Molecular Simulation Study on the Adsorption Mechanisms of Microbial Components and Metabolic Products on Activated Carbon in HVAC Systems

Activated carbon is widely known for its porous structure and diverse surface functional groups, making it an effective adsorbent for removing various organic and inorganic pollutants from air and water. However, as a filtration material in air conditioning systems, activated carbon can also provide favorable conditions for microbial growth, potentially leading to the proliferation of microorganisms on its surface. These microorganisms, along with their metabolic products, can be released into indoor environments, posing potential health risks. This study employs molecular simulation to investigate the adsorption and release mechanisms of microorganisms and their volatile organic compound (VOC) metabolic products on activated carbon. Peptidoglycan (PDG) (as a representative bacterial cell wall component) and p-xylene (as a representative microbial metabolic product) were used as model compounds. The adsorption behavior of these compounds was simulated on activated carbon under different environmental conditions, including varying temperatures. The study found that activated carbon has a higher affinity for peptidoglycan than for p-xylene; at 303.15 K, the diffusion coefficients of peptidoglycan and p-xylene in activated carbon are 0.842 × 10−9 m2/s and 0.587 × 10−8 m2/s, respectively. Temperature plays an important role in affecting adsorption capacity; when the temperature rises by 10 K, the diffusion coefficients of peptidoglycan and p-xylene in activated carbon increase by 32.8% and 34.3%, respectively. These insights contribute to the development of efficient and health-conscious air purification materials, offering theoretical and practical guidance for optimizing the use of activated carbon in HVAC systems.