The main purpose of this paper was to reveal the effect of aluminum (Al)-based coagulants on enhanced coagulation for the removal of algae and the synergistic optimization mechanism among different Al species. The formation, breakage, and regrowth processes of algal coagulation flocs formed by a series of monomeric Al-based coagulants (Al₂(SO₄)₃, Al₁₃, and Al₃₀), Al₁₃/Al₃₀ composite coagulant and poly(diallyldimethylammonium chloride)/Al₁₃ (PDADMAC/Al₁₃) composite coagulant were studied. Results indicated that Al₁₃ mainly employed a charge neutralization mechanism, which was conducive to the destabilization of algae and the regeneration of flocs, while Al₃₀ mainly employed a sweep flocculation mechanism, which was conducive to the formation of algae and the strength of flocs. Meanwhile, the charge neutralization was the main mechanism during the algae coagulation process because it could effectively remove the soluble microbial products (SMP) component in the extracellular organic matter (EOM). Therefore, Al₁₃ could achieve a higher coagulation performance than other monomeric Al-based coagulants. The Al₁₃/Al₃₀ composite coagulant could make up for the deficiency of the sweep flocculation mechanism in Al₁₃ and charge neutralization mechanism in Al₃₀, and achieve the best synergistic optimization performance at Al₁₃:Al₃₀-7:3. Additionally, PDADMAC, as a polymer, could further enhance the charge neutralization ability of Al₁₃ at low dosages and the sweep flocculation ability of Al₁₃ at high dosages, respectively. However, an excessive dosage would lead to charge reversal and thus reduce the coagulation effect. Therefore, controlling the dosage was key when using Al-composite coagulants. The findings of our research could offer a certain theoretical foundation for the development of inorganic polymer flocculants.

Identifying the accurate sources of polycyclic aromatic hydrocarbons (PAHs) in water is crucial for protecting the aquatic eco-health of the Yangtze River. In this study, we investigated 16 types of PAHs in the air and water along the Yangtze River, spanning from Chongqing to Shanghai. Similar spatial distribution pattern of total PAH concentrations that higher levels in the west and lower levels in the east were found between water and air. This distribution may be influenced by factors such as water temperature, energy transformation, and the input of exogenous air masses. Further analysis using diagnostic ratios, the principal component analysis coupled with absolute principal component score (PCA-APCS) model, and air–water exchange fugacity fractions allowed us to apportion the sources of PAHs in the water and air. Interestingly, we found that the sources of PAHs in the water and air were completely different, with ship-transportation contributing to PAHs in the water and biomass combustion contributing to PAHs in the air. To assess the ecological risk to freshwater biodiversity, we employed species sensitivity distribution (SSD) and found that PAHs in the water of the Yangtze River are likely to exert chronic long-term effects on more than 5% of aquatic organisms, which may lead to changes in the ecosystem stability. Although acute lethal effects were insignificant with an msPAF_Total value below 5%, it is important to monitor their changes, especially in the upper and middle regions of the Yangtze River. In conclusion, our study highlights that the burden of PAHs in the water of the Yangtze River, primarily caused by shipping activities, has significant adverse effects on the aquatic ecosystem. Therefore, it is necessary to implement further control measures for ship-transportation to mitigate these impacts of PAHs in the Yangtze River.

Phthalic acid esters (PAEs), a class of synthetic semi-volatile organic compounds, are extensively incorporated into decorative materials. However, their specific occurrence, migration behaviors, and environmental impact on these materials—which comprise the largest surface areas in residential settings—remain insufficiently understood. This study investigated the distribution, emission dynamics, and environmental burdens of PAEs in flooring commonly used in Chinese households. The results showed that PAEs are widespread in flooring, with total concentrations ranging from 1220 to 166,000 ng/g (14,100 ng/g, median value). Solid wood flooring (55,900 ng/g) exhibited significantly higher PAE levels compared to engineered flooring (22,600 ng/g) and laminate flooring (4000 ng/g) (p < 0.05). Migration experiments revealed that solid wood flooring tended to continuously release PAEs, laminate flooring showed a pronounced capacity for PAE absorption, and engineered flooring exhibited both release and absorption behaviors. The initial PAE concentration is the dominant factor influencing migration rates, while the flooring type and substrate density also contribute to varying degrees. The estimated environmental burdens of PAEs resulting from flooring in newly renovated Chinese households ranged from 3.63 × 10⁹ ng to 3.45 × 10¹¹ ng, with a median value of 1.23 × 10¹⁰ ng. Households in the eastern and southwestern regions exhibited the highest PAE burdens, while the southern region showed the lowest. Socioeconomic factors such as residential floor area, number of rooms, household income, and renovation budget significantly influenced the environmental burden of PAEs derived from flooring.

The treatment of antibiotic mycelial residue (AMR) has emerged as a critical challenge hindering the sustainable development of the biopharmaceutical industry. As a representative hazardous solid waste generated during antibiotic manufacturing processes, AMR may pose substantial risks to environmental safety. This review elucidates the properties and hazards of AMR while systematically reviewing current mainstream treatment technologies. Building upon the elucidation of underlying mechanisms, it further examines the application bottlenecks and research progress associated with different techniques. Through a comprehensive understanding of existing research achievements, this paper proposes future development strategies and perspectives for AMR treatment, highlighting that integrated multi-technology treatment approaches may represent the predominant developmental direction in this field.

Emerging pollutants such as microplastics in water environments readily accumulate microorganisms on their surfaces, forming biofilms and concentrating antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Consequently, microplastic biofilms have attracted the attention of researchers. Horizontal gene transfer (HGT) of ARGs is one of the primary ways that bacteria acquire antibiotic resistance. Most studies focus on the effects of nanomaterials on suspended bacteria, but microplastic biofilms as hotspots for horizontal gene transfer also warrant significant investigation. This study primarily explored and compared the effects of nano-titanium dioxide on the conjugation transfer frequency of ARGs in suspended bacteria and microplastic biofilms. Nano-titanium dioxide could promote ARG conjugation in both suspended bacteria and microplastic biofilms, with a greater effect on the former. The mechanism involved nano-titanium dioxide promoting the production of reactive oxygen species (ROS) in suspended and biofilm bacteria, increasing the synthesis of outer membrane proteins, enhancing the cell membrane permeability, and elevating the expression levels of conjugation-related genes, thereby facilitating the conjugation transfer of ARGs. Biofilm bacteria, being heavily encased and protected by extracellular polymeric substances (EPS), exhibit greater resistance to external environmental pressure, resulting in the weaker impact of nano-titanium dioxide on biofilm bacteria compared to suspended bacteria. This study reveals the risk of ARG conjugation transfer within microplastic biofilms induced by nanomaterials, providing valuable insights into the risks of microplastic and antibiotic resistance dissemination in water environments.