零价铁-过硫酸盐体系同时去除水中酸性橙7和磷

采用零价铁(ZVI)活化过硫酸盐(PS)同时去除水中酸性橙7(AO7)和磷.ZVI-PS体系可以产生强氧化性的SO·-4和HO·,从而去除水中AO7.同时,ZVI最终转化为Fe3+,因此可以用来去除水中磷.结果表明,ZVI-PS体系在酸性条件下可以有效的同时去除水中AO7和磷.淬灭实验结果表明,硫酸根自由基(SO·-4)对AO7的降解起主要作用.水中共存的阴离子和腐植酸(HA)对AO7和磷的去除均有抑制作用,其对AO7和磷去除的抑制能力排序均为:HCO-3 NO-2 HA NO-3 Cl-.AO7和磷在超纯水中的去除率高于其他实际水体,但反应60 min后,实际水体中AO7和磷的去除率也分别高达80.31%～92.69%和87.54%～100%,因此,该体系对实际水体中AO7和磷的处理有潜在的应用价值.通过紫外-可见分光光谱和GC-MS分析说明,AO7经过偶氮键断键后的中间产物进一步氧化形成含苯环类物质.同时,TOC有所降低,说明部分AO7被矿化为CO2和H2O.

Simultaneous removal of acid orange 7 and phosphate from water using zero-valent iron activated persulfate system

In the present study, zero-valent iron (ZVI) was used as a catalyst to activate persulfate (PS) for the simultaneous removal of acid orange 7 (AO7) and phosphate from aqueous solutions. Sulfate radicals (SO₄^·-) and hydroxyl radical (HO·) can be generated in ZVI-PS system which may participate in the oxidation of AO7. Meanwhile, ZVI is ultimately transformed to Fe³⁺, which can potentially serve as a coagulant to remove phosphate. Experimental results indicate that AO7 and phosphate could be simultaneously removed in this process. A stronger acidic condition is more favourable for AO7 and phosphate removal. Radical scavenging tests reveal that the predominant reactive oxygen species for AO7 degradation was SO₄^·-. Coexisting substances inhibited the AO7 and phosphate removal, and the inhibition of these substances followed the order of HCO₃^- > NO^- ₂ > humic acid (HA) > NO₃^- > Cl^-. The removal efficiencies of AO7 and phosphate were lower in real waters than in ultrapure water. Nevertheless, up to 80.31%~92.69% and 87.54%~100% of AO7 and phosphate were removed from the real waters within 60 min, respectively. From the analysis of UV-Vis spectra and GC-MS, it is assumed that the oxidation process is initiated by the separation of azo links. The intermediates containing various oxygenated benzene and naphthalene rings further undergo ring-opening reactions, and finally mineralized to CO₂ and H₂O.