Ph.D. in Chemical Engineering Practice
Ph.D. in Chemical Engineering Practice, MIT (2011)
MBA, MIT Sloan School of Management (2011)
M.S. in Chemical Engineering Practice, MIT (2008)
Bachelor of Technology (B. Tech.) in Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India (2006)
Thesis title: Redox-Responsive Polymers for the Reversible Extraction of Butanol from Water
Advisor: Prof. T. Alan Hatton
Sponsored by DuPont-MIT Alliance
Novel, redox-responsive polymers with tunable hydrophobicity were developed. The hydrophobic character of the polymer was cyclically altered by the application of electric potential or chemical redox agents. It was found that when the redox moieties in the polymer were in the reduced state, the polymer was hydrophobic and had a higher affinity for organic compounds like 1-butanol. In the charged state, the redox species made the polymer environment hydrophilic, and the affinity of the polymer for butanol was found to decrease. The difference in selectivity for butanol in the reduced and the oxidized states was used to separate butanol from its aqueous solution. Thermodynamic parameters, like equilibrium distribution coefficients and separation factors, for butanol and water were experimentally measured in the reduced and the oxidized states of the polymer.
Redox polymers were attached to conducting substrates to prepare redox polymer electrodes (RPEs) using techniques like ‘grafting to’ the surface, ‘grafting from’ the surface, initiated chemical vapor deposition, and others. The electrochemical activity of these electrodes and the reversibility of the electrochemical process were established using cyclic voltammetry. Successful proof-of-concept experiments demonstrated the use of these electrodes for reversible extraction of butanol from its aqueous solution when electric potential was used as the stimulus to control the state of the polymer.
Further, the mechanism of electron transport in the polymer coated RPEs was investigated. Diffusion of electrons was found to be the rate-controlling step. It was found that diffusion of electrons due to the ‘hopping’ of electrons from one redox site to the next, and the electronic motion due to the motion of the polymer chains themselves played important roles in determining the apparent diffusivity of electrons.
As part of the PhDCEP Capstone project, the potential of butanol produced through fermentation, commonly known as bio-butanol, was analyzed as a blend for gasoline was analyzed. It was found that although the market for gasoline blend is huge and growing, butanol suffers from higher cost of production with respect to its primary competitor, bio-ethanol. Chances of bio-butanol’s potential success can be enhanced through a combination of technological breakthroughs including development of strains of high yield bacteria, use of inexpensive lignocellulosic biomass, and process design improvements.
Selected Publications and Patent Applications
- Akhoury, A.; Bromberg, L.; Hatton, T. A.; ACS Appl. Mater. Interfaces, 2011, 3(4), 1167-1174
- Akhoury, A.; Bromberg, L., Hatton, T. A.; “Responsive Materials for isolating Organic Compounds”, US Patent Application No. 12/395,004 filed on February 27, 2009