Eggshell-Waste-Derived Calcium Acetate, Calcium Hydrogen Phosphate and Corresponding Eggshell Membranes

Abstract

The development of innovative transformation techniques for various wastes generated by the agri-food industry is one of the goals of sustainable waste management oriented toward “zero-waste” approach. This includes the production of bulk and fine chemicals, bioactive compounds, enzymes and functional materials from various waste. The present research shows the possibility of the production of value-added products from eggshell waste using chemical transformation by acetic and o-phosphoric acid at a laboratory scale level. Eggshell-derived calcium acetate monohydrate and calcium hydrogen phosphate, both of high purity, as well as corresponding eggshell membranes as valuable by-products, were produced. Chemical transformation of 100 g of eggshell waste with 10% (w/v) acetic acid resulted in 111.41 ± 2.13 g of calcium acetate monohydrate and 2.90 ± 0.14 g of eggshell membranes, with a chemical yield in calcium acetate monohydrate of 79.16 ± 1.98%. On the other hand, the transformation of 100 g of eggshell waste in 15% (w/v) o-phosphoric acid yielded 77.06 ± 6.21 g of calcium hydrogen phosphate and 2.94 ± 0.08 g of eggshell membranes, with a chemical yield in calcium hydrogen phosphate of 71.36 ± 5.58%. Eggshell-derived calcium hydrogen phosphate met all prescribed criteria for food-grade additive, as determined by physicochemical analysis. On the other hand, calcium acetate monohydrate met the majority, except water insoluble and formic acid and oxidizable impurities content. Based on the obtained results, it can be concluded that the proposed eggshell waste transformation process by two different acids might be useful for the production of calcium acetate and calcium hydrogen phosphate as food-grade additives, as well as eggshell membranes as valuable by-products.

The technology of green synthesis of calcium acetate from quail egg shells

“…By measuring the distance between the lines of the same ring on the Debye diagram, the Bragg reflection angles can be determined. The Bragg-Wolf formula (2d sinƟ=nλ) helps to obtain the ratio d/n of the distance between reflecting planes to the order of reflection, revealing valuable insights into the material being studied [8,10,13].…”

“…The aim of our research was to obtain calcium acetate, a compound widely used in the pharmaceutical and food industries. Ivica Strelec and co previously studied the production of calcium acetate monohydrate from chicken eggshells, which is of interest to the food industry [10]. Our study focused on obtaining calcium acetate from quail egg shells and modified the production process.…”

“…The chemical and elemental composition were determined by utilizing the Rietveld method and the "Search-Match!3" program. The X-ray diffraction analysis results were also compared with the outcomes of previously conducted studies on calcium acetate [10,11,14]. crystal system is orthorhombic.…”

Utilization of Eggshell-Derived Calcium Carbonate as an Eco-Friendly Fertilizer Enhancing Growth of Rosa Abientina, Rosa, and Fragaria × ananassa, and Soil Health

“…Eggshells, often overlooked as waste, possess valuable nutrients essential for plant growth, making them a promising eco-friendly fertilizer option. (Strelec et al, 2023) Comprising approximately 95% calcium carbonate, eggshells also contain phosphorus, magnesium, sodium, potassium, zinc, manganese, iron, and copper in smaller amounts. (Sachan, 2023)These nutrients play pivotal roles in various physiological processes crucial for plant development.…”

The Preparation and Characterization of Different Types of Eggshells Acidified with Acetic Acid

“…The calcium acetate resulting from the acidification of the eggshells with acetic acid has other applications, such as calcium supplements [27,28] or snow-melting agents [4].…”