This study examined the simultaneous application of absorption and adsorption by adding granular activated carbon to tap water (Absorbent-A) and sodium hypochlorite (Absorbent-B), with the aim of improving the removal performance of gaseous acetaldehyde applying hybrid process. Prior to the main experiment, preliminary tests were conducted to assess the effects of HOCl concentration (50~150 ppm) and reactor temperature (25~35oC). In the main experiment, the removal performance under activated carbon-added conditions was compared using the concentration ratio (Co/ Ci) and its rate of change over time. As a result, the addition of activated carbon led to a more gradual saturation and concentration change compared to the non-addition condition, with the addition showing the most stable trend. This study suggests a basic reference for improving the performance of conventional absorbents enhancing the durability and efficiency with the activated carbon as an auxiliary material for future field applications.