Urea-Assisted Synthesis of Nanospherical and Plate-Like Magnesium Oxides for Efficient Removal of Reactive Dye Wastes

H M S P Randiligama,T C Palihawadana,M M M G P G Mantilaka Mantilaka,Tetiana Dontsova

doi:10.1155/2020/6189061

Abstract

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.

Highlights

Access to potable water is becoming a luxury due to exploitation of the limited amount of freshwater in Earth’s freshwater reserves [1, 2]
The morphologies of precursors, synthesized Magnesium oxide (MgO), and RY-adsorbed MgO samples were observed with the aid of Hitachi SU6600 field-emission scanning electron microscope (FE-Scanning electron microscopy (SEM)) with an acceleration voltage of 15 kV
SEM images as depicted in Figures 2(a) and 2(b) show that the precursor and MgO product prepared in the absence of Triton X-100 surfactant are in plate-like morphology, respectively

Summary

Introduction

Access to potable water is becoming a luxury due to exploitation of the limited amount of freshwater in Earth’s freshwater reserves [1, 2]. Due to high stability towards light, heat and oxidizing agent dyes are resistant to degradation [11]. Among these methods, adsorption is considered the most efficient due to its simplicity and economical ease. Magnesium oxide (MgO) or magnesia is an inorganic metal oxide material, available in its natural form as periclase as well as a synthetic chemical product. The simplicity and the upscalability of this process, use of a readily available magnesium compound as the magnesium source, and use of inexpensive and nontoxic chemicals for the synthesis of nanospherical and plate-like nanoporous magnesium oxide morphologies with the high-quality controllability make this novel approach a distinct process with a higher commercial viability. Reduction efficiency for commercially available Remazol yellow 3RS by synthesized MgO-Nps is studied

Materials and Methods

Characterization of Synthesized Materials

K L Qm

Results and Discussion

Conclusions