(3gp) Advanced Carbon Modification Technologies for Sustainability in Energy and Environmental Applications

• Bioenergy and Biofuels (Biodiesel and Biochar)
• Activation of Carbonaceous Graphitic Structures (Plasma and Ultrasound)
• Wastewater Treatment
• Sono-Physics - Plasma Chemistry
• Computational Fluid Dynamic (CFD) simulation
• Techno Economic Analysis (TEA)

Teaching Interests: All Chemical Engineering Courses

Abstract

By 2050, the world’s population will be 1.3 times the current population and the world energy consumption will grow by nearly 50% (the U.S. EIA). The sustainable food / energy / water (FEW) nexus is arguably the leading grand challenge facing mankind. Our critical reviews of physical modifications (Reviews in Chemical Engineering, 2019, 35(6)) and chemical modifications (Reviews in Chemical Engineering, 2019, 35(7)) of biochar, in addition to our experimental results, suggest that ultrasound, photochemical and plasma treatments, in selected reaction environments and conditions, are capable of inducing either structural or functional group changes on carbonaceous materials. These tunable, low energy material treatments have potential to play a major role in FEW systems through a number of transformative tracks.

Our transdisciplinary team revealed that single-staged ultrasound and photochemical treatments of carbonaceous structures (e.g., biochar, or BC) in H₂O with dissolved CO₂ results in reductive fixation of C from CO₂ and H from water on biochar, exfoliation of BC’s graphitic structure, mineral leaching (including minerals detrimental to gasification), increase in biochar's heating value and, significant increase in BC’s internal surface area and porosity. These synergisms are tunable by feedstock, reactants stoichiometry and reaction conditions in pyrolysis, and treatments. Carbon and hydrogen fixations seem to be connected to the formation of H₂, CO, formic acid, formaldehyde, and associated radicals during sonolysis of aqueous CO₂. Similar to ultrasound waves, non-thermal plasma can split water vapor and CO₂ to excited chemicals and fuels including methanol, H₂ and CO (Current Opinion in Green & Sustainable Chemistry, 2017. 3:45-49). The presence of carbon in these plasma systems has not been explored. However, our results demonstrate that treatment of biochar in non-thermal chlorine plasma yields a high adsorption capacity of elemental mercury in flue gas due to the creation of Cl-active sites.

It is worth noting that conventional carbon activation requires heating the carbon at a temperature greater than 700ºC for over 3 hours; consuming 18,600 kcal / kg of activated BC produced. However, the developed ultrasound activation method and/or Plasma functionalization are conducted at ambient temperature and pressure for a very short duration (~30-60 sec) which requires about 1,135 kcal / kg of activated BC produced. Moreover, the presence of essential small molecules, such as H₂, CO, formaldehyde, etc., produced during the treatments are likely to have other applications in FEW nexus and climate change mitigation. We have assessed the potential routes of the observed synergisms in mitigation of climate change through CO₂ capture/recycle (Fuel, 2018. 225:287-298), energy production through advanced gasification (Fuel, 2019. 235:1131-1145), Remediation of global water resource (Ultrasonics Sonochemistry, 2019, 51, 20-30,). These treatments can also open new routes for modifying carbon electrodes for water de-ionization, increasing Direct Interspecies Electron Transfer using superconductive carbons for biomethane upgrading in anaerobic digestion, improving soil productivity using biocarbon-biopolymer composites, bio-carbon membranes, biocarbon nano catalysts, which will be the goals of our future works.

Key words: Biochar, Ultrasound, Plasma, Functionalization, Activation, Energy.

* For presentation at the 2020 AIChE Annual Meeting, San Francisco, CA, November 15-20, 2020