Antibacterial activity of copper exchanged zeolite Y synthesized from rice husk ash

Increasing problems with antibacterial agent primarily bacterial resistance and environmental pollution due to the high release of antibacterial agents in water necessitates the development of new and effective antibacterial agents. One of the techniques that can be used to overcome these problems is by immobilizing antibacterial compounds or any related compounds on the carrier system such as by using zeolite. In this study, zeolite Y was synthesized from rice husk ash as silica source by using hydrothermal technique and it was used as a carrier system for antibacterial copper (Cu) ions. A series of Cu-exchanged zeolite Y was then prepared by loading with different concentrations of Cu ions (100 ppm, 600 ppm and 900 ppm of the Cu(NO3)2) on the synthesized zeolite Y. The Cu-exchanged zeolite Y was characterized by X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR). These characterization techniques showed that the zeolite Y was synthesized in pure phase and had a good degree of crystallinity. Whereas, from the characterization results, zeolite Y was successfully loaded with different concentrations of Cu ions and no structural changes happen after modification. The antibacterial activity of the samples was determined through disc diffusion technique (DDT) against Gram positive bacteria (Staphylococcus aureus ATCC 6538 and Enterococcus faecalis ATCC 29212) and Gram negative bacteria (Escherichia coli ATCC 11229 and Pseudomonas aeruginosa ATCC 15442). Based on the antibacterial results, the synthesized zeolite Y loaded with 900 ppm of Cu2+ showed the highest antibacterial activity compared to that of loaded with 100 ppm and 600 ppm of Cu2+. The higher the Cu concentration on the zeolite Y resulted in the higher antibacterial activity against wide spectrum of bacteria. As a conclusion, synthesized zeolite Y from rice husk ash could be a carrier system for antibacterial Cu ions and it has the potential for the application as antibacterial agents.