Poly(chitosan-N-vinylcaprolactam-methacrylic acid) microgels as microreactor for Ag(I) ions extraction and in-situ silver nanoparticles formation to reduce the toxins.

The toxicity of organic molecules and transition metal cations imposes their removal from aqueous medium to protect human health. Traditionally, systems have been designed to target either organic molecules or transition metal cations individually. However, a homogenous poly(chitosan-N-vinylcaprolactam-methacrylic acid) P(CVM) microgel system has been introduced to effectively eliminate both types of pollutants. This P(CVM) system was synthesized using the free radical precipitation polymerization (FRPP) method and employed as an adsorbent for the removal of silver (I) (Ag(I)) ions from aqueous medium under various environments, including different Ag(I) ions content, agitation times, pH levels, and dose of P(CVM). The extraction behavior of Ag(I) ions onto P(CVM) was analyzed using different adsorption isotherms, while the kinetics of the process were studied using Elovich model (ElM), pseudo-second-order (Ps2O), intra-particle-diffusion model (InPDM), and pseudo-first-order (Ps1O) models. Furthermore, silver nanoparticles (Ag NPs) were synthesized by using loaded Ag(I) ions within P(CVM) through in-situ reduction approach. The resulting Ag nanoparticles decorated P(CVM) (Ag-P(CVM)) hybrid microgels exhibited the ability to catalytically reduce various contaminants from water such as p-nitroaniline (PNiA), methyl red (MeR), chromium (VI) ions (CrM), and eosin Y (EoY). The catalytic activity was measured by determining the pseudo-first-order rate constant (k), which were found to be 1.166 min, 0.562 min, 0.157 min, and 1.350 min for the catalytic reduction of PNiA, MeR, CrM, and EoY, respectively. Overall, the Ag-P(CVM) system shows superb catalytic activity for various pollutants reduction.