Water contamination by emerging organic pollutants is calling for advanced methods of remediation such as iron-activated sulfite-based advanced oxidation. Sulfate radical, SO4??, and hydroxyl radical, ?OH, are the primary reactive intermediates formed in the Fe(III)/sulfite system, yet the possible involvement of Fe(IV) produced from Fe(II) and persulfates is unclear. Here we explored the role of Fe(IV) in the Fe(III)/sulfite system by methyl phenyl sulfoxide (PMSO) probe assay, electron paramagnetic resonance spectra analysis, alcohol scavenging experiment, and kinetic simulation. Results show that PMSO is partially transformed into methyl phenyl sulfone (PMSO2), thus evidencing Fe(IV) formation. The remaining degradation of PMSO is due to SO4?? and ?OH. The contribution of Fe(IV) versus free radicals is progressively promoted when the Fe(III)-sulfite reaction proceeds, with an upper limit of 80–90%. The contribution of Fe(IV) versus free radicals increases with Fe(III) and sulfite dosages, and decreases with increasing pH. Overall, our findings demonstrate the involvement of Fe(IV) in the Fe-catalyzed sulfite auto-oxidation process.
针对醋糟中木质纤维素利用效率低的问题,通过接种瘤胃微生物可强化木质纤维素水解.采用逐步提升体系有机负荷的方式,考察瘤胃微生物生物强化对醋糟厌氧消化性能的提升效果,并运用绝对定量实时聚合酶链锁反应(Q-PCR)技术探究其微生物学强化机制.结果表明:长期连续运行成功塑造了高效的木质纤维素瘤胃强化体系.该体系的最高有机负荷达8.90 g/(L·d)(以VS计),是强化前的1.53倍,该有机负荷下半纤维素和纤维素降解率分别达73.9%和40.1%,单位质量底物沼气和甲烷产量相应地分别达到451和261 m L/g(以VS计),半纤维素和纤维素较高的降解率是该体系维持高产气性能的主要原因.生物相机制研究表明,瘤胃微生物强化体系中与木质纤维素水解密切相关的GH5(糖苷水解酶家族5)水解菌逐步富集,其基因拷贝数从初始的964×1010copies/g升至最高有机负荷下的6.83×1011copies/g,这是底物在高有机负荷下仍能被高效生物转化的根本原因.研究显示,瘤胃微生物的介入可有效强化体系底物的降解能力,促进醋糟产甲烷性能的提升. 相似文献
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