Activated carbon modified with polyethyleneimine and MgO: Better adsorption of aldehyde and production of regenerative VOC adsorbent using a photocatalyst

In this study, a renewable adsorbent containing a photocatalyst is developed that exhibits effective adsorption performance for polar volatile organic compounds (VOCs) that are not well adsorbed by activated carbon (AC). AC is used as the basic adsorbent, and the surface of the AC is modified with polyethyleneimine (PEI) and magnesium oxide (MgO) for the effective adsorption of polar VOCs. In addition, a renewable VOC adsorbent and filter are demonstrated by introducing titanium dioxide (TiO2) as a photocatalyst to impart regeneration. The changes in the physical and chemical structures of the AC surface due to the modification with PEI and the loading of MgO and its effects are confirmed through scanning electron microscopy, Brunauer–Emmett–Teller (BET) analysis, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy analyses. Developing slit pores containing polar functional groups on the AC through PEI deposition and loading MgO in the pore of AC increase the adsorption capacity of acetaldehyde by four times (3.08–13.8 mg g−1). In addition, PEI deposition shows high regeneration efficiency (86.4 %) with the application of TiO2. This study provides important insights into the development of renewable VOC filters that can be used for various VOCs.