Organic Dyes Research Articles

Solvothermal synthesis, photoelectricity and photocatalysis of biselenide-containing selenidostannate hybrid with one-dimensional structure

A biselenide-containing selenidostannate hybrid with narrow band gap, [Ni(terpy)2]2[Sn3Se7][Sn3Se6(Se2)]·4H2O (1) (terpy = 2,2′:6′,2′’-terpyridine), was prepared using a Ni(II)-terpy complex cation as the template under solvothermal conditions. In 1, two SnSe5 PBUs and one SnSe4 PBU are joined through edge-sharing to form a Sn3Se9 SBU. The Sn3Se9 SBUs are connected into a 1-D [Sn3Se7]n2n− chain by sharing two Se atoms, while the Sn3Se7(Se2)2 SBUs are interlinked via the same conncetion mode to form a [Sn3Se6(Se2)]n2n− polyselenide chains containing biselenide ligands. Compound 1 exhibited sensitive photocurrent responses under Xe light irradiation, and had a steady current density of 6.88 μA·cm−2 under visible light irradiation at power of 150 W. Compound was photocatalytically active in the degradation of the organic dye crystal violet (CV) in aqueous solution at room temperature, and the degradation ratio of CV reached 93.8 % after 60 min of light irradiation. Radical quenching experiments showed that all the ∙O2− and ·OH radicals, and the photogenerated positive holes h+ were involved in the photodegradation of CV.

Solar light-mediated photocatalytic degradation of noxious organic dyes by Co2+ and Y3+ co-doped Ni0.6Mg0.4Fe2O4 spinel nanoferrites

Solar light-mediated photocatalytic degradation of noxious organic dyes by Co2+ and Y3+ co-doped Ni0.6Mg0.4Fe2O4 spinel nanoferrites

Innovative S-Scheme heterojunctions: Boosting methylene blue degradation and antimicrobial efficacy with Ni–CoS@S-g-C3N4

The release of waste, including organic dyes from various industries, directly into water bodies significantly contributes to environmental pollution. Consequently, there is a need for photocatalytic materials that can effectively remove harmful pollutants from water, ensuring its purity and safety. Carbon-based photocatalysts have garnered significant attention in this context because of their exceptional stability, high conductivity, and very small band gap. In the current project, a series of CoS, Ni–CoS, and Ni–CoS/S-g-C3N4 with different concentrations of S-g-C3N4 were synthesized using a simple, efficient, and cost-effective co-precipitation technique, while S-g-C3N4 was constructed through a thermal degradation process using thiourea as a precursor. The produced photocatalysts underwent characterization utilizing sophisticated analytical methods including FTIR, XRD, SEM, and EDX. The photocatalytic degradation behavior of the prepared photocatalysts was assessed using a UV–visible spectrophotometer, and the doping of Ni-metal was found to significantly enhance the degradation rate of methylene blue (MB), a standard pollutant dye in the order of CoS < %8Ni–CoS <8%Ni–CoS@50 % S-g-C3N4.the maximum photocatalytic degradation was shown by the nanocomposites (8%Ni–CoS@50 % S-g-C3N4) i.e. 94 %. The EIS spectra for CoS, 8 % Ni–CoS, and Ni–CoS/50 % SCN were analyzed, and their antimicrobial effectiveness was evaluated.

Green biosynthesis of silver nanoparticles using leaf extract of Ammannia baccifera for evaluating their antioxidant, antibacterial and catalytic potentials

The objective of this work is to create an easy, economical, and environmentally sustainable process for making silver nanoparticles (AB-AgNPs) by employing Ammannia baccifera leaf extract as a provider of reducing agents. A surface plasmon resonance (SPR) peak was observed at 413 nm in the UV–Vis absorption spectrum of AB-AgNPs, and it ensured the formation of nanoparticles. The unique bands in FTIR revealed the participation of phytochemicals with effective functional groups in the reduction and stabilization of AB-AgNPs. SEM revealed almost spherical-shaped AB-AgNPs, while EDX confirmed the presence of metallic silver with a strong signal at 3 eV. TEM further verified the formation of spherically-shaped AB-AgNPs, which ranged in size from 13 to 60 nm. The face-centered cubic (FCC) crystal structure of AB-AgNPs was confirmed by an XRD study. TGA, DLS, and Zeta potential studies also assured the stability and particle size distribution of AB-AgNPs. The DPPH and ABTS radicals were used to investigate the antioxidant activity of plant extract and AB-AgNPs, where the best performance of AB-AgNPs was observed in scavenging the ABTS radical with an EC50 value of 27.52 μg/mL. The green-produced AB-AgNPs showed strong catalytic activity for the breakdown of organic dyes (methylene blue, rhodamine B, and para-nitrophenol), and complete dye degradation was attained for each dye within 20 min. AB-AgNPs also showed efficient activity against Escherichia coli in antibacterial tests. These findings suggest that silver nanoparticles (AB-AgNPs) produced from the extract of Ammannia baccifera leaves, may find use in medicinal and environmental contexts.

Green-synthesized BiFeO3 nanoparticles for efficient photocatalytic degradation of organic dyes, antibiotic and catalytic reduction of 4-nitrophenol

Green-synthesized nanoparticles have recently emerged as promising catalysts for the removal of toxic dyes from water bodies. In this article, Bismuth ferrite (BiFeO3) nanoparticles were synthesized by a simple and low-cost method using Couroupita guianensis plant leaf extract. The particles were used as photocatalysts for degrading RhB, MO dyes, and TC antibiotics, as well as for reducing toxic 4-NP to useful 4-AP. The synthesized nanoparticles were characterized using several state-of-the-art tools. The formation of perovskite structure and the presence of biomolecules on the surface of BiFeO3 nanoparticles was confirmed by FTIR analysis. Raman spectrum revealed a rhombohedral structure of BiFeO3 nanoparticles, corroborating the XRD analysis. FESEM micrograph demonstrated irregularly shaped agglomerated nanoparticles. The average hydrodynamic diameter was estimated to be 51 nm using the DLS technique. The optical energy bandgap of the bismuth ferrite was estimated using Tauc’s relation for direct bandgap semiconductors. SQUID measurements revealed that these nanoparticles exhibit a weak ferromagnetic ordering. Furthermore, these nanomaterials degraded the cationic and anionic dyes effectively because of the formation of hydroxyl radicals, confirmed by the scavenger test. The photocatalytic degradation pathway of RhB dye was investigated through LC-MS analysis, and the intermediate degradation products were identified. The prepared material also exhibited excellent catalytic efficiency in a short duration of time. This study proclaims that these nanoparticles can be used as potential catalysts for the purification of water.

High sensitive synchrone detection based dynamic Sénarmont method for measurements of electro-optical (EO) Pockels and Kerr coefficients in hybrid nanocomposites films.

This study introduces an innovative approach by employing a highly sensitive synchronous detection-based dynamic Sénarmont method for the precise measurement of electro-optical (EO) Pockels and Kerr coefficients within hybrid nanocomposite films. The experimental setup integrates LabVIEW instrumentation software, ensuring accurate data acquisition. The EO-active film compositions encompass diverse polymer (PMMA) and organic dye combinations, including PMMA/organic dyes (DR1 and CPO), as well as PMMA combined with DR1-SiC, DR1-TiO2, and CPO-TiO2. Through meticulous experimentation and calibration of the Sénarmont setup, this research demonstrates exceptional sensitivity in evaluating EO parameters based on film composition. Notably, the study examines the impact of poling conditions, geometric configurations, and the influence of TiO2 nanoparticle integration on electro-optical behavior. The findings reveal distinctive electro-optical responses, highlighting the significant potential for tailored designs and practical applications in optimizing polymer nanocomposite electro-optical properties. Overall, this work offers valuable insights into refining measurement techniques and leveraging nanomaterials for enhanced electro-optical functionalities.

Degradation of organic dyes by Peroxymonosulfate activated with Zn/Co-ZIF

In this study, we successfully synthesized a bimetallic metal-organic framework material Zn/Co-ZIF to start Peroxymonosulfate (PMS) for organic dye degradation in the water body. Material characterization was evaluated by advanced methods, such as XRD, FT-IR, SEM, EDX, and BET. The influence of different factors on methylene blue (MB) decomposition rate was investigated. The results show that Zn/Co-ZIF has a porous structure, a high specific surface area and decomposes 98.22% MB (20 mg/L) in 4 minutes under reaction conditions of 40 mg/L catalyst, 0.814mM PMS, pH = 7. The decomposition efficiency of dyes increases in the order CR (79.85%) &lt;RhB (90.81 %) &lt; DB71 (96.07%) &lt; MO (97.63%) &lt; MB (98.22%). The main ROS for the degradation MB in this study were SO4—-, O2—- and 1O2. This shows that Zn/Co-ZIF materials are potential heterogeneous catalysts to activate PMS to decompose organic pollutants in water.

Needle Tip Tracking through Photoluminescence for Minimally Invasive Surgery.

Minimally invasive surgery continues to prioritize patient safety by improving imaging techniques and tumor detection methods. In this work, an all-optical alternative to the current image based techniques for in vitro minimally invasive procedures has been explored. The technique uses a highly fluorescent marker for the surgical needle to be tracked inside simulated tissues. A series of markers were explored including inorganic (Perovskite and PbS) and organic (carbon dots) nanoparticles and organic dye (Rhodamine 6G) to identify layers of different stiffnesses within a tissue. Rhodamine 6G was chosen based on its high fluorescence signal to track 3D position of a surgical needle in a tissue. The needle was tracked inside homogeneous and inhomogeneous gelatin tissues successfully. This exploratory study of tissue characterization and needle tip tracking using fluorescent markers or photoluminescence technique show potential for real-time application of robot-assisted needle insertions during in vivo procedures.

Optimal donor groups for novel organic dye “3-(5-(4-(diphenylamino)styryl)thiophen-2-yl)-2-cyanoacrylic acid” in the context of N‑type dye-sensitized solar cells: A theoretical investigation

Theoretical modeling using DFT and TDDFT methods explored optimal donor groups for the organic dye “3-(5-(4-(Diphenylamino)styryl)thiophen-2-yl)-2-cyanoacrylic Acid”. Seven different moieties and their derivatives mostly used as donors as obtained from the literature (methylamine, benzene, fluorene, carbazole, phenylaniline, indolizine and pyrrolizine) were investigated, and our calculations highlighted indolizine and pyrrolizine derivatives as the most effective donors among those studied. The strong push pull effect of such derivatives of indolizine and pyrrolizine groups played a role in enhancing the efficiency of the dye sensitizers.

Modification of poly (vinylidene fluoride-co-hexafluoropropylene) membranes by sulfonated poly (ether ether keton) coating for membrane distillation of textile wastewater

The textile and related industries can produce a large amount of wastewater with organic dyes pollutants which can cause uncertain environmental impacts. In this study, the improved poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) hollow fiber membranes were used in a continuous air gap membrane distillation (AGMD) operation for wastewater treatment of the Hamadan textile factory, Iran. The porous membranes were fabricated by a phase-inversion process and the inner surface was coated by a thin layer of sulfonated poly (ether ether keton) (SPEEK). After SPEEK coating, the water contact angle of the membrane decreased from about 93° to 57°. The SPEEK coated membrane presented mean pore size and overall porosity of 10 nm and 82.2%, respectively. For the wastewater treatment, the improved membrane presented the water flux and color rejection of 24.7 kg/m2 h and 99.8% during 72 h of the AGMD operation, respectively. Additionally, the treated wastewater reduced to the turbidity of ∼2 NTU, total dissolved solid (TDS) of 16 mg/L and chemical oxygen demand (COD) of 10 mg/L. The coated membrane presented a reasonable anti-fouling property with a flux recovery ratio (FRR) of 91.7% after 72 h of the operation. Hence, the improved PVDF-HFP membrane can be a potential alternative for the removal of organic dyes from wastewater via a membrane distillation process.

Zeolite-decorated black TiOx quantum dots for photocatalytic degradation of organic cationic dyes under LED light irradiation

Defect engineering is a promising strategy to reduce the band gap of semiconductors, enhancing their photocatalytic activity under visible light by introducing intra-bandgap energy states. Among the materials studied, oxygen-deficient black TiOx stands out due to its potential in photocatalytic reduction and hydrogen evolution. However, the valence band edge maximum (VBM) of TiOx is not thermodynamically favorable for the direct oxidation of water to hydroxyl radicals (H2O/•OH). Although the formation of extensive oxygen vacancies is necessary to extend the light absorption of black TiOx to longer wavelengths, a high density of oxygen vacancies (Ov) significantly shortens the diffusion length of charge carriers within the TiOx, leading to increased recombination of electrons and holes (e-/h+), thereby suppressing photocatalytic activity. To overcome these limitations, confining TiOx particles to the quantum dot (QD) size range and constructing heterojunctions with a secondary phase can substantially improve charge carrier separation and photocatalytic performance. In addition to engineering the electronic structure of composite photocatalysts, the preaccumulation of pollutants and their subsequent degradation is an effective strategy. This method decreases the distance between the adsorbed pollutant and the active sites for reactive oxygen species (ROSs) generation, enhancing the efficiency of the photocatalytic degradation process. In this study, we confined TiOx particles to the quantum dot size range by constructing a heterojunction with H-Beta zeolite, which contains defect-induced energy states within its wide band gap. This type of zeolite is particularly effective in adsorbing cationic azo dyes, facilitating pre-accumulation and degradation. The synthesized catalysts were extensively characterized using HRTEM to determine the average size of the TiOx particles and photoluminescence (PL) analysis to investigate charge carrier separation. Our results demonstrated that while TiOx alone showed negligible degradation efficiency, and no •OH were detected, the QD TiOx/Z4 composite achieved complete oxidation of CV by •OH, as confirmed by TOC analysis. The photocatalytic degradation mechanism was proposed based on these experimental findings. These insights could be of significant interest to researchers exploring defective semiconductors for photocatalytic oxidation of organic pollutants in the liquid phase under visible light (LED) irradiation.

Bionic solar-Driven interfacial evaporator for synergistic photothermal-Photocatalytic activities and salt collection during desalination

Solar-driven interfacial evaporation plays an essential part in the production of potable water. Nevertheless, the intricate water conditions in real-world scenarios continue to pose limitations on its utilization. This study prepared a novel bionic PPy/BiVO4-PI/MXene aerogel composite material with radial center structure through directional freezing as the evaporator, which integrates both photothermal and photocatalytic properties into the evaporation system. In order to evaluate the efficacy of photocatalytic degradation and salt collection during interfacial evaporation, high-concentration saline water, simulated seawater and dyeing wastewater were employed as substitutes for real contaminated water bodies. After being exposed to 1 kW/m−2(−|-) of irradiation, the PPy/BiVO4-PI/MXene composite exhibits an evaporation rate of 1.64 kg m-2h−1 and achieves a photothermal efficiency of 96.77 %. In high-concentration saltwater containing 20 wt% NaCl, the PPy/BiVO4-PI/MXene exhibited an evaporation rate of 1.32 kg m-2h−1 and a photothermal conversion efficiency of 77.41 %. Furthermore, approximately 26.7 g of salt can be collected after 15 days’ continuous evaporation. Furthermore, the PPy/BiVO4-PI/MXene demonstrated exceptional photocatalytic capabilities to organic dyes such as MB, RhB, CR and MG with removal efficiencies of 79.28 %, 70.96 %, 76.70 % and 80.95 %, respectively. This study realizes the synergistic effect of interfacial evaporation, photocatalysis and salt collection, providing a highly promising choice for the treatment of high-salt dyeing wastewaters.

Hydrothermally Synthesized TiO2-Doped MnO2 Nanocomposites for Electrochemical and Photocatalytic Activity

In our study, we synthesize titanium oxide (TiO[Formula: see text] and manganese dioxide (MnO[Formula: see text] using hydrothermal methods, which are TiO2-doped MnO2 nanoparticles. In order to evaluate the essential optical and electronic properties of the proposed nanostructures, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transformation infrared analysis (FTIR), Ultra–Visible infrared spectroscopy (UV–Vis), and Photoluminescence (PL) were applied. Based on the results of the SEM investigation, nanostructures form crystal structures when different compositions are used. It was also confirmed that TiO2 derivatives were produced from the fabricated nanoparticles by their spectral and optical absorption characteristics. During electrochemical measurements, it was found that MnO2 nanocomposite samples doped with TiO2 had a markedly reduced charge transfer resistance, suggesting that electrons and holes were effectively separated by photo-stimulation. Aqueous solutions based on wastewater were shown to be degraded by TiO2-doped MnO2 nanoparticles when irradiated with visible light. It was demonstrated that nanocomposites composed of TiO2-doped with MnO2 and having reduced bandgap could be used for the removal of organic dyes from aqueous solutions as well as wastewater treatment were reported in detail.

Tailoring of Zinc Oxide-based microstructures to efficiently promote piezocatalytic water oxidation and oxygen production

Two zinc oxide (ZnO) nanomaterials, exhibiting distinct morphologies, were synthesized in wurtzite phase through chemical precipitation. The elongated shape rod-like ZnO (R-ZnO) exhibited more pronounced piezoelectric characteristics compared to the more compact flower-like ZnO (F-ZnO). Detailed characterization including piezoforce microscopy, finite element simulation, revealed that the remarkable piezoelectric properties of R-ZnO are due to its strongly anisotropic structure, enabling significant mechanical deformation under ultrasound in aqueous suspension. The piezocatalytical degradation of these materials was assessed using methylene blue as a test organic dye across various ultrasound frequencies, with R-ZnO consistently outperforming F-ZnO. This highlighted the impact of structural deformability on piezocatalytic efficiency. Additionally, the capability of R-ZnO to facilitate oxygen evolution from water through ultrasound-induced stress was explored in an oxygen-free environment. Our findings demonstrate that R-ZnO can effectively catalyze water oxidation and produce oxygen directly, showcasing its potential as a standalone catalyst for environmental remediation and sustainable chemical processes.

Photocatalytic degradation of toxic organic dye (Methylene blue) using ZnO nanoparticles synthesized with petals extract of Rosa rubiginosa plant

Photocatalytic degradation of toxic organic dye (Methylene blue) using ZnO nanoparticles synthesized with petals extract of Rosa rubiginosa plant

Ultrahydrophilic Inorganic Nanosheet-Based Nanofiltration Membranes for High Efficiency Separations of Inorganic Salts and Organic Dyes.

Two-dimensional (2D) inorganic nanomaterials have garnered extensive attention in the fabrication of inorganic nanofiltration membranes due to their unique structures and properties. In this study, we developed a facile process for fabricating large-scale ultrahydrophilic nanofiltration membranes using layered titanate H1.07Ti1.73O4·nH2O nanosheets (HT-ns). A drying deposition process was used to fabricate HT-ns membranes on a poly(tetrafluoroethylene) (TF) substrate. To enhance the bonding strength between the substrate and the deposited HT-ns membrane, the substrate surface was modified with a Cu2+-adsorbed silane monomolecular layer, connecting a negatively charged HT-ns membrane and a positively charged substrate surface. The fabricated HT-ns membrane exhibited an excellent rejection performance for inorganic salts and dye molecules. The ultrahydrophilicity of HT-ns membrane with a low water contact angle of 31° results in an ultrafast water permeance, which is approximately 6 times higher than that of a simple graphene-based nanofiltration membrane. The results open a new avenue to a new category of ultrahydrophilic nanofiltration membranes.

High-permeance nanocellulose/ZnO hybrid membranes with photo-induced anti-fouling performance for wastewater purification

A hybrid ultrafiltration membrane based on nanocellulose and zinc oxide nanoparticles (ZnO NPs) was prepared by simple layered filtration without any chemical modification. Microscopic morphology analysis showed that the loading ZnO NPs significantly increased the membrane roughness, and wettability test demonstrated that the membrane surface possessed underwater superoleophobicity. Due to the “puncture effect” of the embedded ZnO NPs, abundant nanochannels were formed in the nanocellulose membrane and the highest water permeance of 5439.7 L·m−2·h−1·bar−1 was achieved. The hybrid membranes exhibited high rejection of nanoparticles larger than 20 nm and macromolecules with molecular weights higher than 100 kDa. Furthermore, ZnO NPs significantly improved the wet tensile strength of membrane. The hybrid membranes achieved high separation efficiency of nano-sized emulsions via size exclusion and demulsification effect, as well as the efficient removal of organic dyes and antibiotics via filtration-adsorption. The combination of underwater superoleophobicity and photocatalytic self-cleaning performance effectively solved the problem of a sharp decrease in permeance caused by oil contamination. This type of nanocellulose/ZnO hybrid membrane, which integrates high permeance, high filtration accuracy, and photocatalytic anti-fouling performance in one design, offers an innovative approach to the preparation of nanocellulose membranes for the treatment of organic wastewater.

The amalgamated impact of bimetals, amino groups, and cross-linked structures of MOF on MOF for the removal of cationic dyes

To protect the environment, it is important to develop effective materials/methods for eliminating or decomposing pollutants. Metal-organic frameworks (MOFs) have attracted considerable interest due to their special properties, including their exceptional porosity and customizable architecture, which make them highly adaptable for many applications. In this study, bimetallic (Ce/Zr) NH2-UiO-66@NH2-MIL-125 was prepared and characterized by, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric and BET analysis. The prepared bimetallic (Ce/Zr) NH2-UiO-66@NH2-MIL-125 served as a potent adsorbent for the efficient removal of cationic dyes via electrostatic, hydrogen bonding, ionic bonding, and π–π stacking. The adsorption of RhB and MB dyes by bimetallic (Ce/Zr) NH2-UiO-66@NH2-MIL-125 includes both isothermal and kinetic studies. The equilibrium adsorption data was found to conform to the Langmuir isotherm, whereas the kinetic adsorption process followed a pseudo-second-order model. The cross-linked structure of MOF on MOF enhances the stability of the adsorbent, and has the potential to efficiently adsorb and release organic dyes over multiple cycles. The aforementioned interactions as well as stability and reusability make the bimetallic (Ce/Zr) NH2-UiO-66@NH2-MIL-125 one of the most promising adsorbent for the removal of dyes from water.

Effects of UV illumination on organic dye decomposition activity and antibacterial and antiviral activities of rare earth iodates

For this study, we investigated the effects of UV illumination on dye decomposition and antibacterial and antiviral activities of three rare earth iodates (Ce(IO3)4, Ce(IO3)3, and δ-La(IO3)3) that reportedly have antibacterial and antiviral activities in the dark. The objective of this study was to clarify whether bulk materials and eluted ions are involved in these activities under UV illumination. Findings indicate that Ce(IO3)3 and δ-La(IO3)3 exhibit dye degradation activity under UV illumination by a Hg-Xe lamp (7 mW/cm2), suggesting that the dye decomposition activity was caused mainly by photochemical reactions under UV with wavelengths less than 300 nm by Ce3+ and by IO3− ions eluted from the samples. The dye decomposition activity under UV illumination is expressed not only from the eluted ions but also from the bulk materials. UV illumination using a weak (0.1 mW/cm2) UV light from a black light bulb with wavelengths longer than 320 nm increased the antibacterial and antiviral activities of these materials. These results suggest that the increase in antibacterial and antiviral activities is attributable to the photocatalytic reaction of bulk materials. This study revealed that both the bulk and eluted ions are involved in these activities under UV illumination. The extent to which photochemical reactions caused by eluted ions and bulk material contribute to the decomposition activity of organic dyes and antibacterial and antiviral activities depends on the UV illumination wavelength and intensity. This study provides new insights into the use of rare earth iodates as inorganic antibacterial and antiviral materials.Graphical abstract

Efficient degradation of methylene blue and HCHO by nonmetallic B-doped g-C3N5: activity and mechanism analysis

To solve the pollution of natural water bodies by organic dyes and the exceeding of indoor HCHO standards caused by renovation, the study realized the band gap modulation of g-C3N5, a novel semiconductor photocatalytic material, by using H3BO3 as a source of nonmetallic B. The prepared B/g-C3N5 has shown excellent photocatalytic performance and stability for organic dye degradation in water bodies and indoor HCHO removal. The degradation rate of methylene blue (MB) reached 95% in 60 min of visible light, and the removal rate of HCHO reached 96.3% in 180 min of visible light. The MB and HCHO were efficiently degraded to small molecule inorganic compounds such as CO2 and H2O under the oxidation of active groups such as ·O2 − and h+. The doping of nonmetallic B realizes the efficient separation of e−-h+ of g-C3N5, improve the absorption performance of visible light, and broaden the spectral range significantly. The modulation of the g-C3N5 band gap provides a potential application scenario for the development of novel photocatalytic materials.