LAUSR

The photocatalyst poly(methyl methacrylate‐methyl acrylate‐divinylbenzene) (P(MMA‐MA‐DVB)) microcapsules encapsulating both bismuth vanadate (BiVO4) and magnetite (Fe3O4)nanoparticles were prepared by microsuspension iodine transfer polymerization (ms ITP) for dye treatment in wastewater. The visible light‐responsive BiVO4 and Fe3O4 nanoparticles were prepared first. The silane‐modified BiVO4 (m‐BiVO4) nanoparticles increased the number of nanoparticles in an oil droplet during ms ITP, corresponding with the increase of %Loading (%LE) and %Encapsulation efficiency (%EE). The optimum ratios of monomers:m‐BiVO4:Fe3O4 at 65:30:5 and MMA:MA:DVB at 55:25:20 showed the highest %LE and %EE of encapsulated m‐BiVO4 nanoparticles with good colloidal stability. Before dye treatment, the obtained microcapsules were subsequently hydrolyzed to be P(MMA‐acrylic acid [AA]‐DVB) as confirmed by the presence of negative zeta potential to increase their hydrophilicity and pH‐responsive property. In alkaline conditions, the hydrolyzed P)MMA‐AA‐DVB) microcapsules containing Span 80 showed the highest MB treatment efficiency, equal to that of pristine BiVO4 nanoparticles. The addition of Span 80 in an oil phase enhanced the removal of MB, probably due to the increase of porosity at the microcapsule surface. Because of the incorporation of Fe3O4 nanoparticles in microcapsules, they were reused for at least five treatment times by applying the external magnetic field when the treatment efficiency was still higher than 70. Therefore, the obtained reusable pH‐responsive polymer microcapsule‐encapsulated photocatalyst nanoparticles presented high‐performance dye treatment efficacy in the synthetic wastewater.