FeS催化缓释纳米CaO2一体化类Fenton高级氧化材料的创制及其降解氯代烃的作用机制

我们前期研究提示：铁基催化过氧化钙原位氧化治理氯代烃污染地下水技术有效可行，且证实FeS具有催化氧化/还原双重功能。开拓性创制FeS催化缓释纳米CaO2一体化类芬顿高级氧化材料，可突破地下水环境中氧化剂、催化剂及污染物难以按最优配比充分接触而导致修复效率低的技术瓶颈，达到原位精准治理、持续长久、防止污染反弹的目的。本研究首次通过表面浸渍结合化学还原法及溶剂热原位合成法，优化创制FeS-P@nCaO2及Fe/FeS-P@nCaO2一体化缓释纳米氧化材料，揭示其在含水层介质中的传质性能，阐明纳米尺度微环境下材料界面FeS及Fe/FeS作用机制、Fe及FeS与缓释H2O2作用、S2-及零价铁的还原作用与Fe(III)/Fe(II)转化关系、及Fe(II)和柠檬酸协同降解氯代烃的机制，探究材料老化及地下水质和含水层介质对氯代烃降解效果的影响，为实际氯代烃污染地下水原位精准治理提供理论依据和技术支撑。

Our preliminary experimental results clearly indicated that iron-based catalytic in situ chemical oxidation of calcium peroxide to remediate groundwater polluted by chlorohydrocarbons (CHCs) is effective and feasible, and it has been confirmed that FeS has dual functions of catalytic oxidation/reduction. The innovation of FeS-catalyzed sustained-release nano-CaO2 integrated Fenton-like advanced oxidation materials can break through the technical bottleneck of low efficiency of groundwater remediation caused by the difficulty of fully contacting of oxidants, catalysts and pollutants in groundwater environment based upon the optimum proportion, aiming to the achievement of in situ precise remediation, persistence and prevention of contaminants rebound. In this study, the integrated materials of FeS-P@nCaO2 and Fe/FeS-P@nCaO2, for the first time, will be prepared by the methods of surface impregnation combined with chemical reduction and/or solvothermal in situ synthesis. The mass transfer properties of innovative materials in soil media will be revealed. The function mechanisms of FeS or Fe/FeS at the interface of materials in nano-scale environment, the interaction between Fe/FeS and sustained-release H2O2, the relationship of Fe(III)/Fe(II) transformation with S2- and zero-valent iron reduction, and the mechanisms of synergistic strengthened degradation of CHCs by Fe(II) and citric acid will be elucidated. The effects of materials aging, groundwater quality and soil media on CHCs degradation performance will be explored. It is anticipated that the outcome of this research will provide solid theoretical basis and strong technical support for in situ precise remediation of CHCs contaminated groundwater in practice.