Immobilization of Cd and As by Apatite Converted from ...adelaide2019.cleanupconference.com/wp-content/uploads/2019/09/M46f.pdf · Immobilization of Cd and As by Apatite Converted

Immobilization of Cd and As by Apatite Converted from Microbial Induced CaCO3

Shijun Wu, Maolin Wang, Fanrong Chen, Yongqiang Yang

Guangzhou Institute of Geochemistry,

Chinese Academy of Sciences (GIGCAS)

E-mail: [email protected]

[类别名称] [CELLREF]



Contaminated

Background

(National soil pollution survey bulletin of China, 2014)

16.1%

National soil pollution status of China

Heavy metals within inorganic contamination

100%

43.5% 29.8%

16.8% 13.0% 9.9% 9.3% 6.8% 5.6%

As is normally mixed with Cd

H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac

Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Background Microbial Induced Carbonate Precipitation (MICP) and its application

Cation Anion (Advances in Applied Microbiology, 2016)

(Ca,M)CO3

Elements can incorporate into CaCO3

HMs immobilized by MICP

H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac

Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Background

Karst cave

30% of the microbial induced CaCO3 were discoved after 4 months Gat et.al (Chemosphere, 2017)

As Sr

Ba Co

Wunsch et.al (Chemical Geology, 2014)

Release of heavy metals due to the dissolution of CaCO3

Dissolution of CaCO3 and its potential risk

Background

Calcareous soil

~50% phosphate will transform to hydroxyapatite (HAP)

𝐊𝐊𝐬𝐬𝐬𝐬[𝐂𝐂𝐂𝐂𝟏𝟏𝟏𝟏 𝐏𝐏𝐏𝐏𝟒𝟒 𝟔𝟔 𝐏𝐏𝐎𝐎 𝟐𝟐]=1 × 𝟏𝟏𝟏𝟏−𝟓𝟓𝟓𝟓~𝟏𝟏𝟏𝟏−𝟓𝟓𝟓𝟓

𝐊𝐊𝐬𝐬𝐬𝐬 𝐂𝐂𝐂𝐂𝐂𝐂𝐏𝐏𝟑𝟑 = 𝟑𝟑.𝟑𝟑 × 𝟏𝟏𝟏𝟏−𝟗𝟗

Numerous substitution in apatite

Shen et al. (Plant Physiology, 2011)

Rakovan (Reviews in Mineralogy and Geochemistry,2002）

Pan and Fleet (Reviews in Mineralogy and Geochemistry,2002）

Our solution

Cd/As

Microbe

Ca2+ + CO32−

CaCO3

Cd/As PO4

3−

PO43−

Fully convert to apatite

Partially convert to apatite

Cd/As

Cd/As

MICP Conversion

Experiment

Microbe (Bacillus pasteurii)

Ca2+

Urea

NH4H2PO4

HAP

CaCO3

Microbe

Cd/As-CaCO3 CaCO3

MICP

Cd/As

In situ hydrothermal

P P Cd/As

Cd/As-HAP-1 Cd/As-HAP-2

M1-HAP M2-HAP M5-HAP

M4-CaCO3 M3-CaCO3

P

HAP

Cd/As adsorption

Cd/As adsorption

Results: Cd immobilization

Wang et al. (Journal of Hazardous Materials, 2019) XRD patterns of HAP converted from Cd-CaCO3

FTIR of calcite and its converted HAP

12h, 36h, 72h 1μm 0mg/L 1μm 0mg/L 0mg/L 100nm

200nm 0.5mg/L 200nm 5mg/L 200nm 10mg/L

1μm 5mg/L 200nm 200mg/L 200nm 2000mg/L

Convert time

Cd concentration

Cd-CaCO3 to HAP

0.5, 5, 10mg/L

Cd concentration

CaCO3 +Cd to HAP

0.5, 5, 10mg/L

The morphology

of HAP changed

with the Cd

concentration


Wang et al. (Journal of Hazardous Materials, 2019)

More Cd was

immobilized after

the conversion



The residual Cd

after MICP was

immobilized at the

early stage of

conversion


SEM image and the element mapping image of Ca , P and Cd Wang et al. (Journal of Hazardous Materials, 2019)

Cd was enriched in

the near-surface of

the HAP crystal


Cd in calcite/apatite

structure is more stable than

adsorbed Cd.



Release of Cd during the dissolution of calcite and HAP

M4: Cd adsorbed by CaCO3 M5: Cd adsorbed by HAP

M3: Microbial induced Cd-CaCO3 M1: HAP converted from M3 M2: HAP converted from none Cd CaCO3 in Cd solution

The conversion of calcite to

HAP reduced the Cd

release risk up to 88%.

pH2.0 pH7.0 pH10.00

5

10

15

20

80

100

120

140

Rel

ease

d C

d (‰

)

M1 M2 M3 M4 M5

(a)

pH2.0 pH7.0 pH10.00.0

0.2

0.4

0.6

0.8

1.0(b)

Results: As immobilization

How about As？

CaCO3-HAP conversion can remarkable

decline the release risk of Cd .


XRD patterns of HAP converted from As-CaCO3

More As, more HAP HAP favorites As(III) comparing to As(V)

0 500 1000 1500 2000

0

2000

4000

6000

8000

10000

0 500 1000 1500 20001

2

3

4

5

6

7

0 500 1000 1500 20001

2

3

4

5

6

7

0 500 1000 1500 2000

0

500

1000

1500

2000

0 500 1000 1500 2000

1234567

As in

sol

id (m

g/kg

)

As(III) As(V)

(a)

Rem

oval

effi

cien

cy o

f As

(%) (b)

Res

idua

l As

conc

entra

tion

(mg/

L)

(c)

Kd

Initial aqueous As concentration (mg/L)

(d)


As(III)

0 500 1000 1500 2000

0

5000

10000

15000

20000

25000

30000

0 500 1000 1500 2000

2

4

6

8

10

12

14

0 500 1000 1500 2000

0

500

1000

1500

2000

0 500 1000 1500 200002468

10121416

As in

sol

id (m

g/kg

) As-calcite HAP-1 HAP-2

(a)

Rem

oval

effi

cien

cy o

f As

(%)

(b)

Res

idua

l As

conc

entra

tion

(mg/

L)

(c)

Kd

Initial aqueous As(III) concentration (mg/L)

(d)

As(III) released into

the solution during

the conversion of

CaCO3 to HAP.

As-calcite: Microbe induced CaCO3

(calcite) with As(III) HAP-1: HAP converted from As-calcite HAP-2: HAP converted from none As CaCO3 in As(III) solution


As(V) As(V) released into

the solution during

the conversion of

CaCO3 to HAP.

As-vaterite: Microbe induced CaCO3

with As(V)

HAP-3: HAP converted from As-calcite

HAP-4: HAP converted from none As

CaCO3 in As(V) solution

0 500 1000 1500 2000

0

10000

20000

30000

40000

50000

60000

0 500 1000 1500 2000

0

5

10

15

20

25

0 500 1000 1500 2000

0

500

1000

1500

2000

0 500 1000 1500 2000

-10

0

10

20

30

40

50

As in

sol

id (m

g/kg

) As-vaterite HAP-3 HAP-4

(a)

Rem

oval

effi

cien

cy o

f As

(%) (b)

Res

idua

l As

conc

entra

tion

(mg/

L)

(c)

Kd

Initial aqueous As(V) concentration (mg/L)

(d)

Results: As immobilization 12h 36h 96h

Release of As(V)

Growing of HAP

Incorporation of Na

As(III)


As(III) As(V) As in calcite/apatite

structure is more stable than

adsorbed As.

As in apatite structure is

more stable than in calcite.

pH2.0 pH7.0 pH10.00

10

20

30

40

50

60

70R

elea

sed

As

(%)

A1 A2 A3 A4 A5

(a)

pH2.0 pH7.0 pH10.00

10

20

30

40

50

Rel

ease

d A

s (%

)

A6 A7 A8 A9 A10

(b)

Summary

Cd/As

Microbe

Ca2+ + CO32−

CaCO3

Cd/As PO4

3−

PO43−

Fully convert to apatite

Partially convert to apatite

As

Cd

Conversion MICP Soil remediation experiments are under going……

Thank you for your attention!

Shijun Wu

E-mail: [email protected]

Documents

Immobilization of Cd and As by Apatite Converted from ...adelaide2019.cleanupconference.com/wp-content/uploads/2019/09/M46f.pdf · Immobilization of Cd and As by Apatite Converted