Highly effective removal of formaldehyde from aqueous solution using mesoporous ɛ-MnO2 crystals at room temperature

Abstract

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, ɛ-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 ɛ-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.