Preparation of carboxyl-functionalized poly （methyl methacrylate） microspheres and their adsorption behavior towards methylene blue

Abstract

The carboxyl-functionalized poly（methyl methacrylate） microspheres were successfully synthesized via soap-free emulsion polymerization， utilizing methyl methacrylate and styrene as monomers， acrylic acid as functional monomer， and methyl methacrylate isobutylene as crosslinking agent. These microspheres were employed to adsorb methylene blue （MB）， and the impact of acrylic acid contents on the morphology and adsorption capacity of the microspheres was systematically investigated. The SEM， FT-IR， and TG were employed to comprehensively analyze the synthesized products. The results reveal that， when the amount of acrylic acid is 1/3 of the total amount of monomers， the microspheres exhibit uniform morphology with a narrow particle size distribution of about 854 nm. These microspheres demonstrate excellent adsorption performance for methylene blue dye at 303.15 K， with a theoretical maximum adsorption capacity of 177.69 mg·g-1. The adsorption process is exothermic， and the adsorption data fit well with the pseudo-second-order kinetic model and Langmuir isotherm model. After 5 cycles of adsorption-regeneration， the microspheres still maintain an adsorption efficiency of more than 97% for MB.

Keywords

• polymer microsphere
• methyl methacrylate
• acrylic acid
• adsorption
• methylene blue