(337h) Electrochemical Routes to Intensify the Processing of Biomass

The least expensive, renewable resources are those that are currently disposed as waste. Examples include sludges, manures and other agricultural wastes. Although the total amount of such material can be large, it is geographically dispersed and available at each location in relatively small rates, on the order of 10 ton/day. The dispersion of these feedstocks combined with the high cost of transport, necessitates smaller scale technology than is typically used in centralized chemical plants or refineries. Intensified processes that operate at ambient pressure and temperature could reduce the capital costs and thereby facilitate small scale, distributed operations to transform waste resources to fuels.

Electrochemically activated processes offer all of those attributes. Here we will report our development of electrochemical processes to address three aspects of the overall conversion: upgrading of depolymerized wastes, separation of ionic species, and remediation of process water. We have focused on complementing hydrothermal liquefaction with downstream electrochemical processes. For upgrading, we have shown that reduction of at least some of the oxygen-containing functionalities present in whole bio-oil are effected electrochemically. For separation of ionic species, we are considering capacitive deionization¹ but have been initially foiled by the complexation of metal cations by negatively charged chelating complexes. For water remediation, we are testing electrochemical oxidation, which has been deployed for ameliorating water from dyeing and tanning processes.²

References

(1) AlMarzooqi, F. A.; Al Ghaferi, A. A.; Saadat, I.; Hilal, N. Desalination, Application of Capacitive Deionisation in water desalination: A review, 2014, 342, 3-15, 10.1016/j.desal.2014.02.031.

(2) Panizza, M.; Cerisola, G. Environ Sci Technol, Electrochemical Oxidation as a Final Treatment of Synthetic Tannery Wastewater,2004, 38, 5470-5475.