Effect of humic acid on phenanthrene removal by constructed wetlands using birnessite as a substrate

Xiaotong Shen; Jian Zhang; Huijun Xie; Shuang Liang; Huu Hao Ngo; Wenshan Guo

doi:10.1039/d1ra06927f

Effect of humic acid on phenanthrene removal by constructed wetlands using birnessite as a substrate

RSC Adv. 2022 May 18;12(24):15231-15239. doi: 10.1039/d1ra06927f. eCollection 2022 May 17.

Authors

Xiaotong Shen¹, Jian Zhang^{2

3}, Huijun Xie⁴, Shuang Liang³, Huu Hao Ngo⁵, Wenshan Guo⁵

Affiliations

¹ Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences Jinan Shandong 250117 China.
² College of Safety and Environmental Engineering, Shandong University of Science and Technology Qingdao 266590 China zhangjian00@sdu.edu.cn.
³ Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science & Engineering, Shandong University Qingdao 266237 China.
⁴ Environment Research Institute, Shandong University Qingdao 266237 China.
⁵ School of Civil and Environmental Engineering, University of Technology Sydney Broadway NSW 2007 Australia.

Abstract

The binding of polycyclic aromatic hydrocarbons (PAHs) to humic acid (HA) can boost the complexation-flocculation process and promote pollutant oxidation through the role of HA as an electron shuttle. HA-coated biochar (BA) was added to study the effects of HA on phenanthrene (PHE) removal by constructed wetlands (CWs) using birnessite as a substrate. HA reduced the average PHE concentration of effluent by 26.58% due to its role as a complexing agent, based on Fourier-transform infrared spectroscopy analysis. For CWs with birnessite, the PHE removal performance was further enhanced due to the role of electron shuttles. X-ray photoelectron spectroscopy and illumina high-throughput analysis revealed an enhanced Mn-Fe cycle. The total relative proportions of Mn-oxidizing bacteria and iron-oxidizing bacteria in VFBCW-HA/BA were 2.33 and 5.50 times as high as those in VFBCW-BA and VFCW-HA/BA. Humic acid also accelerated the biodegradation of PAHs and the quantity of PAH degradative bacteria in VFBCW-HA/BA was 6.29 times greater than in VFBCW-BA.