Hybrid humic acid/titanium dioxide nanomaterials as highly effective antimicrobial agents against gram(-) pathogens and antibiotic contaminants in wastewater

Humic acids (HAs) provide an important bio-source for redox-active materials. Their functional chemical groups are responsible for several properties, such as metal ion chelating activity, adsorption ability towards small molecules and antibacterial activity, through reactive oxygen species (ROS) generation. However, the poor selectivity and instability of HAs in solution hinder their application. A promising strategy for overcoming these disadvantages is conjugation with an inorganic phase, which leads to more stable hybrid nanomaterials with tuneable functionalities. In this study, we demonstrate that hybrid humic acid/titanium dioxide nanostructured materials that are prepared via a versatile in situ hydrothermal strategy display promising antibacterial activity against various pathogens and behave as selective sequestering agents of amoxicillin and tetracycline antibiotics from wastewater. A physicochemical investigation in which a combination of techniques were utilized, which included TEM, BET, C-13-CPMAS-NMR, EPR, DLS and SANS, shed light on the structure-property-function relationships of the nanohybrids. The proposed approach traces a technological path for the exploitation of organic biowaste in the design at the molecular scale of multifunctional nanomaterials, which is useful for addressing environmental and health problems that are related to water contamination by antibiotics and pathogens.

Automated summary

Hybrid humic acid/titanium dioxide nanostructured materials show promising antibacterial activity against various pathogens and selective sequestering of specific antibiotics, with a technological approach highlighted for the design of multifunctional nanomaterials addressing environmental and health problems related to water contamination by antibiotics and pathogens.