ON/OFF Switchable Smart Poly(N-isopropylacrylamide) Based Hybrid Nanocatalyst for the Response Surface Methodology Based Catalytic Reduction of 2-Nitroaniline

Abstract

Developing smart nanocatalysts capable of modulating the reaction rate is one of the recent research domains currently being explored by scientific academia to address wastewater issues. This study the core@shell assembly was developed via two step methodology (chemical reduction of salt for AgNPs synthesis, followed by the emulsion polymerization step for polymeric shell formation). The TEM micrographs show that the average size of the single assembly particle was found to be less than 20 nm which was utilized as a nanocatalyst for the (CRR) of 2-Nitroaniline (2-NA). The RSM based optimization of the parameters associated with the CRR of the 2-NA was performed and 100% reduction of 2-NA with the apparent rate constant (k_app) value of 2.583 min⁻¹ was documented under the optimized conditions of [2-NA] = 0.025 mM, [AgNPs@PNIPAM-AAC HNGs dose] = 4.5 mg mL⁻¹, [NaBH₄ dose] = 15 mM, temperature = 30, and pH = 6.00 units. Detailed thermodynamic analysis performed for investigating the impact of transitions associated with the polymeric shell with temperature change (5 to 70) revealed that maximum reduction was achieved at 30 where polymeric shell was present in the swelled state to reduce any diffusional barrier in the system.