School of Chemistry & Environment , South China Normal University , Guangzhou 510006 , China.
Guangdong Provincial Engineering Technology Research Center for Drinking Water Safety , Guangzhou 510006 , China.
ACS Appl Mater Interfaces. 2019 Jul 10;11(27):23957-23971. doi: 10.1021/acsami.9b02143. Epub 2019 Jun 24.
The same amount of metal was deposited on the surface of three-dimensional mesoporous MCM-48 by a facile impregnation-calcination method for catalytic ozonation of pharmaceutical and personal-care products in the liquid phase. At 120 min reaction time, Co/MCM-48 and Ce/MCM-48 showed 46.6 and 63.8% mineralization for clofibric acid (CA) degradation, respectively. Less than 33% mineralization was achieved with Co/MCM-48 and Ce/MCM-48 during sulfamethazine (SMZ) ozonation. In the presence of monometallic oxides modified MCM-48 catalysts, total organic carbon (TOC) removal of diclofenac sodium (DCF) was around 80%. The composite Co-Ce/MCM-48 catalyst exhibited significantly higher activity in terms of TOC removal of CA (83.6%), SMZ (51.7%) and DCF (86.8%). Co-Ce/MCM-48 inhibited efficiently the accumulation of small molecular carboxyl acids during ozonation. A detailed research was conducted to detect the nature of material structure and mechanism of catalytic ozonation by using a series of characterizations. The main reaction pathway of CA was determined by the analysis of liquid chromatography-mass spectrometry, in line with the results of frontier electron density calculations that reactive oxygen species (ROSs) were easy to attack negative regions of pharmaceuticals. The Si-O-Si, Co···HO-Si-O-Si-OH···Ce, and O···Co-HO-Si-O-Si-OH···Ce-OH···O basic units in catalysts were constructed to detect the orbit-energy-level difference. The results revealed that a synergistic effect existed at the interface between cobalt and cerium oxides over MCM-48, which facilitated the ROSs sequence in solution with ozone. Therefore, the multivalence redox coupling of Ce/Ce and Co/Co along with electron transfer played an important role in catalytic ozonation process.
采用简便的浸渍-煅烧法在三维介孔 MCM-48 表面沉积相同量的金属，用于液相中药物和个人护理产品的催化臭氧化。在 120 min 的反应时间内，Co/MCM-48 和 Ce/MCM-48 对降解氯菲酸（CA）的矿化率分别为 46.6%和 63.8%。在 Co/MCM-48 和 Ce/MCM-48 存在下，磺胺甲噁唑（SMZ）臭氧化的矿化率小于 33%。在单金属氧化物改性 MCM-48 催化剂的存在下，二氯芬酸钠（DCF）的总有机碳（TOC）去除率约为 80%。复合 Co-Ce/MCM-48 催化剂在 CA（83.6%）、SMZ（51.7%）和 DCF（86.8%）的 TOC 去除方面表现出显著更高的活性。Co-Ce/MCM-48 在臭氧化过程中有效地抑制了小分子羧酸的积累。通过一系列表征，深入研究了材料结构的性质和催化臭氧化的机理。通过液相色谱-质谱分析确定了 CA 的主要反应途径，这与前沿电子密度计算的结果一致，表明反应性氧物质（ROSs）容易攻击药物的负区域。在催化剂中检测到 Si-O-Si、Co···HO-Si-O-Si-OH···Ce、和 O···Co-HO-Si-O-Si-OH···Ce-OH···O 基本单元，以检测轨道能级差。结果表明，MCM-48 上钴和铈氧化物之间存在协同效应，这有利于臭氧溶液中 ROSs 的序列。因此，Ce/Ce 和 Co/Co 的多价氧化还原偶联以及电子转移在催化臭氧化过程中发挥了重要作用。
