The regulating mechanisms of tritonX-100 affected oxidation of PAHs in site soil aggregates using sodium citrate activated Fe2+-persulfate

Here, we present a first investigation of the inhibition mechanism of surfactant Triton X-100 (TX-100) on the oxidation degradation of polycyclic aromatic hydrocarbons (PAHs) in site soil aggregates using sodium citrate assisted Fe 2+ -activated persulfate (SC/Fe 2+ /PS). First, TX-100 was not only competed the adsorption sites of soil aggregates with PS, but also consumed PS, which inhibit the PAHs remediation rate in the TX-100 elution followed by the SC/Fe 2+ /PS oxidation system from 55.6% in the oxidation system to 50.3%. Furthermore, in the oxidation followed by elution system, PAHs was adsorbed on the iron minerals produced during the oxidation, which would be form a bound PAHs that was difficult to react with PS, and then re-eluted to the soil by the TX-100. Additionally, it was found that the oxidative and the elution efficiency of PAHs exhibited negative correlations with aggregate particle sizes. Finally, soil microorganism communities were more strongly changed by SC/Fe 2+ /PS oxidation and PAHs concentration than that of TX-100 elution, with obvious alterations bacteria than fungi, the effects of SC/Fe 2+ /PS and PAHs concentration on microorganism communities were opposite. This study provided a proof of regulating mechanisms for the site soil remediation using surfactants combined with the iron-PS system. Environmental Implications Surfactants may have inhibitory effects in advanced oxidative systems on the removal of PAHs and may alter soil microorganism diversity. It is necessary to comprehensively analyze the intrinsic regulatory mechanisms, and the correlation between the remediation process and soil microbial community structure of surfactants affecting the remediation efficiency of PAHs in site soil aggregates. This work comprehensively discussed the controlling mechanisms of surfactants affect the oxidation remediation of PAHs in the site soil and providing new insights for the design of the remediation technologies for the soil polluted with PAHs in the future.