The environmental sustainability of calcined calcium phosphates production from the milling of eggshell wastes and phosphoric acid

The results of these investigations show1. The substances sold as “Phosphate of lime” and “Calcium Phosphas B.P.” are not pure tricalcic phosphate but are mixtures of di- and tricalcic phosphates.2. Sodium phosphate (Na2HPO4) added to ammoniacal calcium chloride and the resulting precipitate washed with water yields a mixture of di- and tricalcic phosphate and calcium hydrate.3. Bone ash dissolved in hydrochloric acid and precipitated with ammonia, the precipitate being well washed, yields also a mixture of di- and tricalcium phosphate and calcium hydrate.4. When three equivalents of lime (3CaO) are made to act on one equivalent of phosphoric acid (P2O5) and the resulting precipitate removed with little delay pure tricalcium phosphate is obtained.

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Antibacterial Poly(ε-CL)/Hydroxyapatite Electrospun Fibers Reinforced by Poly(ε-CL)-b-Poly(Ethylene Phosphoric Acid)

International Journal of Molecular Sciences ◽

10.3390/ijms22147690 ◽

2021 ◽

Vol 22 (14) ◽

pp. 7690

Author(s):

Ilya Nifant’ev ◽

Dmitry Gavrilov ◽

Alexander Tavtorkin ◽

Maria Chinova ◽

Victoria Besprozvannykh ◽

...

Keyword(s):

Phosphoric Acid ◽

Wound Dressing ◽

Bone Repair ◽

Mechanical Characteristics ◽

High Efficiency ◽

Calcium Phosphates ◽

Close Attention ◽

Bone Surgery ◽

Biodegradable Polyesters ◽

Poly Ethylene

In bone surgery and orthopedics, bioresorbable materials can be helpful in bone repair and countering post-op infections. Explicit antibacterial activity, osteoinductive and osteoconductive effects are essential to achieving this objective. Nonwoven electrospun (ES) fibers are receiving the close attention of physicians as promising materials for wound dressing and tissue engineering; potentially, in high contrast with dense materials, ES mats hamper regeneration of the bone extracellular matrix to a lesser extent. The use of the compositions of inherently biodegradable polyesters (poly(ε-caprolactone) PCL, poly(lactoglycolide), etc.), calcium phosphates and antibiotics is highly prospective, but the task of forming ES fibers from such compositions is complicated by the incompatibility of the main organic and inorganic ingredients, polyesters and calcium phosphates. In the present research we report the synthesis of hydroxyapatite (HAp) nanoparticles with uniform morphology, and demonstrate high efficiency of the block copolymer of PCL and poly(ethylene phosphoric acid) (PEPA) as an efficient compatibilizer for PCL/HAp mixtures that are able to form ES fibers with improved mechanical characteristics. The materials obtained in the presence of vancomycin exhibited incremental drug release against Staphylococcus aureus (St. aureus).

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Solubility of Phosphates, Rates of Solution of Calcium Phosphates in Phosphoric Acid Solutions

Journal of Agricultural and Food Chemistry ◽

10.1021/jf60074a001 ◽

1957 ◽

Vol 5 (4) ◽

pp. 266-275 ◽

Cited By ~ 31

Author(s):

E. O. Huffman ◽

W. E. Cate ◽

M. E. Deming ◽

K. L. Elmore

Keyword(s):

Phosphoric Acid ◽

Calcium Phosphates ◽

Acid Solutions

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Zur Frage der nicht-enzymatischen Bildung von kondensierten Phosphaten unter präbiotischen Bedingungen/ Non-Enzymatic Formation of Condensed Phosphates under Prebiotic Conditions

Zeitschrift für Naturforschung B ◽

10.1515/znb-1986-0704 ◽

1986 ◽

Vol 41 (7) ◽

pp. 815-824 ◽

Cited By ~ 7

Author(s):

F. Seel ◽

K.-P. Klos ◽

D. Recktenwald ◽

J. Schuh

Keyword(s):

Phosphoric Acid ◽

Chemical Evolution ◽

Calcium Phosphates ◽

Aqueous System ◽

Hydrothermal Conditions ◽

Primitive Earth ◽

Spontaneous Condensation ◽

Enzymatic Formation ◽

Condensed Phosphates

AbstractOne of the problems of chemical evolution on the primitive Earth is the question of the possibility of a non-enzymatic spontaneous condensation o f phosphoric acid and hydrogen phosphates to yield polyphosphoric acids and polyphosphates in aqueous system s, by means of which phosphorus might have entered into early metabolisms. The extra- or intra-cellular formation of magnesium diphosphate under geologically plausible hydrothermal conditions from either magnesium hydrogen phosphates or calcium phosphates in media has been demonstrated.

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Phosphatation de résidus minéraux

Environnement, Ingénierie & Développement ◽

10.46298/eid.2003.8051 ◽

2003 ◽

Vol N°31 - 3ème Trimestre 2003 ◽

Author(s):

Blandine Bournonville ◽

Ange Nzihou ◽

Patrick Sharrock ◽

Guy Depelsenaire

Keyword(s):

Heavy Metals ◽

Phosphoric Acid ◽

Municipal Solid Waste ◽

Solid Waste ◽

Calcium Phosphates ◽

Raw Material ◽

Natural Environments ◽

Waste Incinerator ◽

Phosphate Treatment ◽

Rapid Kinetics

The incineration of municipal solid waste generates mineral residues which contain soluble chlorides and heavy metal pollutants. The mineral residue is currently landfilled after a cement solidification. An alternative treatment, the new patented by Solvay process uses phosphoric acid to stabilise mineral residue by the formation of stable minerals such as calcium phosphates which are insoluble in natural environments and can incorporate heavy metals inside their crystalline structure. Two different water-washed municipal solid waste incinerator mineral residues are investigated during the phosphate treatment. Phosphoric acid reacts exothermically with mineral residues with rapid kinetics of the dissolution-precipitation type. Second order rate is observed with respect to the phosphate concentration and activation energies for the phosphate reaction are found to be small (near 20 kJ/mol). Mineral residues react with phosphoric acid mainly as calcium carbonate does. Precipitated amorphous calcium phosphates coat the more inert particles (silicoaluminates, silicates, and calcium sulphates…). The two mineral residues with different compositions show similar behaviour. This indicates the phosphate stabilisation procedure can be widely applied. This chemical treatment can be considered as a first essential step in the effective insolubilisation of extractable trace heavy metals in a mineral material that could find in the future an beneficial reuse after further processing as secondary raw material. Solvay a breveté un nouveau procédé de stabilisation de résidus minéraux contaminés par des métaux lourds et des composés organiques dont l’une des étapes fondamentales est le traitement chimique à l’acide phosphorique. Son objectif est de former des phosphates de calcium de grande stabilité chimique et thermique, capables d’incorporer dans leur structure cristalline les métaux lourds. L’étude de la cinétique de phosphatation montre que la réaction est exothermique. Les phosphates calciques formés enrobent les particules les plus inertes. L’énergie d’activation faible (20 kJ/mol), caractéristique d’une réaction acide-base, est proche de celle de la réaction avec le carbonate de calcium. Les expérimentations menées et les paramètres observés indiquent que la phosphatation peut être généralisée pour tous les résidus minéraux et constituer une première étape dans l’insolubilisation effective des métaux lourds. Ceci permet d’envisager pour le futur une possible revalorisation des résidus minéraux phosphatés et calcinés comme matière première secondaire.

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The concerted use of SEM, TEM, and SCM for examination of resin-dentin interfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100170116 ◽

1994 ◽

Vol 52 ◽

pp. 476-477

Author(s):

B. Van Meerbeek ◽

L. J. Conn ◽

E. S. Duke

Keyword(s):

Surface Layer ◽

Stress Distribution ◽

Phosphoric Acid ◽

Bonding Mechanism ◽

Restorative Dentistry ◽

Dental Adhesive ◽

Low Viscosity ◽

Dentin Adhesives ◽

Acid Etch ◽

Tooth Tissue

Restoration of decayed teeth with tooth-colored materials that can be bonded to tooth tissue has been a highly desirable property in restorative dentistry for many years. Advantages of such an adhesive restorative technique over conventional techniques using non-adhesive metal-based restoratives include improved restoration retention with minimal sacrifice of sound tooth tissue for retention purposes, superior adaptation and sealing of the restoration margins in prevention of caries recurrence, improved stress distribution across the tooth-restoration interface throughout the whole tooth, and even reinforcement of weakened tooth structures. The dental adhesive technology is rapidly changing. An efficient resin bond to enamel has already long been achieved. Its bonding mechanism has been fully elucidated and has proven to be a durable and reliable clinical treatment. However, bonding to dentin represents a greater challenge. After the failures of a dentin acid-etch technique in imitation of the enamel phosphoric-acid-etch technique and a bonding procedure based on chemical adhesion, modern dentin adhesives are currently believed to bond to dentin by a micromechanical hybridization process. This process is developed by an initial demineralization of the dentin surface layer with acid etchants exposing a collagen fibril arrangement with interfibrillar microporosities that subsequently become impregnated by low-viscosity monomers. Although the development of such a hybridization process has well been documented in the literature, questions remain with respect to parameters of-primary importance to adhesive efficacy.

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