Abstract:

Growth behavior and desulfurization ratio of Rhodococcus Erythropolis NCC-1 with the presence of direct currents(DC) were studied. The electric field-activated mechanism was also investigated. The results show that direct current can improve the desulfurization ratio of NCC-1 within an appropriate scope of current density. The optimized current density is 0.72 A/m². Using 0.2 mmol/L dibenzothiophene(DBT) as a probe, the complete removal time of DBT by NCC-1 could be shortened on platinum electrodes, e.g. 24 h less than that without the presence of direct electric fieldor 48 h less than that using titanium electrodes under a current density of 0.72 A/m2. The desulfurization ratio can reach 67.4％ at platinum electrodes under optimized direct current density in a mixture of water to diesel fuel with a ratio of 1∶9. This value is 11.7% and 24.6% higher than those achieved on titanium electrode and in a system without the presence of direct electric field, respectively. This could be ascribed to the different ratio of adsorbed hydrogen to released H2 produced from water on the cathode. The released H2 could significantly promote the shaking culture of the bacterium.

Key words: Rhodococcus Erythropolis NCC-1, direct electric field, adsorbed hydrogen, hydrogen