Without additional templating agent or surfactant, porous and sparse MnCO₃ was synthesized hydrothermally from Mn²⁺ with a CO₂-storage material (CO₂SM). Through thermal decomposition of the as-synthesized MnCO₃, ϵ-MnO₂ crystals with good catalytic performance and stability in HCHO degradation were prepared. The optimum preparation conditions were determined by tuning the preparation conditions and carrying out response surface studies, and the resulting ϵ-MnO₂ crystals could degrade 66.1% of a 10 ml 10 mg l⁻¹ HCHO solution. After the HCHO degradation conditions were optimized, the thermodynamic data could be fitted with the Langmuir isotherm and quasi-secondary kinetic models at T = 25–50°C. The degradation mechanism of HCHO is discussed. This work provides a new strategy for the degradation of HCHO at room temperature.

中文翻译：

---

室温下使用介孔 ε-MnO2 晶体高效去除水溶液中的甲醛

在没有额外的模板剂或表面活性剂的情况下，多孔和稀疏的MnCO ₃由Mn ²⁺与CO ₂储存材料(CO ₂ SM) 水热合成。通过对合成后的MnCO ₃进行热分解，制备了具有良好催化性能和HCHO降解稳定性的ε-MnO _2晶体。通过调整制备条件和进行响应面研究确定了最佳制备条件，得到的 ε-MnO ₂晶体可以降解 66.1% 的 10 ml 10 mg l ^-1HCHO 溶液。在优化 HCHO 降解条件后，热力学数据可以在T = 25–50°C 下与 Langmuir 等温线和准二级动力学模型拟合。讨论了HCHO的降解机制。这项工作为室温下降解 HCHO 提供了新的策略。