A critical review on the application of pyrite in constructed wetlands: Contaminants removal and mechanism

• Published in: Journal of water process engineering 2024-06, Vol.63, p.105353, Article 105353
• Main Authors: Wang, Xiaohong, Shen, Tianyi, Yang, Wenjie, Kang, Longfei, Li, Benhang, Tian, Yajun, Li, Jun, Zhang, Liqiu
• Format: Article
• Language: English
• Subjects: Biogeochemical processes; Constructed wetlands; Pollutant removal mechanism; Pyrite
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2024.105353

Pyrite is increasingly employed as a substrate in constructed wetlands (CWs), exhibiting outstanding denitrification and phosphorus removal efficient, and demonstrating superior removal efficacy for emerging pollutants (e.g., antibiotics). Nevertheless, the removal mechanisms of diverse pollutants in pyrite-substrate CWs remain in a “black box”. The iron and sulfur transformation in the pyrite-based CWs significantly contribute to the removal of various pollutants, a concept elaborated in this review through analyzing the elemental cycles associated with the biochemical processes. In the pyrite-based CW, the highest removal of total nitrogen, total phosphorus, and COD achieved 95.05 ± 1.07 %, 97.4 ± 2.1 %, and 96 %, respectively. Notably, iron autotrophic, sulfur autotrophic, and ferric ammonia oxidation processes are pivotal for nitrogen removal, while the primary phosphorus removal mechanism involves iron hydroxide adsorption. Furthermore, reactive oxygen species (e.g., ·OH) generated through pyrite-activated molecular oxygen is crucial for removing recalcitrant emerging micropollutants, and this abiotic process exhibited more effective in mitigating the accumulation of antibiotic resistance genes. Overall, the pyrite-based CW is anticipated to achieve synergistic and efficient removal of multiple pollutants, representing a matter of considerable engineering significance. •The iron and sulfur cycling in pyrite-CWs is crucial for removing pollutants.•Iron and sulfur, as electron donors, enhanced the denitrification process.•The Feammox was involved in the denitrification process.•Phosphorus is removed mainly via iron-induced coagulation and precipitation.•ROS generated via pyrite-activated O2 enhanced emerging pollutants removal.