Polyelectrolyte Complexes Between Chitosan and Quince Seed Gum: A Rheological, Structural, and Multiple Dye Adsorption Study

Natural polyelectrolyte complexes (PECs) have been the subject of interest for scientific research owing to their sustainable potential in a broad variety of advanced technologies. Herein, bio-based and environmental friendly polyelectrolyte complexes (PECs) of Chitosan (CS) and Quince seed gum (QSG) were formed and studied as a function of polyelectrolyte concentration (0.3 and 0.5% w/v) and CS:QSG ratio (1:3, 1:1 and 3:1). Zeta potential and rheological behavior confirmed the formation of the complexes. The maximum electrostatic interaction occurred at the mixing ratio of 1:1 at 0.3% w/v where the zeta potential was − 2.3 mV. All viscoelastic values showed high dependency on mixing ratio and QSG concentration below and above critical entanglement concentration of QSG (0.3% w/v). Immediate gelation and viscoelastic behavior improvement were observed by time and temperature sweep tests. Fourier transform infrared spectroscopy (FTIR) results showed that the inter-biopolymeric complexes were formed through the interaction of –NH3+ and –COO−, together with hydrogen bonding. All samples depicted lamellar porous interconnected microstructure (maximum BET surface area of 23.5 m2/g) and three-dimensional sponge-like macrostructure. Without any additional crosslinking, the PEC with higher QSG volume ratio (3:1) and higher concentration (0.5% w/v) exhibited higher Methylene Blue (MB) adsorption capacity (30.88 mg/g) and removal efficiency (77.2%) at practical pH 6.0 than zwitterionic Rhodamine B (RB) and anionic Methyl Orange (MO). The experimental data were in line with the pseudo-second-order (PSO) adsorption kinetic and the Freundlich isotherm model. The eco-friendly CS-QSG PECs can be acted as a promising adsorbent for multiple dye removal.