The preparation of calcium phosphate adsorbent from natural calcium resource and its application for copper ion removal

Abstract

Using the hen eggshells (biowaste) as a source of calcium and an environmentally friendly approach, the nanopowder composed of 74% of hydroxyapatite (HA) and 26% of β-tricalcium phosphate (β-TCP) was obtained. Due to the maximum reduction of the stages associated with the use of chemicals and energy, this method can be considered as economically and environmentally friendly. A well-developed surface area and the negative zeta potential at pH above 3.5 indicate good adsorption properties of this material. The obtained material shows high adsorption capacity towards Cu 2+ ions, i.e. 105.4 mg/g at pH 5. Good fit of the Langmuir adsorption model and the pseudo-second-order kinetic model may indicate chemical adsorption probably due to the electrostatic interactions between the Cu 2+ cations and the negatively charged phosphate and hydroxyl groups on the material surface.

Synthesis and Characterization of Calcium Phosphate Materials Derived from Eggshells from Different Poultry with and without the Eggshell Membrane

“…The synthesis of biphasic materials from the eggshells was carried out according to the procedure described previously [34]. The same amounts of each eggshell sample were weighed, dissolved in 15 mL of 1 M nitric acid (the amounts of eggshells were calculated from the DSC results) and stirred for one hour to complete the dissolution of the shells.…”

“…The scope of our research was to obtain the BCP material using wastes in the form of eggshells as a calcium source. In previous papers, the synthesis of biphasic and multiphasic calcium phosphate materials at different pH using hen eggshells has been described [33,34]. An element of the novelty is the reduction of energy consumption through the elimination of the sintering process during the synthesis.…”

Nanomaterials-Upconverted Hydroxyapatite for Bone Tissue Engineering and a Platform for Drug Delivery

“…Several methods have been created, for instance, dry method, wet method, thermal method, or a combination of these methods. 33 Besides that, hydroxyapatite can also be produced from natural sources such as mammalian bones, 41 egg shells 46 and plant sources. 4,45 Each of these methods controls the sizes, chemical composition, crystallinity and morphology of synthesized hydroxyapatite, and those properties influence the biocompatibility, bioactivity, mechanical strength and biological properties.…”

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

“…In continuation of our efforts oriented toward the complete utilization of ESW, in our present research, we have examined the possibility of chemical transformation of ESW with acetic and o-phosphoric acid to the corresponding calcium salts and eggshell membranes. Although the use of o-phosphoric and acetic acid for the production of corresponding Ca-salts from eggshell waste, such as calcium hydroxyapatite [2,8,10,13,[27][28][29][30][31][32][33][34][35][36][37][38][39], calcium triphosphate [13,28,[30][31][32]34,38,[40][41][42], calcium diphosphate [42,43] and much less studied calcium monophosphate [42] or calcium acetate [44,45], have been reported, the novelty of our research lies in the use of eggshell halves and pieces In this respect, our research group has been oriented towards the possibility of the complete utilization of eggshell waste, using the most common industrial processes, such as mixing, filtration, evaporation and drying, but with the aim of producing high-value-added products. Our most recent publication [1] has proven the possibility of ESW utilization for the production of egg white protein solution, calcium chloride dihydrate as a food-grade additive, and eggshell membranes, using ESW transformation with 5% (w/v) hydrochloric acid.…”

“…In continuation of our efforts oriented toward the complete utilization of ESW, in our present research, we have examined the possibility of chemical transformation of ESW with acetic and o-phosphoric acid to the corresponding calcium salts and eggshell membranes. Although the use of o-phosphoric and acetic acid for the production of corresponding Ca-salts from eggshell waste, such as calcium hydroxyapatite [2,8,10,13,[27][28][29][30][31][32][33][34][35][36][37][38][39], calcium triphosphate [13,28,[30][31][32]34,38,[40][41][42], calcium diphosphate [42,43] and much less studied calcium monophosphate [42] or calcium acetate [44,45], have been reported, the novelty of our research lies in the use of eggshell halves and pieces instead of milled ones, the chemical transformation of eggshell waste calcium carbonate with diluted acids instead of those with higher percentages, the use of room temperature during the ESW chemical transformation into salt solutions and ESMs instead of higher ones, as well as the production of calcium salts as the major product and corresponding eggshell membranes as valuable by-products. Moreover, ESW-derived calcium acetate monohydrate and calcium hydrogen phosphate obtained in this research were fully examined in the prescribed demands regarding their suitability as food-grade additives.…”