Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada.
Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada.
J Hazard Mater. 2016 Nov 15;318:371-378. doi: 10.1016/j.jhazmat.2016.06.063. Epub 2016 Jul 1.
Naphthenic acids (NAs) are reported to be the main species responsible for the oil sands process-affected water (OSPW) toxicity. In this study, the degradation of cyclohexanoic acid (CHA) as a model compound for NAs by an ethylenediamine-N,N'-disuccinic acid (EDDS)-modified Fenton process was investigated at pH 8. Optimum dose for Fe-EDDS (EDDS:Fe=2:1) was 0.45mM, and 2.94mM for hydrogen peroxide (H2O2). The time profiles of the main species in the process were studied, including CHA, H2O2, Fe(II), total Fe, and Fe-EDDS (in the main form of Fe(III)EDDS). The second-order rate constant between EDDS and hydroxyl radical (OH) at pH 8 was obtained as 2.48±0.43×10(9)M(-1)s(-1). OH was proved to be the main species responsible for the CHA degradation, while superoxide radical (O2(-)) played a minor role. The consecutive addition of H2O2 and Fe-EDDS led to a higher removal of CHA compared to that achieved by adding the reagents at a time. The half-wave potential of Fe(III/II)EDDS was measured at pH 7-9. The EDDS-modified Fenton process is a promising alternative to degrade NAs.
环烷酸（NAs）被报道是造成油砂加工废水（OSPW）毒性的主要物质。在这项研究中，采用乙二胺二琥珀酸（EDDS）修饰的芬顿工艺，以环己烷酸（CHA）作为 NAs 的模型化合物，在 pH 8 下对其进行了降解研究。Fe-EDDS（EDDS:Fe=2:1）的最佳剂量为 0.45mM，过氧化氢（H2O2）的最佳剂量为 2.94mM。研究了该过程中主要物质的时间分布，包括 CHA、H2O2、Fe(II)、总铁和 EDDS（主要以 Fe(III)EDDS 的形式存在）。在 pH 8 下，EDDS 和羟基自由基（OH）之间的二级反应速率常数为 2.48±0.43×10(9)M(-1)s(-1)。证明 OH 是 CHA 降解的主要物质，而过氧化氢自由基（O2(-)）则起次要作用。与一次添加试剂相比，连续添加 H2O2 和 EDDS 可以更有效地去除 CHA。在 pH 7-9 下测量了 Fe(III/II)EDDS 的半波电位。EDDS 修饰的芬顿工艺是一种很有前途的降解 NAs 的替代方法。
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