Novel reusablepH‐responsive photocatalyst polymeric microcapsules for dye treatment

Abstract

The photocatalyst poly(methyl methacrylate-methyl acrylate-divinylbenzene) (P(MMA-MA-DVB)) microcapsules encapsulating both bismuth vanadate (BiVO 4) and magnetite (Fe 3 O 4)nanoparticles were prepared by microsuspension iodine transfer polymerization (ms ITP) for dye treatment in wastewater. The visible light-responsive BiVO 4 and Fe 3 O 4 nanoparticles were prepared first. The silane-modified BiVO 4 (m-BiVO 4) nanoparticles increased the number of nanoparticles in an oil droplet during ms ITP, corresponding with the increase of %Loading (%L E) and %Encapsulation efficiency (%EE). The optimum ratios of monomers:m-BiVO 4 :Fe 3 O 4 at 65:30:5 and MMA:MA: DVB at 55:25:20 showed the highest %L E and %EE of encapsulated m-BiVO 4 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 BiVO 4 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 Fe 3 O 4 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 pHresponsive polymer microcapsule-encapsulated photocatalyst nanoparticles presented high-performance dye treatment efficacy in the synthetic wastewater.

Box-Behnken Modeling and Optimization of Visible-Light Photocatalytic Removal of Methylene Blue by ZnO-BiFeO3 Composite

“…Given Eg = 1240/λ in which λ is the photocatalytic cut-off wavelength and Eg is the bad gap energy, the optical bandgaps of ZnO, BFO, ZB12, ZB11, and ZB21 are estimated to be 3.29, 2.11, 3.97, 2.49, and 2.37 eV, respectively. By adding more BFO content to the composite samples, the bandgap gets smaller and the excitation wavelength moves toward the visible spectrum (Huo et al 2010;Karamian and Sharifnia 2018;Kaus et al 2021;Liao et al 2021;Srisawang et al 2020). 3, 532.3, 1639.3, and 3454.…”

“…These studies have shown that photocatalytic degradation is a safe method that does not create new contaminants (Zhu et al 2020). Moreover, the low-energy consumption, simple gadgets, and straightforward operation have made it one of the most promising and cost-effective methods (Srisawang et al 2020;Zhu et al 2020). Numerous suitable materials have been synthesized and employed as photocatalysts for the fast degradation of MB under visible light.…”

Pulsed‐UV illumination on graphene oxide: A new strategy in photocatalytic synthesis of electrocatalysts to control the structural and electrochemical properties

“…Composites such as Ag/TiO 2, 27 Pt/TiO 2, 28 Pt/g‐C 3 N 4 , and Cu/ZnO 29 are examples of metals and semiconductors being used. Water splitting and hydrogen production, 30 dye degradation, organic materials oxidation, 31 conversion of CO 2 to fuels, 32 producing electricity from atmosphere moisture, 33 and green synthesis of ammonia 34 are examples of the applications in which the photon energy is either used for the catalyst synthesis or is used to benefit from the final application of the catalyst.…”