Catalyst Research Center, Chemical Engineering Department, Razi University, Kermanshah, 67149-67246, Iran.
Environ Sci Pollut Res Int. 2023 Jun;30(26):68084-68100. doi: 10.1007/s11356-023-26894-6. Epub 2023 Apr 29.
Box-Behnken experimental design was utilized to model and optimize the photocatalytic removal of methylene blue (MB) using ZnO-BiFeO composite under visible light (LED). Three catalysts with different ZnO:BiFeO molar ratios (2:1, 1:2, and 1:1) were synthesized successfully using the hydrothermal method. The structural, morphological, and optical properties of the synthesized photocatalysts were analyzed by X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-ray Spectroscopy (EDX), Fourier Transform Infrared Spectra (FT-IR), Ultraviolet Visible Spectrometer (UV-vis), Transmission Electron Microscopy(TEM), High-Resolution Transmission Electron Microscopy (HR-TEM), and Photoluminescence (PL) Spectrophotometry. FESEM showed the relatively uniform distribution of BiFeO crystalline particles on ZnO ones. UV-vis analysis showed that the photocatalytic performance of pure ZnO and BiFeO under visible light irradiation is weak, while ZnO-BiFeO with a 2:1 molar ratio composite with a bandgap of about 2.37 eV showed high performance. This improved photocatalytic activity may be due to the heterogeneous synergistic effect of the p-n junction. In order to optimize the experimental conditions, four factors of initial MB concentration (5 to 20 mg/L), pH (3 to 12), catalyst dosage (0.5 to 1.25 mg/L), and light intensity (4 to 18 W) were selected as independent input variables. Box-Behnken experimental design method (BBD) suggested a quadratic polynomial equation to fit the experimental data. The results of the analysis of variance (ANOVA) confirmed the goodness of fit for the suggested model (predicted- and adjusted-R 0.99). The optimum conditions for maximizing the photocatalytic MB degradation were found to be an initial MB concentration of 11 mg/L, pH of 11.7, catalyst dosage of 0.716 mg/L, and light intensity of 11.4 W. Under the optimum conditions, the highest photocatalytic MB degradation of 62.9% was obtained, which is in reasonable agreement with the predicted value of 69%.
采用 Box-Behnken 实验设计，利用 ZnO-BiFeO 复合材料在可见光（LED）下光催化去除亚甲基蓝（MB）。采用水热法成功合成了三种不同 ZnO:BiFeO 摩尔比（2:1、1:2 和 1:1）的催化剂。通过 X 射线衍射（XRD）、场发射扫描电子显微镜（FESEM）、能谱（EDX）、傅里叶变换红外光谱（FT-IR）、紫外可见分光光度计（UV-vis）、透射电子显微镜（TEM）、高分辨率透射电子显微镜（HR-TEM）和光致发光（PL）分光光度计对合成的光催化剂的结构、形貌和光学性能进行了分析。FESEM 显示 BiFeO 晶状颗粒在 ZnO 上的分布相对均匀。UV-vis 分析表明，纯 ZnO 和 BiFeO 在可见光照射下的光催化性能较弱，而带隙约为 2.37 eV 的 ZnO-BiFeO 2:1 摩尔比复合材料表现出较高的性能。这种提高的光催化活性可能是由于 p-n 结的异质协同效应。为了优化实验条件，选择初始 MB 浓度（5-20mg/L）、pH（3-12）、催化剂用量（0.5-1.25mg/L）和光强（4-18W）四个因素作为独立输入变量。Box-Behnken 实验设计方法（BBD）建议用二次多项式方程拟合实验数据。方差分析（ANOVA）的结果证实了所建议模型的拟合良好（预测值和调整值 R 0.99）。最大程度地提高光催化 MB 降解效率的最佳条件被发现为初始 MB 浓度为 11mg/L、pH 为 11.7、催化剂用量为 0.716mg/L、光强为 11.4W。在最佳条件下，获得了最高的光催化 MB 降解率 62.9%，与预测值 69%吻合良好。
