The preparation and characterization of poly(acrylamide) hydrogel embedded chitosan/polypyrrole nanoparticle for methyl orange removal

Abstract

The chitosan/polypyrrole (Ks/PPy) nanoparticle composite was synthesized using chitosan (Ks) and pyrrole (PPy) and embedded in a cross-linked poly(acrylamide) (PAAm) hydrogel polymer matrix. Poly(acrylamide) embedded chitosan/polypyrrole (PAAm-Ks/PPy) hydrogels were treated with a hydrochloric acid (HCl) solution, and the poly(acrylamide)-chitosan/polypyrrole-HCl (PAAm-Ks/PPy-H) hydrogels were prepared. The synthesized Ks/PPy nanoparticles were characterized by Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric (TG) analysis, scanning electron microscope (SEM), particle size analysis (Mastersizer), and 4-point electrical conductivity measurements. The size of the synthesized Ks/PPy nanoparticles composite was measured as Dv(90) = 114 nm. The size of the majority of Ks/PPy nanoparticle was observed at approximately 100 nm according to their SEM images. The electrical conductivity of the Ks/PPy nanoparticles was measured as 5.79E–1 mS cm− 1, and this value is approximately 261,000 times higher than the electrical conductivity of Ks biopolymer. Also, the electrical conductivity of chitosan/polypyrrole treated with HCl (Ks/PPy-H) nanoparticles was measured as 2.53 mS cm− 1. The electrical conductivity of Ks/PPy-H nanoparticles increased approximately 4.4 times compared to Ks/PPy nanoparticles after HCl treatment. PAAm-Ks/PPy hydrogel was characterized with the FT-IR, TG, SEM, and 4-point electrical conductivity measurements. The percent of swelling (S%) value of composite P(AAm)-Ks/PPy and P(AAm)-Ks/PPy-H hydrogels was determined as approximately 1949 and 2001%, respectively. The S% values of these hydrogels are about 15% higher than the PAAm hydrogel. Among the synthesized hydrogels, the swelled PAAm-Ks/PPy-H hydrogel has the highest electrical conductivity value with 2.0E−5 ± 8.7E−6 mS cm− 1. The adsorption performance of the synthesized hydrogels was investigated for methyl orange from the aqueous solution. It is determined that the adsorption performance of the PAAm-Ks/PPy-H hydrogel is approximately fourfold and 20-fold higher than the PAAm-Ks/PPy and the PAAm hydrogel, respectively.