氨三乙酸强化零价铁/过一硫酸盐降解橙黄G

采用氨三乙酸(NTA)强化和改善零价铁/过一硫酸盐(Fe0/PMS)体系降解水中偶氮染料的氧化效能,以橙黄G(OG)为目标污染物,研究了NTA强化Fe0/PMS(NTA/Fe0/PMS)体系中OG的降解效果和NTA的强化作用机制,并考察了NTA、Fe0、PMS等主要反应物浓度和水中常见的共存物质对OG降解效能的影响.结...

Degradation of Orange G by Fe0/peroxymonosulfate with nitrilotriacetic acid enhancement

Nitrilotriacetic acid (NTA) was applied to enhance and improve the oxidation efficiency of azo dyes in Fe⁰/PMS system. Taking Orange G (OG) as the target pollutant, the degradation efficiency of OG, the strengthening role of NTA, the effects of NTA, Fe⁰, PMS and general coexistence substances in water on the degradation of OG were studied in Fe⁰/PMS system enhanced with NTA(NTA/Fe⁰/PMS).The results demonstrated that the introduction of NTA could enhance the degradation of OG by Fe⁰/PMS system, and the initial pH had a significant effect on the enhancement. Under neutral (pH=7) and acidic (pH=3) conditions, the apparent rate constants of OG removal by NTA/Fe⁰/PMS system were 31.3 times and 5.5 times higher than those of Fe⁰/PMS system, respectively. Increasing the concentration of NTA, Fe⁰ and PMS facilitated the degradation of OG, but negative effects were observed when NTA or PMS concentration were over 8mmol/L and 1.0mmol/L, respectively. In the context of water quality, the presence of Cl^- promoted the degradation of OG, while HCO₃^-, H₂PO₄^- and Humic Acid showed different degrees of inhibition. In NTA/Fe⁰/PMS system, SO₄^·- and·OH produced at Fe⁰ interface was confirmed to be the dominant active species responsible for OG degradation, and heterogeneous and homogeneous activation of PMS contributed about 83.2% and 16.8% to the degradation of OG, respectively. When adding NTA to Fe⁰/PMS system, Fe³⁺/Fe²⁺ generated could be complexed rapidly with NTA, which not only alleviated the formation of passive layer and promoting the direct activation of PMS on Fe⁰ interface, but also increased the concentration of soluble iron in system, promoting the activation of PMS by homogeneous interaction. Thus, the degradation effect of OG in Fe⁰/PMS system was enhanced by NTA.