Recrystallization of Triple Superphosphate Produced From Oyster Shell Waste for Agronomic Performance and Environmental Issue

Calcium dihydrogen phosphate monohydrate [Ca(H2PO4)2·H2O] (a fertilizer) was successfully synthesized by the recrystallization process by using a prepared triple superphosphate (TSP) that derived from oyster shell waste as starting material. This bio-green, eco-friendly process to produce an important fertilizer can promote a sustainable society. The shell-waste-derived TSP was dissolved in distilled water and kept at 30, 50, and 80 °C. Non-soluble powder and TSP solution were obtained. The TSP solution fraction were then dried and the recrystallized products (RCP30, RCP50, and RCP80) were obtained and confirmed as Ca(H2PO4)2·H2O. Whereas the non-soluble products (NSP30, NSP50, and NSP80) were observed as calcium hydrogen phosphate dihydrate (CaHPO4·2H2O). The recrystallized yields of RCP30, RCP50, and RCP80 were found to be 51.0%, 49.6%, and 46.3%, whereas the soluble percentages were 98.72%, 99.16%, and 96.63%, respectively. RCP30 shows different morphological plate sizes, while RCP50 and RCP80 present the coagulate crystal plates. X-ray diffractograms confirm the formation of both the NSP and RCP. The infrared adsorption spectra confirmed the vibrational characteristics of HPO42‒, H2PO4‒ and H2O existed in CaHPO4·2H2O and Ca(H2PO4)2·H2O. Three thermal dehydration steps of Ca(H2PO4)2·H2O (physisorbed water, polycondensation, and re-polycondensation) were observed. Ca(H2PO4)2 and CaH2P2O7 are the thermodecomposed products from the first and second steps, whereas the final product is CaP2O6.

Synthesis and Characterization of Feed-Grade Monocalcium Phosphate Ca(H2PO4)2·H2O from Oyster Shell

Oyster shells are considered as a byproduct or solid waste in mariculture or related food processing areas that face a major disposal problem at the landfill in coastal regions for sustainable development. Oyster shell is composed mostly of CaCO3, and it is also considered as a secondary source of calcium for various applications. In this paper, we extracted the calcium carbonate from oyster shell and used it as the source of calcium for the preparation of feed-grade monocalcium phosphate (MCP). The investigation shows that the heavy metal contents in oyster shells as well as in the synthesized MCP are extremely low, and the synthesized product meets the requirements for the European Union (EU) maximum limits applied for feed additives. The XRD, TG, and IR data analyses confirmed that the synthesized product is monocalcium phosphate.

Different calcium sources on the productive performance and bone quality of meat quail

ABSTRACT: This study was developed to examine the effect of using charru mussel-, maçunim- and oyster-shell meals as calcium sources on the productive performance, carcass yield and bone parameters of meat quail. A total of 250 one-day-old non-sexed European quail were used. The birds were distributed into five treatments (calcium sources: calcitic lime, calcium carbonate, charru mussel shell meal, maçunim shell meal or oyster shell meal) in a completely randomized design with five replicates and ten birds per experimental unit. Feed intake, weight gain and feed conversion were evaluated from one to 35 days. At 35 days, two birds with the average weight of the plot were slaughtered per plot and used for analysis of carcass yield and bone parameters. There were no significant differences (P > 0.05) in feed intake, weight gain, feed conversion, carcass yield or tibia dry matter content, ash content and strength. The charru mussel-, maçunim- and oyster-shell meals can be used as calcium sources in the diet of European quail without affecting their productive performance, carcass yield or bone mineralization.

A Study on the Conservation and Management of the Painting of Shamanistic Spirits in Chiseonggwang Buddha

This study presents a method for conserving shamanistic spirits in Chiseonggwang Buddha. Scientific investigation has revealed that these spirits have been subject to degeneration as a result of severe exfoliation and pollution. The materials and preservation treatment techniques used in create these shamanistic spirits were identified through visual inspection and using appropriate scientific equipment. The different types of background paper, background material, and color pigments used in create the shamanistic spirits were analyzed using a colorimeter, stereoscopic microscope, and SEM-EDS techniques. The analysis revealed that the pulp paper was used as the background and synthetic fiber polyester as the background material. In addition, the study of the pigment revealed that the color components were all synthetic, except for red lead [Pb3O4] and oyster shell white [CaCO3]. Moreover, it was confirmed that the green pigment, identified as emerald green [Cu(C2H3O2)2.3Cu(AsO2)2], was a major component of shamanistic spirits in the late 19th century. The shamanistic spirits in Chiseonggwang Buddha were conserved by identifying raw materials and pigments through this detailed analysis.

Oyster shell powder (Crassostrea gasar): evaluation of its potential as a natural and sustainable source of calcium in bread

PurposeThe study aims to analyze the composition and mineral profile of oyster shell powder (OSP) and assess its potential as a sustainable source of calcium.Design/methodology/approachA total of two batches of OSP with different particle sizes had been evaluated for centesimal and mineral composition and microbiological quality. OSP with smaller particles (0.85 mm) was used in the production of bread: standard bread (SB) (0%), fortified bread (FB1) (3%) and FB2 (4%). Centesimal and mineral composition and sensory acceptance had been performed. The internal preference map had been constructed using principal component analysis. The Just About Right data and the influence of sensory attributes on bread acceptance had been assessed by a penalty analysis test.FindingsOSP-0.85 mm had calcium content (478.47 ± 2.37 mg.g-1) lower than OSP-1.00 mm (521.15 ± 0.99 mg.g-1) due to retention of particles. In both batches, heavy metals such as chromium, nickel and copper had not detected. FB1 and FB2 had the best nutritional content compared to SB, with higher calcium content (mg.g-1) 0.69 ± 0.07; 13.76 ± 0.72 and 19.47 ± 1.99 for SB, FB1 and FB2, respectively. The internal preference map showed better acceptance of FB1 compared to FB2. The penalty test showed that this acceptance was penalized (p < 0.05) due to the sandy texture.Originality/valueThe large number of shells generated in the processing of oysters is an environmental problem and generates waste of a natural source of calcium. It has been demonstrated that oyster shell powder can be used as a natural and sustainable source of calcium in bread, requiring further studies to assess the bioavailability of calcium.