Extraction of κ/ι-hybrid carrageenan from red algae Chondracanthus chamissoi for methylene blue removal using KCl/chitosan-functionalized κ/ι-carrageenan hydrogels

Ore Y.; Córdova B.M.; Huamani-Palomino R.G.; Quintana M.; Estrada W. · Biochemical Engineering Journal (2026) · DOI: 10.1016/j.bej.2026.110183

Resumen

The increasing pollution of water bodies with basic dyes is causing detrimental effects on the environment and represents a threat to aquatic life and human health. Conversely, the accumulation of seaweeds constitutes a serious disposal problem on touristic beaches, and their valorization has become a topic of growing interest. In this context, this work reports the extraction and characterization of κ/ι-hybrid carrageenan from Chondracanthus chamissoi for the subsequent preparation of hydrogels functionalized with a chitosan/KCl solution for suitable application in methylene blue removal. The application of a 2² factorial design revealed that carrageenan concentration is the primary factor influencing the mechanical properties of hydrogels, followed by KCl concentration and their interaction. Kinetic data fitted well with the pseudo-first-order (R² = 0.98) and intraparticle diffusion (R² = 0.99) models, reaching equilibrium within 72 h at 30°C. The positive values of ΔH (+30.9 kJ mol⁻¹) and ΔS = +94.3 J mol⁻¹ K⁻¹ indicate that the process is endothermic and is accompanied by an increase in disorder at the solid-solution interface. Desorption studies demonstrated that functionalized carrageenan hydrogels possess ion-exchange properties, as evidenced by effective dye recovery when a 2% (w/v) KCl solution is used. Finally, reusability studies yielded promising outcomes, with removal efficiencies of 97% and 68% achieved in the first and fifth cycles, respectively.

Instituciones: Universidad Nacional de Ingeniería