An insight into methylene blue adsorption characteristics onto functionalized alginate bio-polymer gel beads with λ-carrageenan-calcium phosphate, carboxymethyl cellulose, and celite 545

Abstract

Herein, λ-carrageenan-calcium phosphate (λ-Carr-Cp), carboxymethylcellulose (CMC) and celite 545 (Ce545) were used to functionalize sodium alginate bio-polymer (SAB). The water content in the wet beads was about 98%. Fourier Transform Infra-Red (FT-IR) showed that SAB@λ-Carr-Cp, SAB@CMC, and SAB@Ce545 could interact through intermolecular hydrogen and electrostatic interactions. Scanning Electron Microscopy (SEM) revealed that the morphology of the functionalized beads had a porous sheet structure. Energy Dispersive X-Ray (EDX) depicted that the peak intensity of the carbon element became more intense in the case of organic modification. The appearance of mineral elements characteristics of Ce545 (Si, Al) and Cp (P) proved the incorporation of these inorganic reagents into the alginate matrix. The data from batch adsorption experiments indicated that the adsorption of methylene blue (MB) depended on pH, time, temperature, and dye concentration. At equilibrium, the adsorption capacities followed the order: SAB@Ce545 (7.5 mg g−1 wet) > SAB@λ-carr-Cp (6.8 mg g−1 wet) > SAB@CMC (6.5 mg g−1 wet) > SAB (5.77 mg g−1 wet). Kinetic data agreed with pseudo second-order suggesting chemi-sorption mechanism. The equilibrium data fitted for Freundlich. In summary, this provided assembly strategy could offer a new research opportunity for developing functionalized biopolymers with new functions and potential applications.