Environmental pollution from persistent pharmaceuticals like carbamazepine (CBZ) poses severe risks to aquatic ecosystems and human health, yet conventional treatments struggle with low concentrations and secondary pollution. Piezo-photocatalysis, which harnesses mechanical and solar energies to drive charge separation, offers a promising alternative using materials such as molybdenum disulfide (MoS₂), whose layered structure enables tunable piezoelectricity but is hindered by rapid electron-hole recombination and structural instability. However, the mechanistic role of oxygen doping in repairing sulfur vacancies and enhancing symmetry-breaking for improved performance remains underexplored. Here we show that hydrothermally synthesized oxygen-doped MoS₂ (O₅-MoS₂) fully degrades 2 mg L^-1 CBZ in 25 min under combined ultrasound and visible light, achieving a rate constant (k _obs) of 0.13 min^-1-11.4 times higher than undoped MoS₂. This stems from oxygen substitution narrowing the bandgap to 1.94 eV, boosting the piezoelectric coefficient to 63 p.m. V^-1 (versus 26 p.m. V^-1), and generating a 0.19 V built-in potential that drives charge separation, as confirmed by 4.18 μA cm^-2 synergistic photocurrents, density functional theory calculations revealing heightened Mo-O charge transfer (2.08-2.36 e^-), and finite element simulations of deformation-induced fields. Over five cycles, O₅-MoS₂ retains 100 % efficiency with minimal Mo leaching (1.9 %), reducing product toxicity across fish, daphnid, and algal models. These findings delineate oxygen doping's dual role in defect mitigation and polarization enhancement, paving the way for robust piezo-photocatalytic systems in real-world water purification.

Ferrate as an environmentally friendly oxidant has been widely used in the environmental remediation and versatile functionalization of carbon-based materials. In this study, we investigated its ability to induce surface wettability of polymers and its emerging applications in separating mixed plastics through flotation for recycling. It was found that ferrate (VI) formed oxygen-containing groups on the surface of polycarbonates (PCs) by selectively oxidizing the sp³-hybridized carbon atoms into hydroxyl and carboxyl moieties, in addition to introducing nanoscale iron oxides. This facilitated the selective hydrophilization of PC with a water contact angle of 60.7° but did not clearly affect the surface wettability of polyvinyl chloride (PVC). This difference in surface wettability highlighted the distinct floatability properties of PC and PVC, which can be utilized to separate mixtures of these plastics with the aid of flotation. A central composite design (CCD) utilizing response surface methodology (RSM) was applied to model ferrate oxidation and to optimize flotation. Under the optimized conditions, mixtures of PC and PVC were efficiently separated with recovery and purity values of more than 99.8 ± 0.3%. Our findings provide a rational understanding of polymer wettability tailoring and expand its emerging applications in waste plastic recycling to address environmental problems.

Due to the shortage of freshwater and the depletion of groundwater, reuse of wastewater for crop irrigation has become essential, although many pollutants, such as antibiotics, are also introduced into the soil-groundwater system. In order to identify the distribution and transport mechanisms of organic pollutants in the "irrigation wastewater-soil-crop" system under long-term soil irrigation conditions and their potential ecological and health risks, soil samples were collected from five sampling sites in Wangyang River basin, a typical sewage irrigation area in North China. The results of the risk assessment showed that the risk quotients (RQ) of sulfamethoxazole (SMZ), naphthalene (Nap), hexachlorocyclohexane (HCH), and dichlorodiphenyltrichloroethane (DDTs) was greater than 1, indicating that their accumulation in root zone soil was at high risk. The non-carcinogenic risk (HQ) of bis (2-ethylhexyl) phthalate (DEHP) was the largest, reaching 0.41 and 0.16 for adults and children, respectively, and the carcinogenic risk (CR) value was 0.00061, which exceeded the limit of 1 × 10⁻⁶, indicating that DEHP poses a potential carcinogenic risk to human health.