Highly effective removal of 4-chloroaniline in water by nano zero-valent iron cooperated with microbial degradation

Abstract

The misuse of aromatic amines like 4-chloroaniline (4-CA) has led to severe environmental and health issues. However, it’s difficult to be utilized by microorganisms for degradation. Nano-zero-valent iron (nZVI) is a promising material for the remediation of chloroaniline pollution, however, the synergistic effect and mechanism of nZVI with microorganisms for the degradation of 4-CA are still unclear. This study investigated the potential of 4-CA removal by the synergistic system involving nZVI and 4-CA degrading microbial flora. The results indicate that the addition of nZVI significantly enhanced the bio-degradation rate of 4-CA from 43.13 % to 62.26 %. Under conditions involving 0.1 % nZVI addition at a 24-hour interval, pH maintained at 7, and glucose as an external carbon source, the microbial biomass, antioxidant enzymes, and dehydrogenase were significantly increased, and the optimal 4-CA degradation rate achieved 68.79 %. Additionally, gas chromatography-mass spectrometry (GC-MS) analysis of intermediates indicated that the addition of nZVI reduced compounds containing benzene rings and enhanced the dechlorination efficiency. The microbial community remained stable during the 4-CA degradation process. This study illustrates the potential of nZVI in co-microbial remediation of 4-CA compounds in the environment.