Atmospheric pressure non-thermal dielectric barrier discharge (DBD) plasma generated by helium gas at high voltage and input power of about 50 W was first applied to detoxification of Jatropha curcas phorbol esters (J. PEs) as well as standard phorbol ester (4β-12-O-tetradecanoyl phorbol-13-acetate, TPA) in water and methanol. Plasma irradiation on the solution sample was conducted for 15 min. In aqueous solution, only 16% of TPA was degraded and complete degradation of J. PEs was observed. On the contrary, complete degradation of both TPA and J. PEs in methanol was achieved by the same plasma irradiation condition. Hydroxyl radical (•OH) generated by plasma irradiation of the solution is expected as the main radical inducing the degradation of PEs.

The costs associated with the production of biodiesel fuel (BDF) are directly affected by the nature of the feedstock material and the methods used during the production process. In Southeast Asia, many non-edible oils are used to produce BDFs, as exemplified by the recent use of the non-edible oil derived from Vernicia montana Lour. in Laos and Vietnam for the production of BDF. In this work, we developed an improved procedure for the production of BDF from Vernicia montana oil consisting of 80.3%±0.5% α-eleostearic acid moiety (C18:3) using a co-solvent method. Furthermore, the stability of the BDF was evaluated based on its iodine value and unsaturated ester content. The optimized production conditions were determined to be as follows: methanol/oil molar ratio of 6:1, 1% (wt/wt) KOH, 20% (wt/wt) acetone as a co-solvent, and a reaction temperature of 40°C. Under these conditions, we achieved a BDF conversion efficiency of 99%±0.3% within 30 min of initiating the transesterification process. Notably, the BDF produced from Vernicia montana oil showed good stability to air at temperatures ≤30°C for 1 month, showing similar stability properties to the BDF produced from rapeseed oil.