Removal of styrene in air stream by absorption combined with electrochemical oxidation

Aqueous solution absorptions are widely used as an effective way for the treatment of noxious gases discharged from various industrial processes. However, this technology may encounter problems in removing gaseous pollutants with low Henry constants, such as styrene from contaminated air. In this study, a novel electrochemical absorption reactor was devised to remove these air pollutants. The reactor consists of five pairs of stacked mesh electrodes. Each pair of mesh electrodes consists of a Ti/RuO₂ anode and a Ti cathode. The dimension of mesh electrode is 100 mm × 100 mm with 3 mm × 5 mm rhombic holes evenly distributed. The distance between two neighbouring electrodes is 25 mm. The simulated gas was introduced into the reactor from the bottom of the reactor by a gas distributor. The experimental result shows that styrene in the air was effectively removed by the electrochemical absorption reactor, and the removal increased with the increase of current density applied to the reactor. It was found that almost 100% styrene removal was achieved in 1% NaCl solution with 1 pH value and a current density of 0.04 A/cm² applied to the reactor. The major liquid phase products from styrene oxidation were confirmed to be 1-Phenyl-1, 2-ethanediol and benzaldehyde.