Yaoning Chen

In composting, humification is critical for final compost quality and effectiveness and involves small molecules polymerizing into humic substances (HS). Microbial metabolism, as the core process of composting, drives this transformation. However, the full relationship between microbial metabolic processes and humification-related polymerization remains unclear in current research. This review first examines humification polymerization mechanisms from the perspective of precursors through functional group reactions and radical oxidative coupling. Then, it systematically elucidates the central role of microbial extracellular and intracellular metabolisms in driving the humification process. On the one hand, the effects of hydrolases and oxidoreductases of extracellular metabolism on the polymerization are elaborated in detail. On the other hand, it delves into the dual contributions of intracellular metabolism: catabolism supplies essential precursors and active energy for polymerization reactions through substance degradation and oxidative phosphorylation, while anabolism is directly involved in the biosynthesis of humus precursors. This work aims to provide a comprehensive theoretical framework for understanding the microbial driving mechanisms behind humification.

Sludge-derived biochar enables sensitive BDE-47 detection without pretreatment. The modified electrode achieved a 5 ng L ⁻¹ detection limit and was validated in real water samples, offering a robust tool for POPs monitoring.

2,2′,4,4′-Tetrabromodiphenyl ether (BDE-47) is a refractory organic pollutant that is characterized by its persistence, toxicity and potential for bioaccumulation. As a typical biocontrol bacteria, Pseudomonas protegens has not been reported to degrade organic pollutants in the environment. A single strain of Pseudomonas protegens was isolated and acclimated from municipal sludge, and its ability to degrade BDE-47 was investigated. The enhancing effects of different carbon sources and inducers on Pseudomonas protegens were also examined. Through the reinforcement of bacterial enhancers, Pseudomonas protegens was applied to remediate soil and water contaminated with BDE-47. Based on colony characteristics, physiological and biochemical properties, and 16S rDNA gene sequence homology analysis, the strain was identified as Pseudomonas protegens and named YP1. This marks the first discovery of Pseudomonas protegens being capable of degrading BDE-47. Strain YP1 utilized BDE-47 as a carbon source and achieved a degradation rate of 69.57% after 75 h of incubation under conditions of 37 °C, pH 7, and constant temperature in a dark shaking incubator. After comparing the actual enhancement effects, glucose was selected as the carbon source and 2,4-dichlorophenol as the inducer to improve the environmental remediation capability of Pseudomonas protegens. After 14 days of remediation, the degradation rates of BDE-47 in contaminated soil and water reached 48.26% and 52.60%, respectively. The Pseudomonas protegens strain obtained from municipal sludge through screening, acclimation, and enhancement processes exhibits excellent environmental remediation capabilities and promising practical application prospects.

Advanced oxidation processes (AOPs) by carbon‐based single‐atom catalysts (SACs) are recognized as an attractive scientific frontier for water treatment, with the outstanding benefits of ultra‐effective and anti‐interference capability. However, most of the research has paid more attention to the performance of SACs, while the in‐depth understanding of catalytic regulation by molecular interaction is relatively deficient. This critical review delves into deciphering the catalytic mechanism through a micro‐level, which makes it more convenient to interpret apparent catalytic phenomena. It first summarizes basic theories of quantum chemistry, which provide mechanism interpretation and prediction for molecular‐oxidation systems. Additionally, corresponding oxidation pathways of common oxidants are underscored. Following the oxidants, state‐of‐the‐art regulation methods are discussed with special attention to involved molecular interactions and pollutants. Particularly, the preliminary insights into the “oxidant‐catalyst‐pollutants” internal relationships are provided to help construct the SAC‐AOP system from a molecular standpoint. Meanwhile, some cutting‐edge laboratory devices and pilot‐scale engineering are presented to illustrate the ultimate purpose of scientific molecular exploration. Eventually, relative challenges of SACs‐AOPs upon the design of catalytic systems and investigation methods are provided. This review aims to promote the large‐scale potential of SACs‐based AOPs in practical water treatment by emphasizing the pivotal role of micro‐insights.

Novel GNPs-Au modified electrode enables ultrasensitive detection of Pb ²⁺ and Cd ²⁺ (1 ng L ⁻¹ LOD) with 7.2-fold enhanced sensitivity. Achieves 90–113% recovery in real water samples. Ideal for environmental monitoring applications.