Matching Items (3)
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- All Subjects: Salicornia
- Creators: Deng, Shuguang
- Creators: Murty, Rohan Aditya
Description
Layered double hydroxides (LDHs), also known as hydrotalcite-like materials, are extensively used as precursors for the preparation of (photo-)catalysts, electrodes, magnetic materials, sorbents, etc. The synthesis typically involves the transformation to the corresponding mixed metal oxide via calcination, resulting in atomically dispersed mixed metal oxides (MMOs). This process alters the porosity of the materials, with crucial implications for the performance in many applications. Yet, the mechanisms of pore formation and collapse are poorly understood. Combining an integrated in situ and ex situ characterization approach, here we follow the evolution of porosity changes during the thermal decomposition of LDHs integrating different divalent (Mg, Ni) and trivalent (Al, Ga) metals. Variations in porous properties determined by high-resolution argon sorption are linked to the morphological and compositional changes in the samples by in situ transmission electron microscopy coupled with energy dispersive X-ray spectroscopy, which is facilitated by the synthesis of well crystallized LDHs of large crystal size. The observations are correlated with the phase changes identified by X-ray diffraction, the mass losses evidenced by thermogravimetric analysis, the structural changes determined by infrared and nuclear magnetic resonance spectroscopy, and the pore connectivity analyzed by positron annihilation spectroscopy. The findings show that the multimetallic nature of the LDH governs the size and distribution (geometry, location, and connectivity) of the mesopores developed, which is controlled by the crystallization of the MMO phase, providing key insights for the improved design of porous mixed metal oxides.
ContributorsMurty, Rohan Aditya (Author) / Deng, Shuguang (Thesis director) / Nielsen, David R. (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Fossil fuels have been the primary source of energy in the world for many decades. However, they are among the top contributors of the greenhouse gas emissions in the atmosphere. The objective of this research was to produce a more environmentally friendly biofuel from Algae-Helix and Salicornia biomasses. Experiments were conducted using a hydrothermal liquefaction (HTL) technique in the HTL reactor to produce biofuel that can potentially replace fossil fuel usage. Hydrothermal Liquefaction is a method used to convert the biomass into the biofuels. HTL experiments on Algae-Helix and Salicornia at 200°C-350°C and 430psi were performed to investigate the effect of temperature on the biocrude yield of the respective biomass used. The effect of the biomass mixture (co-liquefaction) of Salicornia and algae on the amount of biocrude produced was also explored. The biocrude and biochar (by-product) obtained from the hydrothermal liquefaction process were also analyzed using thermogravimetric analyzer (TGA). The maximum biocrude yield for the algae-helix biomass and for the Salicornia biomass were both obtained at 300°C which were 34.63% and 7.65% respectively. The co-liquefaction of the two biomasses by 50:50 provided a maximum yield of 17.26% at 250°C. The co-liquefaction of different ratios explored at 250°C and 300°C concluded that Salicornia to algae-helix ratio of 20:80 produced the highest yields of 22.70% and 31.97%. These results showed that co-liquefaction of biomass if paired well with the optimizing temperature can produce a high biocrude yield. The TGA profiles investigated have shown that salicornia has higher levels of ash content in comparison with the algae-helix. It was then recommended that for a mixture of algae and Salicornia, large-scale biofuel production should be conducted at 250℃ in a 20:80 salicornia to algae biocrude ratio, since it lowers energy needs. The high biochar content left can be recycled to optimize biomass, and prevent wastage.
ContributorsLaideson, Maymary Everrest (Co-author) / Luboowa, Kato (Co-author) / Deng, Shuguang (Thesis director) / Nielsen, David (Committee member) / Chemical Engineering Program (Contributor) / Economics Program in CLAS (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Fossil fuels have been the primary source of energy in the world for many decades. However, they are among the top contributors of the greenhouse gas emissions in the atmosphere. The objective of this research was to produce a more environmentally friendly biofuel from Algae-Helix and Salicornia biomasses. Experiments were conducted using a hydrothermal liquefaction (HTL) technique in the HTL reactor to produce biofuel that can potentially replace fossil fuel usage. Hydrothermal Liquefaction is a method used to convert the biomass into the biofuels. HTL experiments on Algae-Helix and Salicornia at 200°C-350°C and 430psi were performed to investigate the effect of temperature on the biocrude yield of the respective biomass used. The effect of the biomass mixture (co-liquefaction) of Salicornia and algae on the amount of biocrude produced was also explored. The biocrude and biochar (by-product) obtained from the hydrothermal liquefaction process were also analyzed using thermogravimetric analyzer (TGA). The maximum biocrude yield for the algae-helix biomass and for the Salicornia biomass were both obtained at 300°C which were 34.63% and 7.65% respectively. The co-liquefaction of the two biomasses by 50:50 provided a maximum yield of 17.26% at 250°C. The co-liquefaction of different ratios explored at 250°C and 300°C concluded that Salicornia to algae-helix ratio of 20:80 produced the highest yields of 22.70% and 31.97%. These results showed that co-liquefaction of biomass if paired well with the optimizing temperature can produce a high biocrude yield. The TGA profiles investigated have shown that salicornia has higher levels of ash content in comparison with the algae-helix. It was then recommended that for a mixture of algae and Salicornia, large-scale biofuel production should be conducted at 250℃ in a 20:80 salicornia to algae biocrude ratio, since it lowers energy needs. The high biochar content left can be recycled to optimize biomass, and prevent wastage.
ContributorsLuboowa, Kato Muhammed (Co-author) / Laideson, Maymary (Co-author) / Deng, Shuguang (Thesis director) / Nielsen, David (Committee member) / Chemical Engineering Program (Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05