To address the urgent demand for atmospheric nitrogen oxide pollution control and to align with “high-level, innovative, and challenging” curriculum construction standards, a comprehensive experimental project regarding the preparation and denitration performance evaluation of morphology-controlled MoO₃/CeO₂ catalysts has been designed. Targeting the inherent trade-off between activity and stability in low-temperature denitration catalysts, students are guided to retrieve literature, subsequently analyze technical bottlenecks, and finally independently prepare MoO₃/CeO₂ nanomaterials with three distinct morphologies.

Three CeO₂ supports with distinct morphologies were synthesized via a hydrothermal method using Ce(NO₃)3·6H₂O as the cerium source, with morphologies regulated by adjusting the solvent systems and crystallization conditions. Nanospheres were prepared in an ethylene glycol/glacial acetic acid system at 180 ℃ for 200 min, while nanorods and nanocubes were obtained in a NaOH aqueous solution at 100 ℃ and 180 ℃, respectively, for 24 h; all resulting solids were washed, dried, and calcined at 500 ℃. Subsequently, the active component was loaded via an impregnation method, where the prepared CeO₂ supports were mixed with an ammonium molybdate aqueous solution, followed by water removal via rotary evaporation, drying at 100 ℃ overnight, and calcination at 500 ℃ in air for 3 h to finally obtain the MoO₃/CeO₂ catalysts with different morphologies. To regulate the material characteristics and surface acidity, students use modern analytical methods such as scanning electron microscopy, X-ray diffractometry, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and Raman spectroscopy. The results show that specific morphologies influence the dispersion of active components. On this basis, an efficient gas–solid catalytic reaction system is established, and performance is evaluated to investigate denitration efficiency.

The results demonstrate that the morphology-controlled catalytic system achieves substantially enhanced denitration performance. The MoO₃/CeO₂ (nanosphere) catalyst exhibits superior high-temperature stability and lower by-product formation. Under a gas hourly space velocity (GHSV) of 360,000 mL·(g·h) ⁻¹, the catalyst achieved 80% NO conversion at approximately 270 ℃ and reached a maximum NO conversion of 89% at 330 ℃. Furthermore, the concentration of generated N₂O remained below 20% within the temperature range of 150–360 ℃.

This experiment requires students to complete a full research process, starting with morphology design, material preparation, and micro-characterization and concluding with the interpretation of the catalytic mechanism. This experiment overcomes the limitations of traditional verification experiments. It integrates knowledge from multiple disciplines, such as materials science, chemical engineering, and environmental science. By introducing cutting-edge research technologies, it enhances students’ understanding of core theories (e.g., material synthesis, instrument characterization, and catalytic principles) while cultivating their scientific thinking, practical skills, and innovative spirit for solving complex engineering problems.

To address the practical challenges of treating highly stable emulsified oil wastewater in industries such as petrochemicals and machining, and to meet the curriculum standards of “high-level, innovative, and challenging,” a comprehensive experimental project was designed for wastewater purification via the synergistic application of “membrane filtration–adsorption.” Based on the physicochemical properties of industrial emulsified oil wastewater (oil content: 5%–8%, initial chemical oxygen demand (COD): 3462.5 mg·L^–1, and initial turbidity: 190 NTU; main components: phenol, anthraquinone, alkanes, alkenes, alkynes, and organic acids), students are first guided to review relevant literature, identify technical bottlenecks in controlling membrane pore structure and enhancing adsorbent capacity, and then independently synthesize asymmetric carbon membranes and porous carbon materials.

Asymmetric carbon membranes are prepared using sol–gel and dip-coating methods. Porous carbon is fabricated with two formulations (solid content of 10 wt% and 20 wt%), followed by sol–gel formation, aging, drying, and carbonization. To regulate material characteristics and monitor water quality, students use modern analytical techniques, such as scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, physical adsorption analysis, and ultraviolet–visible spectroscopy. The results show that the asymmetric carbon membrane has a separation layer with a thickness of ~6.25 μm and a pore size of 8.3 nm, whereas the porous carbon with 20 wt% solid content exhibits a higher specific surface area (591.36 m²·g^–1) and micropore volume (0.28 cm³·g^–1). Based on these materials, a multitechnology coupled wastewater treatment system is established by filling porous carbon into the asymmetric carbon membrane tube, and its performance is evaluated using a dead-end filtration device using COD and turbidity as primary indicators. During the experiment, students optimize process parameters, such as transmembrane pressure difference (0.1–0.3 MPa), and investigate the influence of membrane pore size and porous carbon solid content on treatment efficiency.

The “membrane filtration–adsorption” system achieves a COD removal of 84.4% (leaving only small amounts of anthraquinone and organic acids) and 100% turbidity removal using porous carbon with 20 wt% solid content and a transmembrane pressure difference of 0.2 MPa. These results significantly outperform single membrane filtration (72.2% COD removal) or single adsorption (34.7% COD removal). Analysis of the purification mechanism shows that, driven by pressure, emulsified oil wastewater first flows through the asymmetric carbon membrane, where particulate pollutants, color, and most emulsified oil are removed via membrane filtration. The remaining soluble pollutants are subsequently removed through adsorption on porous carbon. The combined use of asymmetric carbon membrane filtration and porous carbon adsorption greatly improves COD removal, enabling efficient, one-step purification of emulsified oil wastewater.

This experiment engages students in the full research process: designing porous materials, analyzing industrial wastewater quality, optimizing process parameters, and interpreting the synergistic purification mechanism. It overcomes the limitations of traditional single-material experiments by integrating knowledge from multiple disciplines, such as environmental and chemical engineering. Simulating real industrial scenarios enhances students’ understanding of core theories (e.g., membrane filtration and adsorption) while cultivating their systematic thinking, practical engineering skills, and innovative problem-solving abilities for complex environmental engineering challenges.