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Presently there is a glut of glycerol as the by-product of biofuel production and it will grow as production increases. The conundrum is how we can consume this material and convert it into a more useful product. One potential route is to reform glycerol to hydrogen rich gas including synthesis gas (CO + H2) and hydrogen. However, there is recent literature on various reforming techniques which may have a bearing on the efficiency of such a process. Hence in this review reforming of glycerol at room temperature (normally photo-catalytic), catalysis at moderate and high temperature and a non-catalytic pyrolysis process are presented. The high temperature processes allow the generation of synthesis gas with the hydrogen to carbon monoxide ratios being suitable for synthesis of dimethyl ether, methanol and for the Fischer-Tropsch process using established catalysts. Efficient conversion of synthesis gas to hydrogen involves additional catalysts that assist the water gas shift reaction, or involves in situ capture of carbon dioxide and hydrogen. Reforming at reduced temperatures including photo-reforming offers the opportunity of producing synthesis gas or hydrogen using single catalysts. Together, these processes will assist in overcoming the worldwide glut of glycerol, increasing the competitiveness of the biofuel production and reducing our dependency on the fossil based, hydrogen rich gas.

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Production of hydroxyapatite coatings using an alkoxide-based sol-gel route requires control of solution aging time and heating schedule. 31P nuclear magnetic resonance spectroscopy was used to investigate the changes during aging of the sol and thermal gravimetric analysis employed to study the behavior of the xerogels as a function of temperature, while final products were determined using X-ray diffraction. Results from 31P nuclear magnetic resonance spectroscopy and thermal analysis revealed that sols must be aged for at least 24 h to complete the reaction of the two reactants. Deposition of the sol for coating production will then yield monophasic hydroxyapatite. Coatings produced from sols aged for less than 24 h yielded calcium oxide in addition to hydroxyapatite. Prefiring is necessary to remove most of the residual organic materials. Final heating up to 800 degrees C produces crystallization at 550 degrees C and removal of the remaining organic constituents for the formation of a thin hydroxyapatite layer.

The thermal decomposition of a lamellar hydroxyapatite precursor containing crystalline complexes leads to the formation of an apatite product with bonelike morphology. Solid-state 13C and 31P nuclear magnetic resonance, infrared, and Raman vibrational spectroscopic data show that the hydroxyapatite precursor contains acetyl hydrogen phosphonates and at least two types of acetate species. Phosphoryl and carboxyl oxygens of the phosphonate group are chelated to the calcium ion. The oxygens of the other acetate groups are involved in either monodentate bonding or chelation. The most important consequence of the morphology of the intermediate is the formation of apatite retaining the precursor morphology. The process emulates the formation of biogenic apatites, where the formation of an intermediate phase with platelike morphology serves as a template for apatite formation with a morphology similar to that of the precursor.

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