EAGER: Nanoparticle Enhanced Near-IR Photobacterial Conversion of Organic Waste to Hydrogen

Grants and Contracts Details

Description

Nanoparticles are extensively used for environmentally important reactions (degradation of pollutants to light activated photolytic reactions with TiO2), and as additives in various formulations. But the combined advantages of nanoparticles which can produce resonant wavelength (near IR) at higher intensity to activate phototrophic bacteria for conversion of waste to high value hydrogen fuel will bring transformative approaches in science and technologies. Another advantage of hydrogen compared to conventional methane fuel approaches is to directly generate electricity by fuel cells. Short-chain fatty acids, such as, acetic, butyric, propionic, etc. are easily produced by fermentation/anaerobic digestion of organic wastes. Although conversion of these acids to hydrogen by phototrophic bacteria (such as, Rhodopseudomonas palustris species designated as purple non-sulfur bacteria (PNS)) has been extensively reported in the literature [1-3], but the H2 production rate and the light conversion efficiency (LCE) have been hampered because of the use of broad wavelength (such as, tungsten lamp) and improper bacteria immobilization approaches. For example, theoretically 1 mole of acetic acid produces 4 moles of hydrogen and 2 moles of CO2. Figure 1 shows some of these literature results and indicates the low efficiency aspects and variability. Thus, there is clearly a need for a high-risk/high-reward approach to dramatically increase light-conversion efficiency while maintaining high substrate-conversion efficiency with the goal of combined waste remediation and renewable energy generation. Our innovative approach using silica-gold core-shell nanoparticles (40-50 nm size with 2-3 nm gold coating) immobilized on a polymer membrane surface will allow us to enhance the intensity of resonant near-IR wavelength. Other nanoparticles like copper can be employed. Literature report has indicated the optimum wavelength for these bacterial Fig.1 Compiled literature data on variable light sources using organic acid conversion to hydrogen by R. palustris bacteria. Fig. 2 Overall proposed research on nanoparticle enhanced conversion of waste acids to hydrogen gas by phototropic bacteria using near-IR wavelength. species to be near IR area (about 850 nm). Our work will establish that if we immobilize the bacteria on top of the nanoparticles through a thin (10-50 nm) dielectric polymer layer in between, it will highly enhance the hydrogen yield/production rate and provide high light efficiency (Figure 2).
StatusFinished
Effective start/end date2/1/171/31/19

Funding

  • National Science Foundation: $100,000.00

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