Augmented antibacterial mechanism of ZnO nanoparticles by labyrinthian-channel configuration of maize-stalk carbohydrate columns and sustainable strategy for water decontamination.

Zinc oxide nanoparticles (ZnO NPs) as a broad-spectrum germicide in environmental remediation applications, is hindered by mild toxicity to organisms during water sterilization. To solve this dilemma, this work provided an eco-benign approach to utilize maize stalk with natural labyrinthine-channel configuration simultaneously acting as microbe trap and bactericide carrier to arouse bactericidal response of ZnO NPs. The preparation comprises in-situ growing ZnO NPs, accompanied by nanoscale delignification, leading to formed carbohydrate complex retaining the intricately porous structure of the stalk. Assembled by maize-stalk carbohydrate (MSC) composites with 9 short composites in serial, the elimination of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) reached up 6.7 and 4.8 orders of magnitude, respectively. Labyrinth-framework MSC provided favorable sites for fusiform flower-like ZnO NPs to strongly adsorb (adsorption energy 5.5-11.7 eV) phosphoryl-involved biomacromolecules of bacterial envelops, causing generation of stable Zn-P and Zn-O(H), then cell incompleteness, cellular redox imbalance and DNA damage. Breakthrough analysis exposed the MSC/ZnO-filter possessing remarkable features of antibacterial exhaustion rate (~ 1.06 g/L) and capacity (~ 9.6 × 109 CFU/g) which were comparable with Ag-based composites. As evaluated by the logistic and Gompertz models, the filters effectively sterilized 0.97-10 L of environmental waters to meet the requirements of drinking water.