Exploiting bioderived humic acids: A molecular combination with ZnO nanoparticles leads to nanostructured hybrid interfaces with enhanced pro-oxidant and antibacterial activity

The waste-to-wealth strategy is encouraging the design of a plethora of new value-added materials, by exploiting the chemical and biological richness of biowastes. Humic Acids (HA) are mostly intriguing because of their amphiphilic supramolecular associations which are responsible for several assets, such as adsorption ability towards small molecules, metal ion chelation, redox behavior, and antibacterial activity. The molecular com-bination of HA with semiconductor nanoparticles represents a valuable strategy to obtain nanostructured hybrid materials and interfaces with advanced features. Concurrently, it permits to overcome intrinsic limits of such organic fraction, including poor stability, fast conformational dynamics, or rapid reactivity in aqueous media. Herein, hybrid HA/ZnO nanoparticles are synthetized through a bottom-up strategy, exerting an improved pro -oxidant behavior by generating Reactive Oxygen Species, even without light irradiation, favoring an enhanced photocatalytic and antimicrobial activity against different bacterial pathogens. Several techniques, including SEM/TEM, DLS, zeta-potential, XRD, FTIR, TGA/DSC, EPR and DRUV, allows to define the structure-property -function relationships, thus highlighting the crucial role of a fine conjugation amongst the metal oxide precur-sor and bioderived fraction to drive the pro-oxidant activity. This study provides strategic guidelines to easily produce low-cost organo-inorganic nanomaterials with redox and biocide properties, aimed at coping environ-mental and health issues.

Automated summary

The waste-to-wealth strategy promotes the design of new value-added materials using biowastes. Humic Acids (HA) are intriguing due to their supramolecular associations, which enable adsorption, chelation, redox behavior, and antibacterial activity. Combining HA with semiconductor nanoparticles allows for the creation of nanostructured hybrids with advanced properties. The study provides insights into producing low-cost organo-inorganic nanomaterials with redox and biocide properties to address environmental and health issues.