Lanthanum Doped Zinc Molybdate: Antibacterial and Photo-Catalysis Properties

This study investigates unique and specific properties of the lanthanum based zinc molybdate nanocomposite material. The lanthanum zinc molybdate nanocomposite material was synthesized using a simple and low cost “co-precipitation” method. The synthesized nano materials had structural, vibrational and morphological properties, determined by X-ray diffraction, fourier-transform infrared spectroscopy and field emission scanning electron microscopy. The synthesized nanomaterial was characterised using a range of techniques. X-ray diffraction was used to determine a particle size of 65.7 nm of the disc shaped hexagonal particle. Further characterisation was done using UV-visible spectroscopy and band gap energy analysis. The band gap value was found to be 3.58 eV. The nanocomposite also exhibited antibacterial activity against bacterial strains of Escherichia coli and Staphylococcus aureus . In the presence of light and air, nanoparticles of lanthanum zinc molybdate nanocomposite were found to inhibit the growth of Escherichia coli due to generation of singlet oxygen and hydrogen oxide radical. However, the same was not observed for S. aureus . Photocatalytic property of lanthanum zinc molybdate nanocomposite was determined using an aqueous solution of methylene blue dye. lanthanum zinc molybdate nanocomposite showed photo-degradation due to the formation of singlet oxygen and hydrogen oxide radical. Complete decolourization of blue colour of the of methylene blue solution at 6 pH was attained, using 40.0 mg lanthanum zinc molybdate nanocomposite, with a constant time interval. With time, the activity of lanthanum zinc molybdate nanocomposite was also found to decrease due to the formation of a hydrogen oxide layer on the surface of the nano material. This could be washed off with ethanol and distilled water. After drying, the catalytic nano particle could be reused for another reaction.