Abstract
The use of cheaper and recyclable biomaterials (like eggshells) to synthesize high purity hydroxyapatite (HAp) with better properties (small particle size, large surface area and pore volume) for applications (in environmental remediation, bone augmentation and replacement, and drug delivery systems) is vital since high-purity synthetic calcium sources are expensive. In this work, pure and mesoporous HAp nanopowder with large pore volume (1.4 cm3/g) and surface area (284.1 m2/g) was produced from raw eggshells at room temperature using a simple two-step procedure. The control of precursor droplets could stabilize the pH value of the reaction solution, because of the size of the needle (of the syringe pump used for precursor additions) leading to production of HAp with high surface area and pore size. The as-produced HAp revealed high ibuprofen (as a model drug) loading (1.38 g/g HAp), enhanced dissolution and controllable release of the drug via solute-saturated supercritical carbon dioxide.
Highlights
As a result of potential applications in several fields, substantial research has been advanced towards the development of inorganic nanocrystals [1]
Analysis of the patterns for the heat treated samples revealed that they were stable albeit little transformation; for instance, the samples produced from phosphoric acid and calcined at 700 °C
We reported the synthesis of HAp with 212.4 m2/g surface area, 16.8 nm pore size and 0.98 cm3/g pore volume previously [17]
Summary
As a result of potential applications in several fields (such as electronics, information technology, ceramics, medicine, pharmacology, tissue engineering as well as environmental control), substantial research has been advanced towards the development of inorganic nanocrystals [1]. This is a big environmental issue; it is an immense biological calcium (bio-calcium) source for countless applications One of such applications (as stated) is conversion of waste eggshells into HAp. previous procedures for converting eggshells into HAp have generated impure products with larger particle sizes, low surface areas and very low pore volumes [15]. Without the use of templates or structure directing agents, HAp with low BET surface areas (31–52 m2/g) is normally produced from waste eggshells by typical hydrothermal and sol-gel procedures [19]. This situation gave birth to renewed and tremendous efforts to produce HAp with better surface properties for various applications. Ibuprofen was dispersed in mesoporous silica using supercritical CO2 as the solvent and showed a maximum drug loading of 42.0% (g ibuprofen/g silica) at 17 MPa and 37 °C [25]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
