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羟自由基(·OH)是自然环境中氧化活性最强的物种,对物质转化具有重要影响.前期研究发现地下水接触O2可产生·OH,其中Fe~(2+)氧化起主导作用,但地下水化学组成对Fe~(2+)氧化产生·OH的影响尚不清楚.通过室内模拟实验,探究了地下水中常见组分(Ca~(2+)、Mg~(2+)、腐殖酸(HA)和磷酸根)对Fe~(2+)氧化产生·OH的影响.结果表明,pH 6.5时0.357mM Fe~(2+)在5h内氧化完全,产生约1.8μM的·OH;Ca~(2+)(1~6mM)、Mg~(2+)(1~4mM)对Fe~(2+)氧化和·OH产生无明显影响;HA(10~30mg/L)促进Fe~(2+)氧化和·OH产生,促进效果随pH降低而增强;磷酸根(0.01~0.03mM)抑制Fe~(2+)氧化,对·OH产生的影响为先抑制后促进.
Hydroxyl radical (· OH) is the most oxidative species in the natural environment, which has an important impact on the material conversion.Previous studies found that the contact of O2 with groundwater produced · OH, in which Fe2 + oxidation played a leading role, but groundwater The effect of chemical composition on the oxidation of Fe · (2+) · OH is not yet clear. By means of indoor simulation experiments, the effects of some common components (Ca 2+, Mg 2+, HA) and phosphate) on the oxidation of Fe 2+ by Fe 2+. The results showed that 0.357mM Fe 2+ oxidized completely within 5h at pH 6.5, (2 +) (1 ~ 6mM) and Mg ~ (2 +) (1 ~ 4mM) had no significant effect on the oxidation of Fe 2+ and · OH. +) Oxidation and · OH production, the promotion effect with the increase of pH; phosphate (0.01 ~ 0.03mM) inhibit the oxidation of Fe ~ (2+), the impact of · OH production first to promote the inhibition.