Abstract
Multiwalled carbon nanotubes (MWCNTs) were synthesized using arc discharge method at a magnetic field of 430 G and purified using HNO3/H2O2. Transmission electron micrographs revealed that MWCNTs had inner and outer diameter of ~2 nm and ~4 nm, respectively. Raman spectroscopy confirmed formation of MWCNTs showing G-band at 1577 cm−1. ZnFe2O4 and ZnFe2O4/MWCNT were produced using one step hydrothermal method. Powder X-ray diffraction (XRD) confirmed the formation of cubic spinel ZnFe2O4 as well as incorporation of MWCNT into ZnFe2O4. Visible light photocatalytic degradation of methylene blue (MB) was studied using pure ZnFe2O4 and ZnFe2O4/MWCNT. The results showed that ZnFe2O4/MWCNT composite had higher photocatalytic activity as compared to pure ZnFe2O4. After irradiation for 5 hours in the visible light, MB was almost 84% degraded in the presence of ZnFe2O4 photocatalyst, while 99% degradation was observed in case of ZnFe2O4/MWCNT composite. This enhancement in the photocatalytic activity of composite may be attributed to the inhibition of recombination of photogenerated charge carriers.
Highlights
Solar energy active photocatalysts have been a promising material for an environmental purification process
The photocatalytic activity of ZnFe2O4 and ZnFe2O4/Multiwalled carbon nanotubes (MWCNTs) was evaluated by degradation of aqueous solution of methylene blue (MB) under visible light irradiation. 50 mg of catalyst was added to 50 mL of 10 mg/L aqueous solution of MB
Predominance of MWCNTs having diameter of around 2–4 nm in the prepared sample was clearly shown by Transmission electron micrographs (TEM) image
Summary
Solar energy active photocatalysts have been a promising material for an environmental purification process. Efforts have been made to synthesize materials capable of utilizing solar spectrum for the photo degradation of industrial waste pollutants and dyes [1]. Degradation of organic pollutants and dyes such as methylene blue, bromophenol blue, and Chicago sky blue from industrial waste water remains as a challenge because of low visible light photo catalytic activity of metal oxides and sulphides [4,5,6]. The advantage of ferrites as photo catalysts is their capability to absorb visible light solar irradiation because of low band gap and large availability of catalytic sites for adsorption of noxious waste and dyes [11]. Degradation of organic pollutants and toxic dyes has been an important aspect to study the photo catalytic efficiency of magnetic CNT composites [25]. Due to enhancement in photochemical activity of ZnFe2O4/MWCNTs composite, it is found to degrade almost 99% of the MB dye
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