Denitrification performance of nitrate–dependent ferrous (Fe2+) oxidizing Aquabacterium sp. XL4: Adsorption mechanisms of bio–precipitation of phenol and estradiol

• Published in: Journal of hazardous materials 2022-04, Vol.427, p.127918-127918, Article 127918
• Main Authors: Xu, Liang, Su, Junfeng, Ali, Amjad, Chang, Qiao, Shi, Jun, Yang, Yuzhu
• Format: Article
• Language: English
• Subjects: Adsorption; Adsorption mechanisms; Bio–precipitation; Denitrification; Estradiol; Iron; Iron oxidation; Nitrates; Oxidation-Reduction; Phenol; Phenol and Estradiol; Water Pollutants, Chemical
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2021.127918

In this study, a nitrate–dependent ferrous (Fe2+) oxidizing strain under anaerobic conditions was selected and identified as XL4, which belongs to Aquabacterium. The Box–Behnken design (BBD) was used to optimize the growth conditions of strain XL4, and the nitrate removal efficiency of strain XL4 (with 10% inoculation dosage, v/v) could reach 91.41% under the conditions of 30.34 ℃, pH of 6.91, and Fe2+ concentration of 19.69 mg L–1. The results of Fluorescence excitation–emission matrix spectra (EEM) revealed that the intensity of soluble microbial products (SMP), aromatic proteins and the fulvic–like materials were obvious difference under different Fe2+ concentration, pH, and temperature. X–ray diffraction (XRD) data confirmed that the main components of bio–precipitation were Fe3O4 and FeO(OH), which were believed to be responsible for the adsorption of phenol and estradiol. Furthermore, the maximum adsorption capacity of bio–precipitation for phenol and estradiol under the optimal conditions were 192.6 and 65.4 mg g–1, respectively. On the other hand, the adsorption process of phenol and estradiol by bio–precipitation confirmed to the pseudo–second–order and Langmuir model, which shows that the adsorption process is chemical adsorption and occurs on the uniform surface. [Display omitted] •A highly-efficient denitrifying strain XL4 under low C/N radio was screened out.•The optimal growth conditions of strain XL4 were fitted by Box–Behnken design.•Adsorption capacity of phenol and estradiol were 192.6 and 65.4 mg g–1, respectively.•Adsorption of bio–precipitation confirmed pseudo–second–order and Langmuir model.