This slide presentation reviews how lunar dust is activated. The presentation includes information on soil chemistry, grinding, and UV exposure

Jeevarajan, Antony S.

Taylor, L. A.

Wallace, W. T.

NASA Technical Reports Server

W.T. Wallace
yle/NASA J•hns•n Space Center
H•ust•n, TX
A.S. Jeevarajan
NASA J•hns•n Space Center
H•ust•n,
L}
TX
P^ L.A.Tayl•r
niversity
^ ^r
	 •f Tennessee-Kn•xville
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1
https://ntrs.nasa.gov/search.jsp?R=20090042860 2019-08-30T08:25:05+00:00Z
Lunar Dust Reactivity
2
Our Unhappy Moon
UV
SW
Grinding 30->100,000
.r

Taylor and McKay 199280	 Fra meatsts m agglutinate
60
	 Agglutinates
	
mineral fragment
basaltci 40
	
Mineral
Fragments
20
immature	 submature	 mature
20	 40	 60	 80
Is
 / FeO
•
ImmatureSubmature	 Mature
20	 40	 60	 80
Is / FeO
â Measurement of Single-Domain, Nanophase Fe 0 (IS) FMR
Normalized IS for Iron Content: I S / FeO
I S / FeO = amount of total iron present as Fe o
â I S / FeO is a Function of Agglutinate Abundance
â Agglutinate Abundance is a Function of Maturity

Quartz Activation by Grinding
• Grinding quartz: electron spin resonance (ESR)
characteristic of Si· or Si-O· radicals
• Increased grinding = higher signal
• Decrease in Si-based radicals in air
• Half-life ~30 hours; at 4 weeks = still 20% signal
• Ground quartz + H 2O = OH- in aqueous
solution produces OH radicals
• Air = Decrease in Radical production
• Half life ~ 20 hours
V. Castranova, Environ. Health Perspect. 102 (1994) 65-68.
V. Vallyathan et al., Am. Rev. Respir. Dis. 138 (1998) 1213-1219 6
What Does “Activated” Mean?
• Presence of reactive sites on surface - Free radicals
• Ability to produce reactive species in solution
fr	 Ik
J. Narayanasamy and J.D. Kubicki, J. Phys. Chem. B 109 (2005) 21796-21807
Reactive Species of Interest
• Hydroxyl Radical, ·OH
• Highly oxidizing
• Damage & Radical species production
8How Should We Monitor ·OH?
• Fluorescence Spectroscopy
–Can also provide quantitative analysis
–Large number of chemical sensors already in
use for other systems
– Need to determine correct probe
• Electron Spin Resonance
– Provides quantitative measure of radical
production
– Equipment is costly and bulky
COO-
OH
COO-
HO
COO- 	 COO-
Fluorescence
Terephthalate	 2- Hyd roxyterep hth a late
(non-flurorescent) 	 (fluorescent) 
9
Sample SiO2 Al2O3 TiO2 FeO MnO MgO CaO Na2O K2O P2O5
JSC-1A-vf, 48.8 15.7 1.49 8.88 + 0.19 8.48 10.4 2.93 0.81 0.66
% oxides 1.71%
Fe2O3
Apollo 16 44.7 27 0.56 5.49 0.7 5.84 15.9 0.44 0.13 0.1
Soil (62241),
% oxides
Is/FeO = 100
Min-U-Sil 99 + < 0.8 < 0.1 < 0.1 0 0 0 0 0 0
Quartz, Fe2O3
% oxides
10
450	 500	 550
	
120 Apollo 16	 \
Soil 62241
100
Z"
	 80
2 ^
C:'
o M 60
^E ^.
w	 40	 ----
20 Fq tzu,^
0
350	 4
62241 Unground	 Wavelength (nm)
Apollo 16
Soil 62241
Simulant
JSC-1 A-vf
	 Simulant
JSC-1 A-vf
quartz
11
0	 5	 10	 15	 20	 25	 30
Grinding Time (min)
ESR
r'
L^ ,.^	 II
`"	 f
^f_rr
II	 w
o a	 x.o	 a;a
	 5 4	 a:o
rl .^'i:n;,,fp,-,^ T^rn.e (^"min}
♦ Grinding: produces higher
number of silicon-based radicals
in ESR spectra
♦ Grinding time: direct effect on
hydroxyl radicals produced
♦ Grinding: increase in hydroxyl
production for lunar simulant and
quartz with increased grinding
♦ Grinding: Apollo Soil
greatly increases *OH
Fluorescence Signal Produced by Grinding
200
n Min-U-Sil 5
180
	 • JSC-1A-vf
160	 Apollo 16 (62241)Ec 140
120 Florescence
ac 100
80	 n
60
40
20
12
W&T'p-7W	 JE---J-SC-1-A: —5 36^- 3
------- i --- (ung ---- : ----------- 	.	 2211^ 1 -------- ! ---- ----------round ------ 3 -.- ,ym	 HI'L—f-g . ....	 ...........
Lunar dust particles (62241-Ground)
100
80
0
60
E 40
20
0
0.01 0.1	 1	 10
Diameter ([im)
7
6
5
4
3
2
1
0
100
Wallace et al., (2009) Mete
	 13
Soil Chemistry and Maturity
Lo-Ti M re
	 -^	 pare H19917affids
Sample
Is/FeO
15071
52
15041
94
71061
14
79221
81
67461
25
67481
31
61141
56
62231
91
62241
100
SiO2 45.9 46.4 39.8 41.7 44.6 44.6 45.0 45.0 44.65
TiO2 1.81 1.83 8.76 6.39 0.35 0.44 0.59 0.60 0.56
Al2O3 13.1 13.5 10.5 13.5 28.4 28.1 26.3 26.3 27
Cr2O3 0.41 0.41 0.48 0.37 0.08 0.10 0.12 0.11 -
MgO 11.3 10.8 10.5 10.3 4.46 4.91 6.39 6.20 5.84
CaO 10.3 10.3 9.90 10.8 16.5 16.2 15.3 15.4 15.95
MnO 0.19 0.20 0.24 0.21 0.06 0.06 0.07 0.09 0.7
FeO 14.9 14.2 17.5 14.0 4.24 4.38 4.80 4.87 5.49
Na2O 0.37 0.41 0.41 0.41	 0.40
0.09	 0.06
0.43 0.43 0.43 0.44
K2O 0.13 0.19 0.09 0.06 0.11 0.12 0.13
P2O5 0.18 0.21 0.06 0.07	 0.04 0.04 0.06 0.07 0.1
SO2 0.12 1	 0.13 1	 0.15 1	 0.19	 0.06 0.04 0.09 0.09 -
University of Tennessee, Planetary Geosciences Institute
Larry Taylor, lataylor@utk.edu
pFe0 20 nm
All Black Dots are
Nanophase Fe Liu et al., 2007
University of Tennessee, Planetary Geosciences Institute
Larry Taylor, lataylor@utk.edu
200
150
E
NC? 100
50
0
350	 400	 450	 500	 550
Emission Wavelength (nm)
250
17
550350	 400	 450	 500
Emission Wavelength (nm)
18
Z%	 200
E
M 150
.^
E	 100
50
0
Highland 62231
e I s/FeO = 91
Mare 79221
I s/FeO = 81
Quartz	
----
250
140
Mare 71061
120 I s/FeO = 14
100
Highland 67461
80
	 I s/FeO = 25
60
40
20	 Quartz
0
350	 400	 450	 500
Emission Wavelength (nm)
550
19
15000
14000
13000
12000
11000
10000
9000
8000
7000
6000
5000
4000
3000
2000
16000 A Mare	 79221
• Highland
15071 A
15041
61141
• ;71061	 •
62231
67461
67481
10 20 30 40 50 60 70 80 90 100
Maturity ( Is/FeO)
20
16000
14000
12000
cd 10000
5 8000U
N12 6000
4000
2000
BET Areas
79221
(81)	 15071
(52)
71061
(14)
	
61141
•	 (56)
62231	 0
(91)	 67461
(25)
Amok
3
	
4
	
5
	
6
Specific-surface Area (m2/g)
21
1.00
0.95
0.90
0.85
C R^ 0.80
0.75
CU 0.70
z^ 0.65
= 0.60CU
E 0.550
z 0.50
0.45
0.40
Deactivation of JSC-1A-vf
n 	 T = 25 oC
Humidity = 50%S
[dust] = 4 mg/mL
τ50% ~ 2 hours
S
i
7
ii
n
i
n
0	 24	 48	 72	 96	 120	 144	 168
Deactivation Time (hours)
n 61141
n 67481
n 67461
n 62231
n 79221
n 15071
n 71061
n 15041
University of Tennessee, Planetary Geosciences Institute
Larry Taylor, lataylor@utk.edu
EP
EPR Spectra of Apollo 62241
Unground
• Same grinding conditions as
fluorescence studies
• Broad peaks
• Si · or Si-O · ?
• g-values: 2.11	 2.09
Ground	 (unground 	 ground)
• Similar to previous results*
2000	 3000	 4000	 5000
Magnetic Field (Gauss)
26
*: D. Haneman and D.J. Miller, Proc. Second Lunar Sci. Conf. 3 (1971) 2529-2541.
Testing for Radicals Using Spin Traps
CH3	 H 3 X
H 3C	 C	 N	 O+ ' X	 H 3C	 C	 N	 O'
CH3	 H 3
2-methyl-2-nitropropane (MNP)
27
*	 * / ^ *	 JSC-1A-vf 10 minute grinding
Spin-trapping of
*	 *	 *62241
Radicals
10 minute grinding
*	 *	 *
Min-U-Si l 5 30 minute grinding
* : spin-adduct triplet 	 100 mM MNP/acetonitrile
• Activity: quartz < lunar dust simulant < lunar dust
• Activated species + acetonitrile = radicals
• Radical has no H (no hyperfine coupling peaks)
• Future testing: DMPO in water
28
29
UV Activation of Unground Lunar
Simulant
200
180
160
140
E 120
^o
100
Ca c 80
LO
M 60
40
20
• 3.8 mg/mL JSC-1A-vf
• 10 mM Terephthalate
• 800 W UV
•~ 5 X 10-4Torr
0	 20 40 60 80 100 120 140 160 180 200
UV Exposure Time (min)
30
Final deactivation
point from initial
lunar dust testing
(> 1 month further
deactivation; upper
limit for activity)
UV Reactivation of Ground,
Deactivated Lunar Dust and Simulant
4000 n 4h deactivation (JSC-1A-vf)- 3.8 mg/mL
• 96h deactivation (JSC-1A-vf)- 3.8 mg/mL
3500	 A 20h deactivation (JSC-1A-vf)- 3.8 mg/mL
v 24h deactivation (JSC-1A-vf)- 3.8 mg/mL
3000
	
Apollo 16 (62241) - 1.2 mg/mL
2500
2000
1500
1000 0
500
0
0	 50	 100	 150
	
200
UV Exposure Time (min) 	 31
Effects of Vacuum on UV
Activation/Deactivation of Lunar Simulant
400
150	 1800	 30	 60	 90	 120
UV Exposure Time (min)
n Unground (Vacuum)
• Ground (Vacuum)
A Deactivated-24 hours (Vacuum)
n Unground (Atmosphere)
• Ground (Atmosphere)
A Deactivated-5 hours (Atmosphere)
1
• 3.8 mg/mL
• 10 mM
Terephthalate
• 800 W UV
Exposure of active
simulant to UV in
air leads to
deactivation!
32
200
1800
1600
1400
CU
a^
1200
1000
800
600
35
30
25
^C ^ 20E
c LO
o M 15
.0
,E 	 10
W
5
0
• JSC-1 A-vf
• 4 mg/mL
• 800 W UV
• ~ 5 X 10-4 Torr
Comparison of Activation by Grinding
and UV Exposure
350	 400	 450	 500	 550
Wavelength (nm)	 33
Summary
• Hydroxyl radical production in solution a measure of reactivity
• Both EPR and fluorescence used
– Further EPR – 02/10
• Reactivity by grinding: lunar dust > simulant > quartz
• Reactivity: Mare > Highland
• Reactivity correlated with maturity (np-Fe concentration)
• Deactivation tested (50% RH, 25 oC)
– 50% of initial reactivity ~ 2 hours for lunar dust simulant and ~ 3-4 hours for lunar
soils
• UV radiation leads to hydroxyl radical production
– UV less efficient than grinding
34
Acknowledgements ^yam
• Dr. Yang Liu
• Dan Garrison
• Dr. Bonnie Cooper
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PProf.-, Lowelle _ ,r r Kispert, _
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• Dr. Tanya
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• Camil Liceaga 4 +
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Nicholas
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 Myers
. 7^N^h^^yrtili`! . ^	 L" ^^^
• Krishna Upadhyaya
35


Activation of Lunar Dust Via Grinding and UV Radiation

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