Preparation and Evaluation of CuMnOx-Modified Activated Carbon Fibers for Indoor VOCs Removals

This study aimed to develop a high-performance Modified Activated Carbon Fiber (ACF) filter for the effective removal of Volatile Organic Compounds (VOCs) generated in workplaces and for application in indoor VOCmitigation devices. ACF was modified with CuMnOx catalysts and evaluated for the removal of formaldehyde, acetaldehyde, and benzene. The modified ACF filter was prepared by introducing CuMnOx via an impregnation method using Cu(NO₃)₂⋅3H₂O and Mn(NO₃)₂⋅6H₂O precursors, followed by a crucial high-concentration oxygen plasma surface treatment (50 sccm gas flow) to effectively incorporate oxygen functional groups, thereby enhancing catalyst dispersion and activity. Characterization of the fabricated ACF/CuMnOx composite revealed that the optimized sample, now designated ACF-P-0.1 (representing both CuMnOx catalyst impregnation and O₂ plasma treatment), exhibited uniformly dispersed CuMnOx particles (<500 nm) on the ACF surface. This stability retained a high specific surface area (1342.7 m²/g) and micropore ratio (92.23%). H₂-TPR analysis demonstrated low-temperature reduction peaks at 140 °C and 205.8 °C, indicating excellent redox properties that enable high catalytic VOC oxidation near room temperature. The oxygen plasma treatment was found to increase the interfacial reactivity between the catalyst and ACF, contributing to further enhancement of activity. Performance tests confirmed that the ACF-P-0.1 sample provided superior adsorption–oxidation synergy. Benzene removal achieved a peak efficiency of 97.5%, demonstrating optimal interaction with the microporous ACF structure. For formaldehyde, a removal efficiency of 96.6% was achieved within 30 min, significantly faster than that of Raw ACF, highlighting the material’s ability to adsorb VOCs and subsequently oxidize them with high efficiency. These findings suggest that the developed ACF/CuMnOx composite filters can serve as promising materials for VOCs removal in indoor environments such as printing, coating, and conductive film manufacturing processes.