ABSTRACT

Nowadays, nanoscale materials have been widely applied in the removal of contaminants from the water system. Reduction of Cr(VI) (as a poisonous species) to Cr(III) (as a slight toxic species) was performed using CuO-Kaolin with ultrasound (US) irradiation. The CuO-Kaolin nanocomposite was synthesized via a facile co-precipitation method. Then X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope and Energy dispersive X-ray spectroscopy analyses were performed to identify the structural features of CuO-Kaolin. The role of influential parameters for the reduction of Cr(VI) was investigated in sonocatalytic advanced oxidation system. About 89.35% of Cr(VI) was removed via US/CuO-Kaolin process after 90 min at optimum conditions (pH = 3, sonocatalyst dosage = 1 g L⁻¹ and [Cr (VI)]₀ = 20 mg L⁻¹). This outstanding result was due to the synergistic effect of the increased electron delivery to conduction band on CuO-Kaolin nanocomposite and the increased reactive surface region of nanoparticles by sonication. The presence of H₂O₂ as an amplifier improved the removal efficiency of Cr(VI) from 89.35% to 100% after 20 min. Kinetic experimental results were well described by a pseudo-first-order kinetic model. Desorption experiments showed excellent stability of sonocatalyst during the reaction and maintenance of the catalytic activity up to 10 sequential cycles.

摘要

如今，纳米级材料已广泛应用于去除水系统中的污染物。使用 CuO-高岭土和超声 (US) 辐射将 Cr(VI)（作为有毒物质）还原为 Cr(III)（作为轻微有毒物质）。CuO-高岭土纳米复合材料是通过简便的共沉淀法合成的。然后进行 X 射线衍射、傅里叶变换红外光谱、扫描电子显微镜和能量色散 X 射线光谱分析，以确定 CuO-高岭土的结构特征。在声催化高级氧化系统中研究了影响 Cr(VI) 还原的参数的作用。^{在最佳条件（pH = 3，声催化剂用量 = 1 g L -1}）下 90 分钟后，约 89.35% 的 Cr(VI) 被去除和 [Cr (VI)] ₀  = 20 mg L ⁻¹ )。这一突出的结果是由于增加电子传递到 CuO-高岭土纳米复合材料的导带和通过超声处理增加纳米颗粒的反应表面区域的协同效应。H ₂ O ₂作为放大器的存在在 20 分钟后将 Cr(VI) 的去除效率从 89.35% 提高到 100%。拟一级动力学模型很好地描述了动力学实验结果。解吸实验表明，声催化剂在反应过程中具有出色的稳定性，并且在长达 10 个连续循环的催化活性维持过程中。