UV Light Irradiation Research Articles

Novel nanoconjugates of metal oxides and natural red pigment from the endophyte Monascus ruber using solid-state fermentation

BackgroundAntimicrobial resistance has emerged as a major global health threat, necessitating the urgent development of new antimicrobials through innovative methods to combat the rising prevalence of resistant microbes. With this view, we developed three novel nanoconjugates using microbial natural pigment for effective application against certain pathogenic microbes.ResultsA natural red pigment (RP) extracted from the endophyte Monascus ruber and gamma rays were applied to synthesize RP-ZnO, RP-CuO, and RP-MgO nanoconjugates. The synthesized nanoconjugates were characterized by different techniques to study their properties. The antimicrobial potential of these nanoconjugates was evaluated. Moreover, the antibiofilm, protein leakage, growth curve, and UV light irradiation effect of the synthesized nanoconjugates were also studied. Our results confirmed the nano-size, shape, and stability of the prepared conjugates. RP-ZnO, RP-CuO, and RP-MgO nanoconjugates showed broad antimicrobial potential against the tested bacterial and fungal pathogens. Furthermore, the RP-ZnO nanoconjugate possessed the highest activity, followed by the RP-CuO against the tested microbes. The highest % inhibition of biofilm formation by the RP-ZnO nanoconjugate. Membrane leakage of E. coli and S. aureus by RP-ZnO nanoconjugate was more effective than RP-MgO and RP-CuO nanoconjugates. Finally, UV light irradiation intensified the antibiotic action of the three nanoconjugates and RP-ZnO potential was greater than that of the RP-MgO, and RP-CuO nanoconjugates.ConclusionThese findings pave the way for exploiting the synthesized nanoconjugates as potential materials in biomedical applications, promoting natural, green, and eco-friendly approaches.

Fabrication of a novel Ag2S-ZnS/ZIF-8 hollow heterojunction by in-situ formation of Ag2S and ZnS on ZIF-8 with enhanced tetracycline degradation performance

Currently, antibiotics are extensively utilized in the pharmaceutical industry to assist humans and animals in combating various infectious diseases. The extensive use of various antibiotics enhances the quality of life. However, it can also have negative effects on the environment and human health, including water pollution and the rise of antibiotic-resistant microorganisms. To date, antibiotics have been detected in rivers, groundwater, and even drinking water. There is an urgent need to design and develop advanced materials for the remediation of antibiotics present in our environment. In this paper, we successfully synthesized a novel Ag2S-ZnS/ZIF-8 hollow heterojunction via facile sulphuration and solvothermal methods. This heterojunction was employed as a catalyst for the degradation of tetracycline (TC) in water under UV and visible light irradiation. The physicochemical properties of the as-synthesized catalysts were thoroughly analyzed using XRD, EDS, SEM, BET, XPS, TEM, ESR, UV–vis techniques. The results demonstrate that Ag2S-ZnS/ZIF-8 displays enhanced photocatalytic activity for TC degradation no matter under visible or UV light irradiation. After 10 min of UV light irradiation, its photocatalytic degradation efficiency was achieved 92.74 %. Additionally, Ag2S-ZnS/ZIF-8 was able to degrade 92.14 % of TC (visible light, with 35 min). The corresponding kinetic rate constant of Ag2S-ZnS/ZIF-8 is 0.145 min−1 (UV light) and 0.043 min−1 (visible light), respectively. Furthermore, Ag2S-ZnS/ZIF-8 also shown excellent stability for the degradation of TC in the presence of visible light. This is a result of its high specific surface area, superior photocurrent and efficient separation of photo-generated electrons-hole pairs. Apart from this, the photocatalytic degradation mechanism of TC over Ag2S-ZnS/ZIF-8 is discussed in detail.

Wearable Inorganic Oxide Chemiresistor Based on Flexible Al2O3-Stabilized ZrO2 Ceramic Sponge Substrate for NO2 Sensing.

Wearable gas sensors, possessing the advantages of high sensitivity, excellent flexibility, high permeability, low weight, and workability at ambient conditions, hold great promise for real-time health monitoring and early warnings of poisonous gases. However, obtaining high-performance wearable gas sensors utilizing the current well-developed inorganic semiconductor oxide sensing materials is still very limited due to their fragile and rigid nature. Herein, a newly designed wearable gas sensor based on an all-inorganic ASZ (Al2O3-stabilized ZrO2)/ZnO/SnO2 nanofibers is introduced for the first time. The flexible ASZ ceramic sponge substrate (with a Young's modulus of 4.15 MPa) and ultrathin ZnO/SnO2 sensing layer endow the wearable gas sensor with promising properties such as super flexibility (with a bending radius of 5 mm), high gas permeability, and low weight. Furthermore, driven by UV light irradiation, this all-inorganic wearable sensor also demonstrates a stable NO2 sensing response under different bending states at room temperature, which enables the gas sensor to be more compatible with wearable sensing applications. This work offers a general method to achieve a high-performance wearable gas sensor based on inorganic materials and provides new insights into their potential in wearable gas-sensing applications.

The transformation of type-I La2O3/α-Bi2O3 into multi-heterojunctions during photocatalysis with enhanced photoreactivity

A small quantity of broad bandgap rare earth lanthanum oxide (La2O3) was incorporated into monoclinic bismuth oxide (α-Bi2O3) through a one-step facile calcining route to construct an efficient type-I La2O3/α-Bi2O3 heterojunction photocatalyst for pollutant degradation under UV-light irradiation. The effect of adding La2O3 on the morphology, textural, optical, photoelectrochemical, and photocatalytic properties of α-Bi2O3 was investigated. Interestingly, feeding as low as five molar percent (5 %) La2O3 could significantly increase the BET surface area and generate more h+ and •O2− for photocatalytic reaction. Moreover, the calcining-induced carbon in La2O3/α-Bi2O3 revealed a vital role in suppressing the charge carrier recombination by quickly transferring charges to the photocatalyst's surface. In particular, during the recycling process, the in-situ formed Bi2O2CO3 changes the charge carrier transferring pathway and reveals a transformation of type-I La2O3/α-Bi2O3 into multi-heterojunction of type-I and type-II. Furthermore, the formation of Bi2O2CO3 results in more active sites for the photocatalytic reaction with improved reaction kinetics. This work provides a new direction for understanding a photocatalytic system's recycling phenomena and intrinsic kinetics.

Synthesis and characterization of nickel cobaltite–supported film for hexavalent chromium photocatalytic reduction

ABSTRACT Hexavalent chromium (Cr(VI)) is a prevalent and highly toxic pollutant, posing a serious threat to human health and ecosystems. This study addresses this issue by exploring the photocatalytic reduction of Cr(VI) using hydrothermally synthesized nickel cobaltite (NiCo2O4) spinel–supported films. The research fills the gap for efficient visible light photocatalytic materials for Cr(VI) reduction, with the aim to synthesize, characterize, and assess NiCo2O4-supported films’ photocatalytic activity. Synthesis was achieved via a hydrothermal method on fluorine-doped tin oxide (FTO) and titanium dioxide (TiO2) over FTO substrate. The films were characterized using several techniques and their photocatalytic activity was tested under UV-A and visible light, with Cr(VI) concentration monitored periodically up to 240 min. The NiCo2O4/TiO2 film demonstrated superior photoreduction performance under both UV and visible light radiation compared to TiO2 and NiCo2O4, achieving photoreduction of Cr(VI) by 76% under UV light with a rate constant of 5.79 × 10−3 min−1 and 60% under visible light with a rate constant of 4.74 × 10−3 min−1. In conclusion, hydrothermally synthesized NiCo2O4/TiO2 film shows promising photocatalytic performance for Cr(VI) reduction, marking a significant advancement in photocatalysis and water treatment technologies. Future research will focus on stability assessment, synthesis process optimization, and real-world water treatment application.

Modulating the Conductivity of Light-Responsive Ionic Liquid Crystals.

In this work, we describe the phase behaviour and the dielectric and conductivity response of new light-responsive ionic liquid crystals, ILCs, which can be applied as controllable electrolytes. The materials include two different dicationic viologens, the asymmetric 6BP18 and the symmetric EV2ON(Tf)2, containing bistriflimide as the counterions, mixed with 5% and 50% molar, respectively, of one new photoresponsive mesogen called CNAzO14. These mixtures exhibit liquid crystal behaviour, light responsiveness through the E-Z photoisomerisation of the azobenzene groups in CNAzO14, and strong dielectric responses. The 5%-CNAzO14/Ev2ON(Tf)2 mixture displays direct current conductivities in the 10-7 S·cm-1 range, which can be increased by a two-fold factor upon the irradiation of UV light at 365 nm. Our findings set the grounds for designing new smart ionic soft materials with nanostructures that can be tuned and used for energy conversion and storage applications.

Photo-induced time-dependent controllable wettability of dual-responsive multi-functional electrospun MXene/polymer fibers

Switchable wettability potential in smart fibers is of paramount importance in various applications. Light-induced controllable changes in surface wettability have a significant role in this area. Herein, smart waterborne homopolymer, functional copolymer with different polarity and flexibility, and multi-functional terpolymer particles containing a time-dependent dual-responsive acrylated spiropyran, as a polymerizable monomer, were successfully synthesized through eco-friendly single-step emulsifier-free emulsion polymerization. Presence of 10 wt% of butyl acrylate and dimethylaminoethyl methacrylate relative to methylmethacrylate as functional comonomers decreased the Tg of the samples almost 20 ℃ and increased their polarity. The optical properties of the particles were investigated, and the UV–vis and fluorescence spectroscopy results showed that not only polarity and flexibility of the polymer chains may have a positive effect on improving the optical properties, but also the simultaneous presence of functional groups has a synergistic effect. The smart polymer particles with flexibility and polarity features exhibited higher absorption and emission compared to other samples. Inspired by these findings, multi-functional smart polymer fibers were prepared using the electrospinning method. The smart multi-functional electrospun fibers containing few-layer Ti3C2 MXenes were synthesized to improve the fibers’ properties and change the surface wettability due to the hydrophilic functional groups of MXene. Field-emission scanning electron microscopy images displayed the successful preparation of few-layer MXenes. Smooth and bead-free fibers with bright red fluorescence emission under UV irradiation were shown using fluorescence microscopy. The study on the surface wettability of fibers revealed that UV and visible light irradiation induced reversible time-dependent changes in the wettability of the smart multi-functional MXene/polymer electrospun fibers from hydrophobic to hydrophilic, reaching a water contact angle of 10° from an initial water contact angle of 100° under UV light and also changing to superhydrophilic state with passing time. Upon visible light exposure, the fibers returned to their original state. Furthermore, the fibers demonstrated a high stability over five alternating cycles of UV and visible light irradiation. This study shows that the fabrication of time-dependent smart fibers, utilizing the flexibility and polarity in the presence of MXenes, significantly improves and controls surface wettability changes. The outstanding dynamically photo-switchable wettability of these fibers may offer exciting opportunities in various applications, especially in the separation of oil from water contaminants.

Hydrolytic‐Resistance Long‐Persistent Luminescence SrAl2O4:Eu2+,Dy3+ Ceramics for Optical Information Storage

AbstractSrAl2O4:Eu2+, Dy3+ (SAED) is one of the most popular materials for information storage and night display applications because it has a wide excitation range and long afterglow duration. However improving the hydrolytic resistance of SAED remains a challenge. In this study, the SAED is presented to be the ceramic type by a solid‐state reaction in a vacuum ambiance. The achieved SAED ceramic has 8200 mcd m−2 initial luminescence intensity. It can also obtain long‐persistent luminescence after UV light irradiation even soaking in water for more than 30 days. This ceramic demonstrates sustained imaging capability irradiated under 365 nm UV light and X‐ray, as well as erasability and reproducibility of storage by lighting and heating. These results indicate the promising applications of SAED ceramics in optical information storage and night display in complex environments. The phase evolution in the SAED ceramic is identified directly in the micromorphology for the first time based on scanning electron microscopy coupled with a cathodoluminescence system.

Photocatalytic degradation of Rhodamine B dye over oxygen-rich bismuth oxychloride Bi24O31Cl10 photocatalyst under UV and Visible light irradiation: Pathways and mechanism

Photocatalytic removal of organic pollutants from wastewater has recently garnered significant attention due to its environmental and ecological significance. In this study, a bismuth-rich bismuth oxychloride (Bi24O31Cl10) was synthesized using a single-step solid-state reaction and applied as a photocatalyst for the degradation of rhodamine B in aqueous solution. The photocatalyst was prepared through an eco-friendly solid-state method by mixing bismuth oxide (Bi2O3) and bismuth oxychloride (BiOCl), followed by direct annealing at 600 °C. The synthesized material was characterized through various techniques, including X-ray diffraction (XRD), Fourier-transform infrared (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analysis, energy dispersive X-ray spectroscopy (EDS), diffuse reflectance, UV–Visible, and photoluminescence (PL) spectroscopies. The electronic structure of the Bi24O31Cl10 bulk material was analyzed using Density Functional Theory (DFT).Rietveld refinement confirmed the formation of a pure monoclinic Bi24O31Cl10 phase with the space group P2/c, and the XRD patterns indicated well-crystallized material. SEM revealed micron-sized crystallites, while BET surface area analysis showed a value of 22.546 m²/g, suggesting that a larger surface area could enhance photocatalytic performance. The band gap of the material was determined to be 2.88 eV, with an absorption edge at 430 nm, indicating a promising response to visible light.The photocatalytic activity of Bi24O31Cl10 was demonstrated by the degradation of rhodamine B (RhB), with complete degradation achieved in 90 min under UV light. Under visible light, 98 % degradation efficiency was reached after 180 min. Kinetic studies showed that the degradation followed a pseudo-first-order model. Optimal conditions for maximum degradation were found at a solution pH of 5, a catalyst concentration of 1 g/L, and a dye concentration of 5 mg/L. Remarkably, the photocatalyst exhibited excellent reusability, maintaining high efficiency over five cycles, with only a slight decrease from 100 % to 90 %.Trapping experiments identified that reactive species such as superoxide radicals (∙O2−) and hydroxyl radicals (∙OH) played key roles in the photocatalytic process. The possible reaction mechanism was proposed, and degradation products were monitored using liquid chromatography-mass spectrometry (LC-MS), allowing for the elucidation of the degradation pathways of RhB. Additionally, the photocatalyst's effectiveness was tested on Methyl Orange (MO) and Methylene Blue (MB), achieving nearly 100 % degradation for MO and 41 % for MB under UV light. This research highlights the significant potential of Bi24O31Cl10 as a photocatalyst for dye degradation in wastewater treatment.

Reinvigorating Photo-Activated R-Alkoxysilanes Containing 2-Nitrobenzyl Protecting Groups as Stable Precursors for Photo-Driven Si-O Bond Formation in Polymerization and Surface Modification.

This study aimed to revitalize silicon-based sol-gel chemistry methodologies utilizing photoprotected R-alkoxysilanes to control the synthesis of unique silicon-based materials. We have investigated the synthesis, characterization, light-induced deprotection, and subsequent polymerization/surface functionalization through the use of 2-nitrobenzyloxy-based photoremovable protecting groups (PPGs) as alkoxy reactive groups on ethyl and phenyl (R x -(alkoxy) y silanes, with x = 0-3 and y = 1-3). The photochemical dynamics, relative efficiencies, and kinetics of the novel alkoxysilane-based PPGs were thoroughly investigated using UV light irradiation by NMR and UV/vis methods. We then explored the tin-catalyzed coupling of photodeprotected products (R x -silanols) to form polymers/oligomers. We have found that photoenabled removal of PPGs and conversion to silanols from all silane systems studied is achieved. Furthermore, these deprotected species are polymerizable into siloxanes and effectively used as light-controlled surface modifiers with masking techniques of which proof-of-concept examples are given, enabling promising application as photolithographic reagents.

The effect of transition metal oxides in the La/TiO2 structure for the photocatalytic degradation of malachite green under UV and visible light irradiation

Herein, La@MxOy/TiO2 (M = V, Cr, Mn and Fe) composite catalysts were prepared based on the sol–gel method as an effective adsorbent and photocatalyst for the degradation of malachite green from an aqueous solution under UV–Vis light. Under experimental conditions, a maximum adsorption capacity of 57.10% for the malachite green dye was achieved with La@Fe2O3/TiO2. Moreover, this composite showed 78.62% photodegradation efficiency for malachite green. A quadratic model constructed using the response surface method showed that the maximum efficiency of photodegradation of malachite green can be achieved at pH 11 and a process time of 35 min.

Rapid Forming, Robust Adhesive Fungal-Sourced Chitosan Hydrogels Loaded with Deferoxamine for Sutureless Short-Gap Peripheral Nerve Repair.

Clinically, conventional sutures for repair of short-distance nerve injuries (< 5mm) may contribute to uncontrolled inflammation and scar formation, thus negatively impacting nerve regeneration. To repair transected peripheral nerves with short distances, a rapid-forming, robust adhesive chitosan hydrogel is prepared by synthesizing maleic and dopamine bi-functionalized fungal-sourced chitosan (DM) and subsequently photopolymerizing DM precursor solution. The hydrogel rapidly polymerized under UV light irradiation (≈2 s) and possessed a strong adhesive strength (273.33 ± 55.07kPa), facilitating a fast bonding of nerve stump. Especially, its tailored degradation profile over 28 days supported both early gap bridging and subsequent nerve regeneration. Furthermore, deferoxamine (DFO), a pro-angiogenic drug, is loaded into the hydrogel to reach sustainable release, accelerating axonal growth synergistically. A 3mm long sciatic nerve defects model in rats is used to investigate the efficacy of DM@DFO hydrogel for repairing peripheral nerve defects. After 60 days, the DM@DFO hydrogel significantly outperformed conventional sutures and fibrin glue, improving motor and sensory recovery by reducing inflammation, inhibiting scar formation, and accelerating vascular regeneration within 14 days post-repair. This work highlights the DM@DFO hydrogel as a promising tissue adhesive for effective short-distance peripheral nerve repair.

Study on rheology of novel UV/visible light sensitive trimeric cationic surfactant/trans-4-phenylazo benzoic acid micelle system

Abstract The trimeric cetyl cationic surfactant (TGC) forms reversible photosensitive micelle systems with the photosensitive counterions trans-4-phenylazo benzoic acid (trans-ACA). The Carreau-Yasuda model was used for the flow curves before and after UV irradiation. The effects of trans-ACA concentration, TGC concentration, and different durations of UV (365 nm) and visible light (465 nm) irradiation on the rheological properties of TGC/trans-ACA were investigated. Prior to UV irradiation, the TGC/trans-ACA system was composed of wormlike micelles, which showed pronounced shear thinning behavior, good thixotropy and viscoelasticity. Macroscopically, it appears as a difficult to flow solution. After UV irradiation, trans-ACA is isomerized to cis-ACA, and the worm-like micelles are transformed to spherical or short rod-like micelles, resulting in a significant decrease in thixotropy and viscoelasticity, and thus a decrease in viscosity and an increase in fluidity. At lower TGC concentrations, UV irradiation can induce a reversal of the rheological properties of the TGC/trans-ACA system, which exhibits a complete solution state. Exposure to visible light restores the rheology of the system to that prior to UV irradiation. Under UV and visible light irradiation at different times, the system obeys to the rheo-kinetic equation. The UV–vis spectrum confirms that the changes in the rheological properties of the TGC/trans-ACA system are due to the reversible photoisomerization of trans-ACA.

Facile synthesis of novel cobalt molybdenum sulfide-graphitic carbon nitride (CoMoS4/g-C3N4) nanocomposite electrode for improved supercapacitor and photocatalytic applications

Supercapacitors have gained significant attention from scientists due to their wide range of applications in energy storage devices. However, searching for abundant and eco-friendly materials on earth is still necessary while preserving their outstanding performance. Herein, cobalt molybdenum sulfide-graphitic carbon nitride (CoMoS4/g-C3N4) nanocomposite was synthesized to explore an exceptional electrode material for energy and photocatalytic applications. The structural analysis, vibrational modes, and porosity within the CoMoS4/g-C3N4 nanocomposite were studied by XRD, Raman, and SEM. The direct energy band gap decreased from 2.54 to 2.44 eV along with the increased ratio of CoMoS4 in the nanocomposite. The electrochemical measurements of CoMoS4/g-C3N4 nanocomposite exhibited an excellent specific capacitance (Cp) of 3675 F/g at 1 mV/s and 3150 F/g at 2.5 A/g with noticeable specific energy density (Eg) of 109.4 Wh/kg, high power density (Pd) of 625 W/kg and retain high capacitance (88 % of its initial value) even after 4000 cycles. Furthermore, the photocatalytic results revealed that high photodegradation efficiency (97.85 %) was attained against methyl orange (MO) dye under UV light irradiation. Prepared electrode materials are promising materials for next-generation energy storage and environmental applications.

Lignocellulosic materials extraction from waste baby diaper to prepare light-responsive metal oxide/carbon composite for efficient organic dye pollutant removal

The bimetal oxide comprising nickel incorporated β-Bi2O3 on graphitic carbon in the form of bismuth nickel oxide (BNO@C) was prepared by waste lignocellulosic materials collected from cheap and readily available baby diapers. The prepared BNO@C was used to photocatalytically degrade methylene blue under UV-light irradiation. Prior to the photocatalytic performance analysis, the formation of BNO@C was confirmed by various morphological and structural analysis including SEM, TEM, XRD, and XPS analyses. As a result, the two-dimensional nanosheet morphology and tetragonal primitive lattice-structure with 2+ and 3+ oxidation stated Ni and Bi in BNO@C structural formulation were confirmed. In photocatalysis experimentation examined with BNO@C, the maximum methylene blue removal percentage of 96.7 % was achieved within 16 min. The influence of Ni2+ in BNO@C was identified by performing the photocatalytic performance of bare NiO@C and Bi2O3@C, yielding maximum dye removal of 32.8 % and 64.5 %, respectively. The efficacy of Ni in BNO@C toward increasing catalytic efficiency was identified using DFT analysis, revealing the acting of Ni as active sites for improved light absorption tendency. These findings show a novel strategy to prepare a low-cost BNO@C catalyst with efficient photocatalytic activity, opening a new path for a cost-efficient wastewater treatment approach.

Nanostructured hexagonal S-doped CeO2 for effective Rh-B and MB dye degradation

The photocatalytic efficiency of CeO2−xSx (x = 0.05, 0.1, 0.2, 0.3, 0.5) hexagonal nanoparticles (HNPs) prepared through the hydrothermal method were tested by performing the degradation of Rhodamine-B and Methylene blue dyes under UV light irradiation. These compounds were thoroughly characterised using XRD, FESEM, EDX, HRTEM, XPS, ESR, FTIR, Raman, UV–vis DRS, BET and PL techniques. XRD analysis verified the cubic crystal structure of S-doped and pure CeO2 HNPs. HRTEM images clearly affirmed that S-doped CeO2 is made from HNPs. Over 94 % of Rh-B and 72 % of MB dyes were degraded by S-doped CeO2 for 180 min under UV light exposure, demonstrating its efficacy towards the photocatalytic activity (PCA). S-doped CeO2 HNPs have enhanced the PCA due to the reduction in the recombination rate of photo-generated electron-hole pairs, the rise in oxygen vacancy (Ov) and the narrowed optical band-gap. The photoluminescence findings clearly validated the increased PCA of S-doped CeO2. The scavenger tests confirmed the OH• and •O2− radicals participation in the quick degradation of both Rh-B and MB dyes.

Efficient photocatalytic degradation of crystal violet dye using time-dependent ZnO nano spindle

Photocatalysis, utilizing metal–semiconductor oxides, has emerged as a promising technique for the oxidation of organic molecules due to its efficiency, cost-effectiveness, and eco-friendly nature. This study presents the synthesis and application of time-dependent ZnO nano spindles for the efficient photocatalytic degradation of crystal violet dye. ZnO nanostructures, known for their high photocatalytic activity, were synthesized using a simple and low-cost coprecipitation method, with the spindle morphology being fine-tuned by varying reaction times. The resulting nano spindles were characterized using X-ray diffraction (XRD), Fourier transmission infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and UV–vis spectroscopy to confirm their structural, morphological, and optical properties. XRD analysis revealed that the ZnO samples possess a hexagonal wurtzite crystal structure with a space group of P63mc. SEM analysis confirmed the formation of spindle-like morphologies, with the synthesized samples measuring just a few nanometers in size. The surface area and porosity of the ZnO samples have been observed by using the Brunauer–Emmett–Teller (BET) analysis. The obtained surface area of all ZnO samples is in the range of 15 to 30 m2g−1. Photocatalytic performance was evaluated under UV light irradiation, demonstrating that the degradation efficiency of CV dye significantly depends on the exposure duration and the morphological attributes of the ZnO nano spindles. The degradation kinetics followed a pseudo-first-order model, with the optimized ZnO nano spindles achieving up to 99 % degradation efficiency within 150 min. This study highlights the potential of time-dependent morphological control in ZnO nanostructures to enhance photocatalytic processes, presenting a viable solution for the treatment of dye-laden wastewater.

Green synthesis of TiO2@g-C3N4 nanocomposites for the photocatalytic degradation of pesticides and toxic organics present in water and wastewater

To address the environmental challenges caused by toxic organics in aquatic systems, photocatalytic degradation is a promising option. This study investigates the green synthesis of TiO2@g-C3N4 nanocomposites by coupling Titanium dioxide (TiO2) and graphitic carbon nitride (g-C3N4) in different mass ratios through solvothermal technique due to their photocatalytic properties. Leaf extract from the Ziziphus jujube plant was utilized as a green template making the synthesis environmentally friendly, utilizing renewable resources, and employing facile and cost-effective methods. The nanocomposites were characterized using various analytical techniques including UV–Vis Diffuse reflectance spectroscopy (UV–Vis DRS), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and energy dispersive X-ray spectroscopy (EDS) to analyze the structural and morphological properties. The wavelength ranged from 385 to 454 nm and band gap energies ranged from 3.22 to 2.73 eV for the synthesized materials. The pure green TiO2 showed the highest band gap energy while pure g-C3N4 showed the lowest band gap energy among the synthesized materials. The photocatalytic activity of the synthesized nanocomposites was evaluated through the degradation of Bisphenol A and Malathion pesticide under UV light irradiation. The results indicated 71 % degradation of Bisphenol A with the 50 % TiO2@g-C3N4 nanocomposites exhibiting 1.422 x 10-2 min−1 rate constant and 74 % degradation of Malathion degraded over 20 % TiO2@g-C3N4 which depicted rate kinetics of 1.022 x 10-2 min−1. Moreover, both showcased higher performance than the individual TiO2 and g-C3N4 nanostructured materials.

Highly efficient defluorination of perfluorooctanoic acid by a BiOCl-ND photocatalyst: Enhanced charge transfer and synergistic mechanism

Considerable attention has been given to the control of perfluorooctanoic acid (PFOA) environmental pollution due to its degradation resistance and potential risks. In this study, Bismuth oxychloride based nanodiamond (BiOCl-ND) composite materials were successfully synthesized by using hydrothermal method. The complete decomposition of PFOA and a high defluorination ratio of 74.6% by BiOCl-ND 10:1 was obtained under UV light irradiation within 60 min, and the composite's degradation rate constant was nearly 3.8 times than that of pure BiOCl. It was demonstrated that critical roles played in PFOA degradation were photogenerated holes (h+) and superoxide radicals (·O2−). A synergistic effect between BiOCl and ND and the heterostructure was revealed, the differences of the energy band structure between BiOCl and ND reduced the recombination of photogenerated e−-h+ and enhanced the charge transfer. In this process, a large number of h+ with oxidizing properties and·O2− generated from both BiOCl and ND played a critical role, and oxygen vacancies (OVs) also participated in the reaction as active species and contributed to electron transfer. Additionally, the photocatalytic decomposition intermediates of PFOA and the release of fluorine ions were analyzed to verify the effective defluorination of PFOA, and the results confirmed a gradual decrease in the toxicity of the reaction matrix during PFOA degradation. Hence, these results might provide insights for the development of photocatalysts to improve the photodegradation effect of PFOA in water.

Controllable Contact-Destructive Hydrogel Actuators.

Constructing hydrogels with spatially heterogeneous structures are crucial for unlocking novel applications. To this end, selectively removing a specific portion of hydrogels by facile and intricate destructive strategies is worth exploring. Herein, a "contact-destructive" hydrogel actuator is presented, composed of a dynamic hydrogel network doped with hydrophilic polyethylene glycol (PEG). The destructive behavior of the hydrogel actuator is attributed to the surface tension-induced spreading effect and the enhanced water absorption due to the additive PEG. Parameters that act on these mechanisms are used to control the destruction of the hydrogel. During the destructive process, the hydrogel actuator exhibits locomotion routes predetermined by the graphic pattern with the aid of 3D printing. Additionally, such self-destructive behavior can be terminated by UV light irradiation when PEG is replaced with poly(ethylene glycol) diacrylate (PEGDA). Significantly, diverse applications including controllable 3D structures collapse, self-erasing, and on-demand cell release, are realized with such self-destructive hydrogel. These results demonstrate that the present hydrogel has great values in soft robotics, anti-counterfeiting, controlled drug delivery, and other related fields.