Study on catalytic properties of graphene/molybdenum sulfide under near-infrared light irradiation

Graphene/MoS2 hybrid material was prepared by the hydrothermal method. The hybrid material was characterized by X-ray diffraction spectrum, Raman spectra, transmission electron microscope and UV-vis-NIRS. It was used as a near-infrared photocatalyst to catalyze and degrade Rhodamine B (RhB). The results showed that when the concentration of the RhB solution was 50.0 mg·L–1, the pH value of the solution was 7, the volume of the solution was 50.0 mL, the amount of G/MoS2 catalyst was 0.05 g and near-infrared radiation was carried out for 3 h, the degradation rate of RhB in the 50 mL solution reached 96.5%. When MoS2 was used as the photocatalyst, the degradation rate of RhB was only 75.5%. After 5 times of recycling, the catalytic efficiency of the hybrid photocatalyst was still more than 90%, indicating that the catalyst is very stable.

Photocatalytic performance of carbon nanotubes/activated carbon composite carrier carrying cadmium sulfide

The in-situ reaction process was used to prepare composite materials loaded with cadmium sulfide, which were respectively loaded by carbon nanotubes, activated carbon, and carbon nanotube/activated carbon composites for the study of photocatalytic degradation of methyl orange. The results show that when carbon nanotubes and activated carbon are used as carriers, the photocatalytic degradation reaction rate constants are 3.6 times and 8.8 times higher than those without a carrier. The photocatalytic performance of the carbon nanotube/activated carbon composite carrier with a mass ratio of 20: 80 to support cadmium sulfide is significantly higher than that of cadmium sulfide supported by carbon nanotubes and activated carbon respectively, and its photocatalytic degradation reaction rate constant is 30% – 40% higher than that under the condition of activated carbon alone as carrier. It shows that when the modified activated carbon is used as a photocatalyst carrier, carbon nanotubes have a significant effect in improving the efficiency of degrading organic matter.

Surface modification of nano-TiO2 with lanthanide-acetylacetonate complexes

The surface modification of nano-TiO2 was carried out with lanthanide-acetylacetonate complexes by adsorption method. The effects of lanthanide complexes content, lanthanide element type, adsorption temperature, solvent dosage, adsorption time and other conditions on the photodegradation activity of methyl orange by the modified catalyst were studied, and suitable modification conditions were obtained. The results show that the photocatalytic activity of the modified nano-TiO2 is much higher than that of the unmodified pure TiO2, and the lanthanide-acetylacetonate complexes is an excellent surface modifier.

Controllable preparation and electrocatalytic hydrogen evolution characteristics of Fe3S4 nanocrystals

In order to obtain better electrocatalytic hydrogen evolution performance, Fe3S4 with different morphologies was synthesized by controlling the reaction conditions. During that progress, the ferric oleate as an iron source, and the sulfur powder dissolved in oleylamine as a sulfur source. Fe3S4 with particle morphology proved to have the best electrochemical catalytic activity after adding 40% carbon black. In dehydrogenation, the overpotential was 234 mV and the Tafel slope was 213 mV/dec at a current density of 10 mA/cm2. Meanwhile, Fe3S4 with a particle morphology exhibited superior electrochemical stability. Therefore, the controllably fabricated Fe3S4 with a particle morphology is a promising electrocatalyst for dehydrogenation.

Synthesis and characterization of polyurethane and its nanocomposite adhesive derived from biobased isocyanate and polyol

In the current research, the vegetable oil based polyurethane nanocomposite (PUNC) adhesive was prepared using transesterified castor oil (CO) based polyol, partially biobased aliphatic isocyanate (PBAI) and organically modified montmorillonite nanoclay (Closite 30B). The transesterified CO was synthesized by reacting CO with ethylene glycol, which was confirmed using proton nuclear magnetic resonance (1HNMR) analysis. Further, the prepared polyurethane (PU) and its nanocomposite adhesive with specific NCO: OH molar ratio 1.3:1 was confirmed by Fourier transform infrared spectroscopy (FTIR) analysis. The increasing of wt% of nanoclay loading level up to 3% into PU matrix increased the lap shear strength of the adhesive systems. Subsequently, the effect of polyurethane nanocomposite adhesives on the bonding strength of wood-to-wood and aluminum-to-aluminum substrate was studied using lap shear strength test. The nanoclay was observed to effectively intercalate into the polymer matrix. Moreover, the phase separation in PU and PUNC adhesive was studied using atomic force microscope (AFM) and differential scanning calorimetry (DSC) analysis.

The role of dysprosium ions as a dopant on linear and nonlinear optical dispersion parameters in a-Se thin film

Thin films of un-doped and doped a-Se with Dysprosium rare-earth ions have been prepared by the thermal evaporation technique. The optical transmission spectra of the investigated films have been measured in a wide spectral range and used to calculate the linear optical constants together with the optical energy gap of studied films. The observed decrease in the values of the energy gap against the increase of the Dysprosium (Dy) content in a-Se films has been explained using Mott and Davis Model and in terms of electronegativity difference of the constituent atoms. Furthermore, the dispersion of nonlinear parameters such as second-order refractive index and nonlinear absorption coefficient (two-photon absorption coefficient) of investigated films are presented and discussed.

Polyaniline modified silica gel coupled with green solvent as eco favourable mobile phase in thin layer chromatographic analysis of organic dyes

This article studies a new green eco-friendly TLC (thin layer chromatography) using silica gel and polyaniline modified silica gel as stationary phase in combination with ethyl acetate (EA), n-butyl acetate (BA) and butane-1-ol (BO) solutions as mobile phase for the comparative study of migration behaviour of organic dyes to identify the most suitable thin layer chromatographic system for the resolution of co-existing dyes. Better separation efficiency was observed by modifying silica gel with polyaniline as compared to pure silica stationary phase. Densitogrpahic presentation of separations achieved on polyaniline modified silica gel Pani@SG-EB1 was also presented. The thin layer chromatographic system comprising of polyaniline modified silica gel Pani@SG-EB1 as stationary phase and n-butyl acetate:DDW, 5:5 as green mobile phase was observed to be the most favourable for the separation of various combinations of three or four-component mixtures of organic dyes viz. methyl thymol blue, tartrazine, carmoisine, rose bengal, amidoblack 10B, bromopyrogallol red and 4-nitrobenzene dizonium tetrafluoroborate. The effect of presence of cations and anions on separation trend was also examined and the limits of detection of the separated organic dyes were estimated. Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron micrograph (TEM) studies were undertaken to characterize silica gel and modified silica gel (stationary phase). The developed method has been successfully applied for the identification of carmoisine in Solvin cold DS syrup and tartrazine in MefastTM syrup.

Optimization of oscillated gas-liquid separator for simultaneous heavy metals determination in water sample

A technique has been developed to detect and determine multi heavy metals simultaneously in a water sample. Hydride generating technique was implemented to convert the analyte which present in the water sample (liquid phase) into another form with an improved separation coefficient, called “derivative”. This process occurred without changing the original chemical structure. Derivatives were separated from the liquid phase by applying custom made gas-liquid separator (GLS), operated with oscillation. Separated species then transferred into a die-electric barrier discharge (DBD) plasma atomizer where a fragmentation of the analyte into free atoms is occurred. The generated atoms were detected by emission spectroscopy. The presented technique was applied for detection of individual and multi heavy metals simultaneously in water sample and proved useful in terms of reducing the effect of the hydrogen generated, through the process, on suppressing the atoms signal in the DBD atomizer.

Study on the physical properties of Cu2ZnSnS4 thin films deposited by pneumatic spray pyrolysis technique

The acquisition of new materials for the manufacturing of high efficiency and low-cost photovoltaic devices has currently become a challenge. Thin films of CuInGaSe and CdTe have been widely used in solar cell of second generation, achieving efficiencies about 20 %; however, the low abundance of In and Te as well as the toxicity of Cd is the primary obstacles to their industrial production. Compounds such as Cu2ZnSnS4, Cu2ZnSnSe4 and Cu2ZnSn(SSe)4 have emerged as an important and less costly alternative for efficient energy conversion in the future. In addition, these compounds have the required characteristics to be used as an absorber material in solar cells (band-gap close to 1.4 eV, an absorption coefficient greater than 104 cm-1 and a p-type conductivity). In this work, we present a study of the structural, compositional, morphological and optical properties of Cu2ZnSnS4 thin films deposited by spray pyrolysis technique as well as their dependence on temperature.

Optimization of electrodialysis unit for partial desalination: Batch and continuous operation

In recently few years, application of membrane technologies in sea water desalination is increased compared to other desalination technologies. Electrodialysis membrane technology is still limited in seawater desalination due to the high operation cost and its limitations for high salty water. Electrodialysis desalination cost is proportional to the amount of salt, which must be carried out through the membrane. Seawater desalination with high salt content of NaCl (42 g/L) was applied using IonTech electrodialysis unit. Partial desalination process was studied in two separate experiments, batch and continuous operation. Operation parameters like voltage applied, electrolyte concentration and time of desalination were studied under batch mode process. Continuous operation process was carried out to confirm the partial desalination process of electrodialysis. The limited current density is determined, 1.49 A/m2 and 1.15 A/m2 for theoretical and experimental, respectively. The specific energy consumption was calculated, 7.15 kWh/m3.