Structuration of biosorbents in the form of reinforced gelled and porous composites based on Opuntia ficus indica (cactus) extract and sodium alginate

The main objective of the proposed work was to optimize an adsorbent gel from biological material with the substitution of PVA by biopolymer extracted from cactus while maintaining the mechanical and sorption properties. The porous composite was based on cactus extract (CE) and sodium alginate (SA) and the mechanical properties and adsorption capacities of these beads were then compared with those modified using polyvinyl alcohol (PVA) and calcium carbonate (CC), respectively. Twenty formulations, based on CE, SA, PVA and CC, have made it possible to prepare, in accordance with an experimental design conducted in Mode 6, four major classes of beads. The three responses used to assess the evolution in bead performance were: the breaking point of the beads, bead rigidity based on a rheological study and the adsorption capacity of pentachlorophenol (PCP). The analysis of these responses showed that CE exerted a positive effect on both the mechanical strength (400–2200 Pa) and rigidity (5%–11%) of the beads, similar to that of PVA with the conservation of bead adsorption capacity (80–120 mg g −1 of dry matter). The beads, based on CE and SA, revealed their regular shape with a porous structure and good chemical and physical stability. The FTIR spectral analysis suggested that the interactions between SA and CE take place via hydrogen interactions and/or covalent bonds between the hydroxyl and carboxyl groups. • A cactus extract can be used to structure a gelled sodium alginate porous composite. • Mechanical behavior is better compared to polyvinyl alcohol addition. • Hydroxyl and carboxyl groups form hydrogen bonds with extracted polysaccharides. • Biocomposite beads are spherical with porous structure and a chemical stability. • Porosity is favorable to pentachlorophenol removal in solution.