可见光辅助水热炭高效活化过硫酸盐降解典型PPCPs的研究

Environmental persistent free radicals (EPFRs) are widely found in atmospheric particulates and contaminated soils, and their lifetime last for hours, or even months. EPFRs contain unpaired electron and possess the oxidation-reduction ability. EPFRs have also been found in hydrochar and play a vital role in the activation of persulfate to produce reactive oxygen species. However, the catalytic activity of hydrochar for persulfate activation is not satisfied, and the mechanism of action of EPFRs in the catalytic process is still unclear. Therefore, this proposal will to prepare hydrochar by hydrothermal carbonization using biomass as raw materials, and degrade diclofenac, a typical pharmaceutical and personal care products (PPCPs), by persulfate oxidation activated with hydrochar and visible light irradiation. First, the electron paramagnetic resonance are used to detect EPFRs formed in hydrochar, and the relationship between the catalytic activity of hydrochar for persulfate activation and the types or quantities of EPFRs will be found. Second, to elucidate the synergistic mechanism of heterogeneous catalysis and photocatalytic for the activation of persulfate, the electron transfer between EPFRs and persulfate will be investigated by spectroscopic and electrochemical methods. The research results of this proposal will provide theoretical guidance and data support for the development of advanced oxidation technology.

环境持久性自由基（EPFRs）广泛存在于大气颗粒物及受污染土壤中，其寿命长达几小时甚至几个月，它们含有未成对电子，具有氧化-还原性能。水热炭材料中也发现有EPFRs，它们在活化过硫酸盐产生活性氧物种过程中发挥重要作用。然而，水热炭活化过硫酸盐的效率较低，且EPFRs在催化过程中的作用机制尚不清楚。因此，本项目拟通过水热碳化生物质制备水热炭，在可见光的协同作用下高效活化过硫酸盐，实现对双氯芬酸——一种典型药品及个人护理品（PPCPs）的降解。首先，采用电子自旋共振技术，对水热炭中产生的EPFRs进行检测，同时结合活性氧物种的定量分析，建立EPFRs的种类和数量与催化过硫酸盐活性之间的关系；其次，采用光谱及电化学等分析手段，考察水热炭表面的EPFRs与过硫酸盐之间的电子传递过程，阐明水热炭多相催化和光催化活化过硫酸盐的协同作用机制。本项目的研究成果将为高级氧化技术的发展提供理论指导和数据支持。

药品及个人护理品（PPCPs）作为一类“新兴污染物”，长期暴露在水体环境中会对水生生物和人类健康造成危害，但是它们在水环境中浓度非常低，如何实现水中微量有机污染物的高效、高选择性降解是亟需解决的问题。本项目：1）利用自然界废弃的生物质为原料制备新型碳材料水热炭，通过无机酸和有机溶剂改性的方法调控水热炭材料表面官能团的种类和相对含量，达到提高水热炭光催化活性的目的，实现在可见光照射下辅助水热炭活化过硫酸盐氧化降解水环境中有机污染物；2）发现水热炭材料在可见光照射下，能够实现光催化还原氧气合成H2O2，原位产生的H2O2可作为有机物降解和水消毒的氧化剂，降低废水处理过程中药剂的使用，降低处理成本；3）建立了磺化酞菁钴/过硫酸盐氧化体系，实现对水体中有机污染物的高效选择性降解，该体系对环境复杂介质表现出良好的抗性，在实际水体中仍能保持较高的氧化效率。