Synthesis of Magnesium-modified Montmorillonite/Cellulose Composite Hydrogel and Its Adsorption Performance for Phosphate

A novel magnesium-modified montmorillonite/cellulose composite hydrogel (Mg-MMT/MCC) was prepared by free radical graft-polymerization method with cellulose as raw material, montmorillonite as filler and magnesium salt as modifier. Scanning electron microscope (SEM), X-ray diffractometer (XRD), thermogravimetric analyzer (TG) were employed to characterize the surface morphology, microstructure and thermal stability of the obtained composite hydrogel, and its swelling property was also analyzed. Meanwhile, the effects of pH value, reaction time, tempe-rature, initial phosphate concentration on the phosphate adsorption capacity of Mg-MMT/MCC were studied. It could be found from the results that the introduction of magnesium modified montmorillonite contributed to the formation of obvious pore structure with larger pore size, thinner pore wall and improved thermal stability. The amount of phosphorus adsorbed by Mg-MMT/MCC increased first and then decreased with the increase of solution pH value, reaching the maxmum at pH=7. The adsorption isotherm data accorded with both Langmuir and Freundlich isotherm adsorption models, with the saturated adsorption capacity of 194.36 mg•g-1. The adsorption kinetic was found to be conformed to the pseudo-second order model. Besides, it is worth noting that the Mg-MMT/MCC could be readily regenerated for reuse. © 2019, Materials Review Magazine. All right reserved.