Carrageenan Assisted Synthesis of Morphological Diversity of CdO and Cd (OH)2 with High Antibacterial Activity

Abstract

This research reports a simple method for the controlled synthesis of cadmium oxide (CdO) and cadmium hydroxide (Cd(OH) 2 ) with different morphology in the presence of NaBH 4 or LiBH 4 as reducing agent, by using k-carrageenan as a capping agent and potassium bromide as a template. The synthesized products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The impacts of reducing agent, reaction atmosphere and concentration of reducing agent on size and morphology of the particles were discussed. We suggested that chemical etching and Kirkendall effect play a key role on morphology of particles, and the etch rate depends on reducing agent concentration. It was found that by increasing the concentration of reducing agent the intensified etching lead to an increase in the size of the particles. The results show an increase in particle size with decreasing reducing agents power. The various morphologies obtained for CdO and Cd(OH) 2 such as hollow cube, macro rod, nanoplate and macroplate were discussed based on the Kirkendall effect and chemical etching. Finally, the antibacterial activity was screened against Escherichia coli and Staphylococcus aureus . The inhibition zones were ranged from 36-47 mm and 25-47 mm for different morphologies of CdO and Cd(OH) 2 respectively.