IADR Abstract Archives
Surface Area and Pore Diameter of Different Activated Charcoal Scavengers
Objectives: Many Dental Anesthesiologists (DAs) are mobile, moving from practice to practice to provide sedation services. Mobile DAs use a passive scavenger system, such as an activated charcoal filter, to remove waste anesthetic gas (WAG) from the operatory to reduce provider and auxiliary staff exposure. This study compared the surface area and pore diameter of six commercially available activated charcoals.
Methods: Each of the six different charcoals (Table 1) was massed to approximately 0.300-0.400g. Samples were exposed to gaseous helium under heating to remove surface contamination. The samples were placed into an AimSizer HMKTest BET Surface Area Analyzer and cooled with liquid nitrogen to 77K. Samples were exposed to a low pressure of an adsorptive gas (N2) to measure surface area and pore diameter. The surfaces and porosity of the samples were examined using a JSM-6010LA scanning electron microscope (JEOL USA, Inc., Peabody, MA). ANOVA testing with post-hoc Tukey was used for significance between surface area and pore diameter between groups (α=0.05).
Results: The surface area and pore diameter of charcoals in groups A, B, C, D, and F were all significantly different from group E; however, no significant differences were noted between any other groups. SEM images showed great variation in the surface features amongst the charcoals that we examined.
Conclusions: Group E, anthracite charcoal, had approximately 1% of the surface area of the other materials tested. This material would be predicted to have a lower reactivity to adsorption of anaesthetic gas, and would not be recommended for use. Further testing is underway to measure the volume of anesthesia adsorbed by each of these charcoals.
Methods: Each of the six different charcoals (Table 1) was massed to approximately 0.300-0.400g. Samples were exposed to gaseous helium under heating to remove surface contamination. The samples were placed into an AimSizer HMKTest BET Surface Area Analyzer and cooled with liquid nitrogen to 77K. Samples were exposed to a low pressure of an adsorptive gas (N2) to measure surface area and pore diameter. The surfaces and porosity of the samples were examined using a JSM-6010LA scanning electron microscope (JEOL USA, Inc., Peabody, MA). ANOVA testing with post-hoc Tukey was used for significance between surface area and pore diameter between groups (α=0.05).
Results: The surface area and pore diameter of charcoals in groups A, B, C, D, and F were all significantly different from group E; however, no significant differences were noted between any other groups. SEM images showed great variation in the surface features amongst the charcoals that we examined.
Conclusions: Group E, anthracite charcoal, had approximately 1% of the surface area of the other materials tested. This material would be predicted to have a lower reactivity to adsorption of anaesthetic gas, and would not be recommended for use. Further testing is underway to measure the volume of anesthesia adsorbed by each of these charcoals.