Structural, compositional and spectral investigation of prawn exoskeleton nanocomposite: UV protection from mycosporine-like amino acids

Preparation and structural characteristics of biphasic calcium phosphates from prawn shell bio-waste

“…Figure 9 shows the survey spectrum and deconvoluted high-resolution spectra of various elements of BCP at 1200°C. XPS spectra of Ca 2p peaks are identified at 346.83 eV (2p 3/2 ), 350.45 eV (2p 1/2 ), and 351.85 eV (2p 1/2 ) (Figure 9 hydroxyl group of HA [29] and O-O bond [27]. Figure 9(d) reveals the high-resolution spectra of P 2p where binding energy at 133.30 is due to the formation of α-TCP [33].…”

“…Figure 9(f) demonstrates the high-resolution spectra of Si 2p where binding energy at 102.59 eV is assigned to the +2 state and binding energy at 106.36 eV is assigned to the +3 state [37,41]. Figure 9(g) illustrates the high-resolution spectra of Mg 1s where binding energy at 1303.29 eV belongs to MgO [27,38] . Table 1 represents XPS core levels of different calcium phosphates.…”

“…The binding energy at 351.85 eV represents the Ca-O bond in hydroxyapatite [39]. Figure 9(c) shows the high-resolution spectra of O 1s peaks where binding energies at 530.76 eV, 532.7, 534.61, 536.38 and 537.21 eV attribute to the Ca-O bond in α-TCP [35], C–O [35], C-OH bond [27], hydroxyl group of HA [29] and O-O bond [27]. Figure 9(d) reveals the high-resolution spectra of P 2p where binding energy at 133.30 is due to the formation of α-TCP [33].…”

“…The prawn shell, a calcite source, was calcined in a muffle furnace at 900°C for 2 h at a rate of 10°C/min. As the prawn exoskeleton consists of calcite, α-chitin and proteins [27], hence calcination helps in the complete removal of unwanted carbons. The calcite was converted into calcium oxide (CaO) by releasing carbon dioxide.…”

“…About 45% of processed seafood consists of prawns; a significant share of industrial waste comes from its exoskeleton. Prawn comprises around 55-65% by weight of edible components, and the remaining 35-45% is bio-waste, utilised as fertiliser, animal feed mix, and source of chitosan and chitin [27]. The exoskeletons of prawns contain a large amount of calcium carbonate.…”