Visible-light-assisted peroxymonosulfate (PMS) activation is flourishing in wastewater decontamination, but exploiting safe and efficient activators remains challenging due to a deficient cognition of the activated mechanisms. Hereby, a metal-free g-C3N4 isotype heterojunction (HCN) was successfully synthesized and activated PMS under visible light. The Z-scheme isotype heterojunction significantly meliorated light absorption and carrier migration, thereby enhancing PMS activation. The optimal HCN + PMS system almost completely removed ranitidine (RAN) in 30 min with 7.46-8.48 times higher activity than the monomers. Through systematic experiments and characterizations, we proposed a non-radical mechanism of PMS activation, which generated predominated surface-activated complex and singlet oxygen (1O2) for pollutant removal. The surfaceactivated complex degraded RAN by drawing its electrons. This non-radical pathway exhibited tolerance towards background substances and pH fluctuations. Additionally, the broad-spectrum decontamination and recyclability of the system further enhanced its practical applicability. Notably, intermediate analyses confirmed the RAN degradation pathways predicted by theoretical calculations, with the resulting intermediates found to be nontoxic. This study significantly contributes to our understanding of the non-radical mechanisms of PMS activation on g-C3N4-based activators for micropollutant degradation.

The impact of the built environment and weather conditions on travel behavior has been widely studied. However, limited studies have focused on better understanding such effects in medium-sized cities with bus-oriented transit systems, particularly from a separate perspective of travelers’ origins and destinations. We took Weinan, China, as a representative of second-tier cities in developing countries that concentrate on bus-oriented development strategies. New evidence of feature importance and nonlinear effects of crucial factors were revealed by an interpretable machine learning-based approach combining XGBoost and Shapley Additive Explanation (SHAP) with multi-source data. Most key factors were critical at both origins and destinations, such as the density of residential and commercial facilities. However, several important factors, such as road density and boarding time, had strong imbalanced effects on travel behavior. These findings provide novel insights and empirical implications to support urban planning strategies in medium-sized cities.

Greenhouses rely on an appropriate environment to support vegetable growth, and multi-pipe earth-to-air heat exchangers (EAHEs) are commonly used to regulate the temperature. In greenhouses, the high humidity resulting from plant respiration and transpiration has a significant effect on the thermal performance of EAHEs. This study employs the Taguchi method to optimize the multi-pipe EAHE for greenhouse applications, and high humidity conditions were taken into account. A complete greenhouse model was established, and experiments were conducted in Shandong province with real-time monitoring data used to verify the thermal environment of the greenhouse. Multivariate analysis was performed on EAHE parameters to evaluate their integrated performance. The optimized design combination was then implemented in the greenhouse. The findings reveal that the inlet air temperature exerted the most substantial influence on the integrated performance of the EAHE system, contributing significantly with a percentage of 45.20%. The velocity of the inlet air and diameter of pipes followed with contributions of 21.98% and 18.39%, respectively. The optimized EAHE system significantly improved the greenhouse's thermal environment, with the air diffusion performance index (ADPI) increasing to 65% and 98.33% at noon and midnight, respectively, making it more suitable for tomato growth. This study provides guidelines for selecting EAHE parameters in greenhouse applications, paving the way for the widespread use of EAHE systems in greenhouses.

The accumulation of highly fluid and biotoxic hexavalent chromium (Cr(VI)) impairs water ecosystems. It is urgent to quickly reduce Cr (VI) to trivalent chromium (Cr (III)) in wastewater. Hereby, Z-scheme MgIn2S4/BiPO4 heterojunction was prepared, and MB-30 (mass ratio of BiPO4 to composite) presented a rapid Cr(VI) (10 mg L−1) removal efficiency of 100% within 10 min, its kinetic rate constant was 9.0 and 30.1 folds that of MgIn2S4 and BiPO4, respectively. After four rounds, MB-30 maintained a high removal rate of 93.18% and stabilized crystal texture. First-principles calculations revealed that the formation of Z-scheme heterojunction could ameliorate charge generation, detachment, migration capability, and light utilization. Meanwhile, the coupling of S and O in the two components produced a tight S–O bond, which acted as an atomic-level access to promote carrier migration. The findings were consistent with the structure superiority and optical and electronic properties of MB-30. The Z-scheme pattern was substantiated based on multifarious experiments, which exhibited an elevated reduction potential while emphasizing the significance of interfacial chemical bond and the internal electric field (IEF) on carrier detachment and migration.

The evidence so far indicates that ranitidine (RAN) contains N-nitrosodimethylamine (NDMA), a strong carcinogen, which is extremely harmful to human health under long-term exposure. Hence, a well-design Zscheme heterostructure composed of 3D MgIn2S4 micro-flower and 2D g-C3N4 nanosheets was fabricated and used to remove RAN. The optimal photocatalyst (MG-30) exhibited the fastest RAN degradation rate of 0.24685 min-1 within 30 min under visible light, which was 78.1 and 19.8 times higher than those of bare MgIn2S4 and gC3N4, respectively. Impressively, MG-30 was exceedingly resistant to environmental variations including organic matter, inorganic salts and aqueous substrates. In the meantime, MG-30 boasted the merit such as wide pH range for RAN removal. The excellent results originated from the construction of Z-scheme heterojunctions, which improved the carrier separation efficiency and retained the strong redox ability of MG-30, thereby contributing to the creation of rich active species. Meanwhile, the 3D/2D structure of MgIn2S4/g-C3N4 overrode the limited reflection of visible light. The active species analyses revealed that superoxide radical (& sdot;O2- ) and hydroxyl radical (& sdot;OH) mainly participated in RAN degradation. Furthermore, the possible degradation pathways of RAN and toxicity analysis of intermediates produced were presented. This work emphasizes practical application potential of Z-scheme heterostructure photocatalysts for emerging contaminants degradation in wastewater.