mr. luke a. gurtowski
TRANSCRIPT
Mr. Luke A. GurtowskiResearch Chemical EngineerEnvironmental LaboratoryU.S. Army Engineer and Development Center
April 2018
Executive Summary• Background
• Insensitive munitions• Benefits• Environmental Concerns
• Treatment Technologies
• Evaluations and Discussion• Adsorptive Removal• Isotherm Models
• Conclusions
2
O
N
N
H3C
O
O
O O
Munitions Constituents
• Insensitive munitions (IMs) are currently being evaluated as alternatives to traditional munitions
• IM formulations contain more than one constituent3
2,4‐dinitroanisole (DNAN)
Nitrotriazolone (NTO)2,4,6‐trinitrotoluene (TNT)
Nitroguanidine (NQ)Hexahydro‐1,3,5‐
trinitro‐1,3,5‐triazine (RDX)
1,1‐diamino‐2,2‐dinitroethene (FOX‐7)
Insensitive MunitionsTraditional Munitions
IM PropertiesCompound Aqueous Solubility (mg/L)
NTO 12,800 (19 ⁰C)
NQ 4,100 (26 ⁰C)
DNAN 280 (25 ⁰C)
TNT 130 (20 ⁰C)
RDX 43.2 (25 ⁰C)
4
• Yellow color associated with IM formulations• pKa of NTO = 3.76
Polysaccharide Adsorbents• Cellulose and chitin are two most abundant biopolymers in the world
• Derivatives formed from acetylation and deacetylation processes
5
Chitin Chitosan
Cellulose Cellulose Acetate
Scope• Proof‐of‐concept evaluation
• 10 mL aliquots of 2‐mg/L solution vs. 500 mg of each adsorbent
• DNAN• NQ• TNT• FOX‐7
• Preparation and evaluation of isotherms• Successful adsorbate‐adsorbent mixtures
6
Proof‐of‐concept Evaluation
• Definitive adsorption of DNAN and TNT via cellulose triacetate.
• Chitin and chitosan show potential adsorption of TNT.
7
0102030405060708090100
DNAN
Fox‐7
NQ
TNT
DNAN
Fox‐7
NQ
TNT
DNAN
Fox‐7
NQ
TNT
DNAN
Fox‐7
NQ
TNT
Cellulose Cellulose Triacetate Chitin Chitosan
Removal (%
)
Preparation of Isotherms
8
• 10‐mL aliquots of 10‐mg/L solutions vs. various adsorbent masses• Only cellulose acetate showed observable adsorption trend
0
10
20
30
40
50
60
70
80
0 20 40 60 80 100 120
Adsorbate Re
moval (%
)
Adsorbent Mass (mg)
DNAN
Chitin Chitosan Cellulose Cellulose Acetate
0102030405060708090
0 20 40 60 80 100 120
Adsorbate Re
moval (%
)Adsorbent Mass (mg)
TNT
Chitin Chitosan Cellulose Cellulose Acetate
Cellulose Triacetate Isotherms
9
y = 0.3303xR² = 0.9625
0
0.5
1
1.5
2
2.5
3
0 2 4 6 8
Unit M
ass A
dsorbe
d (m
g/g)
Equilibrium Concentration (mg/L)
DNAN
y = 0.4613xR² = 0.9958
0
0.5
1
1.5
2
2.5
3
3.5
0 2 4 6 8Unit M
ass A
dsorbe
d (m
g/g)
Equilibrium Concentration (mg/L)
TNT
Compound Distribution Coefficient (mL/g)DNAN 330.3TNT 461.3
Discussion and Next Steps• DNAN and TNT display high affinity for cellulose triacetate.
• Linear adsorption models applicable• Moderate removal of FOX‐7 via cellulose triacetate• Electron‐withdrawing groups cause adsorption
• All adsorbents show very low affinity for NQ and inconsistency for NTO
• NTO is currently undergoing evaluation
• Next steps• Evaluate polysaccharides with electron‐withdrawing groups to optimize removal
• Produce adsorbents for removal of each IM
10
Applications
• Utilization within industrial base for process water treatment
• In‐situ surface water treatment technology for training ranges
• Sustainable alternatives to GAC and destructive processes
Conclusions• Cellulose, chitin, and chitosan are ineffective at removing IMs from solution
• Cellulose triacetate is an effective adsorbent for DNAN and TNT
• NTO speciation provides inconsistent adsorption results
• No material evaluated in this study successfully removed NQ from solution
• Associated Journal Article:• Gurtowski, L.A., C.S. Griggs, V.G. Gude, M.K. Shukla. 2017. An integrated theoretical and experimental investigation of insensitive munition compounds adsorption on cellulose, cellulose triacetate, chitin and chitosan surfaces. J. of Environmental Sciences.
12
Innovative Solutions for a Safer, Better World
13