溶解Mn(III),作为一种有效的单电子转移氧化剂,在自然水域和沉积物中无处不在,并积极参与生物地球化学过程和水处理中有机物的转化。然而,Mn(Ⅲ)的重要作用因其寿命短而长期被忽视。这项研究是首次研究Mn(III)在有机砷转化中的性能并强调其对环境的影响。均相和非均相的Mn(III)基体系均可有效去除对阿桑酸(p-ASA,15μM),降解效率接近40.4%-98.3%。提出了p-ASA的两种降解途径,其中As-C键和氨基是容易受到Mn(III)攻击的位点,导致形成毒性更大的砷酸盐(As(V))和硝酮。通过将有机砷转化为无机砷,总砷和溶解有机物的去除效率分别提高到65.1%-95.5%和16.6%-36.6%,分别,通过混凝或吸附的后处理,伴随着细胞毒性和环境风险的显著降低。特别是,聚合硫酸铁和颗粒状活性氧化铝在总砷去除方面表现出优异的性能。此外,Mn(III)的氧化效率几乎不受常见阳离子和阴离子的影响(例如,Ca2+,Mg2+,NH4+,NO3-,SO4-),卤化物离子(例如,Cl-,Br-)和天然有机物,在复杂的水基质下显示出有机砷去除的高鲁棒性。总的来说,这项研究揭示了锰(III)对富含锰环境中有机砷命运的重要性,并证明了基于Mn(III)的策略在水/废水净化中实现有针对性的去污的潜力。
Dissolved Mn(III), as a potent one-electron transfer oxidant, is ubiquitous in natural waters and sediments and actively involved in the transformation of organics in biogeochemical processes and water treatment. However, the important role of Mn(III) has long been overlooked because of its short life. This study was the first to investigate the performance of Mn(III) in organoarsenic transformation and to highlight the environmental implications. Both homogeneous and heterogeneous Mn(III)-based systems were effective to remove p-arsanilic acid (p-ASA, 15 μM) with degradation efficiency approaching 40.4 %-98.3 %. Two degradation pathways of p-ASA were proposed, in which As-C bond and amino group were vulnerable sites to Mn(III) attack, leading to the formation of more toxic arsenate (As(V)) and nitarsone. Through transforming organoarsenic to inorganic arsenic species, the removal efficiency of total arsenic and dissolved organics were enhanced to 65.1 %-95.5 % and 16.6 %-36.6 %, respectively, by post-treatment of coagulation or adsorption, accompanied with significant reduction of cytotoxicity and environmental risks. Particularly, polymeric ferric sulfate and granular activated alumina showed superior performance in the total As removal. Moreover, oxidation efficiency of Mn(III) was hardly affected by common cations and anions (e.g., Ca2+, Mg2+, NH4+, NO3-, SO4-), halide ions (e.g., Cl-, Br-) and natural organic matter, showing high robustness for organoarsenic removal under complicated water matrices. Overall, this study shed light on the significance of Mn(III) to the fate of organoarsenics in manganese-rich environments, and demonstrated the promising potential of Mn(III)-based strategies to achieve targeted decontamination in water/wastewater purification.