Construction of Shape-Controlled MgO Microstructures by Natural Bischofite for Cost-Efficient Dye Adsorption

In this work, Magnesium oxide (MgO) adsorbents were synthesized by coprecipitation method via natural bischofite (MgCl2 center dot 6H(2)O, >= 96 wt %) as magnesium source, two different morphologies of MgO nanomaterials, flower-spheres-like (MgO-S-1) and lamellas-like (MgO-L-1), were successfully synthesized by control of synthesis conditions. The adsorption experimental results showed on Congo Red (CR) dye that both MgO-S-1 and MgO-L-1 exhibit outstanding adsorption performance with a high adsorption quantity (about 2000 mg center dot g(-1)). Langmuir was the most suitable model to describe the adsorption isotherm. The adsorption kinetics of CR are in accord with the pseudo-second-order kinetics (PSO). As a control, flower-spheres-like (MgO-S-2) and lamellas-like (MgO-L-2) were synthesized by commercial MgCl2 center dot 6H(2)O, and their adsorbing performance on CR dye in wastewater was studied. The results show that MgOs prepared by different Mg resources took on exactly the same shape and nearly the same adsorption properties.