Abstract

The nanocomposite of WO₃/Fe₃O₄ was prepared using a facile precipitation method and characterized by several techniques. XRD patterns showed a magnetite and a monoclinic structure, respectively, for Fe₃O₄ and WO₃ particles. Formation of WO₃/Fe₃O₄ nanocomposite proved using EDX spectra and also EDX element maps indicated the uniform distribution of Fe, W, and O atoms in the prepared nanocomposite. The SEM image approved a spherical shape for nanocomposite particles. Band-gap energy of WO₃/Fe₃O₄ obtained 1.2 eV using DRS spectra. The room temperature hysteresis loops showed magnetization 21.21 emu/g for WO₃/Fe₃O₄ particles. The synthesized magnetite photocatalyst used in treatment of yellow water as one of the effluents of the production process of TNT. Central composite experimental design applied for optimization of independent variables such as pH of the sample, dose of photocatalyst and amount of pollutant. Photodegradation efficiencies were calculated by reducing the COD values of the samples. The p-values of studied variables obtained <0.05 in ANOVA (analysis of variance) results which indicates their impact on photodegradation efficiency. The F-value and p-value of proposed model for photodegradation process were 29.65 and <0.05, respectively, in 95% confidence level. Also, the p-value of “lack-of-fit” (>0.05) showed that predicted data of the proposed model fit to actual experimental response data. A 65% reduction in the COD value of a sample was achieved under optimized conditions of pH 5, dose of photocatalyst 1.0 g⋅L⁻¹ and amount of pollutant 20 mg⋅L⁻¹.

摘要

WO ₃ /Fe ₃ O ₄纳米复合材料是使用简便的沉淀方法制备的，并通过多种技术进行表征。对于Fe ₃ O ₄和WO ₃颗粒，XRD图分别显示磁铁矿和单斜结构。使用 EDX 光谱证明了 WO ₃ /Fe ₃ O ₄纳米复合材料的形成，并且 EDX 元素图表明 Fe、W 和 O 原子在制备的纳米复合材料中分布均匀。SEM 图像证实纳米复合颗粒呈球形。WO ₃ /Fe ₃ O _{4 的}带隙能量使用 DRS 光谱获得 1.2 eV。室温磁滞回线显示WO ₃ /Fe ₃ O ₄颗粒的磁化强度为21.21emu/g 。合成的磁铁矿光催化剂用于处理作为 TNT 生产过程中的废水之一的黄水。中心复合实验设计用于优化自变量，如样品的 pH 值、光催化剂剂量和污染物量。通过降低样品的 COD 值来计算光降解效率。在 ANOVA（方差分析）结果中获得的研究变量的p值 <0.05，这表明它们对光降解效率的影响。该˚F -值和p在 95% 的置信水平下，所提出的光降解过程模型的值分别为 29.65 和 <0.05。此外，“缺乏拟合”的p值 (>0.05) 表明所提出模型的预测数据适合实际实验响应数据。在pH 5、光催化剂剂量1.0 g·L ^-1和污染物20 mg·L ^{-1 的}优化条件下，样品的COD 值降低了65% 。