Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
Sci Total Environ. 2020 Aug 20;731:139172. doi: 10.1016/j.scitotenv.2020.139172. Epub 2020 May 4.
A microwave-assisted hydrothermal preparation of heterostructured graphitic carbon nitride/bismuth tungsten oxide/reduced graphene oxide nanocomposites (denoted as GBR-T, T = microwave irradiation time) is performed. The prepared GBR-T photocatalysts are identified by employing X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), time-resolved photoluminescence (TRPL) and nitrogen adsorption-desorption isotherms. The photocatalytic performance of these GBR-T is evaluated by the photocatalytic degradation of ibuprofen (IBP) under the visible light (λ > 420 nm) and solar light irradiation. Among all prepared photocatalysts, ca. 93% of IBP photodegradation can be achieved with a degradation rate constant (k) of 0.011 min under visible-light irradiation upon the optimal microwave-assisted reaction time of 60 min. The improvement is primarily attributable to the higher crystallization degree, specific surface area and increased charge transfer efficiency as verified by XRD, nitrogen adsorption-desorption isotherms and TRPL, respectively. The photocatalytic performance of this catalyst is further enhanced in the photodecomposition of IBP (ca. 98.6%) under sun light irradiation. The electron spin resonance (ESR) and liquid chromatography-mass/mass spectrometry (LC-MS/MS) studies show that the superoxide radicals and hydroxyl radicals are the dominant active species in the photocomposition of IBP and degradation intermediates are formed through three probable photodegradation pathways. This investigation provides a simple way to prepare triple 2D heterojuction photocatalysts which could be effectively used in the advanced oxidation process for removal of emerging contaminants in wastewater by using renewable energy.
采用微波辅助水热法制备了异质结构的石墨相氮化碳/氧化钨酸铋/还原氧化石墨烯纳米复合材料（记为 GBR-T，T 为微波辐射时间）。通过 X 射线衍射（XRD）、傅里叶变换红外光谱（FT-IR）、扫描电子显微镜（SEM）、高分辨率透射电子显微镜（HRTEM）、时间分辨光致发光（TRPL）和氮气吸附-脱附等温线对制备的 GBR-T 进行了鉴定。通过在可见光（λ>420nm）和太阳光照射下光催化降解布洛芬（IBP）来评价这些 GBR-T 的光催化性能。在所制备的光催化剂中，在最佳微波辅助反应时间为 60min 时，在可见光照射下，IBP 的光降解率约为 93%，降解速率常数（k）为 0.011min-1。这种提高主要归因于更高的结晶度、比表面积和增加的电荷转移效率，这分别通过 XRD、氮气吸附-脱附等温线和 TRPL 得到证实。在太阳光照射下，该催化剂在 IBP 的光分解（约 98.6%）中的光催化性能进一步提高。电子顺磁共振（ESR）和液相色谱-质谱/质谱（LC-MS/MS）研究表明，超氧自由基和羟基自由基是 IBP 光解和降解中间产物形成的主要活性物质，通过三种可能的光降解途径。这项研究提供了一种简单的方法来制备三重 2D 异质结光催化剂，可有效用于利用可再生能源去除废水中新兴污染物的高级氧化过程。
