Degradation of pharmaceutical contaminants by bubbling gas phase surface discharge plasma combined with g-C 3 N 4 photocatalysis

• Published in: Environmental science water research & technology Vol. 7; no. 3; pp. 610 - 621
• Main Authors: Wang, Xiaoping, Luo, Jihang, Huang, Yunzhu, Mei, Jie, Chen, Yixia
• Format: Journal Article
• Language: English
• Published: 10.03.2021
• ISSN: 2053-1400; 2053-1419
• DOI: 10.1039/D0EW00985G

The feasibility of using gas phase surface discharge with microporous bubbling for the degradation of pharmaceutical contaminants was evaluated. After 25 min of treatment, 82% removal of ibuprofen (with an initial concentration of 60 mg L −1 ) and 100% removal of tetracycline hydrochloride (with an initial concentration of 200 mg L −1 ) was achieved. To utilize the UV and visible radiation produced in the discharge process, a g-C 3 N 4 photocatalyst was added into the solution to enhance the degradation efficiency. Adding 75 mg L −1 g-C 3 N 4 can increase the removal of ibuprofen by 18% (initial concentration of 10 mg L −1 ) and tetracycline hydrochloride by 10% (initial concentration of 100 mg L −1 ) after 10 min of discharge treatment. The crystallinity of the used g-C 3 N 4 became higher as the discharge treatment can planarize the g-C 3 N 4 surface via oxidization. In addition, aqueous O 3 , H 2 O 2 and ˙OH radicals under different conditions were measured to investigate the reaction mechanisms. The aqueous O 3 reaches saturation after 30 min of discharge but H 2 O 2 kept accumulating during the two hour discharge. The average ˙OH formation rate is 0.4191 mol L −1 min −1 in distilled water but 0.5640 mol L −1 min −1 with g-C 3 N 4 , which demonstrates the promotion of photocatalytic ˙OH generation. Therefore, combining the bubbling gas phase surface discharge plasma with g-C 3 N 4 photocatalysis leads to an extraordinary performance for the treatment of pharmaceutical additives.