The distributional characteristics of microorganisms in karst cave ecosystems have been widely studied. However, in such a dark, humid, and oligotrophic habitat, studies on the differences in carbon-sequestering bacteria in multiple habitats are limited. Therefore, to learn the distribution characteristics of carbon-sequestering colonies in cave habitats and their correlation with habitat factors (e.g., pH, Ca²⁺, Mg²⁺, etc.), samples from five cave habitats (weathered rock walls, underground river water, drips, sediments, and air) were collected from the twilight and dark zones of Shiziyan Cave (CO₂ concentration 5385 ppm). The results of high-throughput sequencing and statistical analyses showed that there were significant differences in the distribution of communities in different habitats, with higher abundance in sediments habitat and underground river water habitat, and the dominant phyla of Pseudomonadota (30.53%) and Cyanobacteria (75.11%) in these two habitats. The microbial diversity of the carbon-sequestering microbial community was higher in sediments than in underground river water. The pH, and Ca²⁺, ${\mathrm{SO}}_4^{2-}$, and ${\mathrm{NO}}_3^{-}$ concentrations can alter the diversity of carbon-sequestering microbes, thereby affecting carbon cycling in caves. Carbon metabolism analyses suggest that microbes in the habitat can cooperate and coexist by participating in different carbon metabolic pathways. These results expanded our understanding of carbon-sequestering microbial communities in cave systems and their responses to the environment.

In this study, nitrogen-doped TiO₂ heterojunction materials were successfully synthesized via a facile one-step solvothermal approach. A range of advanced characterization techniques were employed to thoroughly analyze the structural and compositional properties of the synthesized photocatalysts, and their application potential for tetracycline (TC) degradation under visible light was studied. The results indicated that N-doped TiO₂ exhibited a well-defined hierarchical micro/nanostructure and formed an efficient anatase/rutile homogeneous heterojunction. The photocatalytic performance of N-TiO₂ for TC degradation under visible light was significantly enhanced, achieving a degradation efficiency of up to 87% after 60 min of irradiation. This improvement could be attributed to the synergistic effects of optimal nitrogen doping, heterojunction formation, and the hierarchical micro/nanostructure, which collectively reduced the bandgap energy and suppressed the recombination rate of photogenerated carriers. Furthermore, density functional theory (DFT) calculations were conducted to systematically explore the impacts of substitutional and interstitial nitrogen doping on the energy band structure of TiO₂.

Bioaerosols are a potential risk of infection in densely populated indoor sites at university campuses. In this study, indoor bioaerosols from the canteen, classroom, and dormitory on campus were sampled and analyzed in the summer of 2021 to investigate the harmful risk. The results showed that bacteria are the predominant microbes, and the total number of bacteria detected in the classroom during no lesson in the morning (33% of samples) and in the canteen during meal times (55% of samples) was greater than the World Health Organization’s recommended value (1000 CFU/m³). The ranges of respirable bioaerosol (<3.3 µm) contributions in the classroom, dormitory, and canteen were 50–75%, 57–70%, and 64–80%, respectively. Bacteroidetes and Firmicutes were the most dominant phyla in all three indoor environments, with a relative abundance of both above 20%. At the family level, Muribaculaceae, Lachnospiraceae, and Bacteroidaceae had high relative abundance in all indoor sites. Some of the microbes carried by bioaerosols were conditionally pathogenic bacteria, such as Micrococcaceae and Enterococcaceae, which may have a harmful risk of causing various inflammatory infections. The results of this study provide basic data to improve indoor environments and control indoor bioaerosol pollution on campus.

Loofah is deemed a promising candidate for the purification of oily fumes. Our research utilized H₃PO₄ for initial activation of loofah (TCS), producing loofahderived carbon (TGSC-0). Subsequently, Fenton’s reagent was utilized for further modification to yield loofah-derived carbon (TGSC-1). TGSC-1 was used in the form of an adsorption column to simultaneously treat multiple pollutants from oily fumes, with surface Fe³⁺, Fe²⁺, and H₂O₂ catalyzing ·OH and ·OOH generation to enhance adsorption of the oils and non-methane hydrocarbon (NMHC). Characterization showed that the specific surface area of TGSC-1 was 427.97 m²/g and pore sizes ranged from 0.50 to 3.50 nm. The rich mesoporous and macroporous structures of TGSC-1 enhanced the capability of carbon layer adsorption. Langmuir adsorption kinetics suggested that adsorption proceeded via monolayer adsorption pathways, while L-τ lines revealed shorter protective effect times for adsorbing PM₁₀ and PM_2.5 than for oils and NMHC. The results indicated that TGSC-1 exhibited maximum saturated adsorption capacities of 25.79, 13.02, 9.82, and 15.99 mg/g for oils, NMHC, PM_2.5, and PM₁₀, respectively. Increasing resistance of the adsorption column exhibited a notable synergistic effect of filtration and adsorption in treating oily fumes. It combines renewable materials with low-energy processing, delivering eco-economic benefits for sustainable development and application.

This study investigates the performance of a multi-media bio-scrubbing system that integrates activated sludge with loofah as a biofilm carrier for the purification of complex pollutants from simulated cooking fumes: oils, Non-Methane Hydrocarbons (NMHCs), PM_2.5/PM₁₀, and Volatile Organic Compounds (VOCs). Compared to conventional carriers like activated carbon, the biodegradable and low-cost loofah, with its hierarchical porous structure and balanced hydrophilic–lipophilic properties, showed enhanced support for microbial colonization (achieving a biomass density of 105 mg/g) and pollutant adsorption. The system achieved high removal efficiencies in lab-scale tests: 97.4% for total VOCs (including 96.5–100% removal of recalcitrant alkanes and olefins), 91.3% for oils, and >88% for PM_2.5/PM₁₀. Mechanistic analysis indicated that the biofilm was dominated by Proteobacteria and Actinomycetes, and the synergistic effect between physical adsorption (via loofah’s porosity) and biodegradation (by microbial consortia) enabled stable performance (maintaining >90% efficiency over a 25-day operation) without observed secondary pollution. The loofah-activated sludge configuration demonstrated improved operational stability and the potential for lower operating costs compared to single-medium systems in this experimental setting. This work explores a promising, eco-friendly approach for treating simulated cooking fumes, utilizing renewable biomass carriers and biological processes, which could contribute to cleaner production strategies.