Separations

In this study, cerium oxide (CeO₂) nanoparticles were successfully synthesized using a simple and cost-effective hydroxide-mediated precipitation method. Comprehensive characterization (XRD, SEM, TEM, FTIR, BET, and UV–Vis) confirmed the formation of uniformly distributed nanoparticles with an average size of ~100 nm, a well-defined crystalline structure, and a high specific surface area of 118.96 m²/g. The CeO₂ nanoparticles also exhibited a mesoporous framework with a pore volume of 0.39 cm³/g and an average pore radius of 2.27 nm, demonstrating favorable properties for adsorption applications. Adsorption experiments showed that CeO₂ nanoparticles effectively removed Pb²⁺ from aqueous solutions, achieving a maximum experimental adsorption capacity of 192 mg/g and a removal efficiency of 80% at pH 6 under the tested conditions. Kinetic analysis revealed that the pseudo-second-order model best described the adsorption process, suggesting chemisorption as the dominant mechanism, while equilibrium data were more accurately represented by the Langmuir isotherm model, which predicted a theoretical monolayer capacity (Qm) of 714.2 mg/g. Overall, the findings demonstrate that CeO₂ nanoparticles possess a strong affinity toward Pb²⁺ ions and exhibit promising adsorption performance, indicating their potential applicability for the treatment of lead-contaminated wastewater and their suitability for reuse following regeneration.

Corona quenching is a major obstacle to the stable and efficient operation of electrostatic precipitators (ESPs) in coal-fired power plants, particularly under high-ash coal combustion. This study evaluates a novel double-V labyrinth pre-collection device as an active strategy to mitigate corona quenching. Field measurements from a 660 MW ultra-supercritical coal-fired unit, combined with computational fluid dynamics (CFD) simulations, demonstrate that the retrofit significantly improved inlet flow uniformity and reduced fly ash concentration before the ESP. Consequently, corona discharge stability was enhanced, overall collection efficiency increased from 99.42% to 99.92%, and outlet fly ash concentration decreased from 81 mg/m³ to 20.5 mg/m³. Although the pressure drop rose modestly (128 Pa to 187.5 Pa), the overall ESP energy demand was reduced due to more stable operation at lower voltages. These results confirm the technical feasibility and engineering applicability of pre-collection technology, providing a cost-effective solution to overcome corona quenching and ensure ultra-low emission compliance in large coal-fired units.

Water with a high fluoride content poses a serious threat to both public health and the natural environment. To enhance fluoride ion removal efficiency, a modified activated carbon adsorbent (HPAC-La) was synthesized by impregnating soybean protein in a lanthanum nitrate solution, followed by freezing–drying and carbonization. The results confirmed that lanthanum nitrate modification significantly improved the adsorption performance. Under optimised experimental conditions (pH = 2.0, [F⁻] = 300 mg·L⁻¹, 12 h, 298 K), HPAC-La exhibited a maximum adsorption capacity for fluoride ions of 126.7 mg·L⁻¹, significantly higher than that of unmodified HPAC (86.1 mg·L⁻¹). The adsorption process followed the pseudo-second-order kinetic model and the Langmuir isotherm model, indicating monolayer chemisorption. The mechanism involves ion exchange via surface hydroxyl groups and fluoride coordination with La sites. This study proposes a method for developing highly efficient adsorbents for the treatment of fluoride-contaminated wastewater.