h photocatalytic degradation process, the intermediate products within the CIP solution no longer posed a threat to E. coli. The TOC analysis confirmed that CIP achieved 86% total mineralization. In the raw sewage, the BOD5/COD and BOD5/TOC ratios were 0.774 and 0.232, respectively. However, after a 120-min photocatalytic reaction, these ratios increased to 1.38 and 0.754, respectively. These findings suggest that non-biological sewage can be successfully transformed into biodegradable effluent through photocatalytic degradation. The photocatalytic process has a reaction rate coefficient that is 8.7 to 20.7 times higher than the adsorption process, depending on the concentration. The half-life constant is 117.4 min for the optimal concentration of 10 mg/L for the adsorption process, while for the photocatalytic process, it is 6.24 min. The research has highlighted the importance of integrating adsorption and photocatalysis, whereby primary reactive oxidative species, including superoxide and hydroxyl radicals, were identified. The study presents a pioneering approach for producing CoFe2O4@3D-TiO2@GA, which has promising potential for environmental applications utilizing visible light.

Photocatalytic degradation of tetracycline antibiotics and elimination of N-nitrosodimethylamine formation potential by BiOCl/ZnIn2S4 heterostructure under visible-light irradiation.

Photocatalysis is an effective method for removing tetracycline antibiotics, which are important precursors to the potential carcinogen N-nitrosodimethylamine (NDMA). Herein, a BiOCl/ZnIn2S4 heterojunction was successfully synthesized using a simple hydrothermal method. This heterojunction was applied for the first time to degrade various tetracycline antibiotics and reduce NDMA formation potential (NDMA-FP) under visible-light irradiation. Characterization of surface morphology, crystal structure, chemical composition and photoelectrochemical properties revealed that the BiOCl/ZnIn2S4 heterojunction significantly improved light absorption, charge transport and carrier separation efficiency, thereby enhancing photocatalytic performance. The BiOCl/ZnIn2S4 catalyst achieved high degradation efficiencies of 88.0%, 90.7%, 88.7% and 91.7% for tetracycline, minocycline, chlortetracycline and doxycycline, respectively, within 60min of visible-light irradiation. Additionally, it exhibited the lowest NDMA-FP values of 1.5%, 3%, 0.9% and 1.4%, respectively. Radical trapping studies and EPR experiments identified •O2- and •OH radicals as the primary reactive species involved in the photocatalytic process. Analysis of the degradation intermediates and structure-activity relationships indicated that the variations in NDMA-FP were closely associated with the number of dimethylamine groups in the antibiotics and the stability of the resulting carbocations. Notably, the BiOCl/ZnIn2S4 catalyst presented satisfactory stability and positive tetracycline degradation in real antibiotic wastewater. Incorporating BiOCl/ZnIn2S4-loaded nonwoven fabric into a continuous-flow reactor efficiently degraded tetracycline in real wastewater under visible light. This work provides new insights on developing Z-scheme photocatalysts for the simultaneous degradation of various antibiotics and highlights their potential as commercially viable photocatalytic system.

Surfactants govern the fabrication of sulfur-enriched heterojunction catalysts for highly selective photocatalytic conversion of toluene

Photocatalytic selective oxidation of toluene represents a milder and more environmentally friendly strategy for the synthesis of benzaldehyde. In order to enhance catalytic performance, efficient carrier separation and transport are crucial in the photocatalytic process. This study focused on the preparation of ZnS@ZnIn2S4 with sulfur vacancies and heterostructures, combining the advantages properties of ZnS and ZnIn2S4 in photocatalysis. The effects of ZnS and surfactants on the catalytic properties of the composites were studied in depth. Characterization tests revealed that surfactant-modified ZnS@ZnIn2S4 exhibited a higher concentration of sulfur defects, which facilitated electron trapping and promoted photogenerated carrier separation and utilization. Additionally, the present study also demonstrated that the incorporation of ZnS and surfactants could reduce the crystal size of ZnIn2S4, thereby facilitating the exposure of additional active sites. The synergistic effect of the aforementioned advantages enabled toluene to undergo oxidation at a conversion rate of 39% in the presence of oxygen, resulting in the production of benzaldehyde with an exceptional selectivity of 92%. This finding offers valuable insights for future endeavors in designing photocatalytic C-H bond oxidation catalysts.

THE HIGHLY EFFICIENT BiOCl/KBiO3 p-n HETEROJUNCTION PHOTO-CATALYSTS UNDER VISIBLE LIGHT IRRADIATION

BiOCl/KBiO3 p-n heterostructures with hierarchical mesoporous architectures were successfully synthesized via a facile in situ method. The X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) results indicate the formation of heterojunctions between BiOCl and KBiO3. The photocatalytic performance of the as-prepared samples was investigated by the degradation of dye Rhodamine B (RhB) under visible light irradiation. BiOCl/KBiO3 composite has never been used to photodegrade the RhB which is a common dye and very difficult to degrade. The results demonstrated that KBiO3 combined with proper amount of BiOCl nanosheets exhibited high efficiency in the photocatalytic process, and BiOCl/KBiO3 with the molar ratio of 70/30 demonstrated the highest photocatalytic activity due to its large surface area, excellent charge separation characteristics and the suppressed recombination of electron-hole pairs. The results of active species detection reveal that the superoxide radical anions (O2-), hydroxyl free radicals (·OH), photogenerated holes (h+) and photogenerated electrons (e-) reactive species work together for the photocatalytic degradation of RhB. A possible and new mechanism of photocatalysis that differs from other teams was also explored and proposed. The present study will benefit the development of the new p-n heterojunction photocatalysts and would be of great importance to meet ever-increasing environmental demands in the future.

A comprehensive review on TiO2-based heterogeneous photocatalytic technologies for emerging pollutants removal from water and wastewater: From engineering aspects to modeling approaches.

The increasing presence of emerging pollutants (EPs) in water poses significant environmental and health risks, necessitating effective treatment solutions. Originating from industrial, agricultural, and domestic sources, these contaminants threaten ecological and public health, underscoring the urgent need for innovative and efficient treatment methods. TiO2-based semiconductor photocatalysts have emerged as a promising approach for the degradation of EPs, leveraging their unique band structures and heterojunction schemes. However, few studies have examined the synergistic effects of operating conditions on these contaminants, representing a key knowledge gap in the field. This review addresses this gap by exploring recent trends in TiO2-driven heterogeneous photocatalysis for water and wastewater treatment, with an emphasis on photoreactor setups and configurations. Challenges in scaling up these photoreactors are also discussed. Furthermore, Machine Learning (ML) models play a crucial role in developing predictive frameworks for complex processes, highlighting intricate temporal dynamics essential for understanding EPs behavior. This capability integrates seamlessly with Computational Fluid Dynamics (CFD) modeling, which is also addressed in this review. Together, these approaches illustrate how CFD can simulate the degradation of EPs by effectively coupling chemical kinetics, radiative transfer, and hydrodynamics in both suspended and immobilized photocatalysts. By elucidating the synergy between ML and CFD models, this study offers new insights into overcoming traditional limitations in photocatalytic process design and optimizing operating conditions. Finally, this review presents recommendations for future directions and insights on optimizing and modeling photocatalytic processes.

Photocatalytic removal of U(VI) from aqueous solution under visible light by bismuth oxyiodide/graphitic carbon nitride composite.

Applicable to convert soluble U(VI) into the less mobile U(IV) form, the photocatalytic process is widely regarded as an efficient solution to uranium pollution. In the present study, BiOI/g-C3N4 (BICN) composites were produced through uncomplicated hydrothermal synthesis, followed by U(VI) photocatalytic reduction. Batch experiments were conducted to demonstrate the exceptional capability of BICN to address uranium contamination. Specifically, the 5%-BICN composite exhibited higher photocatalytic efficiency in U(VI) reduction, with its performance improved by 1.5 times over BiOI and 3.0 times over g-C3N4. Characterized by p-n heterojunction, BICN composites enhance the movement and separation efficiencies of photogenerated carriers, which significantly promotes the production of •O2- radicals that are critical for U(VI) photocatalytic reduction. These results provide crucial guidance on the potential application of BICN composites in environmental remediation processes.

Enhanced degradation of levofloxacin using photocatalysis and peroxymonosulfate oxidation processes by Z-scheme BiVO4/g-C3N4 heterojunction

Constructing a direct Z-scheme heterostructure is an effective way to improve photogenerated charge separation efficiency. In this work, a novel BiVO4/g-C3N4 (BVO/CN) Z-scheme heterojunction was successfully fabricated through a liquid film combustion method and ultrasonic desperation technique. The obtained samples were analyzed by serials characterization techniques, such as XRD, FT-IR, XPS, SEM, HRTEM, EDS, BET, UV-vis, and PL. The results demonstrated a strong integration between CN and BVO, as evidenced by the absorption edge shifting to 520nm and revealing a narrow band gap (Eg=2.47eV), thereby enhancing light absorption capacity. Under visible light irradiation, the removal efficiency of levofloxacin (LVFX) reached 97.7% within 40min using 20 BVO/CN, which was respectively 2.03 and 2.21 times higher than that achieved with BVO or CN alone. The mechanism of the BVO/CN Z-scheme heterojunction was elucidated based on the ESR test and radical trapping experiment. Additionally, the potential degradation pathway of LVFX was analyzed using HPLC-MS. This study demonstrates the feasibility of constructing a Photocatalyst/Visible-light/peroxymonosulfate (PMS) system for mitigating antibiotic-induced ecological pollution.

Performance of Ti/TiO2-ZIF-67 photoanode under LED irradiation applied to the photoelectrodegradation of the antidepressant venlafaxine (VEN) in municipal wastewater effluent

This work describes the direct deposition of ZIF-67 metal-organic framework (MOF) onto Ti/TiO2 nanotubes forming a photoanode for the degradation of the antidepressant Venlafaxine (VEN). This material combines the excellent characteristics of ZIF-67 MOF in enhancing photocatalytic reduction and oxidation reactions induced by UV LED irradiation, as well as the storage of VEN molecules in its pores. Ti/TiO2-ZIF-67 features an eco-friendly technology for degradation of pharmaceutical micropollutants such as antidepressants. The photoanode was prepared, characterized and applied in the degradation of VEN by photocatalysis (PC), electrocatalysis (EC), photolysis (PL) and PEC processes. PEC process presented the best performance when compared to the others processes in both simulated solutions and real wastewater, achieving 100% and 89% degradation of VEN after 60 and 90 min, with TOC removal rates of 50% and 4%, respectively. The lower mineralization rate suggests that the degradation of VEN in complex matrices such as that of real wastewater produced recalcitrant by-products that are difficult to convert into CO2 and H2O. Zeta potential measurement showed that at pH 6 and 8 there is an effect of attraction of opposite electrostatic charges between the surface of ZIF-67 (positive) and VEN (negative), favoring the degradation of VEN in this pH range. The good performance of the Ti/TiO2-ZIF-67 can be attributed to the formation of the Z-scheme heterojunction between the TiO2 nanotubes and the ZIF-67 MOF which contributed to a lower rate of electron-hole (e-/h+) pairs recombination, favoring VEN degradation mainly to higher generation of •OH radical and less contribution of O2•- superoxide produced by UV irradiation forming some degradation by-products through demethylation and oxidation reactions.

Synergistic and efficient photocatalytic degradation of rhodamine B and tetracycline in wastewater based on novel S-scheme heterojunction phosphotungstic Acid@MIL-101(Cr).

To efficiently treat rhodamine B (RhB) and tetracycline (TC) in wastewater, MIL-101(Cr) was prepared by hydrothermal method and encapsulated with phosphotungstic acid (H3PW12O40, abbreviated as PTA) to form an S-scheme heterojunction PTA@MIL-101(Cr)-x (P@M-x, x=50, 100, 150, 200). The experimental results showed that after 180min under visible light at pH 7, the degradation rates of RhB and TC were 97.81% and 99.9%, respectively. Meanwhile, the cycling experiments have showed that the P@M-100S-scheme heterojunction exhibits good stability. Density Functional Theory (DFT) calculations theoretically verified the experimental results and elucidated the electrons migrate to MIL-101(Cr) and hole enrichment on the PTA surface. It was also revealed that the P@M-x photocatalyst belongs to the S-scheme heterojunction. Moreover, •O2- and h+ had been identified as the main active constituents during the photocatalytic degradation process. The synergistic effect of MIL-101(Cr) and PTA enhances the visible light absorption of P@M-x S-scheme heterojunction, resulting in more efficient electron transfer ability and faster photoreaction rate, thereby improved its photocatalytic performance. This study provides a potential solution for addressing aromatic pollutants in water.

Facile synthesis of CQD/g-C3N4 as a highly effective metal-free photocatalyst for the degradation of carmoisine and indigo carmine dye

The development of extensive dye pollution in the water ecosystem seriously endangers the health of the living organism. For effectively eradicating dyecontaminants from water bodies, photocatalysis is consideredan effective, energy-consumption, inexpensive disinfection technique. As an alternative to conventional metal-based catalysts, heterogeneous metal-free photocatalysts are more sustainable and kinder to the environment. Here, we reported the simplehydrothermalchemical production of Carbon Quantum dots (CQD)-doped graphitic carbon nitride(GCN). Analytical instruments such as XRD, SEM, FE-SEM, HR-TEM, EDX, FT-IR, thesurface area of BET analysis, photoluminescence, and UV–vis spectroscopy, zeta potentialwere used to characterize the as-prepared CQD doped GCN (CDCN). The degradation studies reveal that the CDCN catalyst displays the highest rate of degradation performance than pure GCN. Within 60 min, it shows 96 % degradation toward indigo Carmine (IC) and 93 % decomposition towards carmoisine dye (CM). Significant e−/h+ separation, an increased surface area, and a high redox potential capacity to induce charge bears may all contribute to the CDCN catalyst’s enhanced photocatalytic degradation efficiency. The efficiency of the photocatalytic process was optimized by studying and altering many variables. These include Dye concentration, catalyst concentration, and variation of the pH solution were some of these. The nanocomposite exhibited excellent stability after three successive runs of the photocatalytic procedure. According to the kinetics analysis results indicate that the photocatalytic decomposition of Indigo Carmine (IC) and carmoisine (CM) dye follows pseudo-first-order kinetics. For better photodegradation performance, a potential photocatalytic method employing several pairs of electron-hole acceptor scavengershas been put forth. Based on the positionsof the band gap and the result of the characterization, a feasible mechanismpathway for charge carriers was also presented.