Fabrication of Chitosan Porous Structure and Applications on Artificial Photosynthesis Device

2013 ◽  
Author(s):  
Xiang Ren ◽  
Miao Yu ◽  
Xiaohang Zhou ◽  
Qingwei Zhang ◽  
Jack Zhou
Keyword(s):  
Image Processing ◽  
Porous Structure ◽  
Artificial Photosynthesis ◽  
Acrylonitrile Butadiene Styrene ◽  
Reaction Rates ◽  
Co2 Absorption ◽  
Porous Structures ◽  
Energy Product ◽  
Fluidic Devices ◽  
Butadiene Styrene

Research and development on artificial photosynthesis provide a new direction to obtain sustainable energy. To increase the artificial photosynthesis reaction rates and the efficiency of collecting the energy product, a novel artificial photosynthesis device was designed and developed to constrain the photosynthesis reactions in chitosan porous structure. Both 3D printing and molding-casting could be used in fabrication of chitosan structure on artificial photosynthesis devices. In molding and casting, the molds were made by acrylonitrile butadiene styrene (ABS) and polydimethylsiloxane (PDMS). Concurrently, 3D interconnected chitosan channels were built with a user-made heterogeneous 3D rapid prototyping machine, and the lyophilization method was used to generate the micro or nano pores inside the chitosan scaffold. After lyophilization, the pore size and porosity was generated by MATLAB image processing. CO2 absorption was simulated based on porous structures properties when import the chitosan into the artificial photosynthesis devices. The results suggested that chitosan porous structure is a good candidate to be an interface between atmosphere and micro-fluidic devices with biochemical reactions.

scholarly journals Non-uniform porous structures and cycling control for optimized fixed-bed solar thermochemical water splitting

2021 ◽  
pp. 1-24
Author(s):  
Xiaoyu Dai ◽  
Sophia Haussener
Keyword(s):  
Porous Structure ◽  
Gas Flow ◽  
Fixed Bed ◽  
Reaction Rates ◽  
Operating Conditions ◽  
Cycle Duration ◽  
Porous Structures ◽  
Fuel Production ◽  
Single Cycle ◽  
Solar Thermochemical

Abstract Solar thermochemical redox cycles provide a sustainable pathway for solar fuel processing. If done in porous (ceria) structures, they can profit from faster reaction rates owned to the enhanced heat and mass transport characteristics. However, the exact porous structure and operating conditions significantly affect the performance. We present a transient volume-averaged fixed-bed model of a thermochemical redox reactor utilizing macroporous ceria. We studied the porosity-dependent (ε=0.4-0.9) and operating condition-dependent (solar concentration ratio, ratio of oxygen partial pressure to total pressure, gas flow rate) performance of the fixed-bed ceria redox cycle. Structures with large porosity (ε=0.9) showed better performance than low-porosity structures, owning to the enhanced heat absorption and resulting higher temperatures. We show that the cycle duration requires optimization according to the porosity of the structure. Two hours of operation for a structure with ε=0.75 resulted in the largest hydrogen production (115.78) if the single cycle duration was 240 s (i.e. 30 cycles in 2 hours), while nearly five times less was produced for a 15 times longer single cycle duration (i.e. 2 cycles in 2 hours). We subsequently introduced porous structures with different types of non-uniform porosity distributions. For an average porosity of ε=0.75, the most favorable non-uniform porosity media exhibited higher porosity at the boundaries and a denser core. The fuel production of the best non-uniform porous structure was six times larger compared to a uniform porous structure. Adjusting on top of this the cycling conditions, a 14.6 times production gain was achieved. This work suggests that under non-isothermal operation condition for macroporous ceria redox fixed-bed cycling, non-uniform porous structure with higher porosity boundaries and a dense core benefit fuel production and porosity-dependent cycle duration modulation can be used to increase performance.

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