Remediation of PAH contaminated soil through
chemical oxidation
utilizing hydrogen peroxide and RegenOx
I. Heloise H. Tachauer 2011-06-06
Örebro University. School of Science and Technology Biologi C. Självständigt arbete. 15 hp
Abstract
Abstract
The chemical remediation of PAH contaminated soil provided by RGS90 was attempted utilizing two treatment options; hydrogen peroxide and RegenOx. Hydrogen peroxide was utilized at varying concentrations in order to determine the most efficient concentration for remediation. RegenOx, was utilized according to the directions provided by the manufacturer served as a comparison. Pre-treatment was conducted at a constant 1:1 L/S ratio for all treatments including the non-pre-treated as was applicable. Loss of water and loss of ignition studies were conducted with each of the treatments in order to degrade the organic content of the soil. Soil samples were run without pre-treatment as well as utilizing de-ionized water in order to create a comparative standard. Samples were pre-treated and kept covered under the fume hood in order to insure that all reaction occurred to completion and then placed in a 105°C oven for 24 hours to conduct the loss of water studies. A transfer to a 550°C oven for 2 hours then occurred in order to conduct the loss of ignition studies. A set of samples was then analyzed using PLE and gas chromatography with mass spectrometry in order to determine the chemical characterization of the sample and to determine the true efficiency of removing PAHs, specifically the 16 US-EPA classified priority PAHs, due to the treatments conducted. Results for the studies conducted were inconclusive, with the treatment with RegenOx yielding the best relative results, treatment with hydrogen peroxide yielding a low fairly constant percentage removal of organics and PAHs thus illustrating that more studies, potentially utilizing alternative chemical treatments and/or treatments combining chemical and biological methods may be required to obtain more preferable results.
Introduction
Polycyclic aromatic hydrocarbons, known as PAHs are a type of organic chemicals that are composed of two or more fused benzene rings that originate from the combustion of fossil fuels in heat and power generation, refuse burning and coke ovens. [1] Together the aforementioned sources are responsible for the emissions of the carcinogenic hydrocarbon benzo[a]pyrene (BaP). Stationary fuel sources are responsible for 97% of PAH emissions in the air. [10] Vehicle emissions, such as automobile or truck emissions, contribute a portion of the BaP but its contribution is less significant than that of the aforementioned sources. There exist some natural sources of PAHs, sources such as volcanic activity and forest fires, but anthropogenic sources are deemed the most significant in terms of air pollution. [1] Most PAHs located in the environment are there due to being products of incomplete combustion or pyrolysis of fossil fuels. According to
the Swedish Environmental Protection Agency there are roughly 80,000 contaminated sites in Sweden and many of these sites are polluted with PAHs. Plausible locations include old gaswork sites, gas stations and former wood impregnation facilities [4][7]. PAHs with low molecular weights are more susceptible to degradation therefore are found in lower concentrations in industrial sites than those with high molecular weights [2]. PAHs are classified as persistent organic pollutants (POPs) under the UNECE Protocol for Persistent Organic Pollutants; because of this classification the intention is to gradually reduce their production [10].
Remediation of soils is a pertinent matter. Detoxifying and purifying the soil is profitable not only in terms of finances but also in terms or societal health. PAHs are toxic and are identified as being mutagenic (affecting development and reproduction) and carcinogenic. Their mutagenic property is in part because of reactive epoxides are formed that are able to react with DNA during their metabolism [2]. In terms of their carcinogenic property it seems that the PAHs must have a minimum of four rings in order to be characterized as carcinogenic. [2]. Some PAHs are known to cause birth defects and mutations, and consequently pose some risk to wildlife that maybe exposed by environmental emissions.[10] There are 16 recognized PAHs to be of priority, often given the name “priority PAHs” that are strictly monitored. [5] In order to achieve a reduction of PAHs several methods have been utilized with varying degrees in success in order to phase out the presence of this pollutant.
Methods of remediation can be placed under four main characterizations; physical or biological, thermal or chemical and can be utilized as individual methods or in combination. Potential physical treatments include separation techniques such as soil washing and pressurized water extraction. Soil washing utilizes water based solvents, in order to separate the intended substance, its efficiency is limited to coarse soils since there is more permeable for the liquid and are able to bind lower amounts of contaminants since they have a smaller particle surface area per unit volume than silt clay and/or organic contents. [3] [11] In regards to pressurized hot water extraction, separation works due to water utilized being brought to supercritical state. Water is at supercritical state when 374°C and 221 bar of pressure are obtained [2]. Degradation does not occur in the duration of this process, a method such as UV degradation is required as a post treatment in order to render the soil safe for disposal.
and water. Microorganisms are stimulated to consume the contaminants thus removing/degrading them. There are several methods for bioremediation; three of these include land farming, composting and bioreactors/bioslurries. Land farming involves spreading the contaminated soil over a treatment area, and adding microorganisms along with proper nutrients required to stimulate the organisms’ activity and is effective at reducing the concentrations of PAHs with three rings and fewer. [14] Composting involves adding microorganisms to soil that is concentrated with materials high in organic content. Soil that has been composted by microorganisms can be observed in having a higher concentration of organic matter, this higher concentration of organic matter will result in higher microbial activity thus leading to a more efficient rate of degradation. [2] Bioreactors/bioslurries is a method in which a mixture of water and microorganisms is added to soil as a treatment under controlled circumstances. Since, this method can be so controlled in can result in highly efficient contaminant degradation.
Chemical methods are those in which the contaminant’s chemical structure is utilized in order to react with or break down the contaminants components. There are a myriad of possible procedures, and some of these include: ozonation, photolytic and most importantly in terms of this study oxidation. Ozonation is a method of oxidizing, either directly or indirectly, the contaminants utilizing the reaction between the ozone molecule and the contaminant as a method of oxidation. If direct oxidation occurs through reactions with the ozone molecule and the contaminant meanwhile indirect oxidation involves the production of hydroxyl radicals. [2] Photolytic oxidation is a method through which contaminants are oxidized utilizing ultraviolet light. This method is not directly utile for soil remediation but in conjunction with some solubility enhancement method (for ex. Soil washing) or in combination with oxidative methods can aid in the process’ effectiveness. [2]
Chemical oxidation is a method that optimizes the interactive chemical properties in order to destruct contaminants through reaction with an oxidant. Oxidants vary and have various values of standard oxidation potentials. Hydroxyl radicals, sulfate radicals, ozone and hydrogen peroxide have relatively high standard oxidation potentials that vary from 1.8 to 2.8. [2] Hydrogen peroxide was selected as the oxidizing agent since its decomposition by products is water and oxygen which are nontoxic. Two equations that demonstrate the decomposition of hydrogen peroxide to water and oxygen are:
H2O2 H2O + Ö
2H2O2 2H2O+ O2
In order to demonstrate that oxidation can occur in the presence of hydrogen peroxide the following chain of reactions serves as illustration. The formation of the hydroxyl group allows for numerous chemical reactions to occur and aids in the oxidation of PAHs.
H2O2 + Fe2+ Fe3+ + OH- + HO • Fe3+ + H 2O2 Fe2+ + H+ + HO2 • Fe3+ + HO 2 • Fe2+ + O2 + H+ HO • + Fe2+ Fe3+ + OH -HO • + H2O2 HO2 • + H2O HO2 • + Fe2+ + H+ Fe3+ + H2O2 2H2O2 2H2O + O2 [6]
Chemical oxidation and bioremediation each have different functional pathways. Bioremediation utilizes either anaerobic or aerobic condition in addition the biological mechanisms located within the microorganism in order to decompose the contaminant targeted within the soil. Meanwhile chemical oxidation focuses on the release of gases, such as oxygen and carbon dioxide, and formation of byproducts created by direct or indirect interaction with the targeted contaminant in order to remediate.
Thermal treatments are ones in which varying degrees of temperature are utilized in order to conduct remediation. Highly polluted areas where total organic contents exceed 20-25% are considered for this kind of remediation and it is considered an effective technique for degrading PAHs. [13] Thermal desorption is a method through which contaminated soils are heated to between 100-600°C in order to vaporize the contaminants.[2] This method does not destroy contaminants but allows for their collection in order to be destroyed utilizing other methods.
The following are the intentions of this study are:
1.) To remove the most possible amount of PAHs from contaminated soil
2.) To obtain an effective chemical oxidation method utilizing hydrogen peroxide as the oxidant 3.) To compare the oxidative effectiveness of hydrogen peroxide at varying concentrations in comparison with RegenOx
Materials and methods
Materials/sampling:
PAH contaminated soil provide by RGS90 was sifted to obtain those grain sizes smaller than 0.2mm.
Solvents and chemicals:
• Hydrogen peroxide from (Scharlab S.L.. Spain. Batch # 12397502)
• RegenOx (Regenesis. San Clemente. CA)
• Silica gel/powder (Merck)
• Anhydrous sodium sulfate (Fluka)
• N-hexane (Riedel de Haen)
• Dichloromethane (Riedel de Haen)
• Ethanol (Kemetyl)
• Internal PAH standards (Labor. Dr. Ehrenstorfer- Scharfers; Augsberg Germany)
• PAH quantification mixture (Labor. Dr. Ehrenstorfer- Scharfers; Augsberg Germany)
• Recovery standard (Labor. Dr. Ehrenstorfer- Scharfers; Augsberg Germany)
Chemicals were diluted in order to be utilized:
• Hydrogen peroxide: 5%, 10%, 15%, 20%, 25%, 30%, 35% (concentrate)
Preliminary test setup and treatment:
Sifted PAH contaminated soil. 3g. was added to a crucible (Rosenthal Technik. made in Germany). Crucibles were weighed before the addition of sample and after in order to obtain accurate readings. Test was done in triplicate to provide a true representative value. Samples were placed in a 105°C oven/furnace (Electrolux. made in Sweden) for 24 hours. Samples were removed, weighed and water content was calculated. Loss of ignition studies were conducted by placing the samples
in an oven/furnace (Nabertherm. made in Germany) at 550°C for 2 hours. Soil was then weighed and placed back in 550°C oven/furnace for 20 minutes then weighed and placed in the exicator. Loss of ignition was then calculated.
Saturation test:
To discover the optimal amount of hydrogen peroxide required a 4g contaminated soil sample was set up and 35%, hydrogen peroxide was added in a 1:1 L/S. ratio Additional 35%, hydrogen peroxide was added in 24 hour intervals until the sample stopped displaying a visible reaction. Mass of the sample was recorded at each 24 hour interval. After the completion of this test a loss of ignition study was conducted in order to determine if increased reaction efficiency is obtained with increased amounts of hydrogen peroxide.
Sample set up for PAH analysis:
Three sets of samples run in duplicate were created. Samples, 3g, were placed in beakers (Vitlab, made in West Germany) and each pair of samples received different treatments. Hydrogen peroxide utilizing a 1:1 L/S ratio was added, at 35% (concentrate) to one set and at 15% to the other. Samples were left covered in the fume hood for 24hrs to ensure reactions ran to completion. The remaining set was treated with 3mL of de-ionized water, covered and left 24hrs in the fume hood in order to create a comparable set. Samples were transferred to amber jars and kept sealed from air. Sample set up (pretreated) and treatment:
Samples, seven sets of duplicate 3g each, were set up in beakers (Vitlab. made in West Germany). Hydrogen peroxide (Scharlab S.L., Spain) at 35% (concentrate), 30%. 25%. 20%. 15%, 10%, and 5% was added at a 1:1 L/S ratio. A single control utilizing de-ionized water, added at the same ratio and all samples we left covered in the fume hood for 24hrs. Water content and loss of ignition studies were conducted.
Samples were placed in a 105°C oven/furnace for 24 hours. Loss of ignition studies were conducted by placing the samples in an oven/furnace at 550°C for 2 hours. Soil was then weighed and placed back in 550°C oven/furnace for 20 minutes then weighed and placed in the exiccator. Loss of ignition was then calculated.
Soil re-test in order to confirm previous results:
In order to confirm the validity of the results obtained 15 additional 3g samples were prepared. Concentrated, 35%, hydrogen peroxide was added to five of the samples in a 1:1 L/S ratio. De-ionized water was added a 1:1 L/S ratio to five samples and sample was left in its original state for the remaining five samples. Samples were covered and left in the fume hood for 24hrs.
Samples were placed in a 105°C oven/furnace for 24 hours. Samples were removed, weighed placed back in the 105°C oven/furnace for 20 minutes until a stable weight reading was obtained, samples were re-weighed and water content was calculated. Loss of ignition studies were conducted by placing the samples in an oven/furnace set at 550°C for 2 hours. Soil was then weighed and placed back in 550°C oven/furnace for 20 minutes until a stable weight reading was obtained, then weighed and placed in the exiccator. Loss of ignition was then calculated.
Set up for PAH analysis:
Hydrogen peroxide was used in two different concentrations, concentrate and 15%. RegenOx (Regenesis. San Clemente. CA) was prepared according to the manufacturers provided instructions. Samples were run in crucibles in duplicate and four sets were created. Four sets included treatments with: 35% hydrogen peroxide (concentrate), 15% hydrogen peroxide, RegenOx and de-ionized water. Treatments were conducted utilizing samples of 4g each and the oxidants were added at a 1:1 L/S ratio. Samples were left covered in the fume hood over night in order to ensure that all reactions occurred to completion.
The sets of samples were divided in preparation for analysis. Two grams of the treated soil mixture were placed in an amber jar and set aside in the freezer for analysis. Remaining samples in the crucible were placed in a 105°C for 24 hours in order to remove water. Samples were weighed and placed back in the oven/furnace for 20 minutes until a sustained weight reading was obtained. Loss of ignition studies were then conducted by placing the samples in a 550°C oven/furnace for 2 hours, samples were removed and placed back in the oven for 20 minutes until a stable weight reading was obtained.
Pressurized liquid extraction:
Total PAH content of the soil samples was determined utilizing pressurized liquid extraction (PLETM, Fluid Management Systems, Inc.) with in cell clean up [8][9]. Stainless steel extraction
approximately one gram of soil and a layer of Na2SO4 on top. 50 μl of internal standard solution
was added to the top of the soil layer. Extractions were performed in two static cycles using hexane/dichloromethane 9:1. Heat up and extractions times were 10 minutes (120 °C and 1700 psi) and the flush volume was 80 mL. After the second cycle the flush volume was reduced to 30 mL and the remaining extracts were evaporated to roughly 1 mL. Activated copper powder was added to the individual samples to aid in the removal of elemental sulfur. Samples were then filtered through a glass pipette whvile utilizing glass wool and Na2SO4 as filtering mechanisms. The
volumetric flasks, containing the extract were washed three times utilizing hexane, this hexane was filtered through in order to clean the filter and to regain as much of the extract as possible. Samples were then evaporated to approximately 1mL utilizing nitrogen gas and then evaporated into 1mL of toluene and 50 μl of recovery standard was added.
GC-MS analysis:
Samples were analyzed using HP6890 gas chromatograph connected to a HP 5973 low resolution mass spectrometer using electron ionization (EI) at 70eV. The gas chromatograph is equipped with a DB-5 capillary column (30m x 0.25mm, 0.25um film thickness: J&W Scientific). The GC temperature program started with an initial oven temperature at 90°C which was maintained for 1 minute, heating 8 °C /min to 300 °C (held for 5 minutes). The injector
temperature was 300 °C and 1ul of the sample extract was injected in split-less mode.
Detection was made in single ion monitoring (SIM) mode. PAHs were identified and quantified using a quantification standard mixture including all PAHs in addition to the IS and RS. PAH concentrations were calculated using the internal standard method.
3 Results and discussion
Water content and loss of ignition studies were conducted solely on the untreated PAH contaminated soil the data shown in table 1 and table 2, the raw data for which are found in Appendix 1 tables 3 and 4, illustrate that the average loss of water for non-pre-treated soil was 5.11% and that the average loss of organics, determined in conducting the loss of ignition studies was 12.51%.
Table 1: Illustrates the percentage loss of water of the non-pretreated PAH contaminated soil when placed in 105 °C oven/furnace for 24hrs.
Sample # Original Mass (g) Mass after 24hrs at
105°C (g) % water content 1 3.0329 2.8707 5.348 2 3.0226 2.8827 4.628 3 3.0047 2.8435 5.365 Avg: 5.11 %
Table 2: Illustrates the percentage loss of organics of non-pretreated PAH contaminated soil when placed in an 550 °C oven/furnace for 2hrs.
Crucible # Original Mass Final Mass % Loss of ignition
1 2.8707 2.488g 13.33
2 2.8827 2.5469g 11.648
3 2.8435 2.4864g 12.558
Avg: 12.51%
Figure 1 (reference table 5,6,7 in appendix 1 for raw data) illustrates a fairly consistent loss of organics regardless of the concentration of hydrogen peroxide, the average loss of organics ranging from 12.05 to 13.5%. The missing values are due to those samples not being transferable. In order to ensure the validity of these results a secondary test was conducted, illustrated in figure 2 (reference table 8 and 9 in appendix 1 for raw data). Loss of organics maintained relatively unchanged regardless of the treatment conducted, the average loss of organics ranging from 10.95 to 11.17. These unchanged results in the loss of organics could be due to the formation of manganese dioxide because contaminated soil can contain a high concentration thereof. Another potential reason for this result is the formation of the iron oxides due to the presence of iron in soil. Hydrogen peroxide when added during the treatment would firstly react with the manganese and the iron in the soil before coming in contact with the organic material and degrading the PAHs found in the soil, thus explaining the low percentage loss of organics found in this study.
Figure 1: Illustrates the percentage loss of organics due to loss of ignition studies, done in duplicates with decreasing hydrogen peroxide concentrations, starting at concentrated, 35% and decreasing consecutively by 5%.
Figure 2: Percentage loss of organics of PAH contaminated samples under three treatments with 5 replicates each: concentrate hydrogen peroxide, de-ionized water, and soil by itself due to loss of ignition studies
obtained, thus leading us to believe that although hydrogen peroxide is powerful oxidant it is not the option for this particular soil sample.
.
Figure 3: Illustrates the amount of each PAH found within each of the soil samples under three different treatments; 15% H2O2, 35% H2O2, RegenOx and untreated soil when examined by GC-MS.
Figure 3 (raw data Table 10, Appendix 1) illustrates that overall it seems that RegenOx is the most efficient treatment even though the remaining PAH content is still relatively high. It is interesting to note that the untreated sample and the the sample treated with 15% H2O2 have similar PAH
concentrations when analyzed by GC-MS this could be due to the soil samples not being completely homogeneous. When analyzing the percent concentrations of the individual PAHs (appendix 1, Table 11) phenanthrene (concentrations ranging: 17.47811- 21.52335 ng/kg is the PAH with the highest percent concentration, followed by anthracene (concentrations ranging: 14.05053-17.62575ng/kg) and fluoranthene (concentrations ranging: 13.17093-15.40094 ng/kg).
The relatively equal percentages of organics removed indicates that the treatment was not efficient, if the treatment were efficient then the amount of organics removed and the amount of PAHs degraded should have increased. A possible explanation for these low/inconclusive results is that the hydrogen peroxide first reacted with the inorganic compounds and that the reaction ran to completion too quickly so maybe the organics on the surface were degraded but a much lower percentage was degraded below the upper surface. Had the soil samples had a lower organic content thefor the treatment with hydrogen peroxide could have been more efficient.
4 Conclusions
In the process of this experiment it was discovered that there are several potential factors that disrupt successful chemical oxidation of PAH-contaminated soil. Due to the potential formation of iron and magnesium oxides, the degradation of PAHs has been impeded due to the hydrogen peroxide was consumed by their formation. A clearer knowledge of the chemical characterization of the soil initially would aid in determining a more efficient oxidant.
Using GC-MS analysis of PAHs, it was discovered that there was a high remaining concentration of PAHs even after treatment thus leading to the need for further investigative studies. When obtaining the soil samples it is important that a bit of every element in the soil is present in each sample, having a representative soil sample initially not only insures for more efficient treatments but also insures for better overall results. Developing a more effective way of homogenizing the contaminated soil prior to conducting the study may be recommended.
In the future a treatment that combines chemical oxidation with biological methods may be recommended. Chemical oxidation may serve as the preparation/separation step in terms of releasing the PAHs from their current bonds. Separating them may allow for easier access therefore increases the potential of removing more PAHs from the soil.
Acknowledgements
Would like to thank my supervisors, Magnus Engwall and Maria Larsson for their guidance throughout the process of the experiments. Also the input of Stefan Karlsson was invaluable. I would like to thank Marcus Norden and Ola Westman for their solid advice and direction
References
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11. Sedlak. D.L.. Andren. A.W. (1994) The effect of sorption on the oxidation of polychlorinated-biphenyls (PCBs) by hydroxyl radical. Water Res. 28. 1207-1215 12. Sutherson. Suthan S. Remediation engineering: Design Concepts. Boca Raton. FL: CRC
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Appendix 1
Table 3: Illustrates the results of the loss of water studies on the non pre-treated PAH contaminated soil including the mass of the crucibles
Crucible # Empty crucible
weight (g)
Crucible + sample (g)
Crucible + sample after 24hrs at 105 °C (g)
1 25.0455 28.0784 27.9162
2 23.0854 26.1080 25.9681
3 25.5829 28.5876 28.4264
Table 4: Illustrates the results of the loss of ignition studies on the non-pretreated PAH contaminated soil including the mass of the crucibles and the mass of the samples themselves
Crucible # Original mass (g) Mass after 2hrs at 550
°C (g) 15-20 minutes later at 550 °C (g) 1 27.9162 27.5366 27.5343 2.8707 2.4911 2.4888 2 25.9681 25.6323 25.6338 2.8827 2.54693 2.5469 3 28.4264 28.0693 28.0703 2.8435 2.4864 2.4864
Table 5: Illustrates the initial mass of the pre-treated soil samples, treated with H2O2 of varying
concentrations
Conc H2O2 Beaker # Beaker mass (g) Beaker + sample
mass (g) Original mass of sample (g) 35% 1a 9.19 12.19 3.00 1b 9.14 12.14 3.00 30% 2a 9.18 12.18 3.00 2b 9.16 12.16 3.00 25% 3a 9.37 12.37 3.00 3b 9.18 12.18 3.00 20% 4a 9.18 12.18 3.00 4b 9.15 12.15 3.00 15% 5a 9.16 12.16 3.00 5b 9.18 12.18 3.00 10% 6a 9.20 12.20 3.00 6b 9.19 12.19 3.00 5% 7a 9.16 12.16 3.00 7b 9.17 12.17 3.00 H2O/0% H2O 9.41 12.41 3.00
(%) crucible (g) Sample + crucible (g) Crucible after 24hrs at 105 °C (g) at 550 °C (g) minutes at 550 °C (g) 35 1a 23.0845 29.8544 25.6630 25.3440 25.3380 1b 27.2388 35.5047 29.8418 29.5380 29.5354 30 2a 25.0453 28.7277 27.5342 27.7029 27.7007 2b 25.5814 32.5514 28.0267 27.1625 27.1544 25 3a 34.9048 41.1558 37.0124 - -3b 28.9335 35.2606 31.5213 31.1943 31.1887 20 4a 25.9143 38.0743 28.5176 28.1649 28.1609 4b 19.5061 27.2974 22.1288 21.7932 21.7899 15 5a 35.2149 43.9191 37.9404 - -5b 32.8379 43.0980 35.5616 - -10 6a 34.6461 42.3686 37.4110 - -6b 17.4126 27.0063 20.1780 19.8059 19.8079 5 7a 22.3736 32.5928 25.1445 24.7702 24.7665 7b 20.7245 34.9326 23.4774 23.1125 23.1098 0 H2O 23.6391 28.7471 26.3408 25.9801 25.9789
Table 7: Illustrates the mass of the samples, their duplicates when treated with hydrogen peroxide with decreasing concentrations at 5% increments before and after loss of ignition studies
Crucible # Original mass of sample (g) After 2hr at 550 °C (g) After 20 minutes at 550 °C (g) % loss of organics 1a 2.5785 2.2595 2.2535 12.4 1b 2.6026 2.2992 2.2966 11.7 2a 2.4889 2.6576 2.6554 35.35 2b 2.4453 1.5811 1.578 -3a 2.1076 - - -3b 2.5878 2.6808 2.2552 12.64 4a 2.6033 2.2506 2.2466 13.55 4b 2.6227 2.2871 2.3953 12.796 5a 2.7255 - - -5b 2.7237 - - -6a 2.7469 - - -6b 2.7654 2.3933 2.3953 13.5 7a 2.7709 2.3966 2.3929 13.51 7b 2.7529 2.388 2.3853 13.26 H2O 2.7017 2.341 2.3398 13.36
Table 8: Illustrates the initial mass of the samples with varying treatments; utilizing 35% H202,
de-ionized water or the samples left in their initial condition Crucible # Crucible weight
(g)
Crucible + soil (g)
Initial weight (g) What was added
Concentrate 1 23.08 26.08 3.00 35% H202
Concentrate 3 28.93 31.93 3.00 “ Concentrate 4 25.04 28.04 3.00 “ Concentrate 5 25.58 28.58 3.00 “ H1 (de-ionized water) 20.72 23.72 3.00 De-ionized water H2(de-ionized water) 19.50 22.50 3.00 “ H3(de-ionized water) 17.41 20.41 3.00 “ H4(de-ionized water) 23.64 26.64 3.00 “ H5(de-ionized water) 22.37 25.37 3.00 “ Contaminated soil 1 27.24 30.24 3.00 Nothing Contaminated soil 2 21.37 24.37 3.00 “ Contaminated soil 3 23.37 26.37 3.00 “ Contaminated soil 4 20.01 23.01 3.00 “ Contaminated soil 5 23.58 26.58 3.00 “
Table 9: Illustrates the resulting mass of the samples after treatments; concentrate H2O2, de-ionized
water and untreated sample after water content and loss of ignition studies and the resulting percentage losses Crucible # Weight after 24hrs at 105 °C (g) After 20min at 105 °C (g) Weight after 2hrs at 550 °C (g) Weight after 20 min at 550 °C (g) % loss of organics %loss of water C1 25.9086 25.9074 25.5773 25.5754 10.81% 5.71% C2 28.7446 28.7440 28.4218 28.4206 10.65% 5.85% C3 31.7776 31.7750 31.4420 31.4432 10.29% 5.08% C4 27.8652 27.8642 27.5230 27.5192 11.32% 5.83% C5 28.4002 28.3969 28.0525 28.0573 11.70% 6.00% H1 23.5211 23.5281 23.1835 23.1812 12.02% 6.63% H2 22.3579 22.3621 22.0021 220013 10.64% 4.74% H3 20.2453 20.2481 19.8870 19.8797 11.54% 5.49% H4 26.4675 26.4741 26.1075 26.1059 11.88% 5.75% H5 25.2693 25.2728 24.9077 24.9096 9.37% 3.36% S1 30.1075 30.1106 29.7384 29.7403 10.77% 4.42% S2 24.2365 24.2381 23.8631 23.8581 10.96% 4.45% S3 26.2388 26.2416 25.8685 25.8680 10.77% 4.37%
Table 10: Illustrates the quantity of each individual PAH in under four different treatments; 15% H2O2, 35% H2O2, RegenOx and untreated once analyzed by GC-MS
Extracted Soil 0.971 1.0142 0.935 0.5118
dryweight 0.64 0.64 0.64 0.95
Name 15% 35% RegenOx untreated
Naphtalene 143722.3 2 108932.2 2 164393.8 8 170714.5 1 Acenaphtylene 116202.85 139985.8 131346.76 131983.09 Acenaphthene 1018634 1004941.2 947146.22 548707.14 Fluorene 1403671. 6 1368110. 3 1291594. 8 1455435. 3 Phenanthrene 3479273. 1 2817886. 8 2427902. 9 3420971. 2 Anthracene 3019850 2421003. 8 1951774. 9 2539509. 3 Fluoranthene 2564480. 1 2096871. 1 1829587. 6 2447860. 8 Pyrene 1892723.2 1655665.2 1433965.1 1855084.2 benzo(a)anthracene 920798.79 984870 944485.46 676879.33 Chrysene 1037101. 2 994565.4 5 1007075. 4 875675.7 4 Benzo(bfluoranthene 595551.7 8 690246.4 7 696669.2 8 682788.1 Benzo(k)fluoranthene 256230.2 1 222815.2 4 223398.7 3 288611.5 1 Benzo(a)pyrene 353442.8 1 367984.3 1 426651.7 4 401973.8 4 Indeno(1,2,3-cd)pyrene 178020.0 8 196360.2 8 202956.2 2 189951.4 6 Dibenz(ah)anthracene 17599.286 61421.256 61489.639 61334.609 Benzo(ghi)perylene 135872.33 145985.75 150668.95 146748.32 Total concentration 17133174 15277645 13891107 15894228 Ng/g Total concentration 17133.174 15277.645 13891.107 15894.228 mg/kg
Table 11: Percent concentrations of PAHs found after soil treatment, four treatments; 15% H2O2,
35% H2O2, RegenOx and untreated after analysis with GC-MS
Name 15% 35% RO untreated Naphtalene 0.83885 4 0.713017 1.18344 7 1.074066
Acenaphtylene 0.67823 3 0.916279 0.94554 6 0.830384 Acenaphthene 5.94539 6.577854 6.81836 4 3.452241 Fluorene 8.19271 2 8.954982 9.29799 7 9.157005 Phenanthrene 20.3072 3 18.44451 17.4781 1 21.52335 Anthracene 17.6257 5 15.84671 14.0505 3 15.97756 Fluoranthene 14.96792 13.72509 13.17093 15.40094 Pyrene 11.04713 10.83718 10.3229 11.67143 benzo(a)anthracene 5.37436 2 6.446478 6.79920 9 4.258649 Chrysene 6.05317 7 6.509939 7.24978 5 5.509394 Benzo(bfluoranthene 3.47601 6 4.518016 5.01521 8 4.295824 Benzo(k)fluoranthene 1.49552 1 1.45844 1.60821 4 1.815826 Benzo(a)pyrene 2.062915 2.408645 3.071402 2.529055 Indeno(1,2,3-cd)pyrene 1.039037 1.285278 1.461051 1.195097 Dibenz(ah)anthracene 0.10272 1 0.402034 0.44265 5 0.385892 Benzo(ghi)perylene 0.79303 7 0.955551 1.08464 3 0.923281
Table 12: Illustrates the results loss of ignition test conducted on a sample on which a saturation test had been conducted with hydrogen peroxide and the PAH contaminated soil at a 1:1 L/S ratio Massof crucible (g) Mass of crucible + sample (g) Weight after 24hrs at 105 °C (g) After 20min at 105 °C (g) Weight after 2hrs at 550 °C (g) Weight after 20 min at 550 °C (g) % loss of organics # of H2O2 additions at 1:1 L/S ratio 21.3688 35.3607 24.6502 24.6516 24.3013 24.3025 10.63 5
