Figure 1.
Dependence of acidity, alkalinity, and current efficiency on electrolysis time of sodium sulfate (324 mg-eq/dm3) and sulfuric acid (625 mg-eq/dm3) solutions in a three-chamber electrolyzer (cation membrane MC-40; anion membrane MA-41) at a current density of 6.62 A/dm2 (ACEmid = 57.9%; ALEmid = 18.2%)
Figure 2.
Dependence of acidity, alkalinity, and current efficiency on time of electrolysis of sodium sulfate (324 mg-eq/dm3) and sulfuric acid (590 mg-eq/dm3) solution in a three-chamber electrolyzer (cationic membrane MC-40; anionic membrane MA-41) at a current density of 3.97 A/dm2 (ACEmid=55.2%; ALEmid=17.3%)%)
Figure 3.
Dependence of acidity, alkalinity, and current efficiency on time of electrolysis of sodium sulfate (324 mg-eq/dm3) and sulfuric acid (590 mg-eq/dm3) solutions in a two-chamber electrolyzer (cationic membrane MC-40) at a current density of 3.97 A/dm2 (ACEmid = 13.0%; ALEmid = 13.4%)
Table 1.
Dependence of acidity (alkalinity) of anodic, cathodic, and working solutions on the time of electrolysis of sodium sulfate solution (C=32 g/dm3), current density, and type of electrolyzer
| Electrolysis time, t, hours | Number of chambers | I, A/dm2 | Membrane | Cathode zone | Anode zone | Working zone, concentration (C), mg-eq/dm3 | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cationic | Anionic | Acidity, mg-eq/dm3 | B, % | Alkalinity, mg-eq/dm3 | B, % | |||||||
| I | II | I | II | I | II | |||||||
| 3.5 | 3 | 3.97 | MC-40 | MA-41 | 1 | 437 | 55.6 | 1 | 426 | 54.2 | - | 4 |
| 4.0 | 3 | 3.97 | 437 | 828 | 43.6 | 426 | 715 | 32.4 | 4 | 0 | ||
| 3.5 | 3 | 3.97 | 828 | 1096 | 34.2 | 715 | 987 | 34.7 | 0 | 2 | ||
| 4.5 | 3 | 3.97 | 1096 | 1448 | 34.9 | 987 | 1301 | 31.2 | 2 | 0 | ||
| 4.0 | 3 | 3.97 | 1448 | 1751 | 33.8 | 1301 | 1571 | 30.1 | 0 | 6 | ||
| 5.0* | 3 | 6.62 | 9 | 1012 | 53.6 | 1 | 824 | 44.1 | 0 | 586 | ||
| 6.0 | 2 | 3.97 | - | 9 | 346 | 25.7 | 1 | 468 | 34.7 | - | - | |
| 7.0 | 2 | 3.97 | MC-40 | - | 9 | 400 | 24.9 | 1 | 446 | 28.4 | - | - |
Figure 4.
Dependence of acidity, alkalinity, and acid current efficiency on the electrolysis time of sodium sulfate (408 mg-eq/dm3), magnesium sulfate (667 mg-eq/dm3), and sodium sulfate (363 mg-eq/dm3) solutions in a two-compartment electrolyzer (MA-41 membrane) at a current density of 3.97 A/dm2 (ACEmid = 39.0%)
Figure 5.
Dependence of acidity, alkalinity, and acid current efficiency during electrolysis in a three-chamber electrolyzer (cationic membrane MC-40, anionic membrane MA-41) and a two-chamber electrolyzer (anionic membrane MA-41) at a current density of 3.97 A/dm3 of sodium sulfate solution (450 mg-eq/dm3) and alkali (53 mg-eq/dm3) (ACEmid(6)=50.2%; ALEmid(7)=47.81%; ACEmid(8)=33.4%; ALEmid(9)=27.3%)
Figure 6.
Dependence of sulfate concentration, chloride concentration, acidity, alkalinity, and free chlorine content (mCl2) on time of electrolysis of sodium sulfate solution (C=250 mg-eq/dm3), sodium chloride solution (C=517 mg-eq/dm3), and sodium hydroxide solution (C=86 mg-eq/dm3) in a three-chamber electrolyzer (cationic membrane MC-40, anionic membrane MA-41) at a current density of 3.97 A/dm2 (BmidS042−=22.6%; BmidCl−c=1.6%; BmidCl2c=52.4%; ACEmid=24.1%; ALEmid=59.2%)
Figure 7.
Dependency of sulfate concentration, chloride concentration, acidity, alkalinity, and amount of free chlorine (mCl2) on electrolysis time of sodium sulfate solution (C=300 mg-eq/dm3) and sodium chloride solution (C=250 mg-eq/dm3) in a three-chamber electrolyzer (cationic membrane MC-40, anionic membrane MA-41) at a current density of 3.97 A/dm2 (BmidS042−=22.3%; BmidCl−c=1.5%; BmidCl2c = 20.0%; ACEmid=25.0%; ALEmid=37.9%)
Figure 8.
Dependency of sulfate concentration, chloride concentration, acidity, alkalinity, and amount of free chlorine (mCl2) on electrolysis time of sodium chloride solution (276 mg-eq/dm3) and sodium sulfate solution (250 mg-eq/dm3) in a two-chamber electrolyzer (anionic membrane MA-41) at a current density of 3.97 A/dm2 (BmidS042−=11.3%; BmidCl−c=0.3%; BmidCl2c =13.0%; ACEmid=11.7%; ALEmid=16.9%)