RESUMEN
Despite significant improvements in the synthesis of templated silica materials, post-synthesis purification remains highly expensive and renders the materials industrially unviable. In this study this issue is addressed for porous bioinspired silica by developing a rapid room-temperature solution method for complete extraction of organic additives. Using elemental analysis and N2 and CO2 adsorption, the ability to both purify and controllably tailor the composition, porosity and surface chemistry of bioinspired silica in a single step is demonstrated. For the first time the extraction is modelled using molecular dynamics, revealing that the removal mechanism is dominated by surface-charge interactions. This is extended to other additive chemistry, leading to a wider applicability of the method to other materials. Finally the environmental benefits of the new method are estimated and compared with previous purification techniques, demonstrating significant improvements in sustainability.
Asunto(s)
Nanoestructuras , Adsorción , Dióxido de Carbono/química , Microscopía Electrónica de Rastreo , Simulación de Dinámica Molecular , Nitrógeno/química , PorosidadRESUMEN
We present the first report on bioinspired silica - produced using a green method - supported carbonic anhydrase for carbon capture and demonstrate significantly improved carbon capture efficiency and stability relevant to flue gas temperatures.
Asunto(s)
Dióxido de Carbono/química , Enzimas Inmovilizadas/química , Dióxido de Silicio/química , Anhidrasas Carbónicas/química , Anhidrasas Carbónicas/metabolismo , Enzimas Inmovilizadas/metabolismo , Gases/química , TemperaturaRESUMEN
The layered perovskite HLaTiO(4) reacts stoichiometrically with LiOH.H(2)O at room temperature to give targeted compositions in the series H(x)Li(1-x)LaTiO(4). Remarkably, the Li(+) and H(+) ions are quantitatively exchanged in the solid state and this allows stoichiometric control of ion exchange for the first time in this important series of compounds.
RESUMEN
Lithium molybdate has been prepared by grinding LiOH x H(2)O with MoO(3) in air at room temperature. X-Ray powder diffraction data show that the formation of highly crystalline Li(2)MoO(4) is largely complete after 10 min. The phenacite structure of this material is the same as that derived from an X-ray diffraction study of a single crystal obtained from aqueous solution [R3; a = 14.3178(14) A, c = 9.5757(9) A]. Anhydrous lithium hydroxide fails to give the same reaction indicating that the water of crystallisation of LiOH x H(2)O is a vital component in this rapid synthesis. Differential scanning calorimetry measurements show that this reaction can proceed spontaneously between the two stable solid reagents at sub-ambient temperatures and is driven by the liberation of water from the crystalline lattice. Lithium molybdate prepared in this manner has significantly smaller and more regularly shaped particles than samples prepared by other synthetic methods.