3.2 The Distribution of Electrical Conductivity
Electrical Conductivity (EC) is a relevant parameter concerned about the salt accumulation in soil specimen (Bessaim et al., 2019). The distribution of EC across the soil column after the V-EK treatment is illustrated in Fig.3. For the control column that without EK treatment (voltage = 0 V), the soil in surface layer (> -15cm) has the highest EC value at 1721 μS/cm due to the salt rises from the bottom, and the EC values of salty soil under the surface were in the range of 581-1127 μS/cm. With V-EK treatment, the lower values of EC were observed in the soil within 50 cm below the surface with the voltage at 10 V and 20 V, reached to a value of 67-230 μs/cm, which was much lower than the minimum value (581 μs/cm) in control column. Besides, the other lower values of EC were found between EA and EB (electrodes located at the -80cm and -60cm respectively) with range of 93-134 μs/cm, and this is attributed to the transport and movement of ionic compounds toward the electrode of opposite charges by EK processes under the applied electrical filed (Jayasekera & Hall, 2007; Cho et al. 2010; Zhu et al. 2016). Thus, the higher EC values were appeared near EAand EB. And another reason for this was the generation of ions by electrolytic around EA and EB. It can see from the pH changes of around EA and EB (Fig. S3). Additionally, EC value around EA is higher than EB due to the production of H+ at anode, which is very conductive and migrate 1.8 times faster than OH-(Bessaim et al., 2019b). The conclusion is that ions were mitigated effectively under V-EK treatment, especially at the voltage of 10V and 20V.