Microgels stabilized selenium nanoparticles: An efficient photocatalyst for dye degradation

[Display omitted] •Se embedded fluorescent microgels of PNIPAM was developed.•Thermo-responsive behaviour of microgels helps to tune catalytic activity.•Developed material was effective to degrade Victoria blue dye with 985 efficency.•Excellent recyclability and potential usage of hybrid microgel in waste water treatment. We developed selenium nanoparticle (Se-NP)-embedded poly-N-isopropylacrylamide (PNIPAM) hybrid microgel (nano-SeHMG) for the photodegradation of victoria blue (VB) dye in an aqueous medium. PNIPAM microgels were prepared by free radical precipitation polymerization, and Se-NPs were formed inside the polymer network using in situ reduction of selenous acid with NaBH4. Surface characterization of bare Se-NPs, pure PNIPAM, and nano-SeHMG was conducted. Controlled-size Se-NPs, averaging 31 ± 4.8 nm, were embedded within the microgels, providing stability against agglomeration and resulting in a large surface area. Nano-SeHMG achieved 98 % degradation of VB dye in 80 min, compared to 23 % and 68 % degradation with pure PNIPAM and bare Se-NPs, respectively, under the same conditions. The photocatalytic reduction of VB followed pseudo-first-order kinetics with an apparent rate constant of 7.33 × 10-3 min-1. Factors such as contact time, catalyst dosage, initial dye concentration, temperature, and pH significantly influenced the catalytic performance of nano-SeHMG. The thermo-responsive behavior of microgels allowed tunable catalytic activity by adjusting the system temperature. The photocatalyst demonstrated excellent recyclability, making it a cost-effective material for dye degradation. Hybrid microgel-based photocatalysts offer a novel approach in designing smart materials for wastewater treatment.