Rhodamine B Research Articles

High efficiency degradation of RhB by MIL-88A(Fe)/MoS2 activated persulfate and its mechanism

MoS2/MIL-88A(Fe) composite catalyst was prepared by in-situ formation method. The material was characterized by SEM, TEM, XRD and XPS, and the Rhodamine B(RhB) was activated and degraded by persulfate (PMS). The results showed that M-10/M1:2 had the best degradation effect on RhB, the rate constant was 0.66420 min-1, and the degradation rate could reach 1.89-14 times that of other doped composite catalysts. The SEM results showed that M-10 had the least sulfur content, fewer MoS2 flower layers and more exposed Mo4+ atoms, which improved the electron transfer efficiency and accelerated the degradation reaction. The XPS spectra before and after M-10/M1:2 reaction showed that the REDOX reaction of Fe3+/Fe2+ and Mo4+/Mo6+ on the catalyst surface played an important role in the activation of PMS. The results of free radical capture experiment and ESR test showed that the main active substances in M-10/M1:2/PMS reaction system were SO4•−, 1O2, •O2−, and •OH, which only played a role in the degradation of RhB. Finally, based on the ESR results of M-10/M1:2/PMS system and the changes of Fe and Mo elements in XPS characterization before and after the reaction, the degradation mechanism of M-10/M1:2/PMS system was proposed.

A highly efficient Co-based catalyst for peroxymonosulfate activation for rapid degradation of RhB over a wide pH range

Cobalt-based materials have been demonstrated to be effective heterogeneous catalysts for peroxymonosulfate activation in degrading many refractory organic pollutants. In this study, a new cobalt-based catalyst was prepared using cobalt chloride hexahydrate (CoCl2·6H2O) as the Co2+ source, 2,3-pyrazine dicarboxylic acid and 3,6-DI-4-pyridyl-1,2,4,5-tetrazine (4-PYTZ) as ligands. This catalyst was employed as a peroxymonosulfate activator for the degradation of Rhodamine B(RhB). The results indicated that the prepared Co-based catalyst can effectively degrade RhB dye in aqueous solution by activating peroxymonosulfate (PMS). Specifically, when the initial concentration of RhB was 20 mg/L, its degradation rate exceeded 98 % within merely 9 min. The factors influencing the activation of PMS by the Co-based catalyst were examined, including PMS concentration, reaction temperature, solution pH, and the concentration of organic pollutants. Stability and reusability tests demonstrated that the prepared catalyst exhibited good stability, with the degradation rate of RhB remaining above 97 % after four repetitive experiments. Free radical quenching experiments and electron paramagnetic resonance (EPR) analyses revealed that sulfate radicals (SO4−) and hydroxyl radicals (OH) are the primary reactive radicals accountable for the degradation process. Additionally, it displayed excellent adaptability over a wide pH range, particularly within the pH levels ranging from 5 to 9. This study demonstrates that the prepared Co-based catalyst can serve as a stable and effective option for degrading organic dyes in wastewater treatment applications.

Ti3C2 quantum dots-modified oxygen-vacancy-rich BiOBr hollow microspheres toward optimized photocatalytic performance

The Ti3C2 quantum dots (QDs)/oxygen-vacancy-rich BiOBr hollow microspheres composite photocatalyst was prepared using solvothermal synthesis and electrostatic self-assembly techniques. Together, Ti3C2QDs and oxygen vacancies (OVs) enhanced photocatalytic activity by broadening light absorption and improving charge transfer and separation processes, resulting in a significant performance boost. Meanwhile, the photocatalytic efficiency of Ti3C2 QDs/BiOBr-OVs is assessed to investigate its capability for oxygen evolution and degradation of tetracycline (TC) and Rhodamine B (RhB) under visible-light conditions. The rate of oxygen production is observed to be 5.1 times higher than that of pure BiOBr-OVs, while the photocatalytic degradation rates for TC and RhB is up to 97.27% and 99.8%, respectively. The synergistic effect between Ti3C2QDs and OVs greatly enhances charge separation, leading to remarkable photocatalytic activity. Furthermore, the hollow microsphere contributes to the enhanced photocatalytic performance by facilitating multiple light scatterings and providing ample surface-active sites. The resultant Ti3C2QDs/BiOBr-OVs composite photocatalyst demonstrates significant potential for environmental applications.

Synthesis of leek-based N,S self-doped CQDs/TiO2 and its application in the photocatalytic degradation of organic pollutants

In this work, N,S self-doped CQDs (N,S-CQDs/TiO2) were synthesized from leeks via a microwave method, and a new leek-based N,S-CQDs/TiO2 composite photocatalytic material was prepared by roasting. The structural characteristics, optical properties, and electrical properties of the N,S-CQDs/TiO2 composites were characterized by Scanning electron microscope (SEM), Transmission electron microscope (TEM), X-ray powder diffraction (XRD), Solid ultraviolet–visible diffuse reflectance (UV–vis-DRS), Fourier transform infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transient photocurrent response, and Electrochemical impedance spectroscopy (EIS). In addition, the catalytic degradation effect of N,S-CQDs/TiO2 was evaluated by the photocatalytic degradation of Rhodamine B (RhB) and ibuprofen (IBU). The experimental results showed that the photocatalytic degradation effect of leek-based N,S-CQDs/TiO2 was significantly better than that of TiO2, and N,S-CQDs/TiO2 with 1.86 wt% N,S-CQDs (1.86-N,S-CQDs/TiO2), which demonstrated optimal photocatalytic degradation. The photocatalytic degradation rate of RhB (20 mg/L) was 94.65 % within 120 min of high-voltage mercury lamp irradiation, which was 41.15 % higher than that of TiO2(53.50 %), and the degradation rate was 80.10 % after four cycles. After 180 min, the photocatalytic degradation rate of IBU (10 mg/L) was 96.92 %, which was 26.39 % higher than that of TiO2 (70.53 %), and the degradation rate could still reach 78.94 % after four cycles. In this work, the photocatalytic degradation mechanisms of RhB and IBU by N,S-CQDs/TiO2 were explored by free radical capture and ESR free radical detection experiments. This study may serve as an important reference for enhancing the photocatalytic degradation effect by using biomass self-doped CQDs/TiO2 composite photocatalytic materials, and as a reference for the photocatalytic treatment of organic pollutants in water.

An in-depth comparison of dielectric, ferroelectric, piezoelectric, energy storage, electrocaloric, and piezocatalytic properties of Ba0.92Ca0.08Zr0.09Ti0.91O3 and Ba0.92Ca0.08Sn0.09Ti0.91O3 piezoceramics

The futuristic technology demands materials exhibiting multifunctional properties. Keeping this in mind, an in-depth investigation and comparison of the dielectric, ferroelectric, piezoelectric, energy storage, electrocaloric, and piezocatalytic properties have been carried out on Ba0.92Ca0.08Zr0.09Ti0.91O3 (BCZT) and Ba0.92Ca0.08Sn0.09Ti0.91O3 (BCST) lead-free compounds synthesized through the conventional solid state reaction method. Further, the Rietveld refinement against the XRD patterns affirmed the coexistence of orthorhombic (Amm2) and tetragonal (P4mm) phases at room temperature for both compounds. While BCZT compound demonstrated remarkable dielectric, piezoelectric, and piezocatalytic characteristics with maximum dielectric constant () ≈ 13304 near the Curie temperature ( ≈ 105 °C), converse piezoelectric coefficient ≈ 609 pm V-1 , power density () ≈ 89.71 KW cm-3 at room temperature, and 82.7 % Rhodamine B (RhB) dye degradation capability; on the other hand, BCST compound exceled in superior energy storage density () ≈ 191.8 mJ cm-3 with efficiency η ≈ 73.26% near room temperature and enhanced electrocaloric properties with adiabatic temperature change ≈ 0.980 K, isothermal entropy change ≈ 1.15 J Kg-1K-1 and a higher electrocaloric responsivity ) ≈ 0.49 K mm kV-1. These distinctions arise from the difference in ionic radii, lattice distortion, and the electronic configurations of the dopant ions, leading to a greater polarization change and a lower coercive electric field in the BCST ceramic. The outcome of the present study provides valuable insights for selecting a dopant tailored compound for specific application and underscores the potential of such ceramics in energy storage, piezocatalysis, and the development of advanced solid-state cooling devices for future applications.

Green NiO nanoparticle-integrated PVA-alginate hydrogel: potent nanocatalyst for efficient reduction of anthropogenic water pollutants.

Hydrogel nanocatalyst composed of nickel oxide (NiO) nanoparticles embedded in PVA-alginate hydrogels were potentially explored toward the reduction of anthropogenic water pollutants. The NiO nanoparticleswas accomplished via green method using waste pineapple peel extract. The formation of the nanoparticles was affirmed from different analytical techniques such as UV-Vis, FTIR, XRD, TGA, FESEM, and EDS. Spherical NiO nanoparticles were obtained having an average size of 11.5nm. The nano NiO were then integrated into PVA-alginate hydrogel matrix forming a nanocomposite hydrogel (PVALg@ NiO). The integration of nano NiO rendered an improved thermal stability to the parent hydrogel. The PVALg@ NiO hydrogel was utilized as a catalyst in the reduction of 4-nitrophenol (4-NP), potassium hexacyanoferrate (III), rhodamine B (RhB), methyl orange (MO), and malachite green (MG) in the presence of a reducing agent, i.e., NaBH4. Under optimized conditions, the reduction reactions were completed by 4.0min and 3.0min for 4-NP and potassium hexacyanoferrate (III), respectively, and the rate constant was estimated to be 1.14min-1 and 2.15min-1. The rate of reduction was found to be faster for the dyes and the respective rate constants were be 0.17s-1 for RhB, MG and 0.05s-1 for MO. The PVALg@ NiO hydrogel nanocatalyst demonstrated a recyclability of four runs without any perceptible diminution in its catalytic mettle. The efficacy of the PVALg@ NiO hydrogel nanocatalyst was further examined for the reduction of dyes in real water samples collected from different sources and the results affirm its high catalytic potential. Thus, this study paves the path for the development of a sustainable hydrogel nanocatalyst for reduction of hazardous pollutants in wastewater treatment.

Simple precipitation synthesis and solar light-driven photocatalytic degradation of Ag3PO4 floating photocatalysts

Abstract A highly efficient and stable photocatalyst, Ag3PO4, was prepared using a simple co-precipitation method at room temperature. The precursors used in this process were AgNO3 and K2HPO4. The resulting Ag3PO4 photocatalyst forms irregularly-shaped spheres with diameters ranging from 300 to 1 μm. The shape of the Ag3PO4 photocatalyst slightly changes when different surfactants (PVA, PVP, PEG) are used. The powdered Ag3PO4 photocatalyst exhibits excellent visible light-driven photocatalytic performance. It is capable of decomposing rhodamine B (RhB) as a model pollutant in just 5 min under visible light irradiation. This performance is quite remarkable. Interestingly, Ag3PO4 floating composite sheets have been achieved using polystyrene (PS) and fumed silica Aerosil 200. After three cycles, the decolorization of RhB dyes remains at 87% with the 30% Ag3PO4@PS/Aerosil 200 sheet. This indicates that the Ag3PO4@PS/Aerosil 200 photocatalyst is highly reusable and stable.

Excellent Catalytic Performances of Embedded CoFe2O4 and TiO2 Nanoparticles on the Surface of Silica Matrix Toward Reduction of Toxic Cr (VI), Dyes, and Nitroaromatic Compounds

ABSTRACTA novel TiO2/CoFe2O4/SiO2 magnetic nanocomposite was successfully synthesized using sol–gel and hydrothermal methods. This nanocomposite consists of highly dispersed CoFe2O4 and TiO2 nanoparticles on the surface of the SiO2 matrix. The synthesis process involved the utilization of activated carbon, which played a dual role as a support for depositing the CoFe2O4 and TiO2 nanoparticles and as a rigid pattern for producing the silica matrix that enmeshed the nanoparticles. To study the unique characteristics of the samples, a range of analytical techniques, such as FT‐IR, VSM, XRD, SEM, N2 adsorption–desorption analysis, BET and EDX were employed. We carried out a complete examination of the catalytic performance of the TiO2/CoFe2O4/SiO2 nanocomposite for the reduction of different substances, including methyl orange (MO), safranin O (SO), methylene blue (MB), rhodamine B (RhB), chromium (VI) ions, and nitroaromatic compounds such as 2‐nitrophenol (2‐NP), 4‐nitroaniline (4‐NA), 2‐nitroaniline (2‐NA), and 4‐nitrophenol (4‐NP). The findings of our study demonstrate the remarkable efficacy of the TiO2/CoFe2O4/SiO2 nanocomposite in efficiently reducing dyes, Cr (VI), and nitroaromatic compounds to their desired forms in environmentally friendly aqueous solutions. Notably, the nanocomposite stands out due to its simple synthesis process, effortless recyclability, and its convenient separation by a magnet.

Immobilization of MnO2 nanoflowers on coils using direct heating method for organic pollutant remediation

The immobilization of catalysts on supporting substrates for the removal of organic pollutants is a crucial strategy for mitigating catalyst loss during wastewater treatment. This study presented a rapid and cost-effective direct heating method for synthesizing MnO2 nanoflowers on coil substrates for the removal of organic pollutants. Traditional methods often require high power, expensive equipment, and long synthesis times. In contrast, the direct heating approach successfully synthesized MnO2 nanoflowers in just 10 min with a heating power of approximately 40 W·h after the heating power and duration were optimized. These nanoflowers effectively degraded 99% Rhodamine B in 60 min with consistent repeatability. The catalytic mechanisms are attributed to crystal defects in MnO2, which generate electrons to produce H2O2. Mn2+ ions in the acidic solution further dissociate H2O2 molecules into hydroxyl radicals (·OH). The high efficiency of this synthesis method and the excellent reusability of MnO2 nanoflowers highlight their potential as a promising solution for the development of supporting MnO2 catalysts for organic dye removal applications.

Improved purification efficiency and stability of photocatalytic cement-based pavement coated with colloidal graphitic carbon nitride

Photocatalytic coatings applied onto cement-based pavement materials have been intensely developed to purify runoff pollution and vehicle exhaust. However, the masking effect of the adhesive incorporation often results in an unsatisfactory purification efficiency. Thus, developing an adhesive-free photocatalytic coating with high stability and purification efficiency on cement-based pavements is still urgently needed. Herein, a colloidal graphitic carbon nitride (g-C3N4) modified with hydroxyl groups was sprayed onto cement pastes to prepare a photocatalytic coating on the cement-based materials. The results of photocatalytic degradation of Rhodamine B (RhB) indicated that the RhB degradation efficiency and stability of the colloidal g-C3N4-coated cement paste were significantly improved compared to pristine g-C3N4-coated cement paste. After a runoff-washing trial, photocatalytic RhB degradation by colloidal g-C3N4-coated cement paste was 13.8-fold higher than that of pristine g-C3N4-coated cement paste. Mechanistic studies suggested that the well-distributed membrane microstructure of colloidal g-C3N4 and coordinate bonds between colloidal g-C3N4 and calcium-silicate-hydrates were mainly responsible for the improved stability and purification efficiency of colloidal g-C3N4-coated cement pastes. These results support the use of colloidal g-C3N4 as a promising strategy to prepare photocatalytic cement-based pavements with good stability and purification efficiency.

Photocatalytic CO2 reduction and destruction of rhodamine B on Bi0/BiOCl with tunable oxygen vacancies induced by 60 CO γ-rays irradiation

In this work, Bi0/OVs-BiOCl photocatalysts were in-situ constructed by irradiating BiOCl with 60Co γ-rays. The powerful penetrating ability of γ-rays induce the Bi-O bonds in BiOCl to break, thereby leading to the deoxygenation (OVs) and the formation of metal Bi0. The presence of Bi0 and OVs endows the photocatalysts with enhanced separation of photogenerated charges and enriched active sites. Under the excitation of simulated sunlight, the BOC-5 sample with an irradiation dosage of 5 KGy demonstrates the best photocatalytic performance, and the yield of CO on the sample is 2.19 μmol·g−1·h−1, which is 2.27 times higher than that on the reference sample. In-situ diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) reveals the formation of intermediates during the conversion of CO2 to CO. Under irradiation of a 300 W xenon lamp, the degradation rate of rhodamine B (RhB) on the BOC-5 sample is 0.05843 min−1, which is 3.42 times of that on the reference sample (0.01708 min−1). The main active species in the degradation process were explored using electron paramagnetic resonance (EPR) and free radical capture experiments at room temperature. This study provides a novel strategy for the preparation of BiOCl-based photocatalysts with high photocatalytic activity through 60Co γ-rays irradiation.

Integration of Silver Nanoparticles into Carbon-Encapsulated Tungsten Oxide Promoting Visible-Light-Driven Photocatalytic Degradation Efficiency

WO3-based photocatalysts have garnered popularity due to their low cost and high stability. However, the strong photogenerated electron-hole recombination limits their practical applicability. Herein, we developed an innovative heterostructure that integrates silver nanoparticles (Ag NPs) into carbon-encapsulated WO3 (C-WO3) through a combination of solvothermal synthesis and photoreduction methods. Under visible light irradiation, the Ag/C-WO3 photocatalyst demonstrated significant photocatalytic activity for rhodamine B (RhB) degradation, and the fine-tuned Ag/C-WO3 photocatalyst possesses excellent RhB degradation performance, achieving a removal rate of 98.2 % with excellent photostability. The photocatalytic process follows first-order kinetics, with adsorbent diffusion identified as the rate-limiting step. The optimized Ag/C-WO3 had an apparent rate constant of 0.039 min−1, 9.75 times higher than that of the unmodified C-WO3 (0.004 min−1). The enhanced photocatalytic activity is primarily owing to the surface plasmon resonance effect of Ag NP, which increases the absorption of visible light and boosts electron generation. Additionally, the carbon layer that encapsulates WO3 serves as a bridge for electron transfer from Ag to WO3, thereby accelerating the separation of photogenerated electron-hole pairs and elevating the overall photocatalytic degradation efficiency. The Ag NP-decorated C-WO3 with superior degradation properties is expected to be a potential candidate in practical and industrial applications.

Fabrication of a family of BiOI-doped copper-organic frameworks for enhancing photocatalytic degradation of dyes

Organic dyes are one of the most popular dyes used in industrial and consumption nowadays, and the use of dyes has certain hazards. One of the greenest and most efficient methods for breaking down organic contaminants is photocatalysis. It is a green technology that has enormous promise for the environment and energy sectors. In this work, p-type BiOI nanosheets were deposited in situ on n-type copper-based metal–organic framework (Cu-MOF) to create a unique BiOI@Cu-MOF heterojunction. The BiOI@Cu-5 heterojunction that is optimized showed nearly 100 % removal of rose Bengal (RB) under UV irradiation as well as the degradation rates of methyl orange (MO), crystal violet (GV), methylene blue (MB), and rhodamine B (RhB) were 99.70 %, 95.70 %, 27.20 %, and 23.90 %, respectively. First, the introduction of narrow bandgap BiOI into the material can effectively enhance its absorption of sunlight. Secondly, the high specific surface of the Cu-based MOFs material is favorable for improving the catalytic activity of the catalyst. More critically, the intrinsic electric field at the Cu-MOFs/BiOI heterojunction interface facilitates a successful division of photogenerated electron-hole pairs. Further studies revealed that the photogenerated holes are the important active ingredients for RB scavenging. In this paper, Bi-based semiconductors were used to create p-n heterostructures that will bring new ideas for increasing MOF photocatalytic activity.

New recyclable and functionalized chitosan-based polyurethane foams for effective and incessant removal of Orange II (OII) and Rhodamine B (RhB) dyes from water

The development of new efficient materials for the removal of water-soluble toxic organic dyes has been one of the focused research areas in the recent past. There is a strong demand for the new materials as most of the reported techniques/materials suffer from serious limitations. In this regard, a series of flexible chitosan-based task-specific polyurethane foams (PUCS-GP, PUCS-CA-GP, PUCS-TA-GP, and PUCS-GA-GP) associated with naturally available hydroxycarboxylic acids was developed. The basis for the preparation of these task-specific and functionalized PU foams is to possess amine groups for trapping the anionic dyes (example: Orange II denoted as OII) and carboxylic acid groups for attracting the cationic dyes (example: Rhodamine B denoted as RhB) under specified pH conditions. Batch adsorption experiments were conducted to assess and improve various parametric conditions. The experimental results revealed that the adsorption kinetics closely agree with the pseudo-second-order model having a maximum sorption capacity of 38.3 mg/g at pH 3 for OII on PUCS-GP and 48.4 mg/g at pH 6 for RhB on PUCS-CA-GP. Furthermore, the adsorption process was described by isotherms, kinetic equations and thermodynamic parameters (ΔG°, ΔH° and ΔS°). Notably, the regeneration of OII and RhB dyes from the exhausted PUCS-GP and PUCS-CA-GP materials was effectively accomplished. The recovered PUCS-GP shows >90 % OII and PUCS-CA-GP displays >70 % RhB removal efficiency even after twelve adsorption–desorption processes under mild conditions, demonstrating excellent recyclability/durability. The advantages of these functionalized foam materials are facile preparation, high adsorption capacity, good reusability, and very efficient removal of organic dyes from wastewater streams.

Strategically engineered multifunctional graphene oxide hybrid nanomaterials for efficient catalytic degradation and emerging contaminants treatment

The use of functional textiles is growing in all fields of science and technology. Surface functionalization is mainly used to impart conventional textiles with new functionalities and improved performances. In the present study, a cobalt ferrite nanoparticle/graphene oxide (CoFe2O4/GO) coated polyethylene terephthalate (PET) fabric with excellent catalytic and antibacterial properties, has been successfully developed. The PET-coated CoFe2O4/GO samples, ranging from 1 % to 5 % wt. were obtained using a simple dip-coating method in CoFeO/GO solution (1 mg/mL), and were investigated through several physiochemical characterization techniques. CoFe2O4/GO and PET fabric have been shown to establish an interfacial connection by Fourier transform infrared spectroscopy (FTIR). X-ray diffraction (XRD) results showed that CoFe2O4/GO coating did not affect the PET crystallinity and that CoFe2O4/GO hybrid was incorporated in the PET samples, which was proved as well by the morphological study through Scanning electron microscopy (SEM). Furthermore, thermogravimetric characterisation (TGA) verified that the coating does not change or impair the quality of the fibre and that the PET@CoFe2O4/GO as made is thermally stable. Tensile strength tests demonstrated that coated fabrics exhibited outstanding mechanical properties in comparison with pristine PET. Moreover, the coated PET@CoFe2O4/GO fabric was used as a model catalytic system for peroxymonosulfate (PMS) activation in the rhodamine B (RhB) degradation reaction. Total Organic Carbon (TOC) measurements showed that TOC removal reached 89.82 % in only 12 min reaction. The results confirmed that the coated fabrics exhibited high catalytic performances, good stability and reusability in consecutive degradation experiments with a degradation rate over 60 % even after 7 degradation cycles; Moreover, it is easily and simply separated from the mixture, by removing the textile sample from the aqueous solution. It is worth mentioning that the PET@CoFe2O4/GO fabrics showed outstanding antibacterial activity against both Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria with an inhibition diameter zone of up to 13 mm for PET@CoFe2O4/GO (5 %). Overall, these findings are of great importance as they permit the development of a novel multifunctional textile fabric, combining anti-bacterial activity, catalytic performance and mechanical properties. The study provides a textile-based catalyst with improved catalytic performance, re-usability in consecutive degradation reactions and easy catalyst separation compared to traditional supports. Thus, a huge potential application in several fields such as medicine, heterogeneous catalysis, and wastewater treatment.

Constructing a Type-II CdS/Bi2MoO6 Heterostructure: Promoting Photocatalytic Degradation of Contaminants.

Constructing a heterostructure is regarded as one of the most favorable approaches to attaining the separation ability of photogenerated carriers and strengthening photocatalysis efficiency. In this study, a CdS/Bi2MoO6 type-II heterostructure was constructed through a hydrothermal technique. The photocatalytic test result shows that the degradation efficiency of rhodamine B (RhB) and tetracycline (TC) over CS/BMO-1 was 100 and 92% under visible light, respectively, which is the highest compared to other samples. The exceptional photocatalytic efficiency is principally associated with generating an inherent electric field within a type-II heterostructure, effectively restraining the recombination of photogenerated electron hole pairs. The intermediate products during the photocatalytic degradation of RhB and TC were identified through liquid chromatography-mass spectrometry, and the hypotheses were formulated regarding the corresponding photodegradation mechanisms. Furthermore, the outcomes of capture tests exhibited that the primary active species were •O2- and h+, and a mechanism of the photocatalytic degradation procedure has been proposed.

Dual-Enhancement Electrochemiluminescence Device for Ultratrace Uranium Visualized Monitoring in Fish, Hair, and Nail Samples.

Uranium is a nuclear fuel but also a hazardous contaminant due to its radioactivity and chemical toxicity. To prevent and mitigate its potential threat, the accurate monitoring of ultratrace uranium (orders of magnitude of pg g-1) in practical environmental samples has become an important scientific problem. To meet this challenge, we developed an efficient electrochemiluminescence (ECL) UO22+ detection device by a novel dual-enhancement mechanism. In detail, poly[(9,9-dioctylfuor-enyl-2,7-diyl)-alt-co-(1,4-benzo-{2,1,3}-thiadiazole)] polymer dots (Pdots) are modified by the UO22+ DNA aptamer, and rhodamine B (RhB) is combined with dsDNA to quench the ECL signal via a resonance energy transfer (RET) process. UO22+ can cut off the DNA aptamer to release RhB, which generates an ECL enhancement process, and then, UO22+ continuously combines with the DNA chain, inducing another ECL enhancement by the RET process from UO22+ to Pdots. This device achieves an ultralow detection limit (12 pg L-1) and a wide linear range (113 pg L-1-11.3 mg L-1), which can successfully give accurate determination results to the ultratrace uranium in biosamples (<1 pg g-1) to monitor the uranium simulation of fish. This work presents an efficient strategy for ultratrace uranium determination in the environment, highlighting its significance in public health and environmental fields.

Removal of Rhodamine-B dye from Aqueous Solutions Using Alkaline-Modified Activated Carbon from Cocoa Pod Husk.

Rhodamine-B (RhB) dye in wastewater poses health and environmental risks due to respiratory and eye infections, neurotoxicity, and carcinogenicity, necessitating proper disposal for risk mitigation. This study investigates RhB removal from water using NaOH-modified activated carbon derived from cocoa pod husk (CPHAC). Employing a face-centered central composite design, operational variables were optimized to achieve maximum RhB dye removal efficiency. The study reveals a removal efficiency of 98.87 ± 0.84% under optimized conditions: adsorbent dose of 1.34g, contact time of 71.59min, and an initial RhB concentration of 6.61 ppm. The Freundlich isotherm model demonstrated a good fit, suggesting that RhB removal is governed by heterogeneity and multilayer adsorption. Kinetic experiments revealed that adsorption follows a pseudo-second-order model, indicating likely irreversible adsorption with dye molecules forming chemical bonds on CPHAC's surface. Overall, this study demonstrates the effectiveness of CPHAC as an efficient adsorbent for RhB removal from water.

Utilization of photocatalytic degradation and efficiency of engineered geopolymer composite tile doped with nano-particles under ultraviolet light

This study investigates the impact of nano-zinc oxide (ZnO) on the self-cleaning and microstructural performance of engineered geopolymer composites (EGC) for urban cleanliness enhancement. The research focuses on achieving homogeneous dispersion of nano-ZnO through ultrasonication to prevent agglomeration and assess its effects on workability, setting time, mechanical, and microstructural properties of EGC. Results show that incorporating ZnO nanoparticles at 5 % and 10 % concentrations as a surface coating on engineered geopolymer composite creates a highly effective photocatalytic material. This enhanced composite demonstrates significant capability in degrading Rhodamine B (RhB) under UV light exposure over a 15-day period, breaking down organic pollutants into simpler, potentially less toxic substances. The efficiency of degradation depends on factors such as nano-ZnO concentration, UV radiation intensity, and initial pollutant concentration. The optimal dosage of nano-ZnO in EGC is found to be 0.5 %, which enhances hydration and pozzolanic activity, promoting a densified microstructure at the nanoscale. This innovative composite material shows promise as a self-cleaning finishing material for urban buildings, offering potential improvements in both aesthetics and environmental sustainability.

Highly efficient malachite green adsorption by bacterial cellulose and bacterial cellulose/locust bean gum composite

In this study, bacterial cellulose (BC) and BC/locust bean gum (LBG) composite produced from banana hydrolysate were both used as the adsorbent for various organic dyes adsorption especially for malachite green (MG) adsorption for the first time. The BC/LBG(2%) composite exhibited significantly enhanced swelling rate and textural characteristics while maintained the basic structure of BC as depicted by XRD, FT-IR, and NMR, providing a foundation for its application as an excellent adsorbent. The composite exhibited a high adsorption rate and adsorption capacity for MG (exceeding 95 % and 2000 mg/g), and had a good selectivity for MG adsorption in the solution containing crystal violet (CV), rhodamine B (RB), and methyl orange (MO). The MG adsorption process conformed to multiple models including Langmuir and pseudo-first-order models. And the adsorption mechanism mainly comprised chemical adsorption (hydrogen bonding and electrostatic interactions) and physical adsorption. The reusability of BC/LBG(2%) composite was attractive for industrial application that the MG adsorption rate reduced merely a little (still higher than 88 %) after the 5th regeneration process. Overall, considering its adsorption capacity, selectivity, and reusability, BC/LBG(2%) composite prepared by in-situ fermentation with LBG addition was a competent adsorbent for MG adsorption and MG containing wastewater treatment.