ABSTRACT Methylene blue (MB) dye present in industrial wastewater is a well-known carcinogenic source. By utilizing phase pure three dimensional self assembly of magnesium hydroxide nanoparticle (3DSAMHNPs) powders with extremely high surface area (∼342 m2.g–1), very high (∼98%) photocatalytic degradation efficacy for MB dye upon only 60 min direct exposure to sunlight is reported here. The designed mesoporous microstructure of the 3DSAMHNPs chracterized with a narrow pore size distribution range of ∼3-9 nm and an average size of ∼6 nm is achieved at room temperature by a facile, cost effective, simple, wet chemical route. The 3DSAMHNPs powders are characterized by XRD, FESEM, TEM, HRTEM, SAED, EDX, BET surface area, pore size distribution, FTIR, XPS DTA and TGA techniques. Based on the experimental results, a mechanism is proposed for the high MB dye degradation efficacy of 3DSAMHNPs powders developed in the current work. Finally, it is suggested that these 3DSAMHNPs materials may find potential applications in future as reusable photocatalysts for the degradation of MB dye in industrial wastewater. GRAPHICAL ABSTRACT

中文翻译：

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用于在阳光直射下降解亚甲蓝的 3D 自组装 Mg(OH)2 纳米颗粒的独特微观结构

摘要 工业废水中存在的亚甲蓝 (MB) 染料是众所周知的致癌源。通过利用具有极高表面积（~342 m2.g-1）的氢氧化镁纳米颗粒（3DSAMHNPs）粉末的相纯三维自组装，仅在 60 分钟的直接暴露下对 MB 染料具有非常高（~98%）的光催化降解效率这里报告了阳光。设计的 3DSAMHNPs 的介孔微结构具有约 3-9 nm 的窄孔径分布范围和约 6 nm 的平均粒径，是在室温下通过简便、成本有效、简单的湿化学途径实现的。3DSAMHNPs 粉末通过 XRD、FESEM、TEM、HRTEM、SAED、EDX、BET 表面积、孔径分布、FTIR、XPS DTA 和 TGA 技术进行表征。根据实验结果，提出了一种机制，用于当前工作中开发的 3DSAMHNPs 粉末的高 MB 染料降解效率。最后，建议这些 3DSAMHNPs 材料在未来作为可重复使用的光催化剂用于降解工业废水中的 MB 染料有潜在的应用价值。图形概要