Post on 06-May-2015
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1 The world leader in serving science
Richard Jack, Ph.D. Manager, Global Market Development
Anions and Metals Analysis for Waters Impacted by Hydraulic Fracturing
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Hydraulic Fracturing (Fracking) Controversy
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Hundreds of Known Chemicals in Fracking Solutions • Hundreds of chemicals in fracking solutions • 50,000 mg/L salt (10–20x sea water) • The EPA has narrowed the list of compounds down to less than 20. • The EPA is in the process of developing analytical methods for these target compounds.
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Pennsylvania Regulations for Wastewater from Fracking
• In lieu of the trace analysis described in Subsection b, the chemical analysis of wastewater produced from the drilling, completion and production of a Marcellus Shale or other shale gas well must include the following:
• Additional constituents that are expected or known to be present in the wastewater.
*Note: All metals reported as total.
Acidity Alkalinity (Total as CaCO3) Aluminum Ammonia Nitrogen Arsenic Barium Benzene Beryllium Biochemical Oxygen Boron Bromide Cadmium Calcium Chemical Oxygen Demand Chlorides Chromium Cobalt Copper
Ethylene Glycol Gross Alpha Gross Beta Hardness (Total as CaCO3) Iron – Dissolved Iron – Total Lead Lithium Magnesium Manganese MBAS (Surfactants) Mercury Molybdenum Nickel Nitrite-Nitrate Nitrogen Oil & Grease
pH Phenolics (Total) Radium 226 Radium 228 Selenium Silver Sodium Specific Conductance Strontium Sulfates Thorium Toluene Total Dissolved Solids Total Kjeldahl Nitrogen Total Suspended Solids Uranium Zinc
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Monitoring Environmental Impact
• Public concern poses a challenge to environmental laboratories. • Some contaminants do not have approved EPA analytical methods.
• Matrix issue—hypersaline fracking waters can affect analysis of certain compounds.
• Robust analytical methods needed to assess environmental impact from fracking processes.
• Following speakers will discuss inorganic analysis methods for anions and metals.
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Thermo Scientific Dionex Ion Chromatography (IC) Systems for Anion and Cation Analysis
Dionex ICS-5000
Dionex ICS-900
Starter Line IC System
Compact Design Chem. Suppression
DCR Mode
Premier Modular RFIC System
Capillary HPIC Modular Flexible
Single or Dual Channel Eluent Generation Proportioned and RFIC Gradients
Multiple Detectors Multiple Thermal Zones
Dionex ICS-1600
Dionex ICS-1100
Standard Integrated RFIC
System Compact Design
Electr. Suppression LCD Front Panel Column Heater
Integrated Sample Prep Eluent Regeneration
Dionex ICS-2100
Superior Integrated
RFIC System Compact Design
Eluent Generation RFIC Gradient
Electr. Suppression LCD Front Panel Column Heater
Integrated Sample Prep
Basic Integrated RFIC System
Compact Design Electr. Suppression
Integrated Sample Prep Eluent Regeneration
Dionex ICS-4000
Capillary High-Pressure Integrated RFIC System
Capillary HPIC™
Eluent Generation RFIC Gradient
Multiple Detectors, Including
Electrochemical (ED) and Charge (QD)
Reagent-Free™ IC (RFIC™) Systems
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Thermo Scientific Dionex IonPac Anion-Exchange Columns
Column Formats Primary Application
Dionex IonPac™ AS19
0.4 × 250 mm 2 × 250 mm 4 × 250 mm
Recommended hydroxide-selective column for inorganic anions and oxyhalides, e.g., trace bromate in drinking water
Dionex IonPac AS18
0.4 × 250 mm 2 × 250 mm 4 × 250 mm
High capacity hydroxide-selective column for the analysis of common inorganic anions
Dionex IonPac AS18-Fast
0.4 × 150 mm 2 × 150 mm 4 × 150 mm
Hydroxide-selective column for fast analysis of common inorganic anions
Dionex IonPac AS23
2 × 250 mm 4 × 250 mm
Recommended carbonate-based column for inorganic anions and oxyhalides, e.g., trace bromate in drinking water (better solution for Dionex IonPac AS9-HC users)
Dionex IonPac AS22
2 × 250 mm 4 × 250 mm
Recommended carbonate-based column for fast analysis of common inorganic anions (better solution for Dionex IonPac AS14, AS14A and AS4A users)
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Comparison of Hydroxide and Carbonate Eluent for Separation of Common Anions
• Both eluents show excellent anion separation.
• Trace anions are well resolved. • Hydroxide does not show the water dip.
Column/Eluent: A) Dionex IonPac AS19 using hydroxide eluent B) Dionex IonPac AS23 using carb/bicarb eluent Detection: Suppressed conductivity A B Peaks 1. Fluoride µg/L 2. Chlorite 8.8 11.3 3. Bromate 4.7 5.1 4. Chloride 5. Nitrite 6. Chlorate 13.5 9.5 7. Bromide 8. Nitrate 9. Carbonate 10. Sulfate 11. Phosphate
0 . 2
0 . 5
µ S
1
2 3
A
0 5 1 0 1 5 2 0 2 5 3 0 – 0 . 1
0 . 7
µ S
1
2 3
B 4
5 6 7
9
8
4
5 6
7 8 9
1 1 1 0
1 0 1 1
Minutes
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AA, ICP and ICP-MS—Speed and Detection Limit
Detection Limit
Speed
Flame AA
Furnace AA
ICP-MS
ICP-OES
300s for 10 element
Single Element Technique
20 mins for 10 element
Single Element Technique
60s for 10 elements
Rugged Multielement Technique
120s for 10 elements
Sensitive Multielement Technique
Higher Cost < 1ppt DL
Ppm DL
> 1ppb DL
> 100ppt DL
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Complete Inorganic Elemental Analysis
H
Li
Fr Ra
Sc
Ac
Zr
Hf
Nb
Ta
Tc
Re
Ru
Os
Rh
Ir Hg
In
Tl
Ge
Sb
Bi
S
Te
Po
Cl
F
At
He
Ar
Ne
Kr
Xe
Rn
Pa Pu Am Cm Bk Cf Es Fm Md No Lw Np
Not measurable
ICP-MS
Unstable elements
AA/ICP/ICP-MS ICP/ICP-MS
IC
Na
K
Rb
Cs
Be
Mg
Ca
Sr
Ba
Y
La
Ti V Cr
Mo
W
Mn Fe Co Ni
Pd
Pt
Cu
Ag
Au
Zn
Cd
Al
Ga
Sn
Pb
B C O N
Br
I
Si P
As Se
Ce Pr
Th
Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
U
IC is also used for additional anions, such as oxyhalides, SO4 and NO3.
Anion Analysis of Water Associated with Unconventional Natural Gas Extraction John F. Stolz, Ph.D, Duquesne University, Pittsburgh, PA
What is Marcellus Shale?
www.getmoneyenergy.com/wp-content/uploads/2010/01/shale-gas-basins-in-usa.jpg
Horizontal Drilling and Fracking
http://app1.kuhf.org/userfiles/hydraullic_fracturing_natural_gas.gif
Produced Water High Total Dissolved Solids (60–250,000 mg/L)
Chloride, bromide, strontium, barium
Gaudlip et al., 2008. SPE 119898
The System Thermo Scientific Dionex ICS-1100 with:
DS6 Heated Conductivity Cell
AS-DV Autosampler
Thermo Scientific Dionex DAD-3000 UltiMate 3000 Diode Array
Detector (UV-vis)
Thermo Scientific Dionex OnGuard II M Cartridge
Thermo Scientific Dionex IonPac AS-22 Anion Exchange
Column
Running Conditions Eluent: 4.6 mM sodium carbonate/ 1.4 mM sodium bicarbonate Flow Rate: 0.25 ml/min Samples: Filtered 0.22 um (PES filter0) Run Time: 20 min Conductivity Range: 0–1500 uS/cm UV-vis: 195 nm (ch 1), 200 nm (ch 2), 205 nm (ch 3), 215 (ch 4)
Standards (Retention Time): Bromide (6.887 min)
Floride (3.377 min)
Chloride (4.847 min)
Nitrate (7.654 min)
Nitrite (6.201 min)
Phosphate (10.534 min)
Sulfate (11.781 min)
Arsenate (19.05 min)
Arsenite (4.357 min)
Monomethylarsonic acid (9.967 min)
Dimethylarsonic acid (2.623 min)
Five-Point Calibration Curves: a: 0.5, 1, 2.5, 5, 10 ppm Bromide, Floride, Chloride b: 2.5, 10, 25, 50, 100 ppm Nitrate, Nitrite, Phosphate, Sulfate c: 10, 50, 100, 250, 500 uM Arsenate, Arsenite, Monomethylarsonic acid, Dimethylarsonic acid
Table 1: Anion data for impoundment water, coal mine effluent, and freshwater stream water Field Sample Field Sample Field Sample Field Sample Field Sample
Impoundment
Water Impoundment
Water Coal Mine
Effluent Freshwater
Stream Freshwater
Stream
Unit Sample #1 Sample #2 Sample #3 Fonner Run Bates Run Conductivity uS cm-3 102,864 61,477 6,400 387 476
pH 5.38 5.67 7.53 7.91 7.67 Sulfate mg/L 8.64 10.21 3,826 25.07 24.46 Nitrate mg/L ND ND 1.81 0.11 0.58
Bromide mg/L 255 226 14.25 ND ND Chloride mg/L 30,683 27,700 1,241 1.29 6.00 Arsenic ug/L BDL BDL BDL BDL BDL
ND - not detected BDL - below detection limit
J.L. Eastham, 2012
Conclusions The Dionex ICS-1100, equipped with the DS6 Heated Conductivity Cell provides a rapid means for separation and detection of anions (e.g., Cl, Br) commonly found in flowback and produced water associated with unconventional shale gas extraction.
Produced water from Marcellus Shale is higher in chloride and bromide but lower in sulfate, and can be distinguished from coal wastewater and natural streams.
The addition of the Dionex DAD-3000 UltiMate™ 3000 Diode Array Detector in tandem with the Conductivity Cell allowed for the detection of additional anions, e.g., As(III), and arsenic speciation.
Hydraulic Fracturing Flowback Water Analysis by ICP-OES and ICP-MS
Joelle Streczywilk Senior Group Leader Geochemical Testing
Outline
The importance of trace analysis of flowback water Sample preparation Choosing an analysis technique Analysis using the Thermo Scientific iCAP 6500
Duo View ICP Spectrometer Minimizing physical interferences Managing spectral interferences Summary
Importance of Flowback Water Trace Analysis
Gas exploration and development is growing quickly and analysis techniques should evolve with the Marcellus industry.
Flowback water is the main source of wastewater from Marcellus shale gas drilling.
Flowback water can be treated and reused or treated and discharged.
Metals analysis is essential for many reasons: – Ensures that treatment processes are functioning properly. – Meets discharge or storage requirements. – Assesses the hazards that could be related to a spill or leak.
Sample Preparation
EPA Method 200.2 is adequate for most flowback samples.
Use 1% nitric and 0.5% hydrochloric acid digestion (a nitric only digestion may be preferred if analysis will be conducted by ICP-MS).
Reduce sample to approximately 20% of original volume at 85 °C.
Cover sample with watch glass and reflux for 30 minutes.
Fill to original volume with DI water.
Sample Preparation
Flowback waters can be saturated with salts and precipitation may occur.
Precipitation will lead to inaccurate results for both major and trace element analysis.
Avoid crystallization by diluting the sample prior to digestion.
Analysis Techniques
ICP-OES and ICP-MS Governed by the elements of interest, detection
limits required and the makeup of the sample The constituents and permitting needs of flowback
water vary greatly so analysis techniques should be sample specific.
Flowback Water Analysis by ICP-MS
Uranium analysis should be conducted on the ICP-MS because uranium is a heavy isotope with a simple spectrum and a slight interference from 206Pb16O2 (ICP-OES: weak signal and severe interference).
Many other analytes of interest may be analyzed on the ICP-MS with caution due to interferences and high total dissolved solids (TDS). The use of reaction or collision cells can minimize or resolve many interference issues.
ICP-MS Spectral Interferences
Isobaric overlaps: some isotopes occur at the same mass number. – Choose and monitor alternate isotopes. – Correction equation
Polyatomic overlaps: dimers, oxides, hydrides, etc. – Dynamic or empirical correction equations (may not be
accurate depending on the intensity of the interference)
ICP-MS Physical and Matrix Interference
High TDS (some flowback waters are over 10% TDS) – Viscosity—consistent aerosol formation is desired – Plasma loading—reduces ions generated by the plasma – Instrument drift—clogs cones
Minimized by internal standards, robust plasma conditions, keeping dissolved solids below 0.5% – Dilutions: introduce error, raise practical quantitation limit
(PQL), detector life
Flowback Water Analysis by ICP-OES
Most analytes of interest in flowback water can be analyzed accurately with ICP-OES.
iCAP™ 6500 Duo View ICP Spectrometer has the advantage of viewing the plasma both axially and radially. – Enables the analysis of trace metals at low and high
concentrations simultaneously
ICP-OES Line Selection
Line sensitivity – Is based on detection limit required. – Avoid lines that require complex spectral correction
algorithms. – Select a radial or an axial view of the plasma. – Line switching is available for analyte measurements that
are found at both high and low concentrations (extends linear range).
Flowback Example on iCAP 6500
• Diluted prior to digestion
• ^ and * on Barium and Strontium: peak saturation
• ChkFail: check table limit (Ba, Sr, Ca, Li, Mg and Na)
• Sodium defaulted to the low line (linearity and interfering element corrections [IECs])
• RSDs less than 3% for all analytes above the MDL
Minimizing Physical Interferences
Avoidance: dilute if possible High solids nebulizer to minimize “salting out”
effects (Noordermer v-groove) Humidify argon stream Intelligent rinse Use of internal standard
Internal Standard Compensation
Plasma loading from flowback waters – Readings are generally suppressed
Calibration Blank Cts/S
Flowback Sample Cts/S
Internal Standard Recovery
Low axial Sc 4122 3486 85%
High radial Sc 19812 17357 88%
High axial Sc 405400 313240 77%
Flowback Water and Calibration Blank Comparison
Low axial Sc 227 Low axial Se 196
Managing Spectral Interferences
Background interference – Routine and relatively easy to deal with
Direct spectral overlap – Avoidance
Use different line(s)
– Complete a full spectral interference study Trace metals should be studied at a concentration of at least
1000 µg/mL of interferant
Interfering Element Corrections
IECs may be calculated, but should be checked after every calibration. – Use multiple check solutions.
IECs must not be used if the interferer concentration is above the linear range.
IECs should be calculated quarterly and with each nebulizer or torch change.
Spectral Interferences
Spectral tables can be helpful but not depended on.
A matrix study is also important for flowback water sample analysis.
Conduct fullframe analyses of all views in use (high radial, low axial, and high axial).
Low Axial View of a Flowback Sample with Blank Subtraction
Fullframe of 1000 µg/mL Strontium
Summary
The complex matrices of flowback waters make accurate trace analysis difficult.
ICP-OES analysis is more conducive to multi-element determinations for both high and most low analyte concentrations.
ICP-MS is required only for uranium, however it can be used to determine most other elements as well.
Avoidance is the key with both techniques. If avoidance is impossible, caution must be used in
every determination.