Environmental pollution increasingly threatens human health in concealed forms, such as the spread of pathogenic microorganisms and antibiotic resistance genes (ARGs), as well as the widespread presence of low-concentration small-molecule pollutants in water environments. These evolving challenges demand detection technologies with higher selectivity and sensitivity, making the development of advanced sensing platforms a critical research priority. The CRISPR/Cas system can be rationally engineered to recognize specific nucleic acid sequences, offering significant potential for detecting pathogens and ARGs. Its utility has been further extended to small-molecule sensing through the incorporation of aptamers. Nanozymes, which mimic the catalytic functions of natural enzymes while exhibiting unique physicochemical properties, can substantially enhance the performance of CRISPR/Cas-based biosensors. This review systematically examines the fundamental mechanisms and construction strategies of nanozyme-assisted CRISPR/Cas sensing platforms, details their applications in environmental pollutant monitoring, discusses current challenges and potential solutions for real-world implementation, and outlines future prospects. The aim is to provide valuable insights for further research and practical deployment of this innovative technology.

Anaerobic ammonia oxidation (Anammox) technology has emerged as a highly promising biological nitrogen removal approach, exhibiting remarkable technical and economic advantages in treating wastewater with high ammonia nitrogen content and a low carbon-to-nitrogen ratio. However, with the escalating global plastic pollution, microplastics (MPs) have become ubiquitous in wastewater treatment systems. This review systematically collates the research status regarding the sources and classification of microplastics in wastewater treatment plants, and the impacts of MPs on anammox systems. Based on their degradation characteristics, MPs are categorized into two major types: degradable microplastics and non-degradable microplastics. The critical factors influencing anammox processes in the presence of microplastics are comprehensively summarized and analyzed. The impacts exerted by MPs on anammox systems are closely correlated with key factors such as polymer type, particle size distribution, concentration-dependent effects, and exposure duration-dependent responses. Low concentrations of microplastics can act as biofilm carriers or provide carbon sources, thereby facilitating microbial adhesion and growth, and enhancing the nitrogen removal efficiency of the system. In contrast, high concentrations of microplastics usually inhibit anammox activity through pathways including physical clogging, toxic effects, and oxidative stress, which in turn leads to the decline of nitrogen removal performance, damage to sludge structure and alterations of microbial community structure in the system. The underlying mechanisms involve three aspects: shifts in microbial community structure, regulation of functional gene expression, and disturbance of metabolic processes. Finally, this review proposes potential future research directions. This study aims to provide comprehensive theoretical support for the stable operation of anammox systems and environmental risk management against the backdrop of microplastic pollution.

To achieve the high-value valorization of waste cooking oil (WCO) and address the economic bottleneck of microalgae harvesting, this study proposes a sustainable buoy-bead flotation strategy. Emulsions derived from three typical WCO sources (Rapeseed, Peanut, and Soybean) were evaluated to optimize this “waste-to-resource” process. Results demonstrated that Peanut Re-Frying Oil Emulsion (P-RFOE) and Soybean Re-Frying Oil Emulsion (S-RFOE) exhibited superior harvesting performance, achieving efficiencies exceeding 92% under optimized conditions. Mechanistic analysis revealed that these substrates formed highly compact aggregates (Df = 1.48) via aluminum sulfate-mediated cationic bridging, marginally enhancing resistance to hydrodynamic shear. The method’s ecological adaptability was validated through the in-situ remediation of natural blooms in three eutrophic lakes, achieving a peak harvesting efficiency of 98.03% (Chaohu Lake) and a high enrichment ratio of 3.21 (Luoma Lake). Furthermore, a gate-to-gate Life Cycle Assessment (LCA) confirmed the system’s sustainability, featuring a competitive operational cost (1.16/m³), a minimal carbon footprint (0.066 kg CO₂-eq/m³), and no secondary pollution. This study establishes a cost-effective, eco-friendly solution that simultaneously targets eutrophication control and bioenergy feedstock recovery, exemplifying a circular economy approach.

Metal-organic framework–hydrogel (MOF–hydrogel) composites, leveraging their distinctive structural and functional advantages, offer an ideal platform for developing a new generation of optical biosensing technologies for environmental pollutants detection. While conventional analytical methods provide high accuracy, the reliance on bulky instruments and complex operational procedures limits their applicability. This review focuses on design strategies of such composite materials and recent advances in their application to optical biosensing of environmental contaminants. Through approaches such as in situ growth and direct mixing, the structural tunability and catalytic/luminescent properties of MOFs are effectively integrated with the three-dimensional hydrophilic networks and stimuli-responsive characteristics of hydrogels, resulting in synergistic functionality. The review systematically outlines the multifunctional roles of MOFs in sensing, including as luminophores, catalysts, signal modulators, and carriers. Representative applications in detecting pathogenic microorganisms, antibiotics, heavy metal ions, and pesticide residues are categorized and discussed, demonstrating the notable advantages of these biosensing assays in terms of sensitivity, selectivity, and field applicability. Finally, future challenges and research directions are outlined, including improving the environmental stability of materials, developing methods for simultaneous multi-target detection, advancing the portability and intelligence of sensing systems, and expanding the range of applications in environments. MOF–hydrogel composites hold strong promise as a robust material platform for the development of high-performance, field-deployable water quality sensing technologies.