Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu 610065, China.
Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu 610065, China.
J Hazard Mater. 2022 Jun 15;432:128725. doi: 10.1016/j.jhazmat.2022.128725. Epub 2022 Mar 17.
The treatment of tributyl phosphate (TBP) extractant waste from specific industry, eg., nuclear industry, is a great challenge due to its stability and high environmental risk of phosphorus-containing species releasing. Inspired by chemical looping combustion (CLC) technology, a MnO-assisted thermal oxidation strategy is proposed for TBP degradation and simultaneously P immobilization. Under recommended reaction conditions of 220 °C, 10 g MnO mL TBP and 3 h reaction duration, a high P immobilization efficiency of 93.99% is achieved. Material characterization results indicate that P is mainly immobilized in the form of MnPO, which greatly reduces the environmental risk of P-containing species. TBP degradation intermediates are further identified by thermogravimetric-gas chromatography-mass spectrometry (TG-GC-MS), liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS), which facilitates understanding of reaction mechanisms as well as proposing possible pathways of TBP degradation. It is suggested that MnO provides essential oxygen as oxygen carrier for flameless combustion. Meantime, MnO reduction leads to the generation of Mn(III) species. The existence of oxygen vacancy in MnO also facilitates •O radical generation. Under flameless combustion and attacks of Mn(III) and •O, TBP is firstly degraded into intermediates and finally mineralized into CO and HO, while P is mainly immobilized as pyrophosphate.
由于含磷物种释放的稳定性和高环境风险，来自特定行业（如核工业）的磷酸三丁酯（TBP）萃取剂废物的处理是一项巨大的挑战。受化学链燃烧（CLC）技术的启发，提出了一种 MnO 辅助热氧化策略，用于 TBP 降解和同时实现磷固定。在推荐的反应条件下（220°C，10g MnO mL TBP 和 3h 反应时间），实现了 93.99%的高磷固定效率。材料特性分析结果表明，磷主要以 MnPO 的形式固定，这大大降低了含磷物种的环境风险。通过热重-气相色谱-质谱联用（TG-GC-MS）、液相色谱-质谱联用（LC-MS）和气相色谱-质谱联用（GC-MS）进一步鉴定了 TBP 降解中间产物，有助于理解反应机理并提出 TBP 降解的可能途径。MnO 被认为作为无焰燃烧的氧载体提供必要的氧。同时，MnO 的还原导致 Mn(III)物种的生成。MnO 中的氧空位也有利于 •O 自由基的生成。在无焰燃烧和 Mn(III)和 •O 的攻击下，TBP 首先降解为中间产物，最后矿化为 CO 和 HO，而磷主要固定为焦磷酸盐。
