Volatile organic compounds (VOCs) are hazardous chemicals present in outdoor and indoor air. They can be odorous and cause human health problems even at very low concentrations. Therefore, regulations on VOC gas emission are becoming stricter every year. Acetaldehyde is a VOC gas that not only has a very stinging smell but can also harm the human body by inhalation. Representative commercial adsorbents are activated carbon and silica gel. These materials feature a large surface area, which is directly related to the number of adsorption sites. In this study, a silica xerogel was synthesized by sol-gel method. The new material was tested for the adsorption of acetaldehyde in a continuous bed system, and its performance was compared to those of commercial silica gel and activated carbon. The physical properties of the samples were studied by BET analysis. Silica xerogel was characterized by XRD, FT-IR, and 29Si MAS NMR. The inlet and outlet concentrations of the VOC gas were measured from adsorption test tubes using a VOC detecting monitor. The synthesized silica xerogel presented a larger surface area and number of functional groups than the commercial silica gel, leading to improved adsorption performance and selectivity.