Waste biomass such as paddy stubble comprises of cellulose, hemicellulose and lignin, can produce industry-relevant chemicals and fuels, providing an alternative to fossil fuel feedstocks. [1] We study the conversion of biomass-derived furfural (FF) into the furfuryl alcohol (FA) and hydrofuroin (HF). FA and HF are used in biopolymer generation and pharmaceuticals. [1] The biomass-derived FA and HF can be used as fuel with the ability to replace traditional fuels. [1,2,3] The electrocatalytic hydrogenation (ECH) at the cathode is a promising route for biomass conversion because of the reaction at low temperature and pressure with the in situ availability of Hads at the surface. The water oxidation generates oxygen at the anode that complements the cathode reactions. [4,5] Further, the electricity required for the ECH obtained from renewable resources (solar, wind) makes the process sustainable and futuristic, helping to attain a net-zero carbon target. The commercial production of FA and HF requires deploying an electrochemical flow system to cater to the increasing demand for the product. De et al. [6,7,8] generated hydrogen using an electrochemical flow cell, Shang et al. [3] used a flow electrolysis cell for the HF generation, and Dixit et al. [9] used a flow photoelectrochemical cell for the generation of FA, also suggesting an increase in product formation rate. [10]
Herein, we used an electrochemical flow cell for FF ECH to generate FA and HF, where FA and HF could be recovered by solvent extraction methods. The cathode (geometric area: 5 cm2, thickness: 0.5 mm) was prepared by the electro-deposition of silver on nickel foam (ed-Ag/NF) [1], and anode (geometric area: 5 cm2, thickness: 0.5 mm) was prepared by thermal annealing of graphite felt. The catholyte and anolyte were 0.5 M NaOH with 25 mM FF and 0.5 M NaOH, respectively. The electrolyte flow at cathode and anode was maintained at 5 mL min-1, and the applied potential was 3 V. The current density at the applied potential was 1 A cmgeo-2 resulting in 20% single pass conversion, and ~100 % conversion was obtained after six passes. The formation rate of FA and HF was 300 µmol h-1 and 720 µmol h-1, respectively. The study determines the feasibility of the conversion of biomass-derived compounds and paves a way towards sustainable bio-electro-refineries.
Keywords: Bio-oil, hydrofuorin, electro conversion, jet-fuel, furfural
References
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