Mg(OH)2 nanostructures using impure brine: optimization of synthesis parameters by Taguchi robust design and study of optical properties

Abstract

In this research, high purity magnesium hydroxide (Mg(OH)2) nanoparticles were successfully synthesized by the wet chemical precipitation method from an impure precursor. The effective parameters of the synthesis to achieve magnesium hydroxide nanoparticles with smaller crystallite sizes such as the precipitator agent concentration, the reaction temperature, the amount of surfactant, and the suspension aging time were studied. Optimum conditions were determined by using the Taguchi design method. Each of these factors was investigated in three levels. The analysis of variance (ANOVA) was exploited to determine the contribution of various process parameters on the response. Statistical analysis results indicate that among investigated parameters, the reaction temperature, as well as the suspension aging time, has the most effect on the magnesium hydroxide nanoparticles’ crystallite size. Additionally, there is reasonable accordance between the predicted crystallite average size (17.14 ± 3.1 nm) and the obtained crystallite average size in optimum conditions (19.22 nm). Structural and phase investigations, the chemical composition, as well as optical and morphological properties of synthesized nanoparticles, were precisely investigated through XRD, EDS, FESEM, TEM, FTIR, and UV–Vis. The synthesized sample in optimum conditions had a wide optical band gap due to the smallest crystallite size.