Investigation of the Photochemical Reactivity of Soot Particles Derived from Biofuels Toward NO2. A Kinetic and Product Study

In the current study, the heterogeneous reaction of NO2 with soot and biosoot surfaces was investigated in the dark and under illumination relevant to atmospheric conditions (J NO2 = 0.012 s–1). A flat-flame burner was used for preparation and collection of soot samples from premixed flames of liquid fuels. The biofuels were prepared by mixing 20% v/v of (i) 1-butanol (CH3(CH2)3OH), (ii) methyl octanoate (CH3(CH2)6COOCH3), (iii) anhydrous diethyl carbonate (C2H5O)2CO and (iv) 2,5 dimethyl furan (CH3)2C4H2O additive compounds in conventional kerosene fuel (JetA-1). Experiments were performed at 293 K using a low-pressure flow tube reactor (P = 9 Torr) coupled to a quadrupole mass spectrometer. The initial and steady-state uptake coefficients, γ0 and γss, respectively, as well as the surface coverage, N s, were measured under dry and humid conditions. Furthermore, the branching ratios of the gas-phase products NO (∼80–100%) and HONO (