Andre Hauser - kisr

Near-Infrared (NIR) Spectroscopy as a Rapid Monitoring Tool for Total Petroleum Hydrocarbon (TPH) as Environmental Hazard in

Contaminated Soils and Sediments

byAndre’ Hauser*, Fatima Ali and Bashayer Al-Dosari

Central Analytical Laboratory, Kuwait Institute for Scientific Research,

P.O. Box 24885, 13109 Safat, KUWAIT

*Tel.: 00965-4989053E-Mail: [email protected]

3. Remediation of Contaminated Areas- A Challenge

OUTLINE

4. TPH Analysis- Conventional & NIR Technique

1. TPHs-A Short Description

5. Case Study- Testing of Real Field Samples

6. Conventional vs. NIR Analysis- Cost, Efficiency & Throughput Considerations

7. Summary

2. Oil Pollution-A Daily Hazard

TPHsA Short Description

TPHs

TPHs(Total Petroleum Hydrocarbons)

Grease,Lubricants

Refinery Products

Weathered Oil

Transposition Fuel

Crude Oil


TPHs consisting mainly of C and H and to a much lesser extend of S, N, O and heavy metals (V, Ni)

TPHs is a classes of compounds that does not naturally occur in the environment


Typical entities are: Saturates,

S

N

aromatics and heterocyclic compounds


Examples of TPHs

TPHs b.p. /C Aromatics /%

Heavy Metal/ppm

Crude Oil 35 - 700

21 <1,000

Weathered Oil 250 - 700

75 >5,000

Gasoline 35 - 150

20 0


TPHs differ in their toxicity

The higher the content of polyaromatic hydrocarbons (PAHs) and polar compounds (S,N,O) in TPHs the higher is their water solubility

Entity Unit Value

Benzene mg/L 10

Toluene mg/L 25

Benzo(a)pyrene mg/L 0.01

Nickle mg/L 20

WHO-Guidelines for Drinking Water


In arid, oil rich countries like Kuwait high risk of taking up air-borne particles covered with TPHs

Some PAHs are extremely carcinogenic


Source: CA EPA, 1999

PAHs FormulaHealth Risk Value in

µg/(80kg*day)

Benzo[a]pyrene 0.08

Chrysene 0.0008

Dibenzo[a,h]pyrene 0.8

Benz[a]anthracene 0.08

1-Nitropyrene 0.08

http://en.wikipedia.org/wiki/File:Benzo-a-pyrene.svg

http://en.wikipedia.org/wiki/File:Chrysene.svg

http://en.wikipedia.org/wiki/File:Benzanthracene.png

http://en.wikipedia.org/wiki/File:1-nitropyrene.svg

Oil (TPH) PollutionA Daily Hazard

Environmental disasters such as:


Environmental pollution by oil industry:


Environmental pollution by negligence:

Remediation of Contaminated Soil A Challenging Task

Waste disposal (excavation & transportation) Extraction with organic solvents (excavation & washing) Bio-remediation (excavation & mixing with bacteria) Agro-remediation (in situ treatment)

Remediation of Contaminated Soil Tasks for Analytical Chemistry

Screening of large areas for TPH-contamination Assessment of the extent of TPH-contamination Monitoring of clean up process

Determination of end point of clean up process

Remediation of Contaminated Soil A Challenge for Analytical Chemistry

High number of samples

High throughput required

No or low waste disposal per sample

Accuracy as good as needed Low cost per sample

TPH AnalysisConventional Method vs. NIR Spectroscopy

Feature Conventional Method

NIR Spectroscopy

Certification EPA, ASTM No

Sample Preparation Solvent Extraction No

Extract Treatment Silica Gel No

Calibration Yes Yes

Detection Device IR NIR

Detection Limit ppm %

Waste Perhalogenated Solvent

No

Drying Homogeniz Weighing Loading the Soxhlet-extractor

TPH AnalysisConventional Method

Adding of 100ml CCl4/Freon/S-316 (Chlorotrifluoroethylene) Extracting at a rate of about 20 cycles per hour for eight hours


Sample

Solvent

Shaker/Ultra Sonic Bath Extraction

Shaking or sonicating for four hours at RT/300 C.


Sample +Solvent +Silica Gel

Dilution

Filteration

Sample treatment with silica gel for 5 min



Calibration

IR-Measurement

0 1 2 3 4 50

1

2

3

4TPH/IR-Calibration

TPH Conc.

IR-R

esp

on

ds

NIR is a spectroscopic technique that uses infrared (IR) light diffuse scattered on the sample surface (DRIFT) to quantify the analyte (TPHs) in a matrix (soil).

Light Source Detector

TPH AnalysisNIR Spectroscopy

http://www.lapworth.info/energy/light.gif

While the IR-light interacts with the sample it leaves its fingerprint on the detected light

Sample

Light Source Detector


http://www.lapworth.info/energy/light.gif

http://images.google.com/imgres?imgurl=http://shirleybuxton.files.wordpress.com/2009/04/fingerprint-1.jpg&imgrefurl=http://shirleybuxton.wordpress.com/2009/04/25/fingerprints-and-the-gospel/&usg=__O1GiVbzxaFcrnddCq9y-k5tgMeo=&h=1133&w=784&sz=275&hl=en&start=3&tbnid=oRJ1n7pSo7jMZM:&tbnh=150&tbnw=104&prev=/images?q=fingerprints&gbv=2&hl=en

NIR measures the amount of light absorbed by a sample vs. the wavelength of the IR-light.

3700

4200

4700

5200

5700

6200

100000000

200000000

300000000

400000000

500000000

600000000

NIR-Fingerprints

Clean SoilContaminated Soil

Wave Length/cm-1

NIR

-Resp

onds

TPH-Signals


NIR-Spectroscopy is

• Non-destructive

• Without sample preparation

• Uses DRIFT-technique


• Needs calibration

Sample

NIR-spectrometer MPATM

from BRUKER

• No waste

Calibration• NIR predicts TPH-concentration using spectra from similar samples (Reference Value) with known TPH- concentration


• Calibration equations are found by chemometric

methods such as principal component analysis (PCA) and principal component regression (PCR) • Result: Model (equation) were TPH-

concentration is correlated with NIR-spectral features (wavelength, intensity, spectral shape)• QC of the model by cross-validation: Correlation coefficient (R2)≈ 1 Root mean square error (RMSE) ≈ 0.1

• NIR uses calibration equations (Model)

Reference samples ( S =43)


TPHs Matrix TPH-Con./%

No. of Samples

non Soil (particle size <2mm)

Blank 4

Gasoline Soil (particle size

<2mm)002 – 0.51 6

Jet Fuel Soil (particle size

<2mm)0.04 – 1.43 6

Kerosin Soil (particle size

<2mm)0.04 – 1.33 6

Diesel Soil (particle size

<2mm)0.05 -1.88 6

Crude Oil Soil (particle size

<2mm)0.02 – 1.36 7

Atmospheric Residue (I)

Soil (particle size

<2mm)0.5 -1.9 3

Atmospheric Residue (II)

Soil (particle size

<2mm)0.39 – 2.19 4

Weathered Oil

Soil (particle size <2mm)

2.08 1

Cross validation of the model (PCA-Equation)


Cross validation result: R2 = 0.9415; RMSE = 0.158

Case StudyTesting of Real Field Samples

Matrix TPH-Contaminant

Kuwait Soil (north) Crude Oil

Kuwait Soil (north) Weathered Oil

Sediment Atmospheric Residue (II)

Ottawa Sand(certified) Atmospheric Residue (II)

US sand (certified) Atmospheric Residue (I)

Field samples ( S =24)


Field samples were analyzed by conventional (certified) and NIR technique

Data from conventional technique were considered as true

Comparison between data from both technique


Comparison of data from all field samples

Matrix TPH-Contamination




Ottawa Sand(certified)



0 1 2 3 4 5 60

5

10

15

20

25

30

35

40

45

R² = 0.362316798189909

Conventional vs. NIR Technique

Conv. Technique (TPH in %)

NIR

Tech

niq

ue (

TP

H i

n %

)


Comparison of data from Kuwait Soil (north) samples








0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.50

2

4

6

8

10

12

R² = 0.850444628094841



NIR

Tech

niq

ue (

TP

H i

n %

)


0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.50

2

4

6

8

10

12

R² = 0.917870654566115



NIR

Tech

niq

ue (

TP

H i

n %

)

Comparison of data from Kuwait Soil (north) samples contaminated by weathered oil









Comparison of data from sediment samples contaminated by atmospheric residue








0.5 1 1.5 2 2.5 3 3.5 4 4.50

1

2

3

4

5

6

7

8

R² = 0.998695063772374



NIR

Tech

niq

ue (

TP

H i

n %

)


Comparison of data from certified soil samples contaminated by atmospheric residue







US sand (certified) Atmospheric Residue (I) 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

0

5

10

15

20

25

30

35

40

45

R² = 0.955223590954123



NIR

Tech

niq

ue (

TP

H i

n %

)

Conventional vs. NIR AnalysisCost, Efficiency & Throughput Considerations

Feature TechniqueConventional NIR

Capital Cost ~12,000 KD ~20,000 KD

Cost/Sample (Consumable)

~5-6 KD <0.250 KD

Time/Sample ~2 h 5 min

Calibration rather fast time consuming

Waste Disposal/Sample

>100 ml non

Accuracy high medium

Detection Limit 1 ppm 0.5%

Summary

TPHs in the environment pose a potential health risk to humans and destroy the nature

Total petroleum hydrocarbons (TPHs) are a mix of petroleum based chemicals that do not exist naturally in the environment

TPH-contaminated areas need to be identified, their health risk assessed and cleaned up

TPH-quantification is inevitable for hazard evaluation and clean-up activities

Conventional technique is time consuming, costly and harmful to the environment

Conventional technique for TPH-quantification are regulated by EPA & ASTM

Near infrared (NIR) spectroscopy can replace conventional technique

Summary Advantages of NIR: Environmentally friendly, fast and cost effective

NIR is the method of choice for monitoring soil clean-up:

Disadvantages of NIR: Large-scale calibration needed, high detection limit (%) and medium accuracy

• TPHs in %-range

• Large number of samples

• Trend monitoring

• End point determination

Thank You!

Q & A

Research Specialist: Dr. Andre’ Hauser Tel.: 24989053; [email protected] Specialist/Section Head: Dr. Fatima Ali Tel.: 24989050; e-Mail: [email protected] Ms. Bashayer Al-Dosery

Contacts

mailto:[email protected]

mailto:[email protected]

Andre Hauser - kisr

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