Nanospherical and plate-like magnesium oxide has been successfully synthesized by urea precipitation method for the first time. A magnesium oxide precursor was prepared by heating MgCl2 solution with urea for 12 hours at 90°C. Then the calcined precursor was analysed by Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), and high-resolution transmission electron microscopy (HR-TEM). In the presence of the nonionic surfactant Triton X-100 in the system, the reaction yielded in nanospheres of MgO contrast to the plate-like MgO in the absence of the surfactant. The precursor and the calcined product appeared in similar morphologies under SEM in both cases with a slight reduction of size upon calcination. The final product was confirmed as MgO using XRD and FT-IR spectroscopic methods. In TGA, both samples showed similar mass loss values upon elimination of adsorbed water molecules and decomposition of the precursor into MgO; however, the nanospherical MgO sample showed an additional weight loss due to elimination of the associated surfactant molecules. The efficiency of removing reactive dye wastes was quantified by UV-visible spectroscopy using reactive yellow dye. Plate-like MgO showed a porous structure under HR-TEM analysis in the dye adsorption study, and both plate-like and nanospherical MgO showed good dye adsorption capability. MgO nanospheres showed higher capacity of dye adsorption compared to plate-like MgO, explained by its higher surface are-to-volume ratio, while the plate-like MgO also performed well due to having a nanoporous structure. These nanomaterials will offer high potential in purifying waste water and as well in recovering expensive dye products.

中文翻译：

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尿素辅助合成的纳米球形和板状氧化镁，可有效去除活性染料废物

首次通过尿素沉淀法成功合成了纳米球形和片状氧化镁。通过在90°C下将MgCl2溶液与尿素加热12小时来制备氧化镁前体。然后通过扫描电子显微镜（SEM），X射线衍射（XRD），傅里叶变换红外（FT-IR）光谱，热重分析（TGA）和高分辨率透射电子显微镜（HR-TEM）分析煅烧的前体。在系统中存在非离子型表面活性剂Triton X-100的情况下，在MgO纳米球中产生的反应与在不存在表面活性剂的情况下的板状MgO相反。在两种情况下，前体和煅烧产物在SEM下均表现出相似的形态，且煅烧后尺寸略有减小。使用XRD和FT-IR光谱法确认最终产物为MgO。在TGA中，两个样品在消除吸附的水分子并将前体分解成MgO时均显示出相似的质量损失值。然而，由于消除了相关的表面活性剂分子，纳米球形MgO样品显示出额外的重量损失。使用活性黄色染料通过紫外-可见光谱法定量确定去除活性染料废物的效率。在染料吸附研究中，片状MgO在HR-TEM分析下显示出多孔结构，并且片状和纳米球形MgO均显示出良好的染料吸附能力。与板状MgO相比，MgO纳米球显示出更高的染料吸附能力，这是由于其较高的表面积体积比，板状MgO具有纳米多孔结构，因此也表现良好。这些纳米材料将在净化废水和回收昂贵的染料产品方面具有很高的潜力。