Adsorption and photocatalytic properties of NiO nanoparticles synthesized via a thermal decomposition process
- PDF / 634,289 Bytes
- 10 Pages / 584.957 x 782.986 pts Page_size
- 55 Downloads / 209 Views
Martha Purna Chander Rao and Sambandam Anandan Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Trichy-620015, India
Hosakoppa Nagarajab) Materials Research Lab, Department of Physics, National Institute of Technology Karnataka, Surathkal, Mangalore-575 025, India (Received 1 August 2017; accepted 23 January 2018)
NiO nanoparticles (NPs) were synthesized at different annealing temperatures via a thermal decomposition process and characterized using X-ray diffraction, scanning electron microscopy, and UV-vis spectroscopy. The NiO NPs prepared at higher annealing temperature (400 °C) were shown excellent adsorption and photocatalytic activity toward textile dyes reactive black 5 (RB-5) and methylene blue (MB). About 87.2% of RB-5 in 60 min and 70.2% of MB in 5 h was removed using NiO NPs synthesized at 400 °C. The photocatalytic degradation of MB was found to increase with an increase in the annealing temperature of the catalyst. Moreover, the kinetic study revealed that the adsorption and photocatalytic activity of NiO NPs followed the second and first-order kinetics, respectively. The enhanced performance of NiO NPs toward dye removal might be related to its optical and structural properties.
I. INTRODUCTION
Synthetic or azo dyes are extensively used in textiles industries, wherein reactive black 5 (RB-5) and methylene blue (MB) are most abundant, excellent fabric, and have a high wet fastness profile. However, these dyes readily reduce into aromatic amines due to the presence of the characteristic double bond of nitrogen (–N5N–), which are potentially hazardous. Thus, effluent released from textile industries causes not only the coloration of water but also poses a threat to aquatic life.1,2 To degrade or eliminate these dyes from the waste water, first dye molecules could be adsorbed on the catalyst. Therefore, based on their molecular structure, the ability of dye adsorption on the catalyst surface can be quantized before and after exposure to light. Some dyes are normally adsorbed on the catalyst even at mild conditions. Other dyes are resistant to adsorption but can contribute to photocatalysis. In such cases, light can couple a molecular dye and catalyst through their coadsorption on the semiconducting surface, using photon as a scaffold and solid state charge mediator. Contributing Editor: Artur Braun Address all correspondence to these authors. a) e-mail: [email protected] b) e-mail: [email protected] DOI: 10.1557/jmr.2018.30
There are many physical, chemical, and biological methods for removal of dye from wastewater.3–6 The advanced oxidation process is an alternative route for water purification. The photocatalytic process seems to be an efficient tool in the presence of light since it uses oxidizing species such as hydroxyl radicals to degrade the organic affluent. Adsorption is also a very promising technique to eliminate the contaminants due to its simplicity and effectiveness. Carbon-based materials and various metal oxides were used as
Data Loading...
