Preparation Of Hydroxyapatite Powders For Medicalapplications Via Sol-gel Technique

PREPARATION OF HYDROXYAPATITE POWDERS FOR MEDICALAPPLICATIONS VIA SOL-GEL TECHNIQUE. Hydroxyapatite (HA) powders have been prepared via sol-gel procedure using calcium nitrate tetrahydrate and di-ammonium hydrogen phosphate as the precursors for calcium and phosphorus, respectively. An ammoniacal solution of the monomers was heated at 100°C for about 3 –4 h until a white gel of hydroxyapatite mixture were obtained. The obtained gel was then dried at 340°C for 7 h and subsequently subjected to an 820°C calcination for 2 h. The yield of the powder mixture ranged between 50 to 53 g. XRD measurement shown that the powder contained hydroxyapatite crystal with b-TCP ( 15-20%) and calcium oxide (4-6%) as secondary phases. Further treatment was conducted to gain hydroxyapatite powder of higher purity, thus the correct Ca/P ratio, by adding an appropriate amount of di-ammonium hydrogen phosphate and heated while stirring at 90°C for 4 h. Good purity (almost 100%) of the obtained hydroxyapatite was confirmed by XRD analysis.This result proved that our HA powder meets the medical prerequisite: a HA purity of above 95%. Morphological evaluation by SEM measurement shows that the particles of the HA agglomerate are globular in shape with an average size of 1-2 mm in diameter. Meanwhile, the primary particles have a diameter of 70-150 nm in average. Surface area of the powder is 7 m2/g and the mean particle size as measured using X ray sedimentation method is ca. 1 mm. The measurements are not in good agreement with the morphological investigation. We consider, accordingly, that the particles presumably have high surface potentials, thus forming very tightly bonded agglomerate

PREPARATION OF HYDROXYAPATITE POWDERS FOR MEDICALAPPLICATIONS VIA SOL-GEL TECHNIQUE

PREPARATION OF HYDROXYAPATITE POWDERS FOR MEDICALAPPLICATIONS VIA SOL-GEL TECHNIQUE. Hydroxyapatite (HA) powders have been prepared via sol-gel procedure using calcium nitrate tetrahydrate and di-ammonium hydrogen phosphate as the precursors for calcium and phosphorus, respectively. An ammoniacal solution of the monomers was heated at 100°C for about 3 –4 h until a white gel of hydroxyapatite mixture were obtained. The obtained gel was then dried at 340°C for 7 h and subsequently subjected to an 820°C calcination for 2 h. The yield of the powder mixture ranged between 50 to 53 g. XRD measurement shown that the powder contained hydroxyapatite crystal with b-TCP ( 15-20%) and calcium oxide (4-6%) as secondary phases. Further treatment was conducted to gain hydroxyapatite powder of higher purity, thus the correct Ca/P ratio, by adding an appropriate amount of di-ammonium hydrogen phosphate and heated while stirring at 90°C for 4 h. Good purity (almost 100%) of the obtained hydroxyapatite was confirmed by XRD analysis.This result proved that our HA powder meets the medical prerequisite: a HA purity of above 95%. Morphological evaluation by SEM measurement shows that the particles of the HA agglomerate are globular in shape with an average size of 1-2 mm in diameter. Meanwhile, the primary particles have a diameter of 70-150 nm in average. Surface area of the powder is 7 m2/g and the mean particle size as measured using X ray sedimentation method is ca. 1 mm. The measurements are not in good agreement with the morphological investigation. We consider, accordingly, that the particles presumably have high surface potentials, thus forming very tightly bonded agglomerate

PENGARUH STRUKTUR KRISTAL TiO2 DALAM DEGRADASI FOTOKATALITIK AMONIA DAN HIDROGEN SULFIDA

PENGARUH STRUKTUR KRISTAL TiO2 DALAM DEGRADASI FOTOKATALITIK AMONIA DAN HIDROGEN SULFIDA. Film-film titanium dioksida dengan struktur anatase dan rutile telah dipreparasi dengan teknik sol-gel yang termodifikasi di atas pelat silika lebur. Pengaruh struktur kristal TiO2 terhadap karakteristik degradasi fotokatalitik gas amonia dan hidrogen sulfida telah diteliti. Dalam hal ini ditemukan bahwa film anatase memperlihatkan aktivitas fotokatalitik yang lebih tinggi daripada film rutile dalam semua reaksi fotokatalitik yang diamati. Akan tetapi, ditemukan adanya perbedaan karakteristik degradasi kedua gas tersebut akibat perbedaan kapasitas donor elektron dan sifat-sifat elektrokimia dari kedua reaktan tersebut

Hydrophobic organosilica coating on steel and aluminium

Superhydrophobic organosilica was fabricated from Tetraorthosilicate (TEOS) as the precursor using a simple sol gel technique and treated by using perfluoroalkysilane. The super hydrophobic silica has been coated on steel and aluminium surface and was characterised based on the silica content on the coating. The results show that the highest contact angle achieved is 108 degree and all the coating has more than 90 degree water contact angle. Since the contact angle is lower than 150 degree, it only managed to get hydrophobic surface instead of superhydrophobic surface. The high contact angle is believed due to presence of air pocket between water and solid surface that enhance by the roughness of the coating. In addition, water contact angle and surface roughness step up with increasing silica content in the coating. The water contact angle of the coating surface can be predicted using the following equation WA=89.39+0.975SR for steel and WA=83.20+1.097SR for aluminium substrates, where WA is water contact angle and SR is surface roughness

Synthetic bone as a solution for halal bone grafts implantation: demand for bone graft has been increasing steadily

The use of allografted bone substance requires several considerations: pathological clearance to ensure that the bone is free from any disease or harmful bacteria or viruses, the method is legal, allografting is an acceptable culture in the society, etc. Regarding the use of xenografts, pig bones are the most similar to human bones among pigs, mice and rats. Therefore, pig bone is usually used as a model for studyng the molecular genetics of bone-related disorder or even for xenografting. Moreover, with regard to macro- and microstructure, composition and suitability for remodeling, again pig bone is the most similar to human bone among porcine, canine, sheep, goat and rabbit

Lightweight biodegradable cotton/albumen board (CAB) for sustainable environment

The depletion of petroleum resources coupled with environmental awareness have spurred effort to produce biodegradable materials from natural resources, which is stable during storage and can be safely disposed after their intended time of use. These materials also can form the basis for sustainable and ecoefficient products that often results in lightweight structures having high stiffness and tailored properties for specific applications. Thereby, main objective of this work is to develop biodegradable board materials from cotton fiber reinforced egg albumen composites. The investigation is about the effect of fibre content on the mechanical properties, and thermal stability of the CAB. The composites having 0%,toughness was observed with increasing fiber content, with the optimum performance was obtained for the fiber content of 10 %w/w. The results have shown that addition of the cotton fibre increased the tensile strength and impact resistance in the range of 0.7 to 10.773 MPa and 1.3 to 19.0 kJ/m2 respectively, than that of the pristine albumen. The thermal stability of the composites was characterized by thermogravimetry analysis. The morphological study by SEM has revealed that the wettability of cotton fibre and albumen matrix was good for the fibre loading of 10 % w/w

Synthesis of Ti02 N anosized Powder Photocatalyst Via Solgel Method for Bacteria Inactivation Application

Titanium dioxide (Ti02) is the most widely used photocatalyst and has been applied for water and air purification and disinfection of microorganism. Anatase structured Ti02 is a wide bandgap (3.2 eV) semiconductor which, under UV light, is able to degrade chemicals and cell components of microorganisms. In this study, Ti02 nanopowder photocatalyst was synthesized by sol-gel process using a titanium chelate compound, titanium (di-isopropoxide) bis(acetylacetonate) (PTP) as the precursor. The precursor was hydrolyzed under an acidic catalyst condition, followed by reflux for 15 minutes and 1 hour. The precipitate powder obtained after filtration was calcined at 400°C. XRD analysis confirmed that the Ti02 powders A (15 minutes reflux) and B (1 hour reflux) have strongest peak at 25° which indicates anatase crystal structure. The particle size of powder A was smaller than the powder B as proved by calculation using Scherrer's equation. The crystallization temperature of Ti02 powder A was higher due to its smaller particles that needed more heat to crystallize than powder B as confirmed by TGIDTA. FESEM analysis showed powder A have homogenous spherical shape, contrast to powder B showing inhomogenous spherical shape and connected particle. The Ti02 photocatalyst activity in killing bacteria was investigated for 5 hours by varying the concentration 'of Ti02 and UV light intensity