Synthesis, Characterization and Study of Photocatalytic Activity of Cadmium Magnesium Nano Ferrites

After studying the above mentioned literature of different ferrites and metal oxide photocatalytic degradation properties, we have synthesized the Cd-Mg Ferrites to determine its organo pollutant Methyl Orange photo catalytic degradation. Cd-Mg Ferrite is synthesized by co-precipitation method and heat treated to 600°C for phase formation and then characterize by XRD, SEM, FTIR and DSC. After confirmation from their characterization, their band gap energy is determined by using UV-Visible Spectrophotometer and then Photocatalytic properties in the presence of sunlight by degradation of Methyl Orange. Materials and Method


Introduction
Semiconductor oxides are important for many environmental and energy issues because, they cannot only utilize solar energy to eliminate harmful pollutants present in air and water but also effectively detect toxic and hazardous gases as well as biological species [1,2].
The consumption of non-renewable energy sources such as fossil fuels is less favorable nowadays, not only because of current shortage and a final exhaustion of these sources but also for serious environmental considerations [3,4].
The conversion of solar energy (electromagnetic radiation) into a practically applicable form can be achieved by a photo catalyst (i.e. semiconductor with an appropriate band gap and band edges) through a process that is similar to photosynthesis [4,5].
After studying the above mentioned literature of different ferrites and metal oxide photocatalytic degradation properties, we have synthesized the Cd-Mg Ferrites to determine its organo pollutant Methyl Orange photo catalytic degradation. Cd-Mg Ferrite is synthesized by co-precipitation method and heat treated to 600°C for phase formation and then characterize by XRD, SEM, FTIR and DSC. After confirmation from their characterization, their band gap energy is determined by using UV-Visible Spectrophotometer and then Photocatalytic properties in the presence of sunlight by degradation of Methyl Orange.

Co-precipitation method
Chemical methods for the synthesis of are believed to be better than the physical methods because chemical reaction take place at molecular level. Because of this reason shape, size and morphology of the nanoparticles can be controlled in a better way. In this work I followed [6,7] a chemical method Co-precipitation for the synthesis of Cd x Mg 1-x Fe 2 O 4 nanoparticles, which is explained below.
• Stoichiometric quantity of metal salts solution was prepared separately in de-ionized water. These solutions then mixed together and heated to 80°C with continuous stirring.

Abstract
To the best of our knowledge, there are no reports has been cited in the literature on the photo catalytic properties of Cd x Mg 1-x Fe 2 O 4 ferrite nanoparticles under solar light irradiation to till date. Considering the importance of Cd x Mg 1-x Fe 2 O 4 nanoparticles and their wide applications, we made an attempt to synthesize Cd x Mg 1-x Fe 2 O 4 (x=0.3,0.5,0.7,1.0) nanoparticles by co-precipitation method at 80°C then filtered and washed with distilled water. After drying, heat treatment was carried out for 3 hours at 600°C. The prepared samples were characterized using XRD (X-ray Diffraction

SEM analysis
The scanning electron microscopy studies were undertaken for the samples of Cd x Mg 1-x Fe 2 O 4 and images are shown in Figure 2. It is evident from the SEM micrographs that these samples have uniform, almost spherical structural, morphology with a narrow size distribution of the particles. The particle size of these nano ferrites are in the range from 20 nm to 40 nm.

FT-IR
FTIR spectra were recorded in the range of 400-4000 cm -1 as shown in the Figures 3a-3d. The IR bands of solids are usually assigned to the vibrations of ions in the crystal lattice. Two main broad metal-oxygen bands are seen in the FTIR spectra of all ferrites in particular.
• 2 M NaOH solution was prepared separately and heated to 80°C.
• Then poured the NaOH solution into the metal salt solution with continuous stirring and heated for 45 mints, after 45 mints the heating is stopped but stirring continue till the mixture temperature reached to room temperature, then filter the solution through wattman filter and precipitate washed with de-ionized water till pH reached to 7. These precipitates were dried in oven for two hours at 120°C. After drying each sample heat treated in furnace for 3 hours at 600°C.

XRD analysis
To evaluate the crystal structure of Cd x Mg 1-x Fe 2 O 4 analysis were carried out and the XRD images of the samples are presented in Figure  1. D=0.9λ/β cosθ (1) β is the broadening of the diffraction line measured at half maximum intensity (radians) and λ =1.5406 A˚ , the wavelength of     Similarly the lattice vibration of oxide against to metal absorption band in CdFe 2 O 4 is 1120 cm -1 as the Cd concentration increases these value decreases and in Cd 0.7 Mg 0.3 Fe 2 O 4 there is no lattice vibration of oxide to metal. This FTIR spectrum results are quite similar to that given in the literature.

DSC: differential scanning calorimeter
The DSC (Differential Scanning Calorimetric) curves observed for The dried samples peaks at 120°C, show low endothermic peaks near about100°C, with different peak width, grater the peak width greater amount of water is evolving, smaller the peak width less amount of water is present which is evolving from the surface, except CdFe 2 O 4 and many other small endothermic peaks show while heat treated samples at 600°C show one endothermic peak near about 235-250°C showing the trapped water removal, while no other endothermic or exothermic peaks are observed but show straight line in ascending mode., Which

Optical studies
To determine the Band gap energy by using the UV-Visible Spectrophotometer (UV-1800 Shimadzu Japan), the samples first dispersed in ethanol, by using the Sonicator for 10 minutes then each sample run on UV-Visible Spectrophotometer in the range from 200 nm to 800 nm to determine the cut off wavelength by using the ethanol as a reference in the Scan measure mode as shown in the Figures 5a-5d.
By putting the value of cut off wavelength of each sample in the general equation E=hc/λ, band gap energy is determined   Table 2.

MO degradation
To examine the photocatalytic degradation properties of the Cd x Mg 1-x Fe 2 O 4 , we have selected the Methyl Orange which is one of the great Organic pollutants of dyes industries and not easily degraded, therefore we added 0.05 g of each nano ferrite samples in 50 ml of 10      Table 3 and as a graphically shown in Figure 6.

Conclusion
Photocatalytic activity of Co-precipitation synthesized Cd x Mg 1x Fe 2 O 4 was evaluated by photocatalytic decomposition/degradation of MO in aqueous solution at room temperature. 0.05 g of each samples were placed into the 50 ml volumetric flask containing 50 mL of 10 ppm of MO aqueous solutions and mixed by ultrasonication for 10 min. Subsequently, the mixture was stirred in dark to obtain adsorption/desorption equilibrium. Through UV-Vis Spectro photometer, then after different intervals of time the specific volume of samples is separated from the mother solution of each Cd x Mg 1-x Fe 2 O 4 sample and centrifuged and then run against the standard curve and determined its concentration as illustrated in Figure 6 and Table  3. The result shows that with the passage of time the concentration of methyl orange is decreases as tabulated in graph. These results confirm that the effective degradation of the MO occurs only in the presence of Cd x Mg 1-x Fe 2 O 4 and sunlight irradiation, and this is the first time we are reporting Cd x Mg 1-x Fe 2 O 4 as a new photo catalyst to degrade MO organic contaminant. The average particle size of Cd x Mg 1-x Fe 2 O 4 is 35 nm was synthesized by co-precipitation process, and the formation of Cd x Mg 1-x Fe 2 O 4 was confirmed through XRD, SEM, FTIR and DSC. The band gap energy of each sample is determined by using UV-Vis Spectrophotometer. Photocatalytic activity of Cd x Mg 1-x Fe 2 O 4 was evaluated on Methyl Orange degradation under sunlight and found to be effective on degrading the methyl orange at room temperature.