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Article
Publication date: 2 January 2018

Pei Qin, Guobin Yi, Xihong Zu, Huan Wang, Hongsheng Luo and Miao Tan

The aim of this paper is to synthesize graphene-modified titanium dioxide (GR-TiO2) nanorod arrays nanocomposite films, so that these can enhance the photocatalytic properties of…

Abstract

Purpose

The aim of this paper is to synthesize graphene-modified titanium dioxide (GR-TiO2) nanorod arrays nanocomposite films, so that these can enhance the photocatalytic properties of titanium dioxide and overcome the problem of difficult separation and recovery of photocatalysts.

Design/methodology/approach

The GR-TiO2 nanocomposite films were synthesized via hydrothermal method and spin-coating. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), ultraviolet–visible (UV-Vis) diffuse reflectance spectrum and Raman spectrum. The photocatalytic performance of the GR-TiO2 nanocomposite films for degrading Rhodamin B under ultraviolet (UV) was studied by a UV-Vis spectrophotometer. The photocatalytic enhancement mechanism of graphene was studied by photoelectrochemical analysis.

Findings

The introduction of graphene expanded the range of the optical response of TiO2 nanorod arrays, improving the separation efficiency of the photogenerated electron-hole pairs, and thus dramatically increasing its photocatalytic performance.

Research limitations/implications

A simple and novel way for synthesizing GR-TiO2 nanocomposite films has enhanced the photocatalytic performance of TiO2.

Originality/value

The photocatalyst synthesized is easy to separate and recycle in the process of photocatalytic reaction, so it is possible to achieve industrialization.

Details

Pigment & Resin Technology, vol. 47 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 7 September 2012

M. Rashidzadeh, B. Faridnia and M.R. Ghasemi

The purpose of this paper is to study the effect of synthesis conditions on properties of TiO2 nanoparticles to be used for photocatalysis and also producing TiO2 using a low…

1366

Abstract

Purpose

The purpose of this paper is to study the effect of synthesis conditions on properties of TiO2 nanoparticles to be used for photocatalysis and also producing TiO2 using a low temperature method.

Design/methodology/approach

TiO2 nanoparticles were synthesised via a sol‐gel method at low temperature and the effect of parameters such as: synthesis temperature, HNO3 concentration, calcination temperature and synthesis time on properties of TiO2 were studied. The effects of the physico‐chemical properties of TiO2, its concentration and light intensity on photocatalytic properties of TiO2 nanoparticles were investigated also.

Findings

The results showed that TiO2 with Anatase phase were formed at 80‐100°C by using proper HNO3 concentration, synthesis time and calcinations temperature. Calcinations programme and temperature and also the synthesis time affect the formation of TiO2 crystalline phase (i.e. Rutile and Brookite), their surface area and crystallite size. To evaluate the photocatalytic properties of TiO2 nanoparticles, fluorescein was used as a model molecule. Results showed that degradation of fluorescein could be described by pseudo‐first order kinetics. The effect of TiO2 concentration and light intensity on photocatalytic activity showed that increasing concentration of TiO2 and the light intensity would increase the degradation of fluorescein.

Originality/value

The method used in this work to prepare TiO2 nanoparticles is an economic method for low temperature synthesis of TiO2 nanoparticles with high photocatalytic activity, which could find numerous applications in coating technology.

Details

Pigment & Resin Technology, vol. 41 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 30 October 2018

Tanya L. Swer, Komal Chauhan, Prodyut K. Paul, C. Mukhim, Khalid Bashir and Rachna Sehrawat

An upsurge in health and environmental concerns over the use of synthetic color has made the development of color from cheap and easily available natural sources, namely, plants…

Abstract

Purpose

An upsurge in health and environmental concerns over the use of synthetic color has made the development of color from cheap and easily available natural sources, namely, plants, animals, micro-organisms and algae as indispensable. This study aims to extract anthocyanins, an important natural plant pigments, from Sohiong (Prunus nepalensis). This study demonstrated that Sohiong have high anthocyanins content and antioxidant property, indicating an immense potential for the fruit producers and food processors.

Design/methodology/approach

Response surface methodology was used to optimize the conditions for extraction of anthocyanins from Sohiong using conventional solvent extraction.

Findings

The optimum conditions for extraction were found to be 36.75°C temperature, 60.32 per cent ethanol concentration and 2.39 per cent citric acid concentration with recovery of 45 per cent total extract yield, 858.84 mg C3G/100g DM anthocyanin content and 824.91 mg GAE/100g DM phenolic content with in-vitro antioxidant activity of 31.40 mmol AEAC/100g DM for FRAP and 84.66 per cent DPPH scavenging capacity (20mg/ml). The F-values and high values of adjusted determination coefficient for each response imply high level of significance of the fitted models.

Practical implications

Extracted color can be used in food and pharmaceutical industries.

Social implications

Pigment extracted is from a natural source and possesses high antioxidative activity and potential health benefits. With increasing demand for natural colors and other additives, there is a wide range of applications of the pigment as natural colorant in the food and pharmaceutical sector.

Originality/value

Selected plant source, i.e. Sohiong, was not used earlier by any researcher to extract anthocyanins for potential applications as food colorant.

Details

Pigment & Resin Technology, vol. 47 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 16 March 2015

Adriana Bonilla Riaño, Antonio Carlos Bannwart and Oscar M.H. Rodriguez

The purpose of this paper is to study a multiphase-flow instrumentation for film thickness measurement, especially impedance-based, not only for gas–liquid flow but also for…

Abstract

Purpose

The purpose of this paper is to study a multiphase-flow instrumentation for film thickness measurement, especially impedance-based, not only for gas–liquid flow but also for mixtures of immiscible and more viscous substances such as oil and water. Conductance and capacitive planar sensors were compared to select the most suitable option for oil – water dispersed flow.

Design/methodology/approach

A study of techniques for measurement of film thickness in oil – water pipe flow is presented. In the first part, some measurement techniques used for the investigation of multiphase flows are described, with their advantages and disadvantages. Next, examinations of conductive and capacitive techniques with planar sensors are presented.

Findings

Film thickness measurement techniques for oil–water flow are scanty in the literature. Some techniques have been used in studies of annular flow (gas–liquid and liquid–liquid flows), but applications in other flow patterns were not encountered. The methods based on conductive or capacitive measurements and planar sensor are promising solutions for measuring time-averaged film thicknesses in oil–water flows. A capacitive system may be more appropriate for oil–water flows.

Originality/value

This paper provides a review of film thickness measurements in pipes. There are many reviews on gas – liquid flow measurement but not many about liquid – liquid flow.

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