Physical and Chemical Adsorption Properties for Tetracycline Using Activated Carbon with Nitrogen Plasma Treatment

In this study, nitrogen plasma treatment was performed in 5, 10, and 15 minutes to improve the tetracycline adsorption performance of activated carbon. All nitrogen plasma -treated activated carbons showed improved tetracycline adsorption compared to untreated activated carbons. The nitrogen functional groups in activated carbon lead to chemisorption with tetracycline via pi-pi interactions and hydrogen bonding. In particular, in the nitrogen plasma treatment at 80 W and 50 kHz, the activated carbon treated for 10 minutes had the best adsorption performance. At this time, the nitrogen content on the surface of the activated carbon was 2.03% and the specific surface area increased to 1,483 m(2)/g. As a result, nitrogen plasma treatment of activated carbon improved its physical and chemical adsorption capabilities. In addition, since the adsorption experimental results were in good agreement with the Langmuir isotherm and pseudo -second order model, it was determined that the adsorption of tetracycline on the nitrogen plasma -treated activated carbon was dominated by chemical adsorption through a monolayer. As a result, nitrogen plasma -treated activated carbon can be used as an adsorbent to efficiently remove tetracycline from water due to the synergistic effect of physical adsorption and proactive chemical adsorption.