| 废弃物焚烧飞灰中持久性自由基与二噁英及金属的关联探究 |
| 摘要点击 2536 全文点击 1166 投稿时间：2015-08-10 修订日期：2015-10-19 |
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| 中文关键词 自由基 电子顺磁共振 二噁英 焚烧飞灰 金属 数值分析 废物处理 |
| 英文关键词 radicals EPR PCDD/Fs waste incineration fly ash metal numerical analysis waste treatment |
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| 中文摘要 |
| 环境持久性自由基稳定性强,在二噁英生成反应中发现其存在. 为了研究实际废弃物焚烧飞灰中持久性自由基的特性,对6个不同焚烧厂布袋飞灰分别进行了持久性自由基、二噁英以及金属检测,结果表明天津医疗废物焚烧飞灰、江西南昌生活垃圾焚烧飞灰和浙江兰溪生活垃圾焚烧产生的碳黑、炉渣都含有持久性自由基. 其中天津样品信号最强,检测到羟基自由基、以碳原子为中心的自由基及半醌类自由基3种信号. 对比各个样品的二噁英毒性当量(以I-TEQ计)发现,江西南昌飞灰样品的最高,高达7.2294 ng ·g-1,而自由基信号最强的天津样品的二噁英毒性当量却仅有0.0928 ng ·g-1,自由基信号强弱与二噁英含量并未表现出明显的数值关系. 同时样品中持久性自由基自旋浓度随着金属质量分数比重的升高也呈现升高趋势,以Al、Fe、Zn变化情况最为明显,可见自由基信号强弱与金属存在一定的关联性. 此外,Zn在天津样品中含量最高(0.8137%),是其他样品的数倍,同时该样品含有较高浓度的以氧为中心的自由基,可以推测金属 Zn对持久性自由基的形成影响较大,且易形成半衰期长的自由基类型. |
| 英文摘要 |
| Environmentally persistent free radicals (EPFRs) are relatively highly stable and found in the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Recent studies have concentrated on model dioxin formation reactions and there are few studies on actual waste incineration fly ash. In order to study EPFRs and the correlation with dioxins and heavy metals in waste incineration fly ash, the spins of EPFRs, concentration of PCDD/Fs and metals in samples from 6 different waste incinerators were detected. The medical waste incineration fly ash from Tianjin, municipal solid waste incineration fly ash from Jiangxi Province, black carbon and slag from municipal solid waste incinerator in Lanxi, Zhejiang Province, all contained EPFRs. Above all the signal in Tianjin sample was the strongest. Hydroxyl radicals, carbon-center radicals and semiquinone radicals were detected. Compared with other samples, Jiangxi fly ash had the highest toxic equivalent quantity (TEQ) of dioxins, up to 7.2294 ng ·g-1. However, the dioxin concentration in the Tianjin sample containing the strongest EPFR signals was only 0.0928 ng ·g-1. There was perhaps little direct numeric link between EPFRs and PCDD/Fs. But the spins of EPFRs in samples presented an increasing trend as the metal contents increased, especially with Al, Fe, Zn. The signal strength of radicals was purposed to be related to the metal contents. The concentration of Zn (0.8137%) in the Tianjin sample was the highest and this sample contained much more spins of oxygen-center radicals. We could presume the metal Zn had a greater effect on the formation of EPFRs, and was easier to induce the formation of radicals with a longer half-life period. |
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