2.2. Experimental procedure and set-up
The wastewater was treated by different electrochemical methods,
and the scheme of the electrochemical apparatus is shown in Fig. 1. All experimental studies were accomplished at ambient temperature with 300 mL of wastewater,
porous graphite plates (60 mm × 110 mm × 2 mm) were employed as anode and cathode,
which were positioned vertically and parallel to each other.
The direct current voltage was supplied by a DC power source (Type 3240.2, Statron,Germany),
and sodium sulfate (Na2SO4) had been selected as electrolyte,
Fe particles or/and air were also introduced into the direct electrochemical process (EC), respectively.
The different electrochemical methods and conditions are shown in Table 2,
and concentrated H2SO4 solution was used to adjust the pH of wastewater to about 3 in the last electrochemical process, which is the optimum pH of the Fenton process according to the literature [16,18].
During the experiment, aliquots of the processed solution were periodically extracted from the reaction system by airtight
syringes,
filtered and analyzed in time since the current occurred.
All of the chemical reagents used in this work were of analytical grade without further purification.
Fe particles and H2SO4 were obtained from Xi'an