State Key Laboratory of Environmental Aquatic Chemistry, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, POB 2871, Beijing 100085, China.
Environ Technol. 2009 Dec 14;30(14):1585-91. doi: 10.1080/09593330903313810.
In this paper, the applicability of the ferron assay for the characterization of hydrolyzed Fe(III) produced in the Fenton's reaction system was investigated, and then the hydrolysis process of Fe(III) under typical Fenton's reaction conditions was compared with that in a normal ferric sulphate solution system, by applying the ferron assay method and the modified hydrolyticity, B*, a parameter that takes into account all the possibilities of base generation and reduction. It was found that the residual Fe(II) and H2O2 under normal Fenton's reaction conditions had little influence on the Fe(III)-ferron colorimetric reaction. Experimental results showed that the hydrolysis process of Fe(III) in the Fenton system was quite different from that in the ferric salt solution system. Under the same hydrolyticity, the hydrolysis rate of Fe(III) in the Fenton system was faster and more complicated than that in the ferric sulphate system, and the Fe(III) species produced in the Fenton system had a larger polymerization degree. With the increase in H2O2/Fe, Fe(a) and Fe(b) (the monomers and small polymeric Fe(III) species) increased gradually while Fe(c) (the colloidal part) decreased, indicating that the increase in H2O2 had restrained the hydrolysis of Fe(III). This conclusion was also supported by the comparison of effective particulate diameters in the two systems. The fact that larger particles were produced with a shorter time in the Fenton system provided direct proof for the observation of the differences in the hydrolysis of Fe(III) in the two systems. The results of this study are useful for the possible utilization of the hydrolyzed Fe(III) produced in the Fenton's system for the removal of organic pollutants.
本文研究了 Ferron 法在表征芬顿反应体系中生成的水解态 Fe(III)中的适用性，然后通过 Ferron 法和改良水解度 B*（考虑到所有碱基生成和还原可能性的参数）比较了典型芬顿反应条件下 Fe(III)的水解过程与在正常硫酸铁溶液体系中的水解过程。结果表明，正常芬顿反应条件下的残留 Fe(II)和 H2O2 对 Fe(III)-Ferron 比色反应几乎没有影响。实验结果表明，芬顿体系中 Fe(III)的水解过程与铁盐溶液体系中的水解过程有很大的不同。在相同的水解度下，芬顿体系中 Fe(III)的水解速度比硫酸铁体系中的快，且更复杂，并且在芬顿体系中生成的 Fe(III)物种的聚合度更大。随着 H2O2/Fe 的增加，Fe(a)和 Fe(b)（单体和小聚合态 Fe(III)物种）逐渐增加，而 Fe(c)（胶体部分）减少，表明 H2O2 的增加抑制了 Fe(III)的水解。这一结论也得到了两个体系中有效颗粒直径比较的支持。在芬顿体系中，较短时间内生成更大的颗粒，为观察两个体系中 Fe(III)水解的差异提供了直接证据。本研究的结果对于可能利用芬顿体系中生成的水解态 Fe(III)去除有机污染物具有重要意义。
