Photodegradation Process Research Articles

Efficient visible light-based photocatalytic performance for tetracycline degradation by novel dual z-type ZnO nanorods /Bi2MoO6 /ZIF-67 heterostructure: Mechanism and water matrix investigation

BackgroundContamination of water with antibiotics poses environmental challenges. Photocatalytic semiconductor heterostructure technologies prove effective in water purification, particularly in eliminating pharmaceutical pollutants. Achieving high-quality heterostructures remains a considerable challenge. MethodsZnO/Bi2MoO6/ZIF-67 photocatalyst was synthesized using the ambient temperature method and characterized through XRD, FTIR, SEM, EDX, TEM, UV–vis DRS, TGA, PL, and BET analyses.Significant findings: The novel ZnO/Bi2MoO6/ZIF-67 photocatalyst's efficacy in degrading tetracycline under visible light was evaluated. The optimal composite molar ratio of ZnO: Bi2MoO6: ZIF-67 was found to be 1:0.6:0.157, exhibiting superior photocatalytic performance compared to ZnO, Bi2MoO6, and ZIF-67. With ZnO/Bi2MoO6/ZIF-67, the highest removal efficiency of tetracycline reached 90.3 % under ideal conditions (catalyst dose = 0.4 g/L, pH = 6.5, irradiation time= 90 min, tetracycline concentration = 40 mg/L). The photocatalytic degradation of tetracycline follows first-order kinetics. The trapping experiments showed that OH• and •O2– species played a beneficial role in enhancing the photodegradation process.

Biosynthesized copper oxide nanoparticles by Psidium guajava plants with antibacterial, antidiabetic, antioxidant, and photocatalytic capacity

AbstractWith an increasing focus on green technologies, this research aimed to synthesize copper oxide nanoparticles (CuO-NPs) using leaf extracts from Allahabad Safeda and Hisar Safeda for environmental and health protection. A range of concentrations of leaf extracts were employed in the synthesis of nanoparticles, utilizing 1–9% extract from Allahabad Safeda and 3–11% extract from Hisar Safeda. The synthesized CuO-NPs were characterized by UV–visible spectrophotometry, Dynamic light scattering, Fourier transform infrared spectroscopy, and Scanning electron microscope with energy-dispersive X-ray spectroscopy. CuO-NPs synthesized using 3% Allahabad Safeda extract and 5% Hisar Safeda extract exhibited a particle size of 15.88 nm and 14.05 nm, respectively. CuO-NPs synthesized with Allahabad Safeda extract exhibited superior antibacterial, antioxidant, antidiabetic, and photocatalytic properties. Their antibacterial tests demonstrated significant inhibition zones against Staphylococcus aureus (20.5 cm), Streptococcus latis (20.7 cm), Escherichia coli (19.5 cm), and Pseudomonas aeruginosa (19.7 mm). Additionally, CuO-NPs from Allahabad Safeda extract (70 µg/mL) exhibited 68.23% of scavenging activity against 2,2-diphenyl-1-picrylhydrazyl. Moreover, the same CuO-NPs at 100 µg/mL concentration showed 67.32% α-amylase inhibition and 75.18% α-glucosidase inhibition, confirming their antidiabetic activities. Furthermore, these nanoparticles demonstrated high performance in photocatalytic degradation, by degrading 82.31% methylene blue and 88.54% crystal violet within 150 min of UV irradiation. Overall, the findings highlight the feasibility of CuO-NPs synthesis using Allahabad Safeda extract and their potential applications in antibacterial treatment, combating diabetes, antioxidation, and environmentally friendly dye photodegradation process. Graphical Abstract

Chronic toxic effects of erythromycin and its photodegradation products on microalgae Chlorella pyrenoidosa

The photodegradation products (PDPs) of antibiotics in the aquatic environment received increasing concern, but their chronic effects on microalgae remain unclear. This study initially focused on examining the acute effects of erythromycin (ERY), then explored the chronic impacts of ERY PDPs on Chlorella pyrenoidosa. ERY of 4.0 − 32 mg/L ERY notably inhibited the cell growth and chlorophyll synthesis. The determined 96 h median effective concentration of ERY to C. pyrenoidosa was 11.78 mg/L. Higher concentrations of ERY induced more serious oxidative damage, antioxidant enzymes alleviated the oxidative stress. 6 PDPs (PDP749, PDP747, PDP719, PDP715, PDP701 and PDP557) were identified in the photodegradation process of ERY. The predicted combined toxicity of PDPs increased in the first 3 h, then decreased. Chronic exposure showed a gradual decreasing inhibition on microalgae growth and chlorophyll content. The acute effect of ERY PDPs manifested as growth stimulation, but the chronic effect manifested as growth inhibition. The malonaldehyde contents decreased with the degradation time of ERY at 7, 14 and 21 d. However, the malonaldehyde contents of ERY PDPs treatments were elevated compared to those in the control group after 21 d. Risk assessment still need to consider the potential toxicity of degradation products under long-term exposure.

Methylene blue degradation using chitosan-Fe2O3 composite and photo-Fenton

This study aims to study the photodegradation process of methylene blue using a synthetic chitosan-Fe2O3 composite and their characterization. Based on the characterization material synthetic, chitosan-Fe2O3 (1:1) composite showed the best material with the smallest crystal size (1.13 nm), the surface morphology was lumpy and had an uneven shape with the composition of the constituent (Carbon (C) 42.88%, Oxygen (O) 48.68%, and Iron (Fe) 29.90%), and showed the smallest energy band gap (1.41 eV) which led us to conclude that the formation of the chitosan-Fe2O3 composite can reduce the energy band gap of Fe2O3. The best composite material then was used to evaluate the activity in degrading methylene blue. The optimum condition in degrading was reached at a contact time of 180 min and pH 9 with a percentage decrease in methylene blue concentration of 90.00%. The effect of concentration variations occurred at 5 ppm with a decrease of 89.62%. Total organic carbon analysis showed that the decrease in methylene blue concentration reached 92.20%. Based on that, it is concluded that the chitosan-Fe2O3 composite could be a potential alternative material to degrade methylene blue.

Constructing a type-II heterojunction of AgI/CO32−-Bi2O2CO3 for enhanced photocatalytic degradation of organic pollutants

The construction of heterojunctions is a well-established approach for enhancing the photocatalytic efficiency of semiconductor materials. To improve the photocatalytic activity of CO32−-Bi2O2CO3, AgI/CO32−-Bi2O2CO3 type-II heterojunction photocatalysts were synthesized using an electrostatic self-assembly method with varying composite ratios. The performance of AgI/CO32−-Bi2O2CO3 catalyst was investigated by photocatalytic degradation of 2-Hydroxy-1, 4-naphthoquinone and levofloxacin under a 300 W xenon lamp (λ ≥ 420 nm). The results demonstrated that the composite photocatalyst (0.5ACBOC), prepared by incorporating 0.5 mL of AgNO3 and KI, exhibited exceptional photocurrent responsiveness and efficient charge carrier separation. 0.5ACBOC displayed the highest degradation efficiency towards 2-Hydroxy-1,4-naphthoquinone (67.5%) and levofloxacin (78.0%). Free radical capture experiments and electron paramagnetic resonance (EPR) analysis revealed ·O2− as a crucial reactive species in the photodegradation process. Moreover, the photocatalytic degradation of 2-Hydroxy-1,4-naphthoquinone exhibited consistent removal efficiency even after undergoing four cycles, thereby demonstrating the excellent cycle stability of the composite catalyst. These findings highlight that AgI/CO32−-Bi2O2CO3 can be easily synthesized and holds great potential as a photocatalyst for efficient degradation of organic pollutants.

Reversible Photoinduced Ligand Substitution in a Luminescent Chromium(0) Complex.

Light-triggered dissociation of ligands forms the basis for many compounds of interest for photoactivated chemotherapy (PACT), in which medicinally active substances are released or "uncaged" from metal complexes upon illumination. Photoinduced ligand dissociation is usually irreversible, and many recent studies performed in the context of PACT focused on ruthenium(II) polypyridines and related heavy metal complexes. Herein, we report a first-row transition metal complex, in which photoinduced dissociation and spontaneous recoordination of a ligand unit occurs. Two scorpionate-type tridentate chelates provide an overall six-coordinate arylisocyanide environment for chromium(0). Photoexcitation causes decoordination of one of these six ligating units and coordination of a solvent molecule, at least in tetrahydrofuran and 1,4-dioxane solvents, but far less in toluene, and below detection limit in cyclohexane. Transient UV-vis absorption spectroscopy and quantum chemical simulations point to photoinduced ligand dissociation directly from an excited metal-to-ligand charge-transfer state. Owing to the tridentate chelate design and the substitution lability of the first-row transition metal, recoordination of the photodissociated arylisocyanide ligand unit can occur spontaneously on a millisecond time scale. This work provides insight into possible self-healing mechanisms counteracting unwanted photodegradation processes and seems furthermore relevant in the contexts of photoswitching and (photo)chemical information storage.

Ti3C2Tx MXene decorated with NiMnO3 / NiMn2O4 nanoparticles for simultaneous photocatalytic degradation of mixed cationic and anionic dyes

The present report investigated the different mass ratios of Ti3C2Tx MXene decorated NiMnO3 / NiMn2O4 nanoparticles and their enhancement of photocatalytic performance. The NiMnO3 / NiMn2O4 - Ti3C2Tx MXene nanocomposites were synthesized by a simple electrostatic self-assembly method. The physicochemical properties of nanocomposites were analyzed by XRD, SEM, and FESEM with EDAX, FTIR, PL, and UV-Visible spectrometer. The rhombohedral / cubic spinel structure of NiMnO3 / NiMn2O4 was confirmed by the XRD. The SEM and FESEM morphology show that spherical NiMnO3 / NiMn2O4 nanoparticles were decorated on the Ti3C2Tx MXene sheets and also present on the inside of the Ti3C2Tx MXene sheets. The average diameter of NiMnO3 / NiMn2O4 nanoparticles (46 nm) and the interlayer spacing of Ti3C2Tx MXene sheets (56 nm) were measured from FESEM analysis. The energy bandgap of NiMnO3 / NiMn2O4 - MXene nanocomposites was determined as ranging from 1.2 eV to 0.8 eV. The Ni, Mn, O, Ti, C, and F elemental compositions of the composites were analyzed by the EDAX. The effective photo-generated electron transferring from NiMnO3 / NiMn2O4 to Ti3C2Tx MXene was established by the PL quenching of NiMnO3 / NiMn2O4. The 100 % degradation efficiency was achieved in methylene blue (MB). The mixed dye degradation rates achieved for Rhodamine B (RhB), methyl orange (MO), and methylene blue (MB) for 90 %,72 %, and 100 % after 50 min in the presence of NiMnO3 / NiMn2O4 -Ti3C2Tx MXene (20 wt %). According to a scavenger experiment, the predominant species actively involved in the photodegradation process were revealed to •OH and •O2-.

Photocatalytic degradation of organic dyes in water using semiconductor ZnO nanoparticles synthesized using Crataegus mexicana extract

In this work, the synthesis of zinc oxide (ZnO) nanoparticles was made using an eco-friendly methodology with a natural extract. The fruit of tejocote (Crataegus mexicana) was used as a stabilizing agent for synthesizing zinc oxide nanoparticles (NPs). Once the NPs were obtained, diverse characterization techniques were used to determine the physicochemical and optical properties of the ZnO NPs; the ultraviolet–visible spectroscopy was used to determine the uv absorption spectra of ZnO NPs and the bandgap of the material, the FT-IR spectrum of the ZnO NPs shows the presence of the Zn–O bond at 560 cm−1, XRD results show that the ZnO NPs exhibit a hexagonal crystal structure zincite type, the SEM confirms slight agglomerations between nanoparticles, Also from TEM results, the nanoparticles present a quasi-spherical morphology with sizes ranging from 18.25 nm to 36.88 nm, indicating an influence of the concentration of the Crataegus mexicana extract in the synthesis process of ZnO NPs. Photoluminescence spectroscopy of ZnO NPs shows strong emission bands in the visible spectrum around 425 nm, 467 nm, and 492 nm, and weak emission bands in the UV spectrum were observed. Finally, a photocatalytic study was realized for the photodegradation of 5 pollutant dyes: methylene blue (MB), malachite green (MG), congo red (CR), rhodamine b (RB), and methyl orange (MO). The results show degradation of the organic dyes after 180 min by a photodegradation process where ZnO nanoparticles act as a photocatalyst, indicating that the synthesized ZnO nanoparticles have excellent photocatalytic properties.

CTAC-assisted monoclinic BiVO4 with oxygen defects for efficient photocatalytic performances: A combined experimental and DFT study

Developing a photocatalyst with high photocatalytic efficiency, chemical stability, and self-degradation capability is essential for optimizing photodegradation processes in environmental applications. In this study, we synthesized a monoclinic BiVO4 photocatalyst whose surface morphology was modulated by hexadecyltrimethylammonium chloride (CTAC) using a facile hydrothermal method. Experimental results demonstrated a substantial increase in the degradation rate (99%) for the CTAC-modified monoclinic BV/CT25 photocatalyst (with an initial CTAC concentration of 25 g/L) compared to the CTAC-free tetragonal BiVO4 photocatalyst (73%). This highlights the effective enhancement of photocatalytic degradation performance through CTAC modification. Furthermore, density functional theory (DFT) calculations revealed that the band gap of BV/CT25 remained unchanged, suggesting that changes in oxygen vacancies (OVs) and density of states, along with the porous lattice structure, contributed to the improved performance. These findings were further supported by FESEM, as well as EPR and XPS characterizations. In addition, photodegradation tests at various pH conditions and cyclic tests suggested that the modification enhanced the morphological stability and reusability of the modified BiVO4 photocatalysts. Overall, this study provides valuable insights into the design of next-generation photocatalysts, leveraging surfactants to control surface properties and emphasizing the key attributes of high photocatalytic efficiency, chemical stability, and improved reusability.

Reaction solution mediated photo-degradation process and mechanism of tetracycline via semiconductor-insulator composite ZnO:N-BaSO4

Research in contaminants photo-degradation has witnessed significant progress, recently insulator-based catalysts gaining prominence. In this study, N-containing p-type ZnO decorated BaSO4 (ZnO:N-BaSO4) were synthesized and presented a pseudo-first-order kinetic constant of 1.30 × 10−2 min−1 for TC degradation, surpassing that of ZnO:N and their physical mixture by four and seven-fold, respectively. Impressively, the electron transfer in ZnO:N/TC solution interface led to band bending on ZnO:N surface and realized the band matching between ZnO:N and BaSO4. Density functional theory (DFT) calculations unveiled that the strong Zn-O covalent interaction involving 4s states of Zn atoms and 2p states of O atoms, established a distinctive pathway for electron transfer from semiconductor to insulator. Moreover, the catalysts demonstrated robust activity and sustained long-term stability in real wastewater and surface water. This research illuminates the role of wastewater redox potential in semiconductor band adjustment and highlights abundant, eco-friendly insulators as co-catalysts for selective photo-degradation.

Chinese yam-derived aerogel as a versatile platform for efficient freshwater production and pollution remediation

Water scarcity and pollution have become major obstacles to sustainable global development. The development of a versatile platform that can simultaneously produce clean water and remediate pollutants from water is highly desirable but still difficult to realize. Herein, to address this challenge, we have developed a CY@PPy@Ag aerogel with excellent photothermal and photocatalytic capabilities through a freeze-drying process, followed by polypyrrole coating and Ag deposition. The excellent characteristics, including broad-spectrum light absorption (97.2%), localization of converted heat, rapid water transport, and porous open microchannels, enabled it to act as an advanced solar evaporator for efficient and continuous steam generation without salt crystallization. Moreover, the high evaporation rate (1.51 kg m−2 h−1) was maintained even in high concentrations of brine and real seawater. Taking advantage of its enhanced photocatalytic performance, organic dyes in water could be rapidly and completely decomposed by the CY@PPy@Ag aerogel under solar irradiation, and this photodegradation process was significantly accelerated with the help of NaBH4. This work is expected to provide a one-stone-two-birds strategy to simultaneously achieve clean water harvesting and pollution remediation, which holds great promise in the fields of solar energy harvesting, wastewater treatment, and seawater desalination.

Remediation of phenanthrene by highly efficient CdS–SnS photocatalyst and its cytotoxic assessments

Cadmium sulfide-tin sulfide (CdS–SnS) nanoparticles are a novel kind of photocatalyst. These CdS–SnS nanoparticles are synthesized and characterized using UV–Vis, FT-IR, XRD, SEM-EDX, and DLS techniques, to understand their size distribution, crystalline nature, morphology, shape, optical properties, and elemental composition. This research offers insight into the efficient photocatalytic degradation of Phenanthrene (PHE) using CdS–SnS. The CdS–SnS NPs as photocatalyst can effectively photodegrade the polycyclic aromatic hydrocarbons (PAH) such as phenanthrene under simulated solar and UV light. UV–vis spectra of these nanoparticles exhibit peaks at 365 and 546 cm−1 respectively, the mean size of the CdS–SnS NPs in DLS is determined to be 78 nm. The CdS–SnS stretching frequency was observed at wave numbers below 700 cm−1, the absorption peak at 1123 cm−1 indicates the presence of C–N stretch or CS bond of thiourea, while the peak at 1350.38 cm−1 corresponds to the tris-amine C–N stretch in FT-IR. Additionally, the peaks observed at 2026 cm−1 indicate the presence of isothiocyanate (NCS). 1456.23 cm−1 represents the asymmetric scissor deformation vibration. EDAX revealed the presence of elemental Cd and Sn oxides. The antimicrobial studies showed that the CdS–SnS NPs at the concentration of 150 μg/mL, exhibit maximum inhibition (15 ± 1.25 mm) against the strains Proteus mirabilis followed by Staphylococcus epidermidis and Clostridium spp. Among fungal strains Colletotrichum spp. exhibits the maximum zone of inhibition (9 ± 0.25). This research also observed the cytotoxic effects of CdS–SnS NPs on HepG2 and ZF4 cells. HepG2 cells exhibited 50% inhibition at 50 μg/mL and 70% inhibition at 100 μg/mL concentrations, while ZF4 cells exhibited 50% inhibition at 50 μg/mL and 78% inhibition at 100 μg/mL concentrations, respectively. The parameters like concentration of PHE, concentration of CdS–SnS NPs, pH, and sources of irradiation on batch adsorption were examined to maximize the efficiency of the photodegradation process.

Barium oxide nanorods: Catalyst concentration and surface defects' role in degrading methylene blue organic pollutant

In this study, BaO nanorods (NRs) were synthesized with inherent surface defects using the chemical coprecipitation process. The rich oxygen defect BaO NRs exhibited enhanced light sensitivity and effectively interacted with the organic pollutant methylene blue (MB) dye under UV-light illumination for wastewater treatment. The X-ray diffraction (XRD) analysis confirmed the highly crystalline tetragonal structure of the BaO NRs. Microstructural characteristics were examined using theoretical approaches such as Debye-Scherrer (DS), Williamson-Hall (W-H), and Size-Strain Plot (SSP), revealing an average crystallite size of approximately 30 nm. Field emission scanning electron microscopy (FE-SEM) revealed the rod-shaped structure of the BaO nanorods, with particles aligned on top of each other. UV–visible absorption studies demonstrated an increased optical bandgap in the BaO NRs compared to the bulk material. Photoluminescence spectroscopy revealed the presence of oxygen traps and surface defects, which aided the photodegradation process. The photocatalytic activity of the BaO NRs was assessed by degrading MB dye. We found that a concentration of 150 mg of BaO NRs exhibited the highest degradation efficiency at 85 %.

A robust bio-source mediated CeO2 – SnS2 quantum dots @Oryza sativa var. biochar, photo-adsorbent for removal of Baszol Violet 57L dye from aqueous discharge: Development, materialistic analyses, and its application

This research aims to develop an entirely novel kind of photocatalytic adsorbent, known as integrated photocatalytic adsorbent, using a hydrothermal process that is environmentally friendly. This method utilizes an extract derived from Tulsi (Osmium Tenuiflorum) leaves as a stabilizing and capping agent. The purpose of the synthesized material is to effectively remove Baszol Violet 57L (BV57L) dye from wastewater. CeO2, was combined with a semiconductor photocatalyst, SnS2, to create a composite photocatalyst. This choice was made based on the exceptional photocatalytic activity of the catalyst when supported on rice straw (Oryza sativa var.) biochar, specifically for the adsorption of selected pollutants. The study investigated the integrated photocatalytic and adsorption (IPA) characteristics of the fabricated material, using BV57L dye as a representative emerging pollutant commonly found in wastewater. From the Tauc's plots of final nanohybrid (CSB) it was calculated that the energy band gap of CSB was around ∼2.7 eV. The novelty of the current study lies in its examination of the synergistic adsorption and photocatalytic properties under diverse reaction conditions that replicate real-world wastewater conditions. The inclusion of biochar in the CeO2-SnS2 nanocomposite yielded a discernible decline in the rate of charge recombination, thereby causing a notable enhancement in the photocatalytic efficiency of the nanocomposite.The adsorption data confirmed with the Langmuir isotherm model with maximum adsorption capacity of 333.58 mg g−1 at BV57L concentration of 350 mg L−1 under optimal conditions, suggesting the occurrence of monolayer chemosorption and following pseudo-second-order rate kinetics with rate constant of 1.59 × 10−5 g mg−1 min−1. The process of photodegradation exhibits kinetics that can be approximated as pseudo-first-order, with the BV57L dye displaying a significant constant of 0.0731 min−1. A simultaneously processed adsorption and photodegradation model was found to achieve an overall BV57L removal efficiency of 97.26 % within a 90-min timeframe. Additionally, impact of pH, reusability-stability of catalyst, and a photodegradation mechanism for the BV57L removal is also clearly presented. The combination of visible light-induced photodegradation activity in CeO2-SnS2 nanocomposite and the adsorption capability of biochar leads to the highly effective removal of pollutants from the liquid phase.

The Power Effect of Zinc Oxide and Solar Lamp on the Degradation of Orange G Dye Industrial

By conducting multiple tests, the photo degradation of the orange G dye used in industries such as investigating of varying the weight used zinc oxide as a metal oxide. The best weight used of oxide was 0.13 g/100ml as a result of obtaining the largest catalytic decomposition of the dye. It was verified that the effect of different concentration of the dye on the decomposition process. It was found that 30 ppm was the best concentration in which the largest possible amount of catalytic decomposition of the dye took place, in addition to the effect of using different volume of ethanol in the photo degradation process on the dye used. A UV-Visible spectrophotometer was used to study photo catalytic using zinc oxide as a catalyst with radiation from a 125 W mercury lamp.

Cobalt-doped SnS2 nanoplates for high-efficiency catalysis applications

The photocatalysis degradation of methyl iso thiazolinone (MIT) in water was effectively performed using cobalt-doped tin sulfide (Co–SnS2) nanoplates under UV irradiation. X-ray diffraction patterns (XRD) show that the crystallite size of nanoplates increases from 26 nm to 48 nm. Undoped SnS2 nanoplates exhibit plate-like nanostructure with smooth surfaces, with a size of 150–400 μm and a 50–70 nm thickness. Doping SnS2 nanoplates with cobalt increases the nanoplate's size to 300–600 nm. SnS2 and Co-doped SnS2 nanoplates have indirect bandgap energy with values of 1.95 and 1.86 eV, respectively. On the other hand, the electrical conductivity of SnS2 and Co-doped SnS2 nanoplates was 1.67×10−5S.cm−1 and 1.64×10−4S.cm−1, which increases to 6.54×10−4S.cm−1 and 1.25×10−2S.cm−1 upon UV irradiation, respectively. The higher degradation efficiency of a 5 mg/L concentration of MIT via SnS2 and Co–SnS2 nanoplates after 160 min is 66% and 91%, respectively. Finally, the photodegradation process was investigated using UV-VIS and FTIR analysis.

Self‐Degradable Photoactive Micromotors for Inactivation of Resistant Bacteria

AbstractPathogenic bacteria pose a significant threat to human health, and their removal from food and water supplies is crucial in preventing the spread of waterborne and foodborne diseases. Recently, silver‐based photocatalytic micromotors have emerged as promising candidates for inactivating pathogenic microbes due to their high antibacterial activity. In this study, the synthesis of photoactive Ag3PO4 micromotors with a well‐defined tetrapod‐like structure (TAMs) is presented using a simple precipitation method. These TAMs autonomously move and release Ag ions/nanoparticles (NPs) through a photodegradation process when exposed to light, which enhances their antimicrobial activity against Gram‐negative (Escherichia coli) and Gram‐positive (Staphylococcus aureus) bacterial strains. Interestingly, different motion modes are observed under different manipulated light wavelengths and fuels. Furthermore, the self‐degradation of TAMs is accelerated in the presence of negatively charged bacteria, which results in higher removal rates of both bacteria, E. Coli and S. aureus. The findings introduce a new concept of self‐degradable micromotors based on photocatalytic components, which hold great potential for their use in antimicrobial applications. This work offers significant implications for materials chemistry, especially in designing and developing the next generation of light‐driven antimicrobial agents.

Novel SnO2-modified hydrozincite photocatalyst: Material design and application in efficient micropollutants degradation in wastewater

In this work novel photocatalysts have been synthesized based on hydrozincite and SnO2 with varying mol% of SnO2 in hydrozincite. The photocatalysts were prepared via chemical co-precipitation using thermal urea hydrolysis, without calcination or activation processes, and were applied in the photodegradation of micropollutants (in this case, several phenolic compounds). Characterization of the materials using various techniques revealed that the generation of hydroxyl radicals, holes, and superoxide radicals played crucial roles in the photodegradation process. The best photocatalyst was achieved with a 10 mol% SnO2 content in hydrozincite, which shows the highest rate in the pollutants degradation (higher than 93% in all the cases), also higher than TiO2-P25This study presents promising insights for developing highly efficient photocatalytic materials for environmental remediation applications.

One-step synthesis of a diverting erythrocyte-like heterojunction and the augmented activity of wastewater treatment: Morphology modulation, theoretical calculations and mechanism explanation

As a green and sustainable technology, semiconductor photocatalysis mediated by heterojunction has shown great potential in the removal of organic pollutants from water environment. Yet, the nugatory recombination of photogenerated carriers induced by strong Coulombic forces lead to inferior photoactivity of semiconductor photocatalysts. In this paper, the erythrocyte-like composite (BiBrW) was designed to drive Z-type separation of photogenerated carriers through heterojunction interface by tight coupling between BiOBr and Bi2WO6. Combined with the results of characterizations, CTAB used in the synthesis process not only provides a bromine source but also serves as a surfactant to modulate the morphology of Bi2WO6 from petal-like to erythrocyte-like morphology. In contrast with the BiOBr/Bi2WO6 material fabricated via the in-situ growth method, the BiBrW composite displayed a uniform erythrocyte-like morphology with fewer grain boundaries by lamellar stacking of nanosheets. The combined effect of the construction of heterojunction and lessened grain boundaries endowed the BiBrW composite with augmented physicochemical properties, thereby enhancing its photocatalytic removal performance for various contaminants. Based on theoretical calculations, HPLC-MS tests and toxicity analysis, the reaction sites, degradation pathway and toxic evolution of ciprofloxacin (CIP) during the process of photodegradation were thoroughly elucidated, respectively. Moreover, the BiBrW catalyst still exhibits significant degradation performance for CIP under the excitation of natural sunlight. For different water qualities and distinct target pollutants (2-sec-butyl-4,6-dinitrophenol (DNBP), tetracycline (TC) and bisphenol A (BPA)), the catalyst maintains excellent photocatalytic removal capabilities, reflecting the superior universality of BiBrW catalyst. This research proposed novel mentality for preparation of heterojunction photocatalysts with less grain boundaries to assist in restoration of water environment.

Effect of Ag-doping on morphology, structure, band gap and photocatalytic activity of bio-mediated TiO2 nanoparticles

The production of nanoparticles using biogenic synthesis techniques is becoming more prominent due to its diverse applications. In this research, the extract from mango leaf was utilized to fabricate a green method for producing Ag-doped and undoped TiO2 nanoparticles that is non-toxic, economical, and environmentally favorable. Titanium isopropoxide (TTIP) was used as a precursor for Ag-doped and undoped TiO2 nanoparticle production, where the concentrations of the dopant material silver were 2.5 and 3%. Acquired undoped and Ag-doped TiO2 nanoparticles were characterized using several analytical techniques. The morphological, structural, and photocatalytic activity were evaluated using XRD, SEM, EDX, and UV–Vis spectroscopy. In the XRD analysis, undoped and Ag-doped TiO2 nanoparticles indicated the formation of an anatase phase, but there was no rutile phase. The photocatalytic activity and nanoparticles’ band gap were assessed using UV–Vis spectroscopy. The UV–Vis Spectroscopy also revealed a reduced band gap energy (Eg) of Ag-doped TiO2 nanoparticles than the undoped TiO2 Nanoparticles (NPs). The development of photocatalytic activity and features of the “Red-shift” characteristic was established by the progressive photo-degradation of Methylene Blue (MB). The SEM analysis revealed that Ag-doped TiO2 nanoparticles showed more agglomeration than the undoped sample. The average particle size of undoped TiO2 nanoparticles was 38.33 nm, and the size gradually increased for 2.5% and 3% Ag-doping. Utilizing EDX analysis, the doping of Ag+ in the TiO2 lattice structure was confirmed. We can predict from the findings that utilizing biosynthesized TiO2 nanoparticles can be an excellent option for water purification, dye-sensitized solar cells, photo-degradation process, etc., in the long run.