Crystal Dye Research Articles

Industrial dye effluent degradation and in-vitro biological characteristics of MgO NPs anchored few layered g-C3N4 nanoribbons

In recent years, contaminated water consumption by humans and animals are lead to various types of diseases and environmental pollutant. Especially textile dye effluents are the highest contaminants in water bodies than any other industries. This article reports a green process for synthesizing MgO nanoparticles supported by the exfoliated g-C3N4 nano composites for dye effluent treatment. The cubic and hexagonal phase structure was achieved for synthesized MgO NPs and E-GCN, respectively, with spherical and curled ribbon-like morphology. The specific surface area was measured as 70.48, 54.22, and 79.11 m2/g, respectively, for MgO NPs, E-GCN, and MgO/E-GCN nanocomposite. Similarly, corresponding optical properties were achieved with an energy gap of 3.42, 2.48, and 2.78 eV. XPS analysis confirms the formation of MgO/E-GCN nanocomposite by detecting their characteristic elemental peaks. The bioactivities including antibacterial, turbidimetric, and antioxidant efficacy, were also investigated. Thus, the MgO/E-GCN nanocomposites was exhibitd greater susceptibility against pathogenic bacteria due to its production of high reactive oxygen species. Further, the catalysts were used to degrade cationic dye (Crystal Violet) and anionic dye (Eosin Yellow) under sunlight exposure. The photocatalytic efficiency of MgO/E-GCN nanocomposite was highly influenced towards CV (98.9 %) and EY (97.33 %) dye degradation, because of its high surface area with active UV–Visible region. Therefore, the combination of naturally inspired MgO NPs and morphologically modified E-GCN nanocomposites are being a sustainable material development for environmental remediation and biological applications.

Impurity retention and pharmaceutical solid solutions: visualizing the effect of impurities on dissolution and growth using dyed crystals

Anisotropic incorporation of lattice impurities in acetaminophen crystals leads to anisotropic dissolution behaviors, increased drug solubility, and increased crystal fragility.

A method to improve dye-uptakes of less soluble disperse dyes for polyester fibers in supercritical CO2 fluid: A theoretical and experimental study

Two organic small molecules were used as assist-dissolving agents to increase the solubility of some dyes in ScCO2. Theoretical calculations showed that nicotinamide was better than benzoic acid. AIM and IGMH methods confirmed the hydrogen bonding and π-π stacking interactions between the agents and dyes. The mixtures of agents and dyes were made by the physical grinding and mixing method, and their solubilities and melting points were tested. The results indicated that the agents reduced the intermolecular forces in the dye crystals, thus enhancing the dye solubility in ScCO2. The dyeing experiment also proved the improvement of dyeing performance by the agents. The dye uptake increased from 20%∼30% to 60%∼70%, and the color intensity of the fibers improved. The best operating parameters were a temperature of 130 ℃ and a pressure of 28 MPa. The hue and color fastness of the dyed products were similar to those dyed with pure dyes.

Electrically tunable thermoresponsive optic switch for smart window application based on dye-doped cholesteric liquid crystal

We demonstrate a cholesteric liquid crystal (CLC) smart window that functions as a reversible thermo-optic switch between a transparent state at a low temperature and a low-transmission state at a higher temperature. This smart window is based on the addition of a thermoresponsive handedness-reversible chiral dopant in a mixture of a typical chiral dopant, a dichroic dye and nematic liquid crystal, yielding a thermosensitized CLC. In such a homeotropically anchored dye-doped CLC, the thickness-to-pitch ratio increases as the temperature rises, causing the device to switch from the homeotropic texture to the fingerprint texture. The absorption characteristic of the dichroic dye enables the homeotropic and fingerprint configurations in the dye-doped CLC to create two distinct transmission levels—the transparent and opaque optically stable states, respectively. Such a switching mechanism entails no additional electric power and, thus, is energy-saving. Moreover, the switching temperature at which the texture transition takes place can be actively increased by increasing voltage for the smart window. This allows the CLC device to be perfectly adaptable to the need of a user and, in turn, applicable to a wider variety of environments.

Electroluminescence in rare-earth doped n-InSe crystal promising for optoelectronics

n-InSe single crystals were grown by the Bridgman method. Electroluminescence in undoped and rare-earth-doped (Dy and Er) crystals has been experimentally studied. It has been established that in both groups of crystals, electroluminescence is observed at [Formula: see text] 160–165[Formula: see text]K in the wavelength range [Formula: see text]–1.150[Formula: see text][Formula: see text]m, regardless of the values of initial dark resistivity ([Formula: see text]) and concentration (N). The volt-brightness characteristics and the dependence of brightness on the current strength have been investigated. It was found that the brightness also depends on the values of initial dark resistivity and concentration of the impurities. The highest luminescence brightness and the most stable and reproducible characteristics of electroluminescence are observed in doped crystals. The features of electroluminescence in undoped and rare-earth-doped crystals obey the criteria of theoretical concepts developed for spatially homogeneous crystalline semiconductors. All experiments were comparatively performed for both undoped and rare-earth-doped crystals.

Controlled reversible single-molecule white-light emission from keto-enol interconversion of β-diketone dyes

New pyrene-based β-diketone dyes were synthesized. Pure β-diketone ketonic and enolic form dyes were prepared, where ketonic form dyes were obtained under basic solvent condition, and enolic form dyes were obtained by recrystallization. High-quality, green-light emitting single crystals of an enolic form dye were prepared. X-ray single crystal diffraction results reveal intramolecular H-bond-connected, bent-shaped π-system structure of an enolic form dye. π-Stacking-driven supramolecular polymer single crystals were formed from an enolic dye. Exceptional single-molecule single component white-light emission was achieved from a β-diketone ketonic form dye. Ketonic white-light emission and enolic green-light emission could be reversibly interconverted. White-light emission of ketonic dye solution shows a transient state light-emitting color change upon excitation by pulse light.

Reflection-influenced circularly polarised luminescence in dye-embedded polymer-stabilised cholesteric liquid crystal films

Reflection-influenced circularly polarised luminescence based on an AIE-active dye and polymer-stabilised cholesteric liquid crystal films was observed.

Effect of surface hydroxyls and porous nanostructured sensors integrated for SERS monitoring and efficient removal of organic pollutants

As an excellent nanomaterial, AlOOH has a molecular enrichment effect derived from the large number of hydroxyl groups on its surface and its porous structure, which increases the molecular density in the hot spot region of Ag nanoparticles with plasmonic properties, provides the surface-enhanced Raman scattering (SERS) activity and realizes the detection of probe molecules. In our work, the composite AlOOH@Ag is rationally formed as an SERS substrate successfully applied to the detection of Congo Red (CR) molecules even at the trace level thanks to the formation of hydrogen bonds. Our successful analysis of the toxic dye molecules Rhodamine 6G (R6G), Crystal Violet (CV) and CR in a mixture demonstrates the universality of AlOOH@Ag as an SERS substrate and the great potential for recognition of a target. Importantly, the AlOOH@Ag has excellent molecular adsorption properties to remove harmful molecules, and a dual-functional SERS sensor that integrates detection and removal is achieved. Monitoring and adsorption tests under different pH spectrum environments were also performed. Importantly, the detection in real samples is even more successful. This versatile all-in-one SERS substrate provides platforms for the development of convenient sensors to be applied in actual environmental processing.

Adsorption of a Cationic Dye Crystal Violet onto a Binary Mixture of Forest Waste Biopolymer: Advanced Statistical Physics Studies

An eco-friendly and low cost modified mixture of both Wild Carob and Cupressus sempervirens with H3PO4 (Cupcar-H3PO4) was prepared to extract a cationic dye (Crystal Violet) from an aqueous solution in a batch reactor at the laboratory of chemical engineering, Department of Process Engineering, Faculty of Technology, Farhat Abbas Setif University-1. The pH effect, contact time, initial concentration of dye, ionic strength and temperature were investigated in this study. The Maximum adsorption capacity was found to be 117.26 mg/g at 25°C for a natural pH (ph =6.22). The active functional groups of Cupcar-H3PO4. These peak shifts indicated that especially the bonded –OH groups, C–O stretching of ether groups, and C=C group played a major role in CV adsorption onto Cupcar-H3PO4. The new bands of low intensity which appeared at 890 cm−1 and 813 cm-1 after CV adsorption and which could be attributed to a υ (CV-biosorbent) constituted the most striking result. Kinetics of biosorption of crystal violet (CV) was analyzed and the results showed that both pseudo order (PSO) and the pseud nth-order model (PNO) models gave most accurate fit than the pseudo-first-order model (PFO). Isotherm data were analyzed by four classical models, Langmuir and Freundlich with two parameters, Sips and Redlich-Peterson with three parameters. And for more information on the mechanism of CV uptake on the Cupcar-H3PO4 material, three advanced models are applied to isothermal data, Monolayer with one energy (M1), Monolayer with two energies (M2), and Double layer with one energy (M3). For the classical models and in the case of the two parameters models the Langmuir one gives a better fit for the data isotherm according to the R2. In the case of three parameters models, both Sips and Redlich-Peterson accurately described experimental data. Monolayer with two energy sites model (M2) was shown to be the most appropriate advanced statistical physics model for fitting CV biosorption onto the Cupcar-H3PO4 biosorbent, this model suggested that the CV pollutant was adsorbed at two different Cupcar-H3PO4 biosorbent sites, and that a variable number of CV molecules could be adsorbed at each site; from this, the CV dye was adsorbed with 2 different adsorption energies. The changes in the enthalpy, the standard free energy and the entropy were also evaluated and the reaction was found to be spontaneous, endothermic and physical in nature.

Study on the dispersion mechanism of the polycarboxylic acid dispersant for disperse dyes

Taking C.I. Disperse Blue 79 as the simulation object, the dispersion mechanism of polycarboxylic acid dispersant (poly(SMA-g-IP-MPEG)) for disperse dyes was studied by molecular dynamics simulations. The results show that the hydrophilicity of the dispersant mainly depends on the maleic acid residues; the ionized carboxylate groups of the maleic acid residues provide negative charges that make the dyes repel each other; the hydrophobicity of the styrene residues is the driving force that makes the dispersants adsorb to the dye surfaces; the branched chains grasp the dye crystals like claws, which make the dispersants combine with the dye crystals better. When the ratio of main chain monomer is 3:1 and the branched chain length is larger than 12, the branched chain tends to wrap around the main chain. The repulsion between dyes decreases, thus the dispersion performance becomes worse. When the ratio of main chain monomer is 1:1, the dispersion effect increases with the increase of branched chain length. But when the branched chain length increases to 16, the longer branched chain can adsorb with two dye crystals at the same time, which leads to the decrease of dispersion effect. In general, the main chain monomer ratio had little influence on the dispersion effect. The dispersant with the main chain monomer ratio of 1:1 and the branch chain length of 12 had the best dispersion effect on the dye. The experimental results verified the correctness of the simulation results. The design of polymeric dispersants for disperse dyes should consider not only the improvement of hydrophilicity and charge repulsion to maintain the dispersion stability of disperse dyes in water, but also the binding force between dispersants and disperse dyes. The two interactions determine the dispersion performance of the dispersant for disperse dyes.

Elimination of crystal violet from synthetic medium by adsorption using unmodified and acid-modified eucalyptus leaves with MPR and GA application

The aim of this investigation concerns the elimination by batch adsorption method of a primary (cationic) textile dye (Crystal Violet) from the synthetic medium, using raw and acid-modified eucalyptus leaves. Parametric studies, such as pH (2–10), unmodified and acid-modified eucalyptus leaves dose (1–10 g L−1), time (5–300 min), and initial strength of CV (10–300 mg L−1) are performed on the elimination of Crystal Violet from the Synthetic Medium. The R–P model gives the maximum coefficient of correlation (R2 = 0.99), which denotes the best fitting isotherms with the investigational data from the other isotherms. The maximal capacity of adsorption is 141 mg g−1 for Crystal Violet (CV) on PEUL at 25 °C and pH7. The kinetics study of the CV elimination signifies the pseudo 2nd order kinetics model gives the acceptable fitting rate equation (R2 = 0.99) with the investigational data. Intraparticle diffusion model, IPD implies it's not only the rate-limiting step. The overall outcome recommends eucalyptus leaves probably utilized as a low-cost environment-friendly adsorbent for the de-pollution of effluents laden with basic (cationic) textile dye (CV). MPR and GA application on experimental data correctly predicted the removal percentage.

Influence of xylenol orange dye on structural, vibrational, thermal and luminescence properties of TGS crystals

Dye can induce positive change in crystal. Pure and xylenol orange-dyed triglycine sulphate (TGS) large single crystals (> 14 cm2) were grown by solution technique in which dye inclusion pattern along preferred crystallographic planes were visible. Rietveld refinement was used to confirm monoclinic phase with space group P21 in XRD analyses. The crystallite size of both grown crystals were calculated by Scherrer method. In FTIR and Raman analyses, all the observed functional groups were explained. Thermal stability of dyed TGS crystal was increased. UV–Vis–NIR spectra showed that grown crystals were highly transparent with the lower cut off at 230 and 228 nm for pure and dyed crystals, respectively. The characteristics luminescence properties, including hyperluminescence and additional luminescence nature in dyed crystal, were explained. Pure TGS fell in violet region which shifted in blue region in CIE diagram after dyeing. Changes in PL, Raman, UV–Vis and thermal behavior due to dye doping established the TGS crystal as a better candidate for optical applications.

Surface Modified Laterite Soil with an Anionic Surfactant for the Removal of a Cationic Dye (Crystal Violet) from an Aqueous Solution

The work aims to study the removal of crystal violet (CV) using laterite soil with surface modification by surfactant (SML). Surface modification of laterite soil was conducted by pre-adsorption of sodium dodecyl sulfate (SDS) at pH 4 and low ionic strength to enhance removal of CV. The effective conditions for CV removal through adsorption technique using SML were optimized and found to be contact time 60 min, pH 6, adsorbent dosage 5 mg/mL, and 5 mM NaCl as background electrolyte. The highest removal of CV using SML reached to 86.5% under optimum conditions. We used Fourier transform infrared spectroscopy (FT-IR) to evaluate the change of surface vibrational groups of laterite after SDS pre-adsorption and after CV adsorption while the different charged surface was determined by ζ potential measurements. The CV adsorption onto SML increased when increasing ionic strength from 1 to 10 mM. Nevertheless, at high ionic strength, this trend is reversal due to desorption of SDS from laterite surfaces. Adsorption isotherms of CV onto SML at different NaCl concentrations were tried to fit by Langmuir, Freundlich, and a two-step adsorption models. The adsorption kinetics were in good agreement with pseudo-second-order model. The removal efficiency of CV after four regenerations still reached higher than 85%. On the basis of adsorption isotherms, charged surface change by ζ potential and surface modification by FT-IR, we suggest that CV adsorption onto SML was induced by both non-electrostatic and electrostatic interactions. We also demonstrate that SML is a novel, reusable, and low-cost adsorbent for cationic dye removal from aqueous solution.

Effect of sunset yellow dye on morphological, optical, dielectric, thermal and mechanical properties of KDP crystal

Herein, we describe the growth and morphology of well-defined dyed crystals of KH2PO4 (potassium dihydrogen orthophosphate; KDP) containing organic azo (sunset yellow; SSY) dye in the {1 0 1} & {0 0 1} pyramidal growth sectors. An understanding on selective dye inclusion in various growth sector of host crystal is proposed, which will help in designing novel tailor-made dyed photonic crystals. The structural analysis and the identification of various functional groups present in as grown KDP crystals were carried out using powder XRD, FTIR and Raman studies. Solid state transmittance spectra for dyed KDP crystals displayed three absorption peaks at 230 nm, 311 nm and 477 nm, which were blue shifted for SSY dye in KDP crystal relative to neutral aqueous solution of SSY dye. These blue shifts in the absorption maxima confirm the successful incorporation of sunset yellow dye into the pyramidal growth sectors of dyed KDP crystals. The band around 409 nm in the photoluminescence emission spectrum indicates a violet emission. SSY dye doped KDP crystals showed enhanced dielectric properties and thermal stability as compared to pure KDP crystal. The mechanical strength of the KDP crystals estimated using Vickers microhardness test was found to decrease with the increase in SSY dye doping.

Organic single-crystalline whispering-gallery mode microlasers with efficient optical gain activated via excited state intramolecular proton transfer luminogens

A whispering-gallery mode laser with a favored energy level system is achieved based on the single crystals of ESIPT-active organic dyes.

Self-Healable Lanthanoid-Based Metallogels: Dye Removal and Crystallization in the Confined Gel State

The self-healing property of metallogels resembles the innate self-healing of plant and animal biomaterials, making metallogels potential candidates for detailed studies. Tetrazoles with diverse coordination abilities and extensive H-bond formation capabilities may be able to be used as ligands to generate metallogels. In this report, four metallogels (M1G6Cl, M2G6Cl, M1G6NO3, and M3G6NO3) based on different lanthanoids and functionalized with di(1H-tetrazole-5-yl)methane (H2G6) are designed and fabricated. All the metallogels are well characterized by different spectroscopic methods. The mechanical strengths of the metallogels are determined by rheology, and FE-SEM images reveal diverse needle-like morphologies of the metallogels after the formation of ordered self-assembled networks. All the metallogels are found to be photoluminescent in nature, with quantum yields falling in the range 0.75–0.12. The emissive nature of the gels is utilized to perform invisible photopatterning experiments, which show the potential of these metallogels to be used in confidential image or writing applications. Furthermore, the crystallization of the M3G6NO3 metallogel in a confined gel space provides a pathway of elucidating its structure, which can be used to help predict the kinds of noncovalent interactions involved in the ordered self-assembly process. The self-healing nature of the M1G6Cl metallogels makes them the most interesting among all the gels and is further explored by the rhodamine dye-doped approach. Moreover, the low molecular weight, self-healable M1G6Cl metallogels act as unique soft materials for water purification by absorbing 98% Rhodamine B dye from water in 24 h.

Calculating the Lattice Dynamics in the RFe3(BO3)4 Crystals in the Quasi-Harmonic Approximation

The frequencies of lattice vibrations in the RFe3(BO3)4 (R = Pr, Nd, Tb, Dy, or Ho) crystals in the high-temperature R32 phase and their temperature dependence have been calculated using the quasi-harmonic approximation. It has been found that, at the boundary point Λ of the Brillouin zone, the frequency of the unstable vibration mode the structural phase transition R32 → P3121 is related to strong changes with temperature in the TbFe3(BO3)4, DyFe3(BO3)4, and HoFe3(BO3)4 crystals. With increasing temperature, the frequency of the soft mode stabilizes and takes a real value. No significant changes in the phonon spectra, including the boundary point Λ, with increasing temperature for the PrFe3(BO3)4 and NdFe3(BO3)4 crystals have been observed.

Influence of rhodamine 6G dye on the properties of potassium acid phthalate single crystals

Single crystals of Rhodamine 6G dye doped potassium acid phthalate (KAP) were grown by slow evaporation method with the Rhodamine concentration of 10− 4 M. Apparent change in morphology of the dye doped KAP crystals could be observed. Powder X-ray diffraction confirmed the formation of orthorhombic structure with space group Pca21 for both the pure and dye doped KAP crystals. TG-DTA validated the thermal stability of the dye doped KAP crystals. Parallel plate capacitor structures were made using silver electrode to measure the dielectric and impedance properties of the as grown crystal. The Nyquist plot showed interesting behavior at low frequencies which might be due to the polaron hopping. Analysis of morphology, IR and impedance spectra shows the strong interaction of dye to the host KAP molecule.

Remote Thermal Sensing by Integration of Corner‐Cube Optics and Thermochromic Materials

AbstractThermochromic materials (TCMs) change their color in response to temperature variations. Here, presented is a rare combination of TCMs with conventional corner‐cube retroreflectors (CCRs) that are widely used in industry for their ability to return an incident beam of light directly back toward its source. The TCM quoted CCR (TCR sensor) allows remote measurements of the quantitative thermal information of the environment to which the TCR sensor is subjected. Two different commercially available thermochromic systems, a leuco dye and liquid crystals, are utilized as sensing materials. Since the incident (probe) beam and reflected (sensing) beam always follow the opposite directions 180°, this allows the probing and sensing to be carried out remotely from the same spot. Therefore, such remote sensing mechanism is virtually independent of the incident and detection beam angles. The TCR sensor has potential application in the space research, mining, power generation facilities, radioactive environments, and other industries where remote temperature sensing is a stringent requirement.

Effect of Dy-doping on photoluminescence properties of CdTe crystals and their defect structure

The gettering effect by rare earths (RE) in semiconductor CdTe crystals was studied using the photoluminescence (PL) measurements. It was shown that the low-temperature PL spectra of Dy-doped CdTe crystals exhibit two acceptor-bound exciton lines, namely, the most intense sharp A1oX-line and a low-intensity A2oX-line associated with the residual Na(Li) impurity atoms and the cadmium vacancies, respectively. In addition, the donor-bound exciton lines are also observed. It was shown that these lines are caused by the presence of the Cl residual impurity atoms, interstitial Сdi or Nai(Lii) atoms. The PL of donor-acceptor pairs and the emission caused by optical transitions of (e-A) type were revealed. The nature and photoionization energy of different donor and acceptor centers were determined. It was found that the emission associated with the presence of complex acceptor centers is absent in PL spectra. This indicates that the concentration of dislocations is very small for the investigated crystals. The presence of bound and free excitons in the PL spectra as well as free excitons in the reflection spectrum shows high crystalline and optical quality of CdTe:Dy crystals that is due to so-called “cleaning” process of the semiconductor materials by their doping with RE elements.