Ammonium Removal and Electricity Generation by Using Microbial Desalination Cells
Voltage - time curve
35
Voltage (mV)
30
Voltage (mV)
25
20
15 0
10
20
30
40
50
60
70
80
90
Time (h)
Figure 40. Voltage generated by using KMnO4 as catholyte The internal resistance at peak performance in scenario 10 can hardly be measured because the maximum voltage appeared immediately when the catholyte injected and decreased continuously. Instead, internal resistance has been tested at medium efficiency. The MDC showed a maximum power density of 7.65 mW/m2 at ~23000 ohm under medium efficiency condition (21 mV under 440 ohm at that time) and 1.17 mW/m2 at ~6000 ohm under low efficiency (Table 34 and Table 35). The maximum power production was 0.00827 mW at current of 0.0190 mA, where the voltage was 436 mV correspondingly (Figure 41). 0.009
Power (mW)
800
0.008
Voltage (mV)
700 600
0.006
500
0.005
400
0.004
300
0.003 0.002
200
0.001
100
Voltage (mV)
Power (mW)
0.007
0 0 0.000 0.050 0.050 0.042 0.037 0.031 0.019 0.001 Current (mA)
Figure 41. Voltage and power generated as a function of current in Scenario 10 37