Table 1 Summary of experimental configurations. Uncertainties are the largest of either the ICP-MS measurement error derived from the standard error of the calibration curve or standard deviation of the replicate samples taken from the experiment.

From: Semiconducting hematite facilitates microbial and abiotic reduction of chromium

Experiment ID

Electron source

Hematite electrode

Initial Cr concentration (µM)

Cr removal Rate (µmol/s)

Average Current (µA)

Fe(II) production rate (µmol/s)

Elapsed time for rate calculation (hrs)

A

Potentiostat

Bulk

N.D

N/A

5.9E-3

2.8E-4

36

B

Potentiostat

Bulk

14.3 ± 0.8

3.6E-5

6.1E-4

7.7E-7

36

C

Potentiostat

Thin section

11.8 ± 2.0

2.5E-5

4.8E-3

7.8E-4

34

D

S. putrefaciens

Bulk

22.5 ± 1.1

4.9E-6

9.3E-6

N/A

313

  1. The average rate of Cr production, average current, and production of Fe(II) are also given here. The time period considered in experiment A is from the experiment start to the point where the maximum Fe(II) is observed. The elapsed experimental time used to calculate these rates is also stated for comparison.
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