5105 XANES Spectroscopic Analysis of Nickel Collected on 

Quartz Filters 

Contract No. 5105 

AirNova, Inc. 

5485 Clayton Avenue 

Pennsauken, NJ 08109 

Date: 2010-10-12 

Canadian Light Source Inc. 

101 Perimeter Road 

University of Saskatchewan 

Saskatoon, Saskatchewan Canada 

“This document has been prepared by Canadian Light Source Inc. (CLSI), and contains experimental 

synchrotron research and development information. Neither CLSI nor any employees, officers, or directors, 

makes any warranty, expressed or implied, or assumes any legal liability or responsibility for accuracy, 

completeness or usefulness of any information or process disclosed, or represents that its use would not 

infringe on privately owned rights.” 
Report Review 

 Signature Date 

 

Author 

 Jeremy A. Olson 2010-09-27 

 

Reviewer No. 1 

 Lisa Van Loon October 12, 2010 

 

Reviewer No. 2 October 6, 2010 

 Jeff Warner 
Table of Contents Page i 

Table of Contents 

1.0 Introduction .................................................................................. 1

1.1 SAMPLE DESCRIPTION .................................................................................. 1

1.2 MATERIALS AND METHODS ........................................................................... 1

1.2.1 Nickel K-edge XANES ........................................................................ 1

1.2.2 Oxygen K-edge XAS .......................................................................... 2

1.2.3 Spectral Analysis ............................................................................... 2

2.0 Results .......................................................................................... 2

3.0 Use of Report ................................................................................ 3

4.0 References ........................................................................................ 3
5105 XANES Spectroscopic Analysis of Nickel Collected on Quartz Filters Page 1 

1.0 INTRODUCTION 

AirNova, Inc. was interested in determining the speciation of nickel in three quartz filter 

media. In particular, the presence of sulfidic nickel species NiS and Ni3S2 was of interest. 

1.1 SAMPLE DESCRIPTION 

Three used quartz thimble filters (AN1, AN2 and AN3), and one unused filter (ANBlank) 

were received from AirNova, Inc. A thin strip was cut, using a dedicated blade for each 

filter in order to avoid contamination. The strips were then placed into teflon sample 

holders for analysis. The nickel compounds used as standards are listed in Table 1. 

Table 1. Nickel standard compounds used in the analysis of the nickel collected on the 

quartz thimble filters. 

Nickel Standard Compounds 

Nickel sulfide, NiS 

Nickel carbonate, NiCO3

Nickel hydroxide, Ni(OH)2

Nickel sulfate, NiSO4

.

6H2O 

Nickel subsulfide, Ni3S2

Nickel Iron oxide, NiFe2O4

Nickel oxide, NiO 

Nickel nitrate, Ni(NO3)2

Nickel chloride, NiCl2

Nickel(0) powder, Ni0

1.2 MATERIALS AND METHODS 

1.2.1 Nickel K-edge XANES 

The Nickel K-edge XANES spectra were recorded on the Hard X-ray Micro Analysis 

(HXMA) beamline (6ID) at the Canadian Light Source (CLS) in August 2010. The HXMA 

beamline uses a superconducting wiggler operating at 2.0 T as a source magnet. The 

energy region of interest is selected using a double crystal monochromator equipped 

with Si (111) crystals. The beam is further collimated and focused using rhodium 

mirrors. The incident beam was detuned to 70% to minimize the harmonic content of 

the beam at the nickel K-edge. The samples and reference compounds were calibrated 

at 8333 eV using a Ni foil placed between the second and third ion chambers. The 

sample spectra were collected in fluorescence mode using a 32 element solid state 

Germanium detector and the standard compound spectra were collected in transmission 

mode. Sample spectra were recorded from 8160 eV to 8640 eV. Two scans were 

recorded for each filter sample, three scans were recorded for the blank filter and two 

scans were recorded for each of the standard compounds. The scans were averaged in 
5105 XANES Spectroscopic Analysis of Nickel Collected on Quartz Filters Page 2 

the analysis prior to the linear combination (LC) fitting. One strip from each filter was 

cut and placed into the sample holder for analysis using XANES spectroscopy. 

1.2.2 Oxygen K-edge XAS 

The oxygen K-edge XAS spectra were collected on the Spherical Grating Monochromator 

(SGM) beamline (11ID-1) at the Canadian Light Source in September 2010. The energy 

region of interest was selected using a spherical grating monochromator using the low 

grating option. The spectra were collected with a microchannel plate fluorescence yield 

(FLY) detector. Spectra were recorded from 520 eV to 570 eV. The entrance slits were 

set at 250 μm and the exit slits were varied between 25 and 50 μm in order to optimize 

the signal. 

1.2.3 Spectral Analysis 

The sample spectra were analyzed using the XAS data processing software Athena, 

version 0.8.57. (1) Nickel K-edge XANES sample spectra were calibrated using the in-situ 

nickel metal foil collected for each scan. The pre-edge range and post-edge range were 

fit using standard techniques. The normalized spectra were then averaged together to 

create a single sample spectrum for analysis. Least squares linear combination fitting 

was used to identify the predominant nickel species present in each sample by fitting 

each sample spectrum with weighted mixtures of the appropriate reference compounds. 

The nickel spectra were fit over a 100 eV range. 

The fits are limited by the presence of unique spectral features in the spectra and in the 

reference compounds. The complexity of sample matrices can make identification of the 

species present in a sample difficult. This can often limit the technique to an accuracy of 

± 5-10% depending on the number and identity of species present.

2.0 RESULTS 

The nickel K-edge XANES spectra of the standard nickel compounds are shown in Figure 

1. The XANES spectra for the nickel species on the sample filters are show in Figure 2 

(AN1), Figure 3 (AN2) and Figure 4 (AN3) and include the linear combination fit and the 

fitted component spectra. 

Linear combination (LC) fitting requires a library of standard compounds for comparison. 

In this study, ten different nickel compounds were selected, representing nickel sulfides, 

salts and oxides. The best fit is determined using combinations of different standard 

spectra. 

The results indicate that for each of AN1, AN2 and AN3, the major species is 

NiSO4

.

6H2O, Table 2. Differences between the collected spectra and the fits may be 

attributed to the fact that NiSO4

.

6H2O was used as the standard and the actual sulfate 

species in the samples may be the non-hydrated form or may be a more complex nickel 

sulfate compound. The spectra observed for AN1-AN3, and the fit associated with the 

spectra are consistent with results previously reported in the literature for oil fly ash. (2) 

Because the fit is not perfect, it may also be possible that other nickel species that are 

not included in the library of standards used in this fitting attempt are present at low 
5105 XANES Spectroscopic Analysis of Nickel Collected on Quartz Filters Page 3 

concentrations. Oxygen K-edge spectra were collected in order to eliminate NiCO3 as a 

contributing species. Figure 5 shows that the peak positions of the sample correspond 

to peak positions of the NiSO4

.

6H2O. Furthermore, the lack of a broad feature around 

540-550 eV also eliminates NiCO3. 

During the fitting, the presence of oxide species was ruled out due to the lack of a 

prominent peak around 8365 eV. A better fit was obtained in the absence of NiS, and 

nickel sulfide was therefore ruled out as a major contributing species. The presence of 

nickel subsulfide should produce a slight shift in the peak edge, or at the very least a 

prominent shoulder, the lack of these features suggests that nickel subsulfide is not 

present at detectable concentrations for LCF. Because Ni3S2 was of particular interest, 

the LC fitting was tested to determine the detection limits for Ni3S2 when NiSO4

.

6H2O is 

the main component. Fitting standards were created based on the filter results and a 

Ni3S2 component was added. In the fitting, nickel subsulfide could not be detected below 

5%. 

ANBlank, although it looked clean upon visual inspection, showed relatively small 

amounts of nickel in the XANES spectrum which is likely due to contamination. The 

levels of nickel on the blank filter were too low to carry out any meaningful LC fitting. 

Table 1. Results of the linear combination fitting analysis for the four filters. 

Sample 

AN1 ~ 100% NiSO4

.

6H2O 

AN2 ~ 100% NiSO4

.

6H2O 

AN3 ~ 100% NiSO4

.

6H2O 

ANBlank Ni is present. 

3.0 USE OF REPORT 

This report does not provide a legal opinion regarding compliance with applicable laws. 

The findings and conclusions of this report are valid only for those samples analyzed at 

the time this report was prepared. 

4.0 REFERENCES 

(1) Ravel, B.; Newville, M. J. Synchrotron Rad. 2005, 12, 537. 

(2) Pattanaik, S.; Huggins, F.E.; Huffman, G.P.; Linak, W.P.; Miller, A.C. Environ. Sci. 

Technol. 2007, 41, 1104. 
5105 XANES Spectroscopic Analysis of Nickel Collected on Quartz Filters Page 4 

Figure 1. Nickel K-edge XANES spectra of the Ni standard compounds 
5105 XANES Spectroscopic Analysis of Nickel Collected on Quartz Filters Page 5 
5105 XANES Spectroscopic Analysis of Nickel Collected on Quartz Filters Page 6 

Figure 2. Nickel K-edge XANES spectrum for sample AN1. The orange bars indicate the fitting 

range. 
5105 XANES Spectroscopic Analysis of Nickel Collected on Quartz Filters Page 7 

Figure 3. Nickel K-edge XANES spectrum for sample AN2. The orange bars indicate the fitting 

range. 
5105 XANES Spectroscopic Analysis of Nickel Collected on Quartz Filters Page 8 

Figure 4. Nickel K-edge XANES spectrum for sample AN3. The orange bars indicate the fitting 

range. 
5105 XANES Spectroscopic Analysis of Nickel Collected on Quartz Filters Page 9 

Figure 5. Oxygen K-edge XAS spectrum for sample AN3, NiCO3, and NiSO4.6H2O. The vertical 

lines show peak positions of AN3 corresponding to NiSO4.6H2O.