Multimorphology Mesoporous Silica Nanoparticles for Dye Adsorption and Multicolor Luminescence Applications

Abstract

A series of mesoporous SiO2 nanoparticles (MSNs) have been synthesized by a modified sol–gel process. The morphology could be manipulated from flower-like nanospheres to flower-like nanodisks, circular nanodisks and sunken nanovesicles by simply adjusting the amount of ammonia. Among the various morphologies, the flower-like nanospheres (N1) with a large specific surface area of 1037.16 m2 g–1 exhibited the highest and fastest adsorption capacity for dye-RhB because of the most complex surface structure (234.61 mg g–1, approximately 90% in the first 5 min). The RhB adsorption processes on different MSNs were explained by Langmuir, Freundlich and Temkin isotherm models, and a transition from multilayer adsorption to homogeneous adsorption was achieved. The adsorption kinetics was in accord with the pseudo-second-order model, suggesting the rate-limiting step of RhB on MSNs was mainly chemical process. The luminescence properties of different samples revealed that the nanovesicles structure (N5) exhibited the strongest luminescent intensity due to the least surface defects. By reasonably adjusting the doping concentration ratio of Eu3+ and Tb3+ ions, multicolor emissions of red, orange-red, orange, yellow and green can be easily achieved. The excellent adsorption and luminescence performances indicate that the as-prepared multimorphology MSNs have promising applications on efficient wastewater treatment and multicolor optical devices.