1. Use of Spectral Induced Polarization in environmental applications
Gerodimou Konstantina
Τρίτη, 28 Μαρτίου 2017

2. Structure Purpose of the survey
Monitoring methods applied – Geophysical, Geochemical
Contaminant used – Textile waste waters
Remediation agent – Biochar
Experimental Study
Results
Interpretation
Conclusions

3. Purpose of the Survey Physicochemical changes Contaminant + biochar
SIP signal
Contaminant + biochar
Physicochemical changes
Potential for geophysical monitoring tool of the process
Δεν το καταλαβαίνω αυτό...
to biogeophysics δεν έχει σχέση
αν θέλεις να κάνεις ένα flowchart τότε κάνε κάτι σαν αυτό
Contaminant - biochar (remediation agent) - physicochemical changes - SIP signals; potential for geophysical monitoring of the process
Rapidly evolving earth science - Biogeophysics

4. Environmental & Νear Surface Geophysics
Geophysics is the application of physics to investigate the Earth
Solid earth geophysics studies the interior of the earth (up to the core)
Near surface geophysics is concerned with the upper crust.
Geophysics is not limited on Earth, can be applied in other planets / extraterrestrial objects (e.g. moon, which is not a planet)
NSG - typically we say < 100 m; where we have practical applications and typically economic aims
Reynolds defines environmental geophysics:
The application of geophysical methods to the investigation of near surface bio-physico-chemical phenomena that are likely to have implications for the local environment

5. Types of problems addressed?
Ground water exploration
Contaminant mapping and monitoring
Geohazards
Geologic mapping
Archaeology
Advantages
Non (or minimally) invasive
Cost effective
High spatial / temporal resolution
Easier application
Remote monitoring / operation
Long term continuous, application
Based on the problems addressed, change the previous title to Near Surface Geophysics (geologic mapping, hazards and archaeology are not 'Environmental')
Highlight that they are indirect method, so direct method verification / correlation / support is always needed

6. Geophysical Methods
Electromagnetics (MT, TDEM, FDEM, GPR) (active, passive)
Gravity (passive)
Magnetics (passive)
Seismics (Refraction, Reflection, Surface waves, Earthquakes) (active, passive)
Electrical (ERT, SP, IP, SIP) (active, passive)

7. SIP (Spectral Induced Polarization)
IP (induced Polarization)
SIP : The extension of IP
Non invasive electrical method
Applies DC current to the subsurface using 2 electrodes
Soil media act as a capacitor
Electrochemical reactions
Voltage potential
Polarization
Chargeability
Measurements represented by the complex conductivity
Range of frequencies
Electrochemical polarization
MW polarization
Electrical Double Layer (EDL)
Diffuse Layer polarization
Stern Layer polarization
IP can be minimally invasive,
in reality an AC (low frequency) current is applied
we typically use 4 electrodes; 2 for injection and 2 for measurements
what do you mean by electrochemical reactions?
what is the voltage potential?
SIP
τι σημαίνει Meaurement represented by the complex conductivity?
ποια η διαφορά IP - SIP?

8. Spectral Induced Polarization(SIP)
IP (Induced Polarization)
Electrode polarization

9. Electrical Double Layer (EDL)
Electrical double layer, diffuse and Stern layer (Slater 2014)
Tortuosity (Slater 2014)
rock
water

10. SIP (complex resistivity in frequency domain) (Slater 2014)
Time Vp Ip
Phase lag, ϕ
Current
Voltage C+ P- C- P+ a
OK, γιατί όμως έχεις φωτό από field resistivity? ναι, έτσι εφαρμόζεται, αλλά το ίδιο και το IP & Resistivity
magnitude
Phase lag

11. Complex conductivity Is given by : ρ(ω) : complex resistivity
ω:angular frequency
αυτό να το συνδυάσεις με το προήγουμενο slide
επίσης να πεις και κάτι γιατί κάνεις IP/SIP (να εξηγήσεις το real & imaginary component)

12. The wastewater Textile waste water (TWW) Reactive Red 120 (RR120)
Chemical molecule
(C44 H24 C12 N14 Na6 O20 S6)

13. Biochar (BC1)
Solid heterogeneous substance produced by biomass pyrolysis
Carbonization of biomass
Organic carbon 81.9%
Grain size : 2mm

14. Two types of adsorption
Adsorption is the adhesion of atoms, ions or molecules from liquid to a surface
Two types of adsorption

15. Experimental setup
Portable Field/Lab Unit
Acrylic tube columns

16. Experimental setup Liquid filling Non polarized (Ag/AgCl) electrodes
παράξενη φαίνεται η στήλη αριστερά' σα να έχει biochar στα άκρα, και καθαρή άμμο στη μέση

17. Calibration Measurements
Standard solutions
Geometric factor for each column

18. Tests Reference column (sand) and RR120 aqueous solution Current
100% biochar and RR120 aqueous solution
Reference column (sand) and RR120 aqueous solution
Current
electrodes
Potential
electrodes

19. Dynamic and semi-static measurement sets
Semi-static mode
we stopped the flow in every loop.
Sample
In situ conductivity measurement
Continuation of the flow
Dynamic mode
Continuous slow flow.
Samples every 10 min.
In situ conductivity measurement.
Samples in both cases end up in chemistry lab for adsorption measurements.

20. Channel 1 – Column 7 (20% biochar)

21. Channel 1 As time passes, peak frequency shifts towards higher frequencies. Average peak frequency (PF) 0.7Hz
SINGAL OR NOT ??? Accuracy of the instrument :0.5mrad. The phase changes from 4-12 mrad for all frequencies which is greater than the accuracy of the instrument.

22. RR120 VS Water
the second statement is not clear with the data presented here
Results
The phase at RR is frequency dependent (clearly shifted at higher frequencies)

23. 10% Biochar, Phase, Imaginary & Real conductivity, Resistivity change at PF:63Hz

24. BIOGEOPHYSICS : Integration of geophysical measurements with geochemical analysis
10% Biochar-RR Dynamic
χμμμ, εξαρτάται τι θα πεις....

25. 20% Biochar-RR PF: 10 Hz Semistatic 20% Biochar-RR PF: 1 Hz Dynamic
Οκ, καλύτερο correlation
20% Biochar-RR
PF: 1 Hz Dynamic

26. 100% Biochar (RR & Water) - Imaginary & Real conductivity, Phase and Resistivity change at 1 Hz
distinctively
different
trends
different phase magnitude
Water

27. 100% Biochar  Frequency dependence
0.1 Hz RR
Water
1000 Hz
Water RR
10 Hz RR
Water RR
Water
1 Hz
100 Hz RR
Water

28. ? 100% Biochar-RR VS 100% Biochar-Water, PF: 1 Hz - Dynamic
FTIR (biochar before and after treatment) +
DEBYE decomp.
DECOLORATION
Visually evident
Decoloration after 20 min

29. Conclusions (1)
From the diagrams its clear that there is consistency between the measurements, therefore we present reliable results.
Waters and wastes trend is parallel and same, but wastes amplitude is greater. This means that the TWW it is been detected. It has strong spectral signature.
Very significant for the water/TTW comparison is that waters resistivity increases with time in contrast with TWW which decreases with time.
The presented results might suggest a correlation between the geophysical data trend, and the geochemical data trend
RR related processes have distinctively different geophysical signal than water only
The geophysical behaviour appears to be different between water and RR; water saturated columns show increase over time, whereas RR contamination shows decreas - the links with adsorption processes should be further examined

30. Biochar concentration
Conclusions (2)
The presented results might suggest a correlation between the geophysical data trend and the geochemical data trend.
The geophysical behavior appears to be different between water and RR.
Increasing the BIOCHAR concentration, the adsorption increases.
Biochar concentration
Adsorption
10 %
16 %
20 % - semi static
37 %
20 % - dynamic
38 %
100 %
84 %

31. Conclusions (3)
Dynamic and semi-static experimental conditions have the same adsorption.
It is still unknown, which chemical mechanisms and type of adsorption took place into the chamber BUT this work is still in progress (FTIR from Aksaray University-Turkey and DEBYE decomp. Rutgers University, US)

32. Acknowledgements I would like to thank,
Assistant Prof. Dimitrios Kalderis (TEI Crete) for his useful advices and continuous support on geochemical analysis and interpretation of the final results
Panagiotis Kirmizakis (Queens Belfast Univ., UK) for introducing experimental setup of SIP measurements
Associate Research Prof. Dimitrios Ntarlagiannis (Rutgers Univ., US) for supporting my research and teach me the SIP method
Prof. Berkant Kayan (Aksaray Univ., Turkey) for applying the FTIR method to our biochar samples
Ass. Prof. Andrea Ustra (Univ. Sao Paolo, Brazil) and Sina Saneiyan (Rutgers Univ., US) for applying the Debye decomposition to our datasets