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天然有机质(NOM)对纳米铁基材料去除污染物过程中的影响作用机理仍存争议.本工作选取腐殖酸(HA)作为NOM的代表物,研究了HA对生物炭负载纳米镍铁(BC@Ni/Fe)降解十溴联苯醚(BDE209)的动力学影响,结果表明HA对BC@Ni/Fe降解BDE209产生抑制作用,且随着HA浓度的升高,抑制作用越显著.通过HA与BC@Ni/Fe相互作用实验发现,HA能够快速地被BC@Ni/Fe吸附;通过HA对BC@Ni/Fe的Zeta电位和沉降影响实验发现,随着HA浓度的升高可有效提高BC@Ni/Fe的稳定性以及表面电荷,这表明HA不是通过影响BC@Ni/Fe颗粒的性能对BC@Ni/Fe去除BDE209产生抑制作用的.BC@Ni/Fe的腐蚀能力随着HA浓度的升高而降低,这与HA对BC@Ni/Fe去除BDE209反应活性影响成正相关关系.HA中具有电子传递作用的典型醌类化合物2-羟基-1,4-萘醌(Lawsone)和蒽醌-2,6-磺酸钠(AQDS),在反应过程中并没有起到电子传递作用促进反应进行,反而对BC@Ni/Fe去除BDE209起抑制作用.结合BDE209和HA之间的竞争吸附实验发现,HA抑制BC@Ni/Fe反应活性的主导原因是HA优先于BDE209被BC@Ni/Fe吸附,HA包覆于BC@Ni/Fe颗粒表面占据了活性位点,阻碍BC@Ni/Fe与H_2O的接触,减少了Fe0的腐蚀,从而抑制了BC@Ni/Fe对BDE209的降解.
The mechanism of effect of natural organic matter (NOM) on the removal of pollutants by nano-Fe-based materials is still controversial.In this work, humic acid (HA) was selected as the representative of NOM and the effect of HA on the biochar supported nano- @ Ni / Fe), the results showed that HA inhibited the degradation of BDE209 by BC @ Ni / Fe, and the inhibitory effect was more significant with the increase of HA concentration. The results of the interaction with BC @ Ni / Fe show that HA can be rapidly adsorbed on BC @ Ni / Fe. The effect of HA on the Zeta potential and sedimentation of BC @ Ni / Fe was found to be effectively enhanced with the increase of HA concentration BC @ Ni / Fe stability and surface charge, indicating that HA does not inhibit BC @ Ni / Fe removal of BDE209 by affecting the properties of BC @ Ni / Fe particles. The corrosion resistance of BC @ Ni / Which is related to the effect of HA on the removal of BDE209 by BC @ Ni / Fe.The typical quinone compounds with electron transfer in HA such as 2-hydroxy-1,4-naphthoquinone (Lawsone) and Anthraquinone-2, 6-sulfonic acid sodium (AQDS), did not play an electron transfer role in the reaction to promote the reaction, but on BC @ Ni / Fe BDE209 removal .Based on the competitive adsorption experiment between BDE209 and HA, it was found that the main reason that HA inhibits the activity of BC @ Ni / Fe is that HA is preferentially adsorbed on BC @ Ni / Fe by BDE209 and HA is coated on BC @ Ni / Fe The surface of the particles occupied the active site, hindering the contact of BC @ Ni / Fe with H_2O, reducing the corrosion of Fe_0 and inhibiting the degradation of BDE209 by BC @ Ni / Fe.