Examination and research development of new catalysts for removing pharmaceuticals from water

天然水体中药物和内分泌干扰物(EDCs)的存在日益引起人们的关注，因为它们经常出现在水生生态系统中并持续存在，即使在微量浓度下也会对水生生物的健康和安全构成威胁。众所周知，传统的水处理工艺一般不足以消除这些持久性污染物。研究表明，通过常规生物处理工艺，约有50%的EDCs被去除，而9%的EDCs没有被去除。因此，为这些新出现的污染物开发有效和可持续的清除方法是至关重要的。二氧化钛是目前应用最广泛的去除水中有机污染物的光催化剂。然而，一些研究已经报道了与二氧化钛相比，氧化锌对有机污染物的去除效率更高。氧化锌光催化剂具有带隙宽、无毒、成本低等特点，是一种很有发展前途的光催化技术。近年来，人们通过掺杂元素和缩小禁带宽度来提高氧化锌的光催化性能，以便在可见光照射下被激活。然而，任何缩小半导体带隙的努力都会导致氧化还原电位的降低，以及消除和矿化的效率。作为一种替代策略，表面改性被认为是提高吸附和光催化氧化效率的一种策略。可以预期，氧化锌的表面氟化也可以增强对新兴污染物的光催化降解。通过与DaguaTechnology Inc.建立合作伙伴关系，本研究试图合成一种具有高比表面积和稳定性的双功能分级吸附剂/光催化剂，用于低能耗地去除水中的EDCs。为此，本研究将设计管式光反应器，在极端条件下，对水中广泛检测到的抗生素磺胺甲恶唑进行消除和矿化实验。

The presence of pharmaceuticals and endocrine disrupting compounds (EDCs) in natural waters has raisedincreasing concern due to their frequent appearance and persistence in aquatic ecosystem and the threat tohealth and safety of aquatic life, even at trace concentrations. Conventional water treatment processes areknown to be generally inadequate for the elimination of these persistent contaminants. Studies havedemonstrated that about 64% of EDCs are removed by less than 50% while 9% are not removed at all byconventional biological treatment processes. Therefore, the development of efficient and sustainable removalmethods for these emerging contaminants is essential. TiO2 is the most widely used photocatalyst for removalof organic contaminants from water. However, the higher efficiencies of ZnO compared to TiO2 forelimination of organic contaminant has been reported in several studies. Photocatalytic removal of EDCs byusing zinc oxide photocatalyst (ZnO) is a promising process due to the unique characteristics of thisphotocatalyst such as wide band gap, non-toxicity and low cost. Recently, a considerable effort has been madeto improve the photocatalytic performance of ZnO by doping with elements and narrowing band gap in order tobe activated under visible light irradiation. However, any effort to narrow the band gap of semiconductors leadsto the reduction of redox potential, as well as the efficiencies of elimination and mineralization. As analternative strategy, surface modification is considered for enhancing the efficiency of adsorption andphotocatalytic oxidation in this research. It is expected that surface fluorination of ZnO also enhances thephotocatalytic degradation of emerging contaminants. Through building a partnership with the DaguaTechnology Inc., this research is attempting to synthesize a dual functional hierarchical adsorbent/photocatalystwith high surface area and stability for removing EDCs from water with low energy consumption. For thispurpose, a tubular photoreactor will be designed in this study to perform experiments for elimination andmineralization of sulfamethoxazole as widely detected antibiotic in water, under extremely