All the laboratory scale studies were performed using a batch unstirred ohmic heater (Fig. 1). The ohmic heater was attached to the experimental setup as shown in Fig. 2, and was powered by a low-frequency (60 Hz) sinusoidal alternating current. An external cooling system was operated by a Haake F3 Fisons thermostatic water bath having an inflow and outflow attached to the ohmic heater. The cooling was required to perform the experiments at relatively low temperatures and currents to avoid potential explosion hazards due to excessive hydrogen accumulation (in the headspace) and possible arc formation.