Advanced oxidation processes (AOPs) based on peracetic acid (PAA) offer a promising strategy to address antibiotic wastewater pollution. In this study, Fe-doped graphitic carbon nitride (g-C₃N₄) nanomaterials were used to construct Fe-N_x sites, and the electronic structure was tuned by boron nitride quantum dots (BNQDs), thereby optimizing PAA activation for the degradation of antibiotics. The BNQDs-modified Fe-doped g-C₃N₄ catalyst (BNQDs-FCN) achieved an excellent reaction rate constant of 0.0843 min^-1, marking a 21.6-fold improvement over the carbon nitride (CN)-based PAA system. DFT calculations further corroborate the superior adsorption capacity of the Fe-N_x sites for PAA, facilitating its activation. Charge transfer mechanisms, with PAA serving as an electron acceptor, were identified as the source of high-valent iron-oxo species. Moreover, the BNQDs-FCN system preferentially targets oxygen-containing functional groups in antibiotic structures, elucidating the selective attack patterns of these highly electrophilic species. This research not only elucidates the pivotal role of high-valent iron-oxo species in pollutant degradation within the PAA-AOPs framework but also pioneers a wastewater treatment system characterized by excellent degradation efficiency coupled with low ecological risk, thereby laying the groundwork for applications in wastewater management and beyond.

The potential of cyanobacteria to perform a variety of distinct roles vital for the biosphere, including nutrient cycling and environmental detoxification, drives interest in studying their biodiversity. Increasing soil erosion and the overuse of chemical fertilizers are global problems in developed countries. The option might be to switch to organic farming, which entails largely the use of biofertilisers. Cyanobacteria are prokaryotic, photosynthetic organisms with considerable potential, within agrobiotechnology, to produce biofertilisers. They contribute significantly to plant drought resistance and nitrogen enrichment in the soil. This study sought, isolated, and investigated nitrogen-fixing cyanobacterial strains in rice fields, and evaluated the effect of Mo and Fe on photosynthetic and nitrogenase activities under nitrogen starvation. Cyanobacterial isolates, isolated from rice paddies in Kazakhstan, were identified as Trichormus variabilis K-31 (MZ079356), Cylindrospermum badium J-8 (MZ079357), Nostoc sp. J-14 (MZ079360), Oscillatoria brevis SH-12 (MZ090011), and Tolypothrix tenuis J-1 (MZ079361). The study of the influence of various concentrations of Mo and Fe on photosynthetic and nitrogenase activities under conditions of nitrogen starvation revealed the optimal concentrations of metals that have a stimulating effect on the studied parameters.