Synthesis and characterization of new β-chitin/calcium phosphate (DCPA) based composite using natural resources for environmental application

- New β-chitin/calcium phosphate DCPA was synthesized from biogenic CaCO3 structure.
- The presence of β-chitin distorts the crystal structure of DCPA material.
- β-chitin in DCPA leads to defined microstructure described by rectangular blocks.
- High uptake efficiency of β-chitin/DCPA for Cu2+-rich solution compared to DCPA.

The synthesis of new β-chitin/calcium phosphate (DCPA) based composite was successfully produced from cuttlefish bone as a source of calcium and β-chitin, and concentrated phosphoric acid by using simple and effective chemical conversion method. Cuttlefish bone is a marine structure; it is a composite biogenic material formed by aragonite calcium carbonate, CaCO3 and small content of β-chitin with special architecture and composition. It is readily converted to calcium phosphate under moderate conditions of temperature. In this study, the comparison of the structural characterization of new β-chitin/DCPA composite and conventional DCPA prepared from calcite was performed using X-Ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR), Scanning Electronic Microscopy (SEM-EDS) and Thermo-Gravimetry and Differential Thermal Analysis (TG/DTA). The results show that β-chitin/DCPA composite provides some structural changes with respect to the DCPA structure. The presence of β-chitin within the composite implies a decrease of crystallinity and a distortion of the crystal lattice of DCPA. β-chitin/DCPA composite displays a well-defined microstructure characterized by regular rectangular shape with small particle sizes, while the pure DCPA is formed by heterogeneous large plate-like crystals. Adsorption experiments showed the high immobilization efficiency of β-chitin/DCPA composite for Cu2+-rich solution, due to the potential adsorption sites (OH) of β-chitin.

97