弱磁场强化零价铁对水中偶氮染料脱色降解的作用初探

本文以橙黄Ⅰ、橙黄Ⅱ、橙黄Ⅳ和日落黄4种偶氮染料为目标染料,首次尝试利用外加弱磁场(~20 mT)的方法来强化零价铁脱色降解偶氮染料。结果表明加磁或不加磁时反应过程均符合一级反应动力学。在磁场的存在下,4种偶氮染料的降解速率都较不加磁场时有很大的提高,提高倍数分别为110.67、111.97、59.51和94.00。弱磁场对零价铁降解偶氮染料的促进作用可能是由于外加磁场所产生的洛伦兹力以及零价铁表面产生的感应磁场所产生的磁场梯度力促进了Fe2+的释放,加快了零价铁的腐蚀,促进零价铁释放更多电子和新生态氢,加速了—N=N—键的断裂,从而强化了染料的脱色降解。

Preliminary Study on the Effect of Zero Valent Iron Enhanced by Weak Magnetic Field on the Azo Dyes Decoloration in the Water

The effects zero valent iron （ZVI） enhanced by weak magnetic field （WMF, -20 mT） on the azo dyes decoloration were investigated in this paper for the first time, taking orange Ⅰ, orange Ⅱ, orange Ⅳ and sunset yello FCF as the target azo dyes. The results showed that the reaction processes fit well with first - order kinetics model both of in and out of the WMF. A great improvement of degradation of these azo dyes was observed in the presence of WMF compared to the case without WMF. In the presence of WMF, the degradation rate of each azo dye was 110. 67, 111.97, 59.51 and 94. 00 times larger than that without WMF, respectively. The improvement of degradation might result from the Lorentz force produced by the external magnetic field and the magnetic field gradient force generated from the induced magnetic field produced by the magnetized ZVI particles. These two forces accelerated the release of Fe2 ＋ and thereby promoted the ZVI corrosion. As a result, more electron and hydrogen were released from ZVI corrosion, accelerated the rupture of -N = N- , and improved the degradation of azo dyes.