Production and Characterization of Oxyhydroxyapatites

Abstract

The amount and alignment of hydroxyl ions influence the bioactivity of hydroxyapatite. Hydroxyl ions in hydroxyapatite are the most mobile and upon heating are the first to leave the lattice to form oxyhydroxyapatite. This work describes a method for producing hydroxyapatite with different amounts of hydroxyl ions, and reports on the changes in Fourier transform infrared absorption at increasing level of dehydroxylation. Detailed analysis of spectra in the 500 – 700 cm-1 range showed a peak shift for the hydroxyl ion absorption line at 632 cm-1 to 637 cm-1 and an increase in the wavenumber for the phosphate line at 575 cm-1.

Effect of Modified Natural Rubber on the Mechanical and Thermal Properties of Poly(Lactic Acid) and Its Composites with Nanoparticles from Biowaste

“…In the case of commercial HA, the characteristic hydroxyl group (OH) peaks in the HA structure appear at 3467 cm −1 and 634 cm −1 [ 33 ], while nHA exhibits only a tiny peak at 669 cm −1 . The observed shift of the peak to a higher wavenumber is attributed to the lower OH concentration in the nHA structure [ 34 ]. The OH stretching of adsorbed water is indicated by the broad peak around 3400–3500 cm −1 , with an additional peak at 1627 cm −1 corresponding to the bending of the OH groups in water molecules (H 2 O) [ 31 ].…”

Fabrication of Calcium Phosphate Coatings by the Inflight Reaction of Precursor Feedstocks Using Plasma Spraying

“…Liao et al speculated that both OA and OHAp are present during HA degradation. OA is stable between 800 and 1050 °C, but can absorb water at 600 °C in a vacuum, due to its highly reactive nature, which links to the idea that it exists with some hydroxyl groups present in the structure ( Ref 15,26,[28][29][30][31][32]. As a result, dehydroxylated HA is often described as a solid solution of stoichiometric HA and OA, which is referred to as OHAp ( Ref 11,33,34).…”

Sustainable Utilization of King Coconut Husk as a Feedstock in Biochar Production with the Highest Conversion Efficiency and Desirable Properties

“…The process of bottling king coconut water for export thereby results in a significant amount of husk waste. Due to the lack of commercial value, a sizeable amount of this IOP Publishing doi:10.1088/1755-1315/1235/1/012009 2 waste material is currently found in factories and coconut plantations (Pluduma et al 2018) and is buried in coconut lands as a cultural practice (Dissanayake et al 2019). King coconut husk cannot be utilized to make coir pith or fiber as it is harvested at an early immature stage.…”

“…The goal of adding biochar to soils is to sequester carbon while preserving or enhancing the functions of the soil. Biochar is a carbonaceous, solid, and recalcitrant material produced by pyrolysis in an oxygen-limited atmosphere (Tomczyk et al 2020, Tomczyk et al 2010, Pluduma et al 2018). Four criteria can be used to categorize the effectiveness of biochar and its mechanisms for enhancing soil fertility; as a nutrients source to increase soil fertility, to improve the physical and chemical properties of soils, to store nutrients, and to be used as a slow-release fertilizer and to improve soil biological properties such as microbial abundance, structure, and activity (Ding et al 2016).…”