Phase change absorbents are deemed a promising alternative for CO₂ capture due to their excellent CO₂ absorption performance, good stability, and low renewable energy consumption. To address the issues of insufficient loading capacity, low regeneration efficiency, and high energy consumption during regeneration in current chemical absorbents, a novel phase change absorbent was developed. As an amino acid ionic liquid phase change absorbent with tetraethylenepentamine as the cation, imidazole as the anion, and n-propanol as the phase separation agent, this absorbent offers a potential solution. The highest absorption capacity of the [TEPAH][Im]/NPA/H₂O system at the optimal n-propanol-H₂O ratio (1:1) reaches 1.34 mol·mol⁻¹, and the viscosity of the CO₂-rich phase amounts to a mere 3.58 mPa·s. Additionally, the desorption efficiency reached 91.1% at 363.15 K, while the loading capacity in the fifth cycle remained over 1.16 mol·mol⁻¹. As n-propanol is present in the [TEPAH][Im]/NPA/H₂O system, the rich phase makes up roughly 30% of the total volume. The energy consumption for regeneration of the [TEPAH][Im]/NPA/H₂O phase change absorption system is 2.20 GJ·t⁻¹ CO₂. Under identical regeneration conditions, the system can reduce the regeneration energy consumption by 41.6%.

Ground-level ozone (O₃) pollution in the North China Plain has become a serious environmental problem over the last few decades. The influence of anthropogenic emissions and meteorological conditions on ozone trends have become the focus of widespread research. We studied the long-term ozone trends at urban and suburban sites in a typical city in North China and quantified the contributions of anthropogenic and meteorological factors. The results show that urban O₃ increased and suburban O₃ decreased from 2010 to 2020. The annual 90th percentile of the maximum daily 8-h average of ozone in urban areas increased by 3.01 μgm⁻³year⁻¹ and, in suburban areas, it decreased by 3.74 μgm⁻³year⁻¹. In contrast to the meteorological contributions, anthropogenic impacts are the decisive reason for the different ozone trends in urban and suburban areas. The rapid decline in nitrogen oxides (NO_X) in urban and suburban areas has had various effects. In urban areas, this leads to a weaker titration of NO_X and enhanced O₃ formation, while in suburban areas, this weakens the photochemical production of O₃. Sensitivity analysis shows that the O₃ formation regime is in a transition state in both the urban and suburban areas. However, this tends to be limited to volatile organic compounds (VOCs) in urban areas and to NO_X in suburban areas. One reasonable approach to controlling ozone pollution should be to reduce nitrogen oxide emissions while strengthening the control of VOCs.

Major experimental teaching plays a crucial role in cultivating the ability of undergraduates majoring in environmental engineering to solve complex engineering problems. The study explores the integration of scientific research resources into undergraduate experimental teaching, aiming to enhance the quality of talent cultivation by transforming scientific research teams, projects, and resources into corresponding teaching entities. An innovative experimental course based on research projects of the scientific research teams was designed, focusing on the evaluation of photocatalytic oxidation of organic pollutants. The course encourages independent exploration, interdisciplinary knowledge application, and emphasizes thinking training in process assessment. Over a three-year period (2018–2020), 33 undergraduates participated in various experimental projects derived from scientific research. Data collected through questionnaires, discussions, and performance assessments revealed significant improvements in the undergraduates’ ability to solve complex environmental engineering problems, increased learning interest, and the development of critical thinking and innovative consciousness. The proposed mechanism not only enriches experimental teaching content but also effectively promotes the cultivation of innovative and compound talents in environmental engineering.