Microsolvation effects on the optical properties of crystal violet

We present a joint experimental and theoretical study of the photoabsorption and photodissociation behavior of crystal violet, that is, the tris[p-(dimethylamino)phenyl]methyl cation. The photodissociation spectra of isolated and microsolvated crystal violet have been measured. A single band is observed for the bare cation. This is in good agreement with the calculated vibronic absorption spectrum based on time-dependent density functional theory calculations. The interaction of crystal violet with a single water molecule shifts and broadens the photodissociation spectrum, so that it approaches the spectrum obtained in solution. Theoretical calculations of the structure of the complex suggest that the shift in the absorption spectrum originates from a water molecule bonding with the central carbon atom of crystal violet.     

Formation and properties of hydrophobic CeO2 nanoparticles

Uniform hydrophobic cerium oxide (CeO₂) nanoparticles in a cubic structure with an average size of 4.6 nm were obtained by a novel oil-water interface method in the presence of 0.40 M NaOH. Effects of reactants concentration, oxidation reaction temperature, and the type of surfactants on the final products were investigated. The products were characterized by X-ray diffraction, transmission electron microscopy, UV-visible spectroscopy, room-temperature photoluminescence spectroscopy and contact angle measurements. The products exhibited high luminescence and strong hydrophobicity. The data suggest that Ce(OH) _x ^4?x (x < 4) is a precursor complex for the formation of CeO₂ nanoparticles in liquid phase and its concentration controls the size of CeO₂ particles. The adsorption of the surfactant influences the formation of the hydrophobic particles of CeO₂ by the oil-water interface method.     

Spectral characteristics and nonlinear studies of crystal violet dye

Solid-state dye-doped polymer is an attractive alternative to the conventional liquid dye solution. In this paper, the spectral characteristics and the nonlinear optical properties of the dye crystal violet are studied. The spectral characteristics of crystal violet dye doped poly(methylmethacrylate) modified with additive n-butyl acetate (nBA) are studied by recording its absorption and fluorescence spectra and the results are compared with the corresponding liquid mixture. The nonlinear refractive index of the dye in nBA and dye doped polymer film were measured using z-scan technique, by exciting with He-Ne laser. The results obtained are intercompared. Both the samples of dye crystal violet show a negative nonlinear refractive index. The origin of optical nonlinearity in the dye may be attributed due to laser-heating induced nonlinear effect.     

Nanocomposite hydrogel from grafting of acrylamide onto HPMC using sodium montmorillonite nanoclay and removal of crystal violet dye

Hydrogel nanocomposites were synthesized from grafting of acrylamide onto hydroxypropyl methylcellulose using methylenebisacrylamide crosslinker and sodium montmorillonite (Na-MMt) nanoclay. The effect of nanoclay content on the swelling of nanocomposites was investigated and an optimum swelling capacity was obtained at 12.7 wt% of Na-MMt. The effect of salt solutions on the swelling of nanocomposites revealed that the degree of swelling of samples depends only slightly on the salinity. The structure of nanocomposites was characterized by XRD, SEM, FTIR, and TEM techniques. The XRD and TEM results confirmed the exfoliation of Na-MMt nanoclay in nanocomposite matrix. The morphology of the nanocomposites was characterized by SEM technique and according to the results a loose surface was observed. The nanocomposite hydrogels were evaluated to remove cationic crystal violet dye from water. The investigation of the dye adsorption capacity and rate of nanocomposite hydrogels as a function of Na-MMt content revealed that the both adsorption capacity and rate is enhanced as the nanoclay content is increased in nanocomposite composition. The experimental equilibrated adsorption capacity of nanocomposites was analyzed using Freundlich and Langmuir isotherm models. The best fit to the experimental data was obtained with the Langmuir model.     

Effect of preparation procedure on the properties of CeO2

The effect of preparation procedure on the physicochemical and catalytic properties of CeO₂ was studied. Differences in the electronic and structural characteristics of CeO₂ depending on preparation procedure and treatment temperature were found using X-ray diffraction analysis, transmission electron microscopy, UV-visible electronic spectroscopy, and X-ray photoelectron spectroscopy. With the use of the temperature-programmed reaction with CO, it was demonstrated that CeO₂ samples with a high concentration of point defects—oxygen vacancies caused by the presence of Ce³⁺—were characterized by an increased mobility of bulk oxygen. The samples of CeO₂ with a high concentration of structural defects—micropores of size 1–2 nm and stepwise vicinal faces in crystallites—exhibited a high catalytic activity in the reaction of CO oxidation.     

Growth, structural, optical and thermal properties of gamma-glycine crystal

Single crystals of gamma-glycine were grown from a mixture of glycine, water and lithium bromide. Single crystal X-ray diffraction analysis confirmed the growth of gamma-glycine phase. Presence of various functional groups of gamma-glycine was identified by FTIR spectrum. Optical absorbance spectrum recorded in the wavelength range of UV-vis-NIR revealed that this crystal has good optical transparency in the range 250-1500 nm. Vickers microhardness values were estimated on the prominent (100) face. Thermogravimetric and differential scanning calorimetric analyses were carried out to study the thermal properties of gamma-glycine. Second harmonic generation efficiency of the crystal measured by Kurtz's powder method using Nd:YAG laser is about three times that of KDP.     

Effects of slight Fe (III)-doping on structural and optical properties of TiO2 nanoparticles

Journal of Sol-Gel Science and Technology - In this research work, undoped and slight Fe-doped-TiO2 nanoparticles (Fe–TiO2 NPs) were prepared using simple chemical sol–gel method and...     

Synthesis and properties of oil-soluble butyl crystal violet lactone

A novel compound of butyl crystal violet lactone (BCVL) has been prepared by oxidizing leuco butyl crystal violet lactone (LBCVL), which was obtained by the mixture of N,N-dibutylaniline, p-(dibutylamino) benzaldehyde and methyl-m-(dibutylamino) benzoate. The structure of BCVL was characterized by ¹H-nuclear magnetic resonance (NMR), infrared (IR), and mass spectrometry (MS). The color of BCVL can change reversibly in some acid or alkali solvents. The result of the dissolution experiment showed that solubility of BCVL in organic solvent was improved compared with crystal violet lactone (CVL). Translated from Journal of Fudan University (Natural Science), 2006, 45(3): 375–379 [译自: 复旦学报(自然科学版)]     

A novel triphenylamine-based dye sensitizer supported on titania nanoparticles and the effect of titania fabrication on its optical properties

A new synthesised triphenylamine-based dye having a branched structure with one OH-ending branch able to interact with the surface hydroxyl moieties of mesoporous TiO₂ is reported. Optical properties of the dye-titania hybrid material are presented and the higher efficiency of the dye on pure anatase TiO₂ compared to the commercial Degussa P25, which contains a rutile phase component, is confirmed. The optical and chemical properties of the dye make it a promising candidate as a metal-free dye for DSSCs or as a host for a variety of transition or main group metal ions for different applications.     

Ultrasound facilitates and improves removal of triphenylmethane (crystal violet) dye from aqueous solution by activated charcoal: A kinetic study

This work was aimed at removing crystal violet (CV) from an aqueous solution via an ultrasound-aided sorption process. Different operational parameters, such as contact time, ultrasonic power, and the sorbent dosage, were investigated. The results indicated that the sorption process was more rapid compared with the previously stated process; a sorption equilibrium was obtained after 1.5 h. The increase in the dose from 0.02 to 5.0 g/L increased the adsorption efficiency by 100%. The decolorization of the CV pigment occurred very rapidly at the highest sound power, 200 W, and it reached ～85%. The kinetics study indicated that the sorption process fitted the pseudo-second-order model with the chemisorption mechanism. The sorption isotherm data were also interpreted by the mass-transfer model, which established the intraparticle diffusion. Additionally, to estimate the rate-limiting step mechanisms, the intraparticle diffusion was not considered as the sole rate-controlling step. The maximum sorption capacity (q_max) increased from 19.0 to 24 mg/g during the ultrasound and indicated the positive synergistic effect of the ultrasound. The proposed sonosorption technique is a low cost-effective method for purifying water and wastewater from organic pollutants.     

Thermal,structural and optical properties of Al2CoO4-Crocoite composite nanoparticles used as pigments

Novel zinc(II) complex compounds of general formula Zn(C₆H₅COO)₂·L₂ (where L=caffeine (caf) and urea (u)) were synthesized and characterized by elemental analysis and IR spectroscopy. The thermal behaviour of the complexes was studied during heating in air by thermogravimetry. It was found that the thermal decomposition of the anhydrous Zn(II) benzoate compounds with bioactive ligands was initiated by the release of organic ligands at various temperatures. On further heating of the compounds up to 400°C the thermal degradation of the benzoate anions took place. Zinc oxide was found as the final product of the thermal decomposition of all zinc(II) benzoate complex compounds heated to 600°C. Results of elemental analysis, infrared spectroscopy, mass spectroscopy and thermogravimetry are presented.     

Effect of sodium hydroxide pre-treatment on the optical and structural properties of lyocell

Lyocell is a type of regenerated cellulose. Fibres spun from cellulose solution in N-methylmorpholine-N-oxide hydrate consist of crystalline cellulose II and amorphous cellulose. Lyocell fabrics were treated with aqueous sodium hydroxide solution (NaOH) to study the influence of alkali on optical and structural properties. It was observed that sodium hydroxide treatment causes the density, orientation and crystallinity of lyocell fibre to decrease with increasing sodium hydroxide concentration, a corresponding decrease in tensile strength is also observed. The greatest change in fibre properties occurs between 3.0 and 5.0 mol dm⁻³ NaOH. This is attributed to the onset of formation of Na-cellulose II at 3.0 mol dm⁻³ NaOH; a fully formed Na-cellulose II structure is expected above 6.8 mol dm⁻³ NaOH. Formation of Na-cellulose II causes plasticization of the lyocell fibres as both inter- and intra-molecular hydrogen bonds are broken by these higher sodium hydroxide concentrations.     

Effect of synthesis parameters on the structural,morphological characteristics,and photocatalytic activity of La2O3 nanoparticles

This study investigates the influence of synthesis processes such as sonication, sol-gel, and microwave on the production of highly crystalline Lanthanum oxide nanoparticles (La₂O₃) employing Lanthanum nitrate and Ammonium hydroxide (NH₄OH) as precursors. X-ray diffraction (XRD), particle size analysis (DLS), Field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR), ultraviolet–visible absorption spectroscopy (UV–Vis), and electrochemical impedance spectroscopy (EIS) were used to examine the most effective processing method and its effects on the nanoparticle characteristics, such as structure, morphology, and optical and electrical behavior. Sonication produces La₂O₃ NPs with a smaller crystalline size, an agglomerated nanorod structure, a higher bandgap, and better electrical responsiveness than sol-gel and microwave techniques. Structural and optical characterization tests discovered this. The photocatalytic degradation activity of cationic Safranin and anionic Congo red dye exhibits degradation efficiency of around 90.13% and 89.66%, respectively.     

Effect of polar solvents on the optical properties of water-dispersible thiol-capped cobalt nanoparticles

We were able to stabilize cobalt nanoparticles dispersible in water by optimizing the synthetic procedure using small polar thiol containing compounds as the capping agents. The nanoparticles were found to be spherical. The optical properties of the cobalt nanoparticles were investigated by monitoring the changes in the surface plasmon resonance (SPR) spectrum in various polar solvents. The extent of solvent dependence of the SPR spectrum was found to be dependent on the nature of the capping agent, the size of the cobalt nanoparticles, as well as the nature of the solvent. The Drude model was applicable for the particles capped with mercaptopropionic acid, while the effect of variations in the free electron density in the particles at different solvents became predominant in the nanoparticles capped with mercaptoethanol. The absorption spectra of the Co nanoparticles were simulated with the help of the classical Mie theory, and the results supported the effect of free electron density due to different capping agents on the spectra of the particles.     

Fabrication and characterization of CMC‐based magnetic superabsorbent hydrogel nanocomposites for crystal violet removal

In this research work, novel magnetic superabsorbent hydrogel nanocomposites (MSHNs) based on carboxymethyl cellulose were prepared via a facile “one‐pot” two step approach. Magnetic iron oxide nanoparticles were in situ synthesized and incorporated into carboxymethyl cellulose/poly(acrylic acid) polymer hydrogel. The morphology and chemical composition of MSHNs as well as the presence of magnetic iron oxide nanoparticles were evaluated by using Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, X‐Ray diffraction, ultraviolet–visible spectroscopy, thermogravimetric analysis, and vibrating sample magnetometer. The effect of different reaction parameters on the swelling capacity of MSHNs was investigated. Furthermore, batch adsorption experiments of crystal violet dye onto MSHNs were studied by varying solution pH, initial dye concentration, and temperature. Evaluation of thermodynamic parameters of crystal violet adsorption confirmed that the adsorption was spontaneous and endothermic process in nature. The equilibrium study revealed that the dye adsorption behavior of MHSNs followed the Redlich‐Peterson isotherm model. Finally, the dye adsorption experiment data was well fitted by the pseudo‐second‐order kinetic model with the regression coefficient (R²) of 0.9979. Our results suggest that the MHSNs with facile preparation method, high swelling capacity, and high dye adsorption capacity may be used as promising adsorbents for fast removal of various dyes from aqueous solutions. Copyright © 2016 John Wiley & Sons, Ltd.     

Effect of TiO2 nanoparticles on self-assembly behaviors and optical and photovoltaic properties of the P3HT-b-P2VP block copolymer

An ordered nanostructure can be created from the hybrid materials of self-assembly poly(3-hexyl thiophene-b-2-vinyl pyridine) and nicotinic acid-modified titanium dioxide nanoparticles (P3HT-b-P2VP/TiO(2)). TEM and XRD analyses reveal that the TiO(2) nanoparticles (NPs) are preferentially confined in the P2VP domain of P3HT-b-P2VP whereas TiO(2) NPs interact with either pure P3HT or a blend of P3HT and P2VP to produce microsized phase segregation. The morphologies of lamellar and cylindrical structures are disturbed when the loading of TiO(2) NPs is 40 wt % or higher. Cylindrical P3HT-b-P2VP/TiO(2) exhibits a small blue shift in absorption and photoluminescence spectra with increasing TiO(2) loading as compared to P3HT/TiO(2). The NPs cause a slightly misaligned P3HT domain in the copolymer. Furthermore, the PL quenching of P3HT-b-P2VP/TiO(2) becomes very large as a result of efficient charge separation in the ordered nanodomain at 16 nm. Solar cells fabricated from self-assembly P3HT-b-P2VP/TiO(2) hybrid materials exhibit a >30 fold improvement in power conversion efficiency as compared to the corresponding 0.3P3HT-0.7P2VP/TiO(2) polymer blend hybrid. This study paves the way for the further development of high-efficiency polymer-inorganic nanoparticle hybrid solar cells using a self-assembled block copolymer.