Kinetics of sodium borohydride hydrolysis in aqueous-basic solutions

Retnamma, Rajasree; Rangel, C. M.; Novais, Augusto Q.; Matthews, Michael A.

http://hdl.handle.net/10400.9/2001

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Abstract(s)

Liquid-phase catalytic hydrolysis of sodium borohydride (NaBH4) for hydrogen production necessitates long-term stability of base-stabilized NaBH4 solutions at higher temperatures. The present paper reports the kinetics of aqueous-basic solutions containing 20 wt% NaBH4 with 1-15 wt% sodium hydroxide (NaOH) at 80 0C. The established kinetic model employs a modified isoconversional method assuming single-step kinetics. The estimation of kinetic parameters is performed by gPROMS (general PRocess Modeling System) parameter estimation tool. The reaction kinetics differs from low to highly-concentrated NaOH solutions. In highly-basic (.10 wt% NaOH), aqueous solutions of NaBH4, the rate is independent of NaOH concentration, while for lower-basic (< 10 wt% NaOH) solutions, the dependence is -0.57, confirming the inhibition of hydrolysis kinetics by NaOH.

Keywords

Sodium Borohydride Hydrogen production Isoconversional method Gproms Kinetics

URI

http://hdl.handle.net/10400.9/2001

Citation

Retnamma, R.; Rangel, C.M.; Novais, A.Q.; Matthews, M.A. Kinetics of sodium borohydride hydrolysis in aqueous-basic solutions. In: HYCELTEC'2013 - IV Iberian Symposium on Hydrogen, Fuel Cells and Advanced Batteries, Book of Abstracts, Estoril, 26-28 June, 2013