Rhodamine B Research Articles

Oxygen-Doped Porous Ultrathin Graphitic Carbon Nitride Nanosheets for Photocatalytic Hydrogen Evolution and Rhodamine B Degradation.

Graphite phase carbon nitride (g-C3N4) is a highly promising metal-free photocatalyst, but its low activity, due to limited quantum efficiency and small specific surface area, restricts its practical application. While exfoliating bulk crystals into porous thin-layer nanosheets and incorporating dopants have been shown to improve photocatalytic efficiency, these methods are typically complex, time-consuming, and costly processes. In this study, we developed a simple approach to synthesize oxygen-doped porous g-C3N4 (OCN) nanosheets. The resulting OCN exhibited significantly enhanced light absorption and visible-light photocatalytic activity compared to bulk g-C3N4 (BCN) and g-C3N4 (CN). The OCN achieved an impressive hydrogen evolution reaction (HER) rate of 8.02 mmol g-1 h-1, eight times greater than BCN, and demonstrated a high Rhodamine B (RhB) degradation rate of 97.3 % owing to the generation of abundant singlet oxygen. These improvements in photocatalytic performance are attributed to the narrow band gap and enhanced electron transfer properties, suggesting a promising route for the efficient design of g-C3N4-based photocatalysts.

Gamma-irradiated copper-based metal organic framework nanocomposites for photocatalytic degradation of water pollutants and disinfection of some pathogenic bacteria and fungi

BackgroundAlthough there are many uses for metal–organic framework (MOF) based nanocomposites, research shows that these materials have received a lot of interest in the field of water treatment, namely in the photodegradation of water contaminants, and disinfection of some pathogenic bacteria and fungi. This is brought on by excessive water pollution, a lack of available water, low-quality drinking water, and the emergence of persistent micro-pollutants in water bodies. Photocatalytic methods may be used to remove most water contaminants, and pathogenic microbes, and MOF is an excellent modifying and supporting material for photocatalytic degradation.MethodsThis work involved the fabrication of a unique Cu-MOF based nanocomposite that was exposed to gamma radiation. The nanocomposite was subsequently employed for photocatalytic degradation and as an antimicrobial agent against certain harmful bacteria and fungi. The produced Cu-MOf nanocomposite was identified by XRD, SEM, and EDX. Growth curve analysis, UV lighting impact, and antibiofilm potential have been carried out to check antimicrobial potential. Additionally, the membrane leakage test was used to determine the mechanism of the antimicrobial action. In an experimental investigation of photocatalytic activity, a 50 mL aqueous solution including 10.0 ppm of Rhodamine B (RB) was used to solubilize 10 mg of Cu-MOF. It has been investigated how pH and starting concentration affect RB elimination by Cu-MOF. Ultimately, RB elimination mechanism and kinetic investigations have been carried out.ResultsSEM images from the characterization techniques demonstrated the fact that the Cu-MOF was synthesized effectively and exhibited the Cu-MOF layers' flake-like form. Uneven clusters of rods make up each stratum. The primary peaks in the Cu-MOF's diffraction pattern were found at 2θ values of 8.75◦, 14.83◦, 17.75◦, 21.04◦, 22.17◦, 23.31◦, 25.41◦, and 26.38◦, according to the XRD data. After 135 min of UV irradiation, only 8% of RB had undergone photolytic destruction. On the other hand, the elimination resulting from adsorption during a 30-min period without light was around 16%. Conversely, after 135 min, Cu-MOF's photocatalytic breakdown of RB with UV light reached 81.3%. At pH 9.0, the greatest removal of RB at equilibrium was found, and when the amount of photocatalyst rose from 5 to 20 mg, the removal efficiency improved as well. The most sensitive organism to the synthesized Cu-MOF, according to antimicrobial data, was Candida albicans, with a documented MIC value of 62.5 µg mL−1 and antibacterial ZOI as 32.5 mm after 1000 ppm treatment. Cu-MOF also showed the same MIC (62.5 µg mL−1) values against Staphylococcus aureus and Escherichia coli, and 35.0 and 32.0 mm ZOI after 1000 ppm treatment, respectively. Ultimately, it was found that Cu-MOF (1000 µg/mL) after having undergone gamma irradiation (100.0 kGy) was more effective against S. aureus (42.5 mm ZOI) and E. coli (38.0 mm ZOI).ConclusionFrom the obtained results, the synthesized MOF nanocomposites had promising catalytic degradation of RB dye and high antimicrobial potential which encouraging their use in wastewater treatment against some pathogenic microbes and polluted dyes. Due to the exceptional physicochemical characteristics of MOF nanocomposites, it is possible to create and modify photocatalytic nanocomposites in a way that improves their recovery, efficiency, and recyclability.

Sonophotocatalytic degradation of rhodamine B dye using Zr doped ZnO nanoparticles: Kinetic study and toxicity assessment

This study investigates sonophotocatalysis for the oxidation of Rhodamine B (RhB) dye using Zr doped ZnO nanoparticles. The synthesized nanoparticles were characterized by scanning electron microscope, Fourier-transform infrared, X-ray diffraction, Brunauer Emmett-Teller, thermogravimetric analysis, and photoluminescence. The hybrid sonophotocatalysis system achieved 98.73 ± 1.25% degradation of RhB under the conditions: RhB dye concentration = 10 ppm, 4 wt% of Zr doped ZnO = 0.1 g, reaction temperature = 30 °C, time = 60 min, pH = 7. A kinetic model was developed to predict the efficiency of RhB degradation through intrinsic elementary chemical reactions. The high coefficient of determination (R2 = 0.96) indicates the model's prediction accuracy in describing the degradation kinetics of RhB within sonophotocatalysis system. The electrical energy per order (EEO) analysis demonstrated that US + UVC + 4 wt% of Zr doped ZnO significantly reduced EEO (1055 kWh m−3 order−1). The synergy index for this combination was approximately 1.60, demonstrating a significant synergistic effect. Density Functional Theory (DFT) studies were utilized to propose the most probable degradation pathway, identifying reactive sites and potential byproducts. The simulations revealed the central carbon atom (1C site) as highly susceptible to radical attacks, indicating potential decolorization pathways such as N-de-ethylation, chromophore cleavage, and ring opening. Toxicity assessments of both the parent dye and its intermediates were conducted using ECOSAR (Ecological Structure Activity Relationship) to evaluate their ecological impacts. The combination of experimental results and kinetic modeling and simulations offers a deep understanding of RhB degradation complexities, driving advancements in sustainable water treatment technologies.

Surface Hydroxyl‐Assisted BiOBr Nanostructure Evolution for Remarkable Visible Light Photocatalytic Capability

Herein, various BiOBr nanostructures are successfully synthesized using a facile solvothermal method. A series of structural and morphological analyses clearly indicate that due to the nucleation protection provided by KOH and the presence of surface‐absorbed hydroxyl groups, BiOBr transforms from nanosheet microspheres to nanopillow aggregations (BNP) and finally to nanoneedle matrix. The open‐porous nanostructure of the BiOBr nanopillows (BNPs), along with their enhanced visible light absorption capacity and the presence of surface hydroxyls, enables them to adsorb nearly 100% of organic dyes, including rhodamine B (RhB), methylene blue, and methyl red. Furthermore, the BNP exhibits remarkable visible light photocatalytic activity, degrading higher concentrations of RhB in ≈20 min.

Photocatalytic degradation of organic dyes under sunlight using a mononuclear Zn complex-embedded-functionalized porous material.

In this study, mesoporous materials (MCM-41 and MCM-48) were synthesized and functionalized with an acid group through a post-synthetic modification method. A mononuclear Zn complex [Zn(dmp)Cl2] (dmp = neocuprine) was also prepared and incorporated into a functionalized mesoporous material. Extensive characterization of the material married was carried out using techniques such as X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), and Fourier-transform infrared spectroscopy (FT-IR) to evaluate the characteristics of modified materials. The characterization results revealed that the post-synthetic modification did not alter the phase purity, crystallinity, or morphology of the mesoporous materials while confirming the successful grafting of the desired sulphonic acid functionality and Zn complex. The Zn complex-grafted-functionalized mesoporous materials were then assessed for their photo-degradation using methylene blue (MB) and rhodamine B (RB). The results demonstrated exceptional photo-degradation efficiency of the modified materials under sunlight. Within 15min, 10mg/ml of dye concentration, and adsorbent dosage 0.15mg/ml and 0.1mg/ml, degradation efficiencies of 99% and 92%, were achieved for MB using M-48-S-Zn1 and M-41-S-Zn1, respectively. Similarly, 91% and 78% degradation rates were achieved within 30min for RB using the same materials. The modified mesoporous materials exhibited a remarkable degradation performance even in challenging environments, including highly acidic, basic, and salt-concentrated conditions. This highlights the versatility and robustness of the modified materials in different environmental scenarios.

Artificial Light-Harvesting Systems with a Three-Step Sequential Energy Transfer Mechanism for Efficient Photocatalytic Minisci-Type Late-Stage Functionalization.

The natural process of photosynthesis involves a series of consecutive energy transfers, but achieving more steps of efficient energy transfer and photocatalytic organic conversion in artificial light-harvesting systems (ALHSs) continues to pose a significant challenge. In the present investigation, a range of ALHSs showcasing a sophisticated three-step energy transfer mechanism is designed, which are meticulously crafted using pillar[5]arene (WP[5]) and p-phenylenevinylene derivative (PPTPy), utilizing host-guest interactions as energy donors. Three distinct types of fluorescent dyes, namely Rhodamine B (RhB), Sulforhodamine 101 (SR101), and Cyanine 5 (Cy5), are employed as acceptors of energy. Starting from PPTPy-2WP[5], energy is sequentially transferred to RhB, SR101, and Cy5, successfully constructing a multi-step continuous energy transfer system with high energy transfer efficiency. More interestingly, as energy is progressively transferred, the efficiency of superoxide anion radical (O2 •-) generation gradually increased, while the efficiency of singlet oxygen (1O2) generation decreased, achieving the transformation from type II photosensitizer to type I photosensitizer. Furthermore, in order to fully utilize the energy harvested and reactive oxygen species (ROS) obtained, the ALHSs employ a multi-step sequential energy transfer process to enhance Minisci-type alkylation reactions with aldehydes through photocatalysis for late-stage functionalization in an aqueous environment, achieving a 91% yield.

FeBTC MOF‐Derived Fe3O4@C Nanocomposite: Controlled Synthesis and Application as Potential Adsorbent for Rhodamine Dye Elimination From Wastewater

ABSTRACTThis study explores the controlled synthesis of a novel Fe3O4@C magnetic nanocomposite derived from FeBTC metal–organic framework (MOF) and its application as an efficient adsorbent for the removal of rhodamine dye from wastewater. The FeBTC MOF was first synthesized and then thermally decomposed in a controlled oxygen atmosphere at 375°C (1 h) to form the Fe3O4@C nanocomposite with a magnetic Fe3O4 core embedded in a porous carbon matrix. A comprehensive characterization of the nanocomposite was performed using x‐ray diffraction (XRD), transmission electron microscopy (TEM), and x‐ray photoelectron spectroscopy (XPS) to confirm the successful formation and to evaluate its structural and morphological properties. The morphological investigation revealed that the particles of Fe3O4 had a spherical shape with diameter of 10–15 nm. The carbon coating appeared as a thin amorphous layer surrounding the Fe3O4 nanoparticles. The adsorption capacity of Fe3O4@C for rhodamine B (RhB) dye was assessed under various conditions, including different pH values, contact times, initial dye concentrations, and temperatures. Complete dye removal was attained in 45 min using 50 mg of the nanocomposite and 50 mL of 5.0 ppm RhB at the optimum pH of 9.1. Under the same experimental conditions, the highest adsorption capacity of 13.0 mg/g was obtained, but using 15.0 mg of the nanocomposite. Fe3O4@C nanocomposite exhibits high adsorption efficiency, with a maximum removal capacity of 100%, which is clearly superior to many conventional adsorbents. This performance can be attributed to the synergistic effects of the magnetic Fe3O4 and the large surface area of the carbon matrix. Kinetic models were employed to understand the adsorption mechanism. The adsorption kinetics followed a pseudo‐second‐order model. The reusability of the adsorbent was tested over multiple cycles and showed a minimal loss of performance (drops to 93.0% after five removal cycles). The study demonstrates that the Fe3O4@C nanocomposite is a promising candidate for the effective removal of organic dyes from wastewater, offering potential benefits for environmental remediation and sustainable water management.

Enhancing the Light‐Driven Photocatalytic Degradation Activity of ZnO Nanoparticles With the Synergistic Incorporation of Er and Tb Elements

ABSTRACTThe existence of organic pollutants in aqueous media has become a vital issue and a critical threat to human health, where organic toxic dyes represent the major contaminants in wastewater. Over the past few years, photocatalytic techniques have garnered a lot of interest in dye removal from wastewater. In this study, a series of ErxTbxZn1 − 2xO nanophotocatalysts (where x = 0.00, 0.01, 0.03, and 0.05) were synthesized and coded as ZET0, ZET1, ZET2, and ZET3 NPs (nanoparticles). The chemical and physical characteristics of the NPs were investigated using Fourier‐transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy‐dispersive X‐ray (EDX) spectroscopy, and ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS) techniques. Further examination by performing photocatalytic experiments, ZET1 NPs demonstrated effective Rhodamine B (RhB) dye degradation within 60 min. It was found that the kinetic rate constant values were 0.008, 0.097, 0.050, and 0.040 min−1 for ZET0, ZET1, ZET2, and ZET3 NPs, respectively. Aside from their remarkable photocatalytic degradation efficiency, these ZET1 photocatalysts are highly stable even after five consecutive cycles. In addition, the active species test revealed that the primary oxidation species involved in the photocatalytic process are holes (h+) and hydroxyl radicals (•OH), and a possible photocatalytic mechanism for degrading RhB by ZET1 photocatalysts was tentatively proposed. The enhancement of the photocatalytic degradation efficiency is due to the low recombination rate of photogenerated charge carriers, as well as a strong synergistic impact of Tb, Er, and ZnO components. Thus, the current study could offer a versatile strategy for the design of new and effective nano photocatalysts for wastewater purification in the future.

Iron complexes synthesized from FeOCl with carboxylic acid based ligands as Fenton-like catalysts for the highly efficient degradation of organic dyes over a wide pH range

Iron-based materials have garnered significant attention as Fenton-like catalysts for the degradation of organic dyes. However, challenges remain in optimizing hydroxyl radical (•OH) utilization and broadening the effective pH range for practical applications. In this study, three iron-based catalysts (complex 1, 2, 3) were synthesized via a hydrothermal method, utilizing iron oxychloride (FeOCl) as the metal ion source and 4,5-imidazole dicarboxylic acid, furan-2,5-dicarboxylic acid, and 5-hydroxyisophthalic acid as ligands, respectively. The results indicate that these synthesized Fe-based catalysts exhibit enhanced visible light absorption and superior photo-Fenton activity, outperforming FeOCl in the degradation of rhodamine B (Rh-B), crystal violet (CV), and methylene blue (MB). Moreover, the Fe-based catalyst system operates effectively over a wide pH range (1–8) and efficiently degrades organic dyes. In free radical scavenging experiments, hydroxyl radicals (•OH) and superoxide radicals (•O2-) were identified as the primary agents responsible for photocatalytic degradation. Among the catalysts, complex 1 displayed notable stability, retaining its catalytic activity after three reuse cycles. This work presents a promising approach for designing highly efficient and stable Fenton-like catalysts, offering excellent environmental remediation capabilities across a broad pH range.

Fabrication and adsorption characteristics of cuprammonium cellulose-based membranes for removing anionic and cationic dyes

A cotton linter-based source was used to form conjugate electrospun membranes composed of cuprammonium cellulose, polyethylene oxide, and polyacrylonitrile for the removal of the anionic and cationic dyes from aqueous media. The highest removal efficiencies of 94 %, 89.9 %, 87.4 % were achieved for the anionic dyes Congo red (CR), Metanil yellow (MY), and Methyl orange (MO), respectively, and less so on the cationic dyes Crystal violet (CV), and Rhodamine B (RB) were 55.8 % and 15.1 %, respectively. The pseudo-second-order model effectively described the adsorption kinetics for both types of dyes. The composite membrane exhibited adsorption behaviors following the Dubinin-Radushkevich (D-R) isothermal model. Thermodynamics study suggests that the adsorption process was spontaneous except for the RB dye. The activation energy values of CR, MY, MO, CV, and RB dyes were 27.65, 21.17, 11.50, 10.47, and 71.12 kJ/mol, respectively, confirming the physisorption phenomenon for CR, MY, MO, and CV dyes, while chemisorption occurs for RB dyes. This study investigates the potential of a conjugate electrospun membranes as a reusable adsorbent for dye removal. The effects of solution pH, temperature, and dye concentration on adsorption performance were systematically evaluated. The conjugate electrospun membrane efficiency declined by only 10 % after undergoing five adsorption/desorption cycles.

Synthesis of rhodamine B amine derivatives with improved light resistance and its application in thermochromic materials

Rhodamine B (RhB) is a widely utilized xanthene dye known for its strong fluorescence, high quantum yield, bright color, and versatility in various applications. However, RhB type dyes face significant limitations due to their susceptibility to photodegradation. Herein, four RhB amine derivatives (RhB-1, RhB-2, RhB-3, and RhB-4) were synthesized to improve the light resistance through functionalization of the 4' position of the carboxyphenyl ring with acrylamide, butylamine, octylamine, and cyclohexanamine, respectively. The mechanism of improving light resistance was analyzed. The results show that the derivatives demonstrated significantly enhanced light resistance compared to RhB, with the ability to form supramolecular structures including dimers and aggregates that protect against UV degradation. Light resistance for RhB-1 was significantly improved with increasing concentration as the photodegradation efficacy drops from 84.8% (1.5×10-5 mol/L) to 10% (2.0×10-4 mol/L), due to the dominant changes from monomers to J-dimers to H-aggregates. When incorporated into three-component thermochromic systems, the derivatives not only improved the light resistance with double duration of UV irradiation but also expanded the range of color change temperatures. This work advances the development of RhB derivatives with superior optical properties and durability, enhancing its applicability in environments requiring prolonged exposure to light.

Adsorptive behavior of Rhodamine B dye over hierarchical N-doped carbons from hexamine-based complexes: Equilibrium and kinetics

Pollution from water-soluble dyes is a common issue due to high toxicity and diffiulty in degradation, and its effectively removal is critical for human health and sustainability. In this work, N-doped hierarchical carbons were derived by facile pyrolysis of Co-including hexamine-based complex using glucose as a cross-linker, showing high removal ability using Rhodamine B (RhB) as a model dye. Porous architecture and N-coordination can be easily altered by pyrolysis temperature, where the GNC-900 sample obtained at 900 °C exhibits the best removal ability even outperforming several classical carbons under equal conditions, owing to synergistic effects from large surface areas, high ratio of pyrrolic-N, enhanced interaction between RhB molecules and pore walls, and possible Co-Nx active sites. Adsorptive behaviour is better fitted by pseudo-second-order kinetic model, and the maximum RhB capacity over GNC-900 determined by Langmuir model is highly up to 400.1 mg/g, following mechanisms of pore filling, π-π conjugation, electrostatic, surface complexation and H-bonding. Thermodynamics indicate that RhB removal is exothermic and spontaneous process. Moreover, GNC-900 can be readily regenerated using ethanol and reused at least six times without notable loss in capacity. This novel method facilitates synthesis of N-doped carbons from metal-based complexes, exhibiting high efficiency as adsorbents for water remediation.

In situ construction of Flowerlike bismuth oxide (BiO2-x)/N-rich carbon nitride (C3N5) S-scheme heterojunctions with enhanced structural defects for the efficient photocatalytic removal of tetracycline antibiotic and RhB

Efficient photocatalysts for the simultaneous removal of organic dyes and antibiotics are crucial for sustainable environmental management. In this study, we designed and synthesized a C3N5/BiO2-x S-type heterojunction photocatalyst with structural defects using a hydrothermal method, aimed at degrading both Rhodamine B (RhB) and tetracycline (TC). The degradation kinetic constants for RhB and TC were 0.0809 min−1 and 0.0535 min−1, respectively, showing improvements of 9.52 and 25.48 times over pure C3N5, and 2.90 and 1.49 times over BiO2-x. This enhanced performance is attributed to the unique electron transfer mechanism of the S-scheme heterojunction and the structural defects that facilitate efficient separation of electron-hole (e−-h+) pairs. Free radical trapping experiments indicated that the main reactive oxygen species (ROS) involved are ·O2− and h+. Additionally, electrochemical impedance spectroscopy (EIS) and transient photocurrent response (TPR) measurements confirmed improved separation and transfer of photogenerated e−-h+ pairs in the C3N5/BiO2-x heterojunction. The higher density of structural defects in C3N5/BiO2-x compared to individual BiO2-x counterparts enhances its ability to activate and photo-oxidize TC and degrade RhB. Consequently, C3N5/BiO2-x demonstrates significant potential as a photocatalyst for improving water quality.

A sustainable pathway for the photodegradation of Rhodamine B dye using Mn-doped CaFe2O4 anchored on citrus fruit peel-derived biochar matrix

This report details the synthesis of Mn-doped CaFe2O4 nanoparticles supported on biochar. We evaluate the photocatalytic activity of the resulting nanocomposite towards the degradation of Rhodamine B (RhB) dye, a well-known environmental pollutant. Doping CaFe2O4 with Mn and subsequently incorporating it onto biochar results in enhanced visible light absorption and diminished photoluminescence (PL) intensity. The photocatalyst Mn-doped CaFe2O4/Biochar was synthesized via a hydrothermal method. The morphology and photocatalytic characteristics of the synthesized catalyst were comprehensively scrutinized through powder X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), ultraviolet–visible diffuse reflectance spectroscopy (UV-DRS), and photoluminescence (PL) investigations. The photocatalytic properties of the catalyst were further assessed through the degradation of RhB dye, revealing a degradation efficiency of 97.31% within a 70-minute timeframe. The photocatalyst exhibits reusability for up to five cycles while maintaining a photocatalytic efficiency of more than 80%.

Efficient RhB degradation and antimicrobial activity with molecular docking study of polymers doped ZnSe nanostructure

A facile coprecipitation approach was adopted to synthesize zinc selenide (ZnSe) doped with a fixed amount (3 wt%) of cetyltrimethylammonium bromide (CTAB) and different concentrations (2 and 4 wt%) of eudragit to form ternary nanostructure (NSs). Eud and CTAB inhibit the dimension and reduce the rate of recombination of NSs to intensify catalytic performance against rhodamine B (RhB) and bactericidal action against MDR Staphylococcus aureus (S. aureus). Doped ZnSe increase active sites, porosity, and surface area to enhance the degradation of RhB dye and antimicrobial efficacy to kill pathogenic S. aureus. Assessment of 4 wt% Eud/CTAB exhibited effective performance for degradation of RhB and bactericidal potential highlights an impressive 94.3 % degradation efficiency and 8.85 ± 0.05 mm of the inhibition zone against MDR S. aureus. Computational molecular docking studies suggest that NSs, such as Eud/CTAB-doped ZnSe, have the ability to inhibit the DNA gyrase enzyme in MDR S. aureus.

Efficient removal of cationic dyes by a bivanadyl capped, highly reduced Keggin polyoxometalate through flocculation

Flocculation is widely applied for dye wastewater treatment, due to its low cost, high efficiency and convenient operation. However, finding novel flocculant with high performance and low cost is still a challenge. Therefore, a fully characterized bivanadyl capped, highly reduced Keggin polyoxometalate (Et3NH)5[PMoV6MoVI6O40(VIVO)2] (PMoV2) was explored as flocculant for the treatment of simulated cationic dye wastewater. The effect of initial pH, PMoV2 dosage, and concentrations of dyes and inorganic salts on the flocculation rate of methylene blue (MB)/ crystal violet (CV)/rhodamine B (RhB) was investigated. Under the optimum conditions, the flocculation rates of MB, CV and RhB were 99.7%, 99.8% and 99.7% in 5min, respectively. In addition, PMoV2 and dyes could be easily recovered from flocs. PMoV2 exhibited high selectivity for CV in the binary systems of CV-MB and CV-MO. Even after five recycling tests, PMoV2 still kept high flocculation rate of MB/CV/RhB. The possible flocculation mechanisms for MB/CV/RhB single system, and MB-CV and MO-CV binary systems were charge neutralization, charge neutralization and π-π interaction, and charge neutralization and electrostatic interaction, respectively. PMoV2 was better than the reported flocculants in the respect of easy availability and operation conditions, reusability and high flocculation rate. The cost effectiveness, eco-friendly nature and excellent flocculation performance in individual and binary dye systems made PMoV2 competitive in the field of water environment remediation and material development. This is the first report about the flocculation activities of bivanadyl capped, highly reduced Keggin polyoxometalate.

Using Rhodamine to Tag Mites for Studies of Pre- and Post-Copulatory Sexual Selection.

Our understanding of sexual selection is advancing with new technologies that tag individuals or their sperm, revealing how females use post-copulatory processes to discriminate between competing mates. Many tagging methods have been devised primarily for model insect organisms like Drosophila or Gryllidae. Developing such novel methods, however, is expensive and requires intensive investment. In this experiment, we trial the use of Rhodamine B (RhB) and Rhodamine 110 (Rh110) in a small arachnid, the bulb mite Rhizoglyphus echinopus, for pre- and post-copulatory observations as it is a relatively inexpensive and simple way to tag individuals and their ejaculate proteins. First, we tested whether RhB and Rh110 applied to food can be used as a tagging method to track and distinguish between individuals. Second, we explored whether Rhodamine applied in this way can be used to track sperm transfer. We found that both tagging probes worked well in tagging individuals and that we were able to distinguish between individuals using both LED and fluorescent microscopy. We also found that Rhodamine degraded rapidly in the animals, likely due to their fast metabolism. Due to the rapid degradation, we observed variable results in the sperm transfer trials. We suggest multiple uses for Rhodamine and highlight other invertebrates where this method may come into use for the study of sexual selection.

Facile synthesis of ultrafine Co3O4/Al2O3 catalysts for superior peroxymonosulfate activation in rhodamine B degradation

Advanced oxidation processes based on persulfate (PS-AOPs) have emerged as effective strategies for environmental remediation, with cobalt-based oxides serving as prominent catalysts for peroxymonosulfate (PMS) activation. In this study, we developed a highly active Co3O4/Al2O3 catalyst (Co/AA) featuring ultrafine nanoparticles, synthesized via a facile approach using tannic acid (TA) as a coordinating agent and activated alumina as a robust support. Co/AA-0.1, as the representative catalyst, was characterized and exhibited outstanding performance in degrading rhodamine B (RB) via PMS activation. Our findings highlight TA's critical role in reducing Co3O4 nanoparticle size, thereby increasing the availability of active sites. The degradation mechanism was elucidated through reactive oxygen species (ROS) quenching experiments and electron paramagnetic resonance (EPR) analysis, revealing that sulfate radicals (SO4•−) are the dominant ROS. The high activity of Co/AA-0.1 is confirmed by analyzing X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller surface area and O2-temperature programmed desorption data of the samples. We also investigate the effects of various factors, such as anions, reaction temperatures, and PMS dosage, on RB degradation. Higher temperatures for treating the catalyst are found to reduce activity but improve stability. Notably, the catalyst synthesized through EDTA-assisted synthesis showed balanced activity and stability. Furthermore, the versatility of our synthesis method was demonstrated by successfully applying it to other supports, such as SiO2 and TiO2, offering the development of more efficient and stable catalysts for environmental applications.

Cysteine assisted synthesis of Bi2S3/BiOBr nanocomposites for photocatalytic decomposition of rhodamine B

Novel Bi2S3/BiOBr nanocomposites (NCs) were prepared via L-Cysteine-assisted hydrothermal avenue as efficient photocatalysts to degrade rhodamine B (RhB). As a result, the obtained Bi2S3/BiOBr NCs exhibited the slice-like microstructure with the average diameters of ca. 100 nm. The elemental analysis of X-ray photoelectron spectroscopy indicates that the nanocomposites were combined by Bi2S3 and BiOBr. Then, the photo-induced degradation of RhB was performed with a Xenon lamp to simulate the sunlight ([Formula: see text] 400 nm) and the photo-decomposition rate was calculated. The following results showed that the Bi2S3/BiOBr NCs possessed excellent photocatalytice performance, which was better than that of other samples as control. Thus, this avenue provides a new reference for the facile synthesis of photocatalysts with low cost and high efficiency.

Five novel Pb/Zn/Co metal-organic frameworks using 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene and carboxylate ligands: Synthesis, characterization, DFT calculation and catalytic PMS degradation of RhB

Five new metal-organic frameworks (MOFs), namely {Pb(atpt)(3-bpd)0.5}n (1); {Co(cbz)2(3-bpd)(H2O)2·2H2O}n (2); {Co(imdc)(3-bpd)(H2O)·H2O}n (3); {Co(tdca)(3-bpd)(H2O)2·DMF}n (4); {Zn(tdca)(3-bpd)(H2O)2·DMF}n (5), were assembled with metal ions Pb²⁺, Zn²⁺, and Co²⁺ using 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene (3-bpd) as the main ligand, combined with 2-aminoterephthalic acid (H2atpt), 4-cyanobenzoic acid (Hcbz), 4,5-imidazoledicarboxylic acid (H2imdc), and thiophene-2,5-dicarboxylic acid (H2tdca) as auxiliary ligands via hydro/solvothermal methods. Their molecular structures were analyzed by single-crystal X-ray diffraction and characterized by FT-IR and PXRD. Complex 1 has a three-dimensional structure with a hepta-coordinated, semi-directed {PbNO6} metal center. The central metal ions in complexes 2–5 exhibit a six-coordinated {MN2O4} (M = Co or Zn) octahedral geometry. In complex 2, the carboxylate ligand does not function as a bridging ligand, resulting in a 1D chain structure, while complexes 3- 5 extend into 2D layered structures. Thermogravimetric analysis indicates good thermal stability for complexes 1–5. Then, the prepared complexes were used as catalysts to degrade Rhodamine B (RhB) during the monopersulfate (PMS) activation. Complexes 3 and 4 demonstrated significant efficiency, achieving degradation rates of 93.61 % and 98.56 % within 10 min. Radical scavenging experiments and EPR analysis identified that the activation of PMS for dye degradation by the two catalysts occurs through both radical and non-radical pathways, with SO4•− and •OH radicals being the dominant species. Density functional theory (DFT) calculations explained the superior catalytic performance of complex 4 compared to complex 3.