Manuscript number SEPPUR_2019_686_R1Title Equilibrium and kinetics of nitrous oxide, oxygen and nitrogen adsorption on activated carbon and carbon molecular sieve
Article type Full Length Article
AbstractTo evaluate candidate adsorbents for the recovery of nitrous oxide (N2O) from adipic acid off-gases, the equilibrium and kinetics of N2O and O2 adsorption on activated carbon (AC) and of N2O, O2, and N2 adsorption on a carbon molecular sieve (CMS) were evaluated at 293, 308, and 323 K under pressures up to 1000 kPa using a high-pressure volumetric system. Adsorption amount of N2O on AC and CMS exceeded those of N2 and O2, and the adsorption isotherms for O2 and N2 were similar. The experimental N2O and O2 uptakes on AC and CMS were fitted to a nonisothermal adsorption model, whereas the model was ineffective for predicting N2 uptake on CMS. The isothermal dual-resistance model, considering surface barrier resistance and pore diffusion, adequately predicted N2 uptake on CMS. The rate of adsorption of N2O on AC was much lower than that of O2 and N2 whereas the rate of adsorption on CMS flowed the order: O2 > N2O >> N2, even though N2O has higher adsorption affinity and smaller kinetic diameter than O2. The Lewis structure of N2O was also found to influence the adsorption kinetics.
Background
A significant discovery was recently made in which participation in physical activity and sedentary behavior, two contrasting lifestyles, was found to be related to the frequency of hyperuricemia diagnosis. The purpose of this study was to identify the association between sedentary behavior and physical activity levels in South Korean men and women diagnosed with hyperuricemia.
Methods
This study included 161,064 healthy men and women participants who had obtained a complete health examination. Physical activity levels and sitting time were assessed by the validated International Physical Activity Questionnaire Short Form Korean version. The presence of hyperuricemia in the subjects was determined by measuring serum uric acid (SUA) concentration (SUA ≥6 mg/dL [male], SUA ≥7 mg/dL [female]). Logistic regression analysis, adjusting other confounding factors, was conducted to identify the association of sedentary behavior and physical activity levels with hyperuricemia (
p
<0.05).
Results
Subjects who spent ≥10 hr/day in sedentary behavior were more likely to have hyperuricemia than those who spent <5 hour/day in sedentary behavior (OR=1.08, 95% CI=1.03–1.12). The subject group that more frequently participated in health enhanced physical activity (HEPA) had a lower hyperuricemia odds ratio than the subject group with lower physical activity participation rate (OR=0.90, 95% Ci=0.86–0.93). From the analysis of sex (male, female), age (young, middle, older), methods of measuring obesity (body mass index, waist circumference, body fat percentage), the association of sedentary behavior and physical activity levels with hyperuricemia was shown differently in different multivariable models.
Conclusion
Participation in regular physical activity and reduced sedentary time is highly recommended in order to reduce the prevalence of hyperuricemia.
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