effects of ph value, chloride and sulfate concentrations ... · effects of ph value, chloride and...

©CSIRO 2016 ©CSIRO 2015 Environ. Chem. 2016, 13, 602–610 doi:10.1071/EN15156_AC

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Supplementary material

Effects of pH value, chloride and sulfate concentrations on galvanic corrosion between

lead and copper in drinking water

Ding-Quan NgA and Yi-Pin Lin

B,C

ADepartment of Civil and Environmental Engineering, Faculty of Engineering, National University of

Singapore, 117576, Singapore.

BGraduate Institute of Environmental Engineering, National Taiwan University, Number 1, Section 4,

Roosevelt Road, Taipei 10617, Taiwan.

CCorresponding author. Email: [email protected]

Table S1. SEM-EDX results of scales collected after 7 days in completely mixed conditions at

pH 7.0

Conditions 250 mg L–1 Cl– 250 mg L–1 SO42– 250 mg L–1 Cl–

and 250 mg L–1 SO42–

Element Weight % Atomic % Weight % Atomic % Weight % Atomic % C 13.83 49.35 21.87 52.53 18.57 55.60 O 12.61 33.75 21.27 38.35 13.91 31.22 S 0.01 0.01 0.73 0.66 0.16 0.18 Cl 1.09 1.32 0.59 0.48 1.56 1.58 Cu 1.25 0.85 0.57 0.26 0.01 0.01 Pb 71.20 14.72 54.7 7.62 65.79 11.42

©CSIRO 2016 ©CSIRO 2015 Environ. Chem. 2016 doi:10.1071/EN15156_AC

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Fig. S1. Photographs of experimental setup. Lead wire tied round copper wire (left) and the wires are

suspended in plastic bottle with a polyester thread (right).

Fig. S2. Total copper as a function of time at different pH values under completely mixed conditions (M).

Error bars represent standard deviation.

0

50

100

150

200

250

300

350

0 20 40 60 80 100 120 140 160 180

Tota

l Cu

(µ

g L-1

)

Time (h)

pH 6 - separate (M) pH 6 (M)

pH 7 - separate (M) pH 7 (M)

pH 7.8 - separate (M) pH 7.8 (M)


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Fig. S3. Total lead as a function of time at pH 6.0. S, stagnant; M, completely mixed.

Fig. S4. Solution pH as a function of time at different solution pH. S, stagnant; M, completely mixed.

0

2000

4000

6000

8000

10000

12000

0 20 40 60 80 100 120 140 160 180

Tota

l Pb

(µ

g L-1

)

Time (h)

pH 6 (M)

pH 6 (S)

pH 6 - separate (M)

pH 6 - separate (S)

5

6

7

8

9

10

0 20 40 60 80 100 120 140 160 180

pH

Time (h)

pH 6 (S) pH 7 (S) pH 7.8 (S)

pH 6 (M) pH 7 (M) pH 7.8 (M)

©CSIRO 2016 Environ. Chem. 2016 doi:10.1071/EN15156_AC

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Fig. S5. Summary of total lead release under (a) stagnant and (b) completely mixed conditions after 7 days.


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Fig. S6. Soluble lead under (a) stagnant and (b) completely mixed conditions as a function of time with

different chloride dosages. TW, tap water (pH = 7.0, 35 mg L–1 Cl– and 18 mg L–1 SO42–).

0

400

800

1200

1600

0 20 40 60 80 100 120 140 160 180

Solu

ble

Pb

(µ

g L-1

)

Time (h)

TW TW + 60 mg L-1 Cl- TW + 95 mg L-1 Cl- TW + 120 mg L-1 Cl- TW + 250 mg L-1 Cl-

0

400

800

1200

1600

2000

0 20 40 60 80 100 120 140 160 180

Solu

ble

Pb

(µ

g L-1

)

Time (h)


(a)

(b)


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Fig. S7. Total copper as a function of time with different chloride dosages under completely mixed conditions.

TW: tap water (pH = 7.0, 35 mg L–1 Cl– and 18 mg L–1 SO42–).

0

20

40

60

80

100

120

0 20 40 60 80 100 120 140 160 180

Tota

l Cu

(µ

g L-1

)

Time (h)



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Fig. S8. Solution pH under (a) stagnant and (b) completely mixed conditions as a function of time with

different chloride dosages. TW, tap water (pH = 7.0, 35 mg L–1 Cl– and 18 mg L–1 SO42–).

6.5

6.6

6.7

6.8

6.9

7.0

7.1

7.2

7.3

7.4

7.5

0 20 40 60 80 100 120 140 160 180

pH

Time (h)


6.5

6.6

6.7

6.8

6.9

7.0

7.1

7.2

7.3

7.4

7.5

0 20 40 60 80 100 120 140 160 180

pH

Time (h)


(a)

(b)


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Fig. S9. Soluble lead under (a) stagnant and (b) completely mixed conditions as a function of time with

different sulfate dosages. TW, tap water (pH = 7.0, 35 mg L–1 Cl– and 18 mg L–1 SO42–).

0

200

400

600

800

1000

1200

1400

0 20 40 60 80 100 120 140 160 180

Solu

ble

Pb

(µ

g L-1

)

Time (h)

TW + 250 mg L-1 SO42-

TW + 120 mg L-1 SO42-

TW + 60 mg L-1 SO42-

TW

0

200

400

600

800

1000

1200

1400

1600

1800

2000

0 20 40 60 80 100 120 140 160 180

Solu

ble

Pb

(µ

g L-1

)

Time (h)

TW + 250 mg L-1 SO42-

TW + 120 mg L-1 SO42-

TW + 60 mg L-1 SO42-

TW

(a)

(b)


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Fig. S10. Solution pH under (a) stagnant and (b) completely mixed conditions as a function of time with

different sulfate dosages. TW, tap water (pH = 7.0, 35 mg L–1 Cl– and 18 mg L–1 SO42–).

6.5

6.6

6.7

6.8

6.9

7.0

7.1

7.2

7.3

7.4

7.5

0 20 40 60 80 100 120 140 160 180

pH

Time (h)

TW TW + 60 mg L-1 SO42- TW + 120 mg L-1 SO42- TW + 250 mg L-1 SO42-

6.5

6.6

6.7

6.8

6.9

7.0

7.1

7.2

7.3

7.4

7.5

0 20 40 60 80 100 120 140 160 180

pH

Time (h)

TW TW + 60 mg L-1 SO42- TW + 120 mg L-1 SO42- TW + 250 mg L-1 SO42-

(a)

(b)


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Fig. S11. Comparison between the effects of chloride and sulfate additions of about 2.65 mM on total lead

concentration under stagnant conditions. Experimental conditions: pH = 7.0.

Fig. S12. Soluble lead as a function of time with different chloride and sulfate additions at a constant CSMR

of 1 in stagnant and completely mixed conditions. TW, tap water (pH = 7.0, 35 mg L–1 Cl– and 18 mg L–1

SO42–); S, stagnant; M, completely mixed.

0

200

400

600

800

1000

1200

1400

1600

0 20 40 60 80 100 120 140 160 180

Tota

l Pb

(µ

g L-1

)

Time (h)

2.63 mM SO42-

2.68 mM Cl-

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

0 20 40 60 80 100 120 140 160 180

Solu

ble

Pb

(µ

g L-1

)

Time (h)

TW + 60 mg L-1 Cl- and SO42- (M) TW + 60 mg L-1 Cl- and SO42- (S)




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Fig. S13. X-Ray diffraction (XRD) patterns of scaling collected after 7 d under completely mixed conditions

at pH 7.0. (a) Chloride dosage of 250 mg L–1, (b) sulfate dosage of 250 mg L–1. Reference standards for

hydrocerussite and cerussite obtained from PDF cards: 00-013-0131 and 00-047-1734 respectively.

effects of ph value, chloride and sulfate concentrations ... · effects of ph value, chloride and...

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