Synthesis, Characterization, and Antibacterial Properties of 4-Hydroxybenzoic Acid-Capped ZnO Nanoparticles
Faculty Mentor Information
Dr. Jerry Harris, Northwest Nazarene University; and Dr. Jamee Nixon, Northwest Nazarene University
Presentation Date
7-16-2026
Abstract
Zinc oxide nanoparticles have received attention for both their photocatalytic and antimicrobial applications. The materials are inexpensive, have desirable physicochemical properties, and are more environmentally friendly than alternative materials. Zinc oxide was capped with 4-hydroxybenzoic acid (4HBA) to enhance ZnO’s antimicrobial properties. A 2:1 ratio of capping ligand-to-zinc was used for the synthesis. The materials were prepared using both a rapid and a slow synthesis method. ZnO was also prepared without capping molecules to serve as controls. The nanomaterials were synthesized using zinc nitrate and 4-hydroxybenzoic acid in isopropanol solutions by alkali precipitation, isolated by centrifugation, washed with water and methanol, and then annealed at 200˚C under an inert atmosphere. The synthesis temperature was 82˚C. The materials were characterized by FTIR, TGA, XRD and TEM. The thermal analysis found that the capped materials lost 27-38% of their mass when heated to 1,000˚C. The materials were also tested against a panel of microbes, including Escherichia coli, Bacillus cereus, and Candida albicans, to determine IC50s and Minimum Inhibitory Concentrations.
Synthesis, Characterization, and Antibacterial Properties of 4-Hydroxybenzoic Acid-Capped ZnO Nanoparticles
Zinc oxide nanoparticles have received attention for both their photocatalytic and antimicrobial applications. The materials are inexpensive, have desirable physicochemical properties, and are more environmentally friendly than alternative materials. Zinc oxide was capped with 4-hydroxybenzoic acid (4HBA) to enhance ZnO’s antimicrobial properties. A 2:1 ratio of capping ligand-to-zinc was used for the synthesis. The materials were prepared using both a rapid and a slow synthesis method. ZnO was also prepared without capping molecules to serve as controls. The nanomaterials were synthesized using zinc nitrate and 4-hydroxybenzoic acid in isopropanol solutions by alkali precipitation, isolated by centrifugation, washed with water and methanol, and then annealed at 200˚C under an inert atmosphere. The synthesis temperature was 82˚C. The materials were characterized by FTIR, TGA, XRD and TEM. The thermal analysis found that the capped materials lost 27-38% of their mass when heated to 1,000˚C. The materials were also tested against a panel of microbes, including Escherichia coli, Bacillus cereus, and Candida albicans, to determine IC50s and Minimum Inhibitory Concentrations.