The removal of NO2 gas by some natural adsorbents by using the adsorption method

Nitrogen dioxide (NO2) is one of the most dangerous pollutants in the environment. NO2 certainly causes lung damage at high concentrations. Exposure to its moderate levels (50 ppm) for a short period may produce irritation of the eyes, nose, and throat, cough, hemoptysis, dyspnea, and chest pain and contact to its high concentrations (> 100 ppm) can result in pulmonary edema, which can be fatal. Therefore, it is very important for environment the removing of the pollutant from air. The aim of this study has been the removal of NO2 gas by some natural adsorbents by using the adsorption method.

 In this work, it has been investigated the removal of NO2 gas by adsorption on different natural adsorbents including eggshell, eucalyptus bark, fennel seed, pine leaf, tea waste, and wheat straw. It was also studied the effect of some experimental conditions including adsorbent column length and initial NO2 amount on the adsorption percentage.

The most desirable adsorption percentage obtained with adsorbent column length 50 cm and initial NO2 amount 6.3 mmol. In addition, Fennel seed and eggshell can adsorb 96.8 and 92.1% of NO2 gas in the optimum conditions, respectively.

Among the used adsorbents, the most appropriate adsorbents are fennel seed and eggshell for the adsorption process. In addition, it was correlated the equilibrium data with the adsorption isotherms such as the Langmuir, Freundlich, Temkin, and Harkin-Jura and the results showed that Harkin-Jura isotherm describes the experimental results better than the other isotherms.