Performance Enhancement of Kaolin/Chitosan Composite-Based Membranes by Cross-Linking with Sodium Tripolyphosphate: Preparation and Characterization

• Published in: Membranes (Basel) 2023-02, Vol.13 (2), p.229
• Main Authors: Rekik, S Bouzid, Gassara, S, Bouaziz, J, Baklouti, S, Deratani, A
• Format: Article
• Language: English
• Subjects: Chemical engineering; Chemical properties; Chemical Sciences; Chemicals; Chitin; Chitosan; composite ceramic/polymer membrane; Composite materials; Contact angle; Crosslinking; finger-like morphology; Functional groups; Kaolin; low-cost and environmentally friendly fabrication; Manufacturing; Material chemistry; Materials; Mechanical properties; Membranes; Membranes (Technology); Microfiltration; Molecular weight; Morphology; Permeability; Phase separation; Polyethylene glycol; Polymers; Pore formation; Pore size; pore size adjustment; Sintering; Sodium; Sodium triphosphate; Sodium tripolyphosphate; Solvents; Thickness; Ultrafiltration
• ISSN: 2077-0375; 2077-0375
• DOI: 10.3390/membranes13020229

A new family of environmentally friendly and low-cost membranes based on readily available mineral and polymeric materials has been developed from cast suspensions of kaolin and chitosan using aqueous phase separation and polyethylene glycol as a pore-forming agent. The as-fabricated membranes were further cross-linked with sodium tripolyphosphate (STPP) in order to strengthen the properties of the obtained samples. The functional groups determined by FTIR and EDX confirmed that the reaction occurred. A detailed study of the effects of cross-linking time on the physicochemical, surface and permeation properties showed that a 30-minute reaction enabled the composite membrane to be stable in acidic media (up to pH 2) and increased the mechanical strength twofold compared to the non-cross-linked membrane. A similar morphology to that generally observed in polymeric membranes was obtained, with a sponge-like surface overlaying a finger-like through structure. The top layer and cross-section thicknesses of the membranes increased during STPP post-treatment, while the pore size decreased from 160 to 15 nm. At the same time, the molecular weight cut-off and permeance decreased due to the increase in cross-linking density. These results observed in a series of kaolin/chitosan composite membranes showed that STPP reaction can provide control over the separation capability range, from microfiltration to ultrafiltration.