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The purpose of this paper is to provide an investigation on a new kind of photocatalytic material, namely, the porous ceramic foam loading titanium dioxide, which can make an effective photocatalytic degradation of the methyl orange (MO) solution in the wastewater.

The natural zeolite powder has been used as the primary raw material to produce a sort of lightweight porous ceramic foam by impregnating polymer foam in slurry and then sintering. With the sol-gel method, a kind of open-cell reticular porous ceramic foam loading TiO₂ film was obtained having a good photocatalytic action, and the resultant porous composite product presents the bulk density of 0.3~0.6 g/cm³ to be able to float on water.

The MO could tend to be completely degraded in the solution with a certain concentration by the TiO₂-loaded ceramic foam irradiated with ultraviolet light, and this composite foam was found to have high degradation efficiency for the MO solution in a wide range of pH.

This work presents a TiO₂-loaded ceramic foam that can effectively photo-catalyze to degrade the MO in water, and the degradation efficiency were examined under different conditions of the MO solution with various pH values.

This study aims to investigation of the guar gum-manganese dioxide (GG/MnO₂) nanocomposite (NC) synthesized using an environment-friendly method and the degradation of reactive yellow (RY 145) dye in the UV system.

Characterization of the GG/MnO₂ NCs were conducted using field emission scanning electron microscopy, X-ray diffraction and Fourier-transform infrared spectroscopy. Experiments were conducted using a 1 L glass reactor coupled with Ultraviolet (UV-C) blue light bulb of wavelength 250 nm and power of 8 W.

The NC (2.25 g/L) displayed high RY 145 dye degradation (81%) with 10 mg/L of concentration at pH 3. The coefficient of determination (R² 0.99) also depicted that the model fits the experimental data. The analysis of variance (ANOVA) showed that the F-values of 464.75, 276.04 and 5.15 are related to the dose of GG/MnO₂ NCs, initial concentration of RY 145 dye and solution pH, respectively.

The GG/MnO₂ NCs followed by photo oxidation process (UV-process) could be used to degrade the RY 145 dye from synthetic wastewater.

There are two main innovations. One is that the novel process is performed successfully for RY 145 dye degradation. The other is that the optimized conditions are obtained by Box–Behnken design. Also, the effects of different variables on the RY 145 dye removal efficiency were investigated.

This study aims to embed anatase, rutile and brookite TiO₂ nanoparticles (NPs) with different crystal phases into cotton fabrics by epoxy silane and to examine the effect of these applications on the photocatalytic and mechanical properties of the fabric.

Different aqueous dispersions which contain anatase, rutile and brookite were prepared at three different concentrations (5%, 10% and 15%). These NPs were embedded in cotton fabrics by using GPTS [(3-glycidyloxypropyl) trimethoxysilane]. Characterization tests were performed by scanning electron microscopy (SEM), Raman and Fourier-transform infrared spectroscopy (FT/IR). Samples were stained with methylene blue (MB) and then exposed to solar light for different periods. Color changes of the samples were examined with a spectrophotometer. Air permeability, abrasion and tear strength tests were applied to all samples.

According to SEM images, the NPs were successfully attached to the cotton fabrics, and epoxy silane coating surrounded the fiber surfaces. The presence of the coating was also confirmed by Raman spectroscopy and FT/IR. The treatments reduced the stainability of the samples. The most effective applications for ensuring photocatalytic activity in cotton fabrics were suspensions as 10% brookite, 10% anatase and 5% anatase, in descending order. The applied coating slightly reduced the samples’ air permeability, and wear and tear strength.

The importance of this study is to determine the optimal crystal phase and its concentration by using epoxy silane to ensure self-cleaning properties on cotton fabrics. The sample treated with 10% brookite is the most approached its original white color by 99.65% as a result of degradation of MB (after 120 min). On the other hand, using the pure rutile with epoxy silane was not suitable for removing MB from the fabric.

The purpose of this paper is to study the effect of gamma-rays on murexide (Mx) dye and its possible use as radiation dosimeters in two different dosimetry systems. The first system depends on the Mx dye as a liquid dosimeter. The second dosimetry system depends also on the same dye but as in a gel form, which is more sensitive to gamma-rays.

The prepared Mx (solutions/gels) have a considerable two peaks at 324 and 521 nm that upon irradiation, the intensity of these peaks decreases with the increasing radiation dose.

The gamma-ray absorbed dose for these dosimeters was found to be up to 2 kGy for the solution samples and 40 Gy for the gels. Radiation chemical yield, dose response function, radiation sensitivity and before and after-irradiation stability under various conditions were discussed and studied.

It is expected that the radiolysis of the Mx dye can be used as radiation dosimeters in two different dosimetry systems; liquid and gel dosimeters. This can be applied in a wide range of gamma radiation practical industrial applications in water treatment, food irradiation dosimeters, radiotherapy and fresh food irradiation and seed production.

Both of the prepared Mx dyes, either as solutions or gel samples, can be facilely prepared from commercially, cheap, safe, available chemicals and suitable for useful applied Mx solutions and gels radiation dosimeters.

Dyeing and printing are important steps in textile manufacturing. After the process completion, these dyes are released in the effluent. These dyes impart an unacceptable appearance but are also toxic to the soil and water bodies. The present research has been carried out to study the rate of photocatalytic degradation of an azo dye, namely, CI Direct Green 26, using titania nanoparticles under ultra violet (UV) irradiation as a function of temperature and time. Azo dyes account for the majority of all dyestuffs are produced and extensively used in the textile, paper, food, leather, cosmetics and pharmaceutical industries. Titania nanoparticles have been found to successfully degrade these dyes in the presence of UV light. The purpose of the present paper was to study the photodegradation of azo dyes using titania nanoparticles at different temperatures and time periods.

Titania nanoparticle concentration of 0.1% (w/v) was dispersed in distilled water by sonication for 1 h in sonication bath. The of rate of degradation of Direct Green 26 dye in the titania nanoparticle dispersion, under UV-A exposure was studied at different temperatures ranging from 25°C to 65 °C for time periods ranging from 1 h to 6 h. Photocatalytic degradation tests were performed in a specially designed UV reactor chamber. Raman spectroscopy of Titania nanoparticles, dye and titania/dye mixture before and after UV exposure was carried out using Confocal Laser Dispersion Raman Microscope (Renishaw, UK) with 785 nm excitation laser.

Titanium dioxide is an efficient photocatalyst for decolourisation of direct dye. The photodegradation of the direct Green dye was found to follow the pseudo first-order reaction. The Arrhenius activation energy was found to be 24.8 kJ/mol with A value of 0.0013 for the photocatalytic degradation of the dye. Raman spectroscopy also confirmed the adsorption of dye on titania nanoparticle and its complete degradation on exposure to UV light.

This research highlights the application of titania nanoparticles for the effective degradation of dye in the effluent from textiles, clothing, paper and any kind of dyeing process. Azo dyes account for the majority of all dyestuffs are produced and extensively used in the textile, paper, food, leather, cosmetics and pharmaceutical industries. Titania nanoparticles have been found to successfully degrade these dyes in the presence of UV light which can be very beneficial for the effluent treatment plants in textile and other industries.

Azo dyes are one of the harmful pollutants released in textile waste water. The degradation and removal of the coloured waste in the textile effluent is an important environmental concern and needs to be investigated. The research is one of the first to investigate and understand the mechanism of the degradation of an azo dye in the presence of titania nanoparticles by Raman spectroscopy.

This paper aims to introduce two methods for immobilisation of TiO₂ nanoparticles on a glass plate by means of silicon resin as a medium. Then, to ensure the effectiveness of these stabilisation methods, the photocatalytic degradation and mineralisation of the dye C.I. Reactive Blue 21 (RB21), as a model organic pollutant, were compared using these immobilised systems and the suspended one utilizing UV and sunlight irradiations individually.

TiO₂ nanoparticles were supported onto a glass support by silicon resin as an adhesion agent by spraying of TiO₂ nanoparticles on the resin surface, which covered the glass plate or brushing the mixture of TiO₂ and the resin onto the glass. The characteristics of the applied nano-TiO₂ were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Brunauer

Emmett–Teller. Photocatalytic degradation and mineralisation of C.I. Reactive Blue 21 (RB21) by two immobilised systems were compared with suspended system in a batch mode under UV and sunlight irradiations after 2 h of treatment.

The results showed that these immobilised modes had efficiencies, including 82-87 per cent degradation of RB21 and 52-58 per cent decrease in chemical oxygen demand (COD) for the operational time of 120 min, comparable to that of the suspended mode (91 per cent degradation of RB21 and, consequently, COD is decreased by 65 per cent). Comparison between photocatalytic efficiencies of two immobilised systems revealed that coating by spraying method performed better than brushing one due to more available surface area of TiO₂. Finally, the results obtained from the mentioned supported systems under sunlight indicated the efficiencies about 87 to 89 per cent in comparison of the suspension system regardless of the reaction time enhancement up to 15 h compared to the UV irradiation.

In this research, the fixation of TiO₂ nanoparticles on a substrate such as normal glass by an easy, inexpensive, durable, repairable and repeatable technique for wastewater treatment was introduced. Due to the simplicity and cheapness of these stabilisation methods and as these stabilisation methods are applicable on other substrates such as concrete, ceramics, etc., you can use these methods in major scales for purification of contaminated water, for example for stabilisation of TiO₂ nanoparticles on wall pool utilized for water purification can be used.

Two introduced immobilisation methods in this study are novel. The photocatalytic efficiency of these immobilised systems in degradation of water contaminants was investigated by using these systems in degradation and mineralisation of the dye C.I. Reactive Blue 21 (RB21), as a model organic pollutant compared with same TiO₂ nanoparticles in an aqueous suspension system under UV light. Furthermore, this paper investigated replacing of inexpensive sources of UV light instead of UV lamps, and then the same photocatalytic reactions were carried out under sunlight as a UV source and degradation efficiencies by two UV sources were compared.

This paper aims to investigate the reusability of metal/metal oxide-coupled ZnO nanorods (ZnO NRs) to degrade rhodamine B (RhB).

ZnO NRs particles were synthesized by precipitation method and used to remove various types of metal ions such as Cu²⁺, Ag⁺, Mn²⁺, Ni²⁺, Pb²⁺, Cd²⁺ and Cr²⁺ ions under UV illumination. The metal/metal oxide-coupled ZnO NRs were characterized by scanning electron microscope, X-ray diffraction and UV-Vis diffuse reflectance. The photodegradation of RhB dye by these metal/metal oxide-coupled ZnO NRs under UV exposure was assessed.

The metal/metal oxide-coupled ZnO NRs were successfully reused to remove RhB dye in which more than >90% of RhB dye was degraded under UV exposure. Furthermore, the coupling of Ag, CuO, MnO₂, Cd and Ni particles onto the surface of ZnO NRs even enhanced the degradation of dye. The dominant reactive species involved in the degradation of RhB dye were ^•OH- and ^•O₂⁻-free radicals.

The coupling of metal/metal oxide onto the surface of ZnO NRs after metal ions removal could affect the photocatalytic performance of ZnO NRs in the degradation of organic pollutants in subsequent stage.

A good reusability performance of metal/metal oxide-coupled ZnO NRs make ZnO NRs become a desirable photocatalyst material for the treatment of wastewater, which consists of both heavy metal ions and organic dyes.

Metal/metal oxide coupling onto the surface of ZnO NRs particles improved subsequent UV-assisted photocatalytic degradation of RhB dye.

The purpose of this paper is to improve the degradation efficiency of Rhodamine B (RhB) by new photocatalytic materials.

Binary Z-scheme g-C₃N₄/Bi₂WO₆ photocatalytic material was synthesized by the one-step hydrothermal reaction. The construction of Z-scheme heterojunction led to the rapid separation of photogenerated electrons and holes, which would degrade RhB into small molecular substances to achieve the purpose of degradation.

It was found that Bi₂WO₆/25%g-C₃N₄ displayed the highest photocatalytic activity, which was about 1.44 and 1.34 times higher than that of pure Bi₂WO₆ and g-C₃N₄, respectively. According to the trapping experiments, the superoxide radical (·O²⁻) was the major active species of the RhB decomposition in Bi₂WO₆/g-C₃N₄ catalysts.

The successful synthesis of Z-scheme Bi₂WO₆/g-C₃N₄ provides new ideas and references for the design of catalysts with high photocatalytic activity, which should have wide applications in the future.

This study aims to investigate the morphology and physicochemical properties of BiOBr/Polyvinylidene fluoride (PVDF) composite membranes and the differences in the properties of BiOBr/PVDF composite membranes made by adding different precursor ratios during the casting process.

In this paper, sodium bromide and Bi(NO3)3 were used as precursors for the preparation of BiOBr photocatalysts, and PVDF membranes were modified by using the phase conversion method in conjunction with the in situ deposition method to produce BiOBr/PVDF hydrophilic composite membranes with both membrane separation and photocatalytic capabilities.

The characterization results confirmed that the composites were successfully and homogeneously co-mingled in the PVDF membranes. The related performance of the composite membrane was tested, and it was found that the composite membrane with the optimal precursor incorporation ratio had good photocatalytic efficiency and antipollution ability; the removal efficiencies of methyl orange, rhodamine B and methylene blue were 80.43%, 85.02% and 86.94%, respectively, in 2.5 h. The photocatalytic efficiency of composite membranes with different precursor ratios increased and then decreased with the increase of the precursor addition ratio.

The composite membrane is prepared by phase conversion method with in situ deposition method, and the BiOBr material has unique advantages for the degradation of organic dyes. The comprehensive experimental data can be known that the composite membrane prepared in this paper has high degradation efficiency and good durability for organic dyes.

This paper aims to report a novel preparation method of titanium dioxide (TiO₂)/zinc oxide (ZnO) composites with different mole ratios of TiO₂:ZnO and their photocatalytic activity.

TiO₂/ZnO composites are prepared by a facile route. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and ultra-violet–visible diffuse reflectance spectra (UV-vis DRS) are used to characterize the products. Photocatalytic activity of the samples is evaluated by degradation of persistent organic pollutant pentachlorophenol under ultra-violet (UV) irradiation.

It is found that all the as-prepared TiO₂/ZnO composites not only have good catalytic activity under UV light irradiation, but also have excellent circulation stability. The optimal mole ratio of TiO₂:ZnO is 0.75:1.

This report presents a simple and rapid method for the preparation of TiO₂/ZnO composites with excellent photocatalytic activity. Experimental results could provide useful reference for the treatment of chlorophenols in the future.