The study focuses on enhancing the adsorption of acetone, a prevalent oxygenated volatile organic compound (VOC), using HNO3-modified AG-3 activated carbon (AC) to mitigate its environmental and health impacts. It aims to optimize HNO3 modification of AG-3 AC, targeting enhanced acetone adsorption capacity and improved kinetics.
Methods: In this work, commercial AG-3 was treated with 2 M, 4, M and 6 M HNO3 solutions through reflux heating at 100 °C, followed by washing and drying. Adsorption experiments were conducted using gravimetric analysis at 25 °C and 1 atm, with kinetic data fitted to pseudo-first-order, pseudo-second-order, Elovich, and Mor-ris-Weber models. The modified ACs were evaluated for their specific adsorption capacities and time-dependent adsorption behaviors.
Results: Results showed that HNO3 treatment enhanced acetone adsorption, with the 2 M HNO3-treated AC (HAC-2) exhibited the highest capacity of 0.2951 g/g, a 15 % improvement over unmodified AG-3 (0.2570). Kinetic studies revealed that the pseudo-second-order kinetic model best described the adsorption process, indicating chemisorption as the primary mechanism. As concentration of HNO3 increased (4 M and 6 M), it led to reduced adsorption capacity compared to HAC-2, suggesting excessive oxidation may damage the carbon structure.
Conclusions: The study concludes that the optimal HNO3 concentration for enhancing acetone adsorption on G-3 AC lies around 2 M. This approach highlights the potential of HNO3-modified AG-3 as an effective adsorbent for acetone remediation in adsorption application.