Effect of Molarity on Methylene Blue Dye Removal Efficacy of Nano Ca(OH)2

Abstract

AbstractWith the increase in demand of textiles products, the polluted groundwater problem in the world is increasing proportionally and leading to environmental and health problems. Hence in this present work, we report on the dye removal efficacy of nano Ca(OH)2 by changing the molarity of the reactants. In the process, the chemical precipitation technique is used to synthesize the phase pure nano Ca(OH)2 powders using equimolar concentrations (e. g., 0.4 M, 0.6 M, 0.8 M and 1 M) of [Ca(NO3)2 ⋅ 4H2O] and NaOH solutions. The prepared material was characterized using XRD, FTIR, and UV‐Vis spectroscopy. The results from the characterization study show, that the dye removal behaviour is complex and is sensitive to a simultaneous combination of many factors e. g., the molarities of the reactants, the resultant nanocrystallite size, band gap energy, the concentration of the dye and, the temperature of adsorption. Therefore, these results are discussed in terms of relative variations in the microstructure, lattice strain, band gap energy, defect structure, and the amount of (OH−) ions. Further, the probable mechanism of dye removal behaviour is suggested. Finally, the consequences of these results in terms of microstructurally tuned nano Ca(OH)2 materials development for prospective futuristic applications are highlighted.