Organic Dyes Research Articles

Novel green synthesis approach of eco-friendly magnetic/semiconductor nanocomposites as magnetically separable and reusable photocatalyst for organic dye degradation

Eco-friendly and effective separation of photocatalytic nanoparticles from the reaction mixture is crucial to facilitate their repeated use in photocatalysis. The development of magnetic/semiconductor nanocomposites with high catalytic performance and easy separation is an efficient strategy for wastewater treatments. In this study, we explore the potential of combination of magnetic (CoFe2O4) and semiconductor (ZnS) synthesized via a green approach using Moringa oleifera leaf extract as magnetically separable photocatalysts for dye degradation. X-ray diffraction analysis confirmed the presence of the cubic spinel ferrite phase of CoFe2O4 and the cubic zinc blend phase of ZnS within the nanocomposites. The micrographs illustrated nearly spherical nanoparticles with average particle sizes of 12 nm for CoFe2O4 and 26 nm for CoFe2O4/ZnS, respectively. The presence of SO suggested the incorporation of ZnS on the surface of CoFe2O4/ZnS nanocomposites. The UV–visible spectra revealed an increase in the band gap energy from 3.7 to 4.5 eV with increasing ZnS concentrations. Magnetic properties analysis signified that the CoFe2O4/ZnS nanocomposites exhibited ferromagnetic characteristics. The optimal degradation efficiency of photodegradation methylene blue was observed for CoFe2O4/ZnS 50 %, achieving 78.3 % degradation within 80 min with intervals 20 min. The magnetically separable capability allows for the recycling of nanocomposites after three consecutive cycles. Therefore, CoFe2O4/ZnS nanocomposites emerge as promising candidates as separable photocatalysts for the removal of organic pollutants in environments.

High-capacity adsorption of organic dyes using separable pullulan gel encapsulated with PDA-modified ZIF-8

In this investigation, a hydrogel adsorbent featuring remarkable efficiency in dye adsorption was successfully synthesized by the integration of natural polysaccharide (pullulan) and nanoparticles (ZIF-8@PDA). The prepared natural polysaccharide nanocomposite hydrogels not only exhibit superior mechanical strength and biocompatibility, but also demonstrate adeptness in the removal of dye pollutants. The dye removal capacities were 615.4 mg/g for malachite green (MG) and 525.8 mg/g for Congo red (CR), respectively. Notably, the adsorption process exhibits minimal susceptibility to variations in water quality and the presence of co-existing ions. The pH-responsive surface charge conversion capability of the adsorbent renders it recyclable, maintaining a dye adsorption performance exceeding 88 % even after 5 cycles of repeated usage. Overall, these environmentally friendly natural polysaccharide nanocomposite hydrogels hold potential for addressing complex wastewater treatment challenges and long-term use.

Self-Assembly of Polynuclear Coordination Cage and Organic Dyes Adsorption Behavior in Water

Self-Assembly of Polynuclear Coordination Cage and Organic Dyes Adsorption Behavior in Water

Adsorption of crystal violet dye with selenium nanoparticles obtained by green synthesis from cherry (Prunus avium L.) fruit stalk

Crystal violet (CV) dye is a water-soluble, toxic, resistant organic dye that is quite dangerous for the ecosystem and causes environmental pollution. This study synthesized selenium nanoparticles (Se NPs) from agricultural Prunus avium L. (PaL.) wastes and removed crystal violet (CV) dye. In batch adsorption tests, the effects of pH, amount of adsorbent, time, initial concentration, and temperature were investigated. In this study, where 3 different kinetic and isotherm models were tested, it was determined that the most suitable kinetic and isotherm models for the removal of CV dye with PaL-Se NPs were Pseudo second order (R2:0.999) and Langmuir (R2:0.997), respectively. Additionally, the maximum adsorption capacity (qmax) was calculated as 142.61 mgCV/g PaL-Se NP. Accordingly, it can be said that low-cost PaL-Se NPs synthesized by environmentally friendly methods are a suitable alternative for the removal of CV dye.

PCN-222/H3PW12O40/graphene oxide@cotton cloth with improved photocatalytic/photothermal properties for water decontamination

In this study, a novel visible-light-driven PCN-222/H3PW12O40/graphene oxide@cotton cloth (PCN-222/HPW/GO@Cot) photocatalytic platform was developed for efficient water sterilization and purification. PCN-222/HPW/GO ternary photocatalyst was prepared via one-pot solvothermal method, and anchored onto cotton cloth though catechol-amine reaction. By introducing HPW as the quasi-semiconductor co-catalyst and efficient electron trap, the photocatalytic activity of PCN-222 was boosted. Besides, the addition of GO further enhanced electron transfer capability and photothermal properties. PCN-222/HPW/GO@Cot exhibited significantly improved organic dye photodegradation and sterilization efficiencies compared to PCN-222 and PCN-222/HPW coated cotton cloths. It also maintained consistent organic dye removal efficiency over reuse cycles and retained high sterilization activity after repeated washings, indicating its remarkable durability and coating stability. The band positions and the enhanced photocatalytic/photothermal mechanisms were investigated in depth. This research suggests the great potential of PCN-222/HPW/GO@Cot photocatalytic platform for practical water purification and sterilization applications, and the potential to become multifunctional textiles.

Comparative Evaluation of Fenton and Persulfate Processes with UV/H2O2 for Batik Wastewater Treatment: Optimizing Fe2+ and S2O8 2- Ratio by H2O2 for Enhanced Pollutant Degradation

Wastewater generated from industrial processes including the batik industry in Indonesia contains high organic pollutants and dyes. In this study, the advanced oxidation process that will produce hydroxyl radicals was used to degrade pollutants in this batik industry wastewater. This study aims to compare the Fenton and Persulfate processes with the influence of variations in the concentration of Fe2+ and S2O8 2- added. This method is carried out by adding H2O2 as an oxidant which is added to each catalyst, namely Fe2+ and S2O8 2- in the presence of a combination of UV light. Fenton process was carried out in 60 minutes and Persulfate process was carried out in 45 minutes. In this study, there was a tendency to increase the efficiency of COD and color removal along with the increasing concentration of each catalyst added. The highest COD and color removal efficiency occurred at a ratio of H2O2:Fe2+ and H2O2: S2O8 2- of 1: 0.08.

Removal of Organic Dye by Ti-Doped Bi2O3/MMT with Enhanced Visible-Light Photocatalytic Activity

Removal of Organic Dye by Ti-Doped Bi2O3/MMT with Enhanced Visible-Light Photocatalytic Activity

Early Detection and Noninvasive Staging of Kidney Dysfunction by a PEGylated Conventional Fluorophore via GFR-Sensitive Renal Transport.

Noninvasive fluorescence imaging of renal function is a valuable technique for understanding kidney disease progression and the development of renal medicine. This technique requires sensitive imaging probes for reporting renal dysfunction accurately at early stage. Herein, a molecularly engineered imaging probe (800CW-PEG45-COOH) was synthesized by simply PEGylating conventional near-infrared fluorophore IRDye800CW with NH2-PEG45-COOH (molecular weight ∼2100 Da) for early detection and staging of renal dysfunction through noninvasive real-time kidney imaging. 800CW-PEG45-COOH not only cleared through the kidney efficiently (>90% injection dosage at 24 h postinjection) but was also found to be freely filtered by glomeruli without renal tubular reabsorption and secretion. Despite this simple construction strategy, the transport of 800CW-PEG45-COOH within the kidneys was extremely sensitive to the alteration of the glomerular filtration rate (GFR), which enabled it to detect renal dysfunction much earlier than commonly used serum biomarkers and stage kidney function impairments (mild vs severe dysfunction) via imaging-based kidney clearance kinetics. This work not only provides a promising optical imaging probe for the noninvasive evaluation of kidney function but also highlights the utility of PEGylation in enhancing the performance of conventional organic dyes in biomedical applications.

Temperature-Sensitive Template for Preparation of ZnO/CeO2 Composite Photocatalytic Materials and Its Catalytic Performance.

In this work, a series of thermosensitive ionic liquid functionalized polymers, PNx(IL)y, with controllable morphology and particle size were prepared by free radical polymerization. Then, using the polymer PN64(IL)8 with uniform morphology as a templating agent, the ZnO composite photocatalytic materials doped with rare earth metal Ce were prepared in combination with a microwave-assisted and templated hydrothermal reaction method. Series different Ce-doping amount photocatalytic materials ZnO-Ce-x‱ were characterized by XRD, SEM, TEM, XPS, and other methods. The results demonstrated that the templated materials PN64(IL)8 can prepare ZnO-Ce-2‱ with uniform petaloid ambulacra shape, good distribution of elements, and excellent photocatalytic performance. Photocatalytic degradation experiments of methyl orange (MO) showed that when the Ce-doping amount is only 2‱, the degradation rate of organic dyes can reach 96.5% by reacting the photocatalytic materials in water for 1 h. In addition, this kind of photocatalyst can be used for the degradation of high-concentration MO, as well as being easily recovered and effectively reused by simple filtration. Therefore, the structure of this kind of photocatalyst is controllable in the preparation process with an extremely low Ce-doping amount compared with current reports, and it has a good application prospect in the field of wastewater treatment technology.

Evaluation of NiO nanoparticles infused Lup@CS nanocomposites for the degradation of Acridine orange and rose Bengal dyes

One of the most critical issues facing the globe today is the lack of readily available potable water, and scientists have made significant progress toward a solution. Compared to traditional treatment methods, nanotechnology-treated water is preferable because it eliminates dangerous microorganisms and organic pigments. In this study, we have fabricated Nickel Oxide - Lupeol loaded chitosan Nanoparticle (Lup@CS-NiO) nanocomposite via ionic gelation method and this nanocomposite was subjected to various characterization, that includes FTIR, FESEM, EDX, XRD, XPS, and UV–Vis to gain more information about the synthesized nanocomposite. We used visible light irradiation to examine the photodegradation of two organic dyes, Acridine Orange (AO) and Rose Bengal (RB), to determine how well the NiO/Lup@CS nanocomposites worked. The NiO/Lup@CS nanocomposites showed remarkable photocatalytic activity, long-term stability, and the rapid degradation of the dye solution to 85.98% (AO) and 86.46% (RB) in only 60 min. When compared to pure NiO nanoparticles, the degrading efficiency of the NiO/Lup@CS nanocomposites was much higher. In visible light irradiation studies using trapping, the reactive oxidative species involved in the photocatalytic process include superoxide radical anion (O2 radical) and OH radical. The photocatalyst was able to attain a 100% recovery rate by a simple hand-picking method, and it remained stable even after three uses. The study introduces a new Lup@CS nanocomposite that is loaded with NiO nanoparticles. It shows great effectiveness in breaking down the Acridine Orange and Rose Bengal dyes. The innovation's potential environmental effect is underscored by the fact that it provides a viable alternative for wastewater treatment.

Dyeing of wooden parts with organic dyes by boiling together method

Dyeing of wooden parts with organic dyes by boiling together method

Adsorption-desorption behavior of malachite green on aged microplastics in seawater environment

The role of microplastics (MPs) as carriers of contaminants in the water environment is an emerging concern, significantly impacting migration and transformation. This study aims to compare the adsorption behavior of MPs with Malachite green (MG) dye before and after simulated short-term seawater aging (especially during the initial phase of the aging process) and to analyze in-depth the mechanism by which the aging process influences adsorption behavior. Results showed that after aging, the adsorption capacities of Polypropylene (PP), Polyethylene terephthalate (PET), and Polyethylene (PE) for MG were 2.58, 2.43, and 1.59 mg g−1, respectively. The adsorption capacity of other MPs for MG increased significantly, except for PE, which remained nearly unchanged. Calcium chloride (CaCl2) plays a significant role in the seawater aging process, and increasing the concentration of CaCl2 leads to a decrease in the adsorption amount of MG. Additionally, the adsorption capacity for MG varies significantly across different particle sizes and types of MPs, as well as the adsorption capacity of PP for different dyes. The Langmuir and Freundlich models indicate that the adsorption aligns more with the Freundlich model, which suggests that adsorption primarily occurs as multi-layer adsorption on a non-homogeneous surface. These results provide a scientific foundation for evaluating the ecological and environmental risks when MPs and organic dyes coexist. We also propose a novel approach of “treating waste dye with MPs” to mitigate their pollution in the aquatic environment.

Modifying Parallel Excitations into One Framework for C(sp3)─H Bond Activation with Energy Combined More Than Two Photons.

Natural photosynthesis enzymesutilize energies of several photons for challenging oxidation of water, whereas artificial photo-catalysis typically involves only single-photon excitation. Herein, a multiphoton excitation strategy is reported that combines parallel photo-excitations with a photoinduced electron transfer process for the activation of C(sp3)─H bonds, including methane. The metal-organic framework Fe3-MOF is designed to consolidate 4,4',4″-nitrilotrisbenzoic units for the photoactivation of dioxygen and trinuclear iron clusters as the HAT precursor for photoactivating alkanes. Under visible light irradiation, the dyes and iron clusters absorbed parallel photons simultaneously to reach their excited states, respectively, generating 1O2 via energy transfer and chlorine radical via ligand-to-metal charge transfer. The further excitation of organic dyes leads to the reduction of 1O2 into O2 •- through a photoinduced electron transfer, guaranteeing an extra multiphoton oxygen activation manner. The chlorine radical abstracts a hydrogen atom from alkanes, generating the carbon radical for further oxidation transformation. Accordingly, the total oxidation conversion of alkane utilizing three photoexcitation processes combines the energies of more than two photons. This new platform synergistically combines a consecutive excited photoredox organic dye and a HAT catalyst to combine the energies of more than two photons, providing a promising multiphoton catalysis strategy under energy saving, and high efficiency.

Fluorescent covalent organic framework as an ultrasensitive fluorescent probe for tyrosinase activity monitoring and inhibitor screening

BackgroundAs a significant biomarker of melanocytic lesions, tyrosinase (TYR) plays an essential role in the clinical diagnosis and treatment of melanin-related diseases. Thus, it is important to develop robust methods for assessing TYR activity. Covalent organic frameworks (COFs) have garnered considerable attention owing to their unique properties, including high chemical stability, good biocompatibility, and large surface area compared with organic dyes, noble metal nanoclusters, and semiconductor quantum dots. However, most COFs are insoluble in water and exhibit weak or no fluorescence emission. Therefore, the development of a water-soluble fluorescent COF for detecting TYR activity in biological samples remains highly desired. ResultsIn this work, a sensitive and facile fluorometric method based on fluorescent COF was constructed for the detection of TYR activity in human serum samples. The water-soluble COF was fabricated through the condensation polymerization of 4′,4‴,4′′′′′,4′′′′′′′-(1,2-ethene-diylidene) tetrakis [1,1′-biphenyl]-4-carboxaldehyde and 2,4,6-tris-(4-aminophenyl)-triazine. The resulting COF displayed yellow-green fluorescence with a maximum emission peak at 560 nm. Tyrosine was catalyzed by TYR to produce melanin-like polymers which formed a coating on the surface of COF and effectively quenched its fluorescence due to fluorescence resonance energy transfer. The proposed approach demonstrated a strong linear correlation in the range of 0.5–80 U/L with a low detection limit of 0.09 U/L. Additionally, the limit of detection for kojic acid, serving as a representative TYR inhibitor, was determined to be 0.0004 μg/mL. SignificanceOur proposed fluorometric sensing platform exhibited exceptional selectivity, sensitivity, and satisfactory recoveries in human serum samples, which is of paramount importance for the clinical diagnostics of melanin-related diseases. Furthermore, the proposed approach was further employed for the screening of TYR inhibitors, suggesting the potential applications in clinical treatment and pharmaceutical research.

A green approach: Cinnamomum tamala-functionalized ZnO nanoparticles for efficient degradation of organic dyes

A green approach: Cinnamomum tamala-functionalized ZnO nanoparticles for efficient degradation of organic dyes

Enhanced catalytic reduction of 4-nitrophenol using bimetallic MOFs: a one-pot synthesis approach

ABSTRACT Several organic pollutants can harm the environment and human health. A typical environmentally toxic contaminant, 4-Nitrophenol (4-NP), may cause serious health issues. Therefore, catalytic reduction (hydrogenation) of 4-nitrophenol into less toxic 4-aminophenol (4-AP) is mostly preferred. A three-dimensional (3D) metal-organic framework of Ni-MOF-74 is mostly used which contains maximum unsaturated metal sites and the catalytic activity is enhanced due to partial exchange at the node position in MOF. In order to study the catalytic hydrogenation/reduction of organic dye, 4-nitrophenol as a model reaction, a bimetallic MOF, FeNi-MOF-74 was prepared by partially substituting Ni with Fe metal. The catalyst was synthesised using a one-pot solvothermal technique, and 4-nitrophenol was then reduced catalytically in aqueous media. For the reduction of nitrophenol, the FeNi-MOF-74 catalyst surpassed Ni-MOF (9.3 × 10−3 s−1) and Fe-MOF (5.4 × 10−3 s−1) with a lower reduction time and a higher rate constant; (1.6 × 10−2 s−1). The high conversion rate and economical induction time are attributed to the bimetallic synergistic effect.

Fabrication of Ag-doped BiOF-reduced graphene oxide composites for photocatalytic elimination of organic dyes

Bismuth oxyfluoride (BiOF) is an emerging class of material with notable chemical stability, unique layered structure and striking energy band structure. Bi-based semiconductor materials and reduced graphene oxides (rGOs) have attracted considerable attention due to their broad spectrum of potential applications. Herein, we successfully synthesised an efficient photocatalyst comprising BiOF–rGO nanocomposites with embedded Ag nanoparticles using a simple hydrothermal method. The synthesised nanocomposites were characterised through Fourier-transform infrared spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy and ultraviolet (UV)–visible spectroscopy. The XRD results indicated the crystalline structures of the BiOF, Ag-doped BiOF and Ag-doped BiOF–rGO composites. Photocatalytic activity assessments focused on the degradation of methylene blue (MB) and methyl orange (MO) dyes under UV-light and sunlight irradiation. The Ag-doped BiOF–rGO composite exhibited significantly enhanced degradation efficiency, achieving 61.81 % and 74.25 % degradation of MB and MO, respectively, after 300 min under UV-light irradiation. On the contrary, pure BiOF demonstrated only 17.63 % and 48.29 % degradation for MB and MO, respectively, under similar conditions. Furthermore, under sunlight irradiation, the Ag-doped BiOF–rGO composite exhibited an MB removal efficiency of 43.87 % after 300 min, whereas pure BiOF showed only 27.47 % under identical conditions. These results underscore the potential of Ag-doped BiOF–rGO composites as highly efficient and adaptable photocatalysts for the photodegradation of organic dyes in industrial wastewater.

Peptide-IR820 Conjugate: A Promising Strategy for Efficient Vascular Disruption and Hypoxia Induction in Melanoma.

Photothermal therapy (PTT) has emerged as a noninvasive and precise cancer treatment modality known for its high selectivity and lack of drug resistance. However, the clinical translation of many PTT agents is hindered by the limited biodegradability of inorganic nanoparticles and the instability of organic dyes. In this study, a peptide conjugate, IR820-Cys-Trp-Glu-Trp-Thr-Trp-Tyr (IR820-C), was designed to self-assemble into nanoparticles for both potent PTT and vascular disruption in melanoma treatment. When co-assembled with the poorly soluble vascular disrupting agent (VDA) combretastatin A4 (CA4), the resulting nanoparticles (IR820-C@CA4 NPs) accumulate efficiently in tumors, activate systemic antitumor immune responses, and effectively ablate melanoma with a single treatment and near-infrared irradiation, as confirmed by our in vivo experiments. Furthermore, by exploiting the resulting tumor hypoxia, we subsequently administered the hypoxia-activated prodrug tirapazamine (TPZ) to capitalize on the created microenvironment, thereby boosting therapeutic efficacy and antimetastatic potential. This study showcases the potential of short-peptide-based nanocarriers for the design and development of stable and efficient photothermal platforms. The multifaceted therapeutic strategy, which merges photothermal ablation with vascular disruption and hypoxia-activated chemotherapy, holds great promise for advancing the efficacy and scope of cancer treatment modalities.

Synthesis of CoMnFe2O4 hollow microstructure decorated GO for photocatalytic degradation of organic dyes

Over the past decade, safeguarding marine life and aquatic ecosystems against deleterious dye pollutants has emerged as a paramount concern. Methylene blue dye stands out as one such pollutant capable of inflicting irreversible damage to marine ecosystems even at minute concentrations. Addressing this pressing issue, we synthesized a novel CoMnFe2O4/graphene oxide nanocomposite employing a microwave-ultrasonic method. This composite, comprising soft superparamagnetic CoMnFe2O4 hollow microstructures integrated onto graphene oxide surfaces, revealed a mesoporous structure with a notably high surface area, which was about 96.4654 m2.g−1. Various analytical techniques were employed to scrutinize the crystal structure, functional groups, surface chemical composition, and morphologies of the synthesized CoMnFe2O4/graphene oxide nanocomposite (X-ray diffraction, Fourier-Transform Infrared Spectroscopy, energy-dispersive X-ray spectroscopy, field emission scanning electron microscopy, and high-resolution transmission electron microscopy). The CoMnFe2O4 crystal phase appears to be cubic in the X-ray diffraction with a 28.91 nm Avg. crystallite size. The measured band gap energies for the CoMnFe2O4, graphene oxide, and CoMnFe2O4/graphene oxide nanocomposite are 2.23 eV, 2.90 eV, and 1.89 eV, respectively. Remarkably, under visible light irradiation, the nanocomposite exhibited an impressive degradation efficiency of 97.54 % within just fifty minutes (at pH = 7, Methylene blue conc. = 15 mg/L, and catalyst dose = 0.05 g.), attributed to a photo degradation rate constant (k value) reaching 0.07330 min−1. Notably, this efficiency nearly doubled with the introduction of H2O2 peroxide. The outstanding recyclability of the CoMnFe2O4/graphene oxide nanocomposite, sustaining optimal performance over four cycles without significant degradation, underscores its potential for long-term environmental remediation efforts. Moreover, its magnetic extractability from contaminated solutions enhances its suitability for advanced environmental applications.

Exploring the hetero-catalytic proficiencies of pristine and carbon-doped titania nanocatalysts in dye degradation and their synergetic profiles against bacteria

Herein, carbon-doped titania nanostructures (C/TNTs) were prepared via a facile hydrothermal route using different carbon sources, i.e., carbon sheets (CSs), acetylene black (AB), graphene oxide (GO), and reduced graphene oxide (rGO), as doping agents. The morphological characteristics, crystalline nature, nanometric size, and phase purity were determined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and powder X-ray diffraction (XRD), which revealed a tube-like morphology with a ∼30 nm size, anatase nature, and titanium-oxygen structure, respectively. The as-synthesized nanostructured materials were investigated as photocatalysts under sunlight irradiation for the degradation of methylene blue (MB), a model dye, and for the inactivation of Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive), which are representative microorganisms. Compared with that of a bare titania nanocatalyst (60 %), the photocatalytic degradation efficiency of the as-prepared C/TNT nanostructures was remarkably high (approximately 74 to 94 %) when utilizing a 10 mg of catalyst under sunlight for 40 min. Moreover, these nanocatalysts exhibit exceptional antibacterial properties by restraining the growth of bacteria. The antibacterial analysis demonstrated that the C/TNT nanocatalysts had a significant impact on all bacteria as opposed to bare TNTs. These results revealed that doping with carbon enhanced the photocatalytic activity of TNTs under sunlight irradiation against MB dye as well as selected microbes, especially the rGO/TNT nanocatalyst, which exhibited superior photocatalytic and antibacterial activity. In addition, the rGO/TNTs have good recycling ability, with an MB degradation ratio of more than 81 % after five cycles. We hope that this high activity of the C/TNT nanocatalyst under sunlight irradiation for organic dye degradation and bacterial inactivation implies that hydrothermal synthesis allows for the preparation of efficient and low-cost carbon-doped photocatalysts for a wide range of environmental applications.