Frontiers in Environmental Science (Oct 2024)

Sorption/desorption of phenanthrene and ofloxacin by microbial-derived organic matter-mineral composites

  • Fangfang Li,
  • Qiuling Yan,
  • Zhongwen Li,
  • Zhicheng Tan,
  • Yuxuan Li,
  • Siyao Wang,
  • Jiawen Guo,
  • Hongbo Peng,
  • Hongbo Peng,
  • Lin Wang,
  • Lin Wang

DOI
https://doi.org/10.3389/fenvs.2024.1485328
Journal volume & issue
Vol. 12

Abstract

Read online

IntroductionSoil organic matter plays an important role in the long-term “locking” of organic contaminants in soil environment. Recently, microbial-derived organic matter have been recognized as essential components of stabilized soil carbon pools. However, the contribution of microbial-derived organic matter to sorption of organic contaminants remains unclear.MethodsHere, we obtained microbial-derived organic matter-mineral composites by inoculating model soil (a mixture of hematite and quartz sand (FQ) or montmorillonite and quartz sand (MQ)) with natural soil microorganisms and different substrate-carbon (glycine (G), glucose (P), or 2, 6-Dimethoxyphenol (B)), which were named GF, PF, BF, GM, BM, and PM, respectively. Batch sorption/desorption experiments were conducted for phenanthrene (PHE) and ofloxacin (OFL) on the composites.Results and DiscussionThe composites cultured with 2,6-dimethoxyphenol had the highest carbon content (0.98% on FQ and 2.11% on MQ) of the three carbon substrates. The carbon content of the composites incubated with MQ (0.64%–2.11%) was higher than that with FQ (0.24%–0.98%), indicating that montmorillonite facilitated the accumulation of microbial-derived organic matter owing to its large specific surface area. The sorption of PHE by microbial-derived organic matter was mainly dominated by hydrophobic partitioning and π-π conjugation, whereas the sorption of OFL was mainly dominated by hydrophobic hydrogen bonding and π-π conjugation. The sorption of OFL onto the composites was more stable than that of PHE. Microbial-derived organic matter -mineral composites can reduce the risk of organic contaminant migration in soil, particularly ionic organic contaminants.

Keywords