REMEDIATION IN-SITU OF WATER CONTAMINATED WITH DIESEL BY OXIDATION

WITH HIDROGEN PEROXIDE

Santiago Cardona-Gallo and Rosario Iturbe-Argüelles

Institute of Engineering, National Autonomous University of Mexico. P.O. Box 70-472,México, D.F. Tel: 56223335 ext. 05. Fax.56162164. Email: scardonag@iingen.unam.mx

ABSTRACT

The big quantities of hydrocarbons that take place in the world and in Mexico, have caused spills of raw and their derived, deteriorating in great measure the environment and particularly the sources of supply of underground water. In Mexico 27% of the drinkable water comes from the underground. The above-mentioned has lead to the necessity of obtaining treatment systems that are able to reduce rapid and economically viable contamination. This work presents the oxidation of the diesel fuel in solution with an oxidant agent like the hydrogen peroxide from industrial grade to 50%. It was used H 2O2, a well-known stronger oxidizer, its easy handling, low cost and a bigger breakup in the water than in the oxygen. Having an initial concentration of diesel of 45,000 mg/L in solution, in continuous horizontal agitation in a batch system during 114 hours. Periodic samples were taken. At the end of the 114 hours, the concentration of the hydrocarbon decline to 24,000 mg/L, obtaining a speed of reaction of 0.0047 h-1 (0.1128 d-1). The study was carried out without catalyst. The effluents presented a pH interval between 6.5 and 7.5. With the previous results some columns were designed which were operated by portion and compared with columns with hydrogen peroxide addition. This system for efficiency and low cost can be applied in different systems of treatment of diesel, in permeable reactivate barriers or in reactive zones.

Keys: diesel, oxidation, hydrogen peroxide

INTRODUCTION

During the last decade, the chemical oxidation has been developed and has shown be a useful technology; to clean contaminated places. While the chemical oxidation of an organic compound this compound is modified by an agent to final simpler products, having high oxygen content or a low hydrogen content than the original compound. The oxidative agents which are used in different circumstances include chlorine dioxide (CIO2) sodium hypochlorite (NaOCl) o calcium (Ca(OCl)2), hydrogen peroxide (H2O2), air, ozone (O3), phenton reaction, sodium permanganate (NaMnO4), solid redox reactions (ORC, oxigen release compound), and recently the potassium permanganate (KMnO4) which is considered a strong chemical oxidative to chlorinated organic compounds (Suthersan, 1997; Siegrist, 2000 y 2001). Several studies have been carried out where dibenzotiofeno has been oxidized using H2O2

(Collins et al., 1997), phenol (Ince y Apikyan, 2000), phenol y chlorophenols (Grigoropoulou y Philippopoulos, 1997), diesel (Tae Lee y Woong Kim, 2002, Kong et al., 1998), chlorinated hydrocarbons, solvents, oil hydrocarbons y valatile organic compounds (Yin y Allen, 1999).

METHODOLOGY

Batch. The kinetics oxidation of diesel was determined by means of the hydrogen peroxide in order to obtain its speed of transformation during 114 hours. The oxidation test was made in triplicate with a concentration in each lane of 40,000 mg/L diesel. 25 mL of synthetic contaminated solution were added. Afterward, 6.1 mL of H2O2 were applied according to the stoichiometrical equation. The lanes were placed under agitation by 48 hours to 50 revolutions per minute. Finally, the residual diesel in liquid phase was analyzed. The lanes had 40 mL. The kinetics of transformation works by the first order reaction (Crittenden, et al. 1999, Suthersan, 1997, Jenkins, 1997, Siegrist et al., 2000). The diesel equation proposed by Jackson (1990) C15H30, was applied to the stiochiometry oxidation of diesel by means of the hydrogen peroxide. C15H30 + 45H2O2 60H2O + 15CO2. C15H30 kg requires 4 kg of O2 = 7.29 kg of H2O2. Columns: They were daily fed by its upper part with a volume of 300 mL and a concentration of 10, 000 mg/L of diesel completely mixed. Every day the samples of all the columns were collected; from each column 300 mL were taken. Every 6 days the corresponding sample was analyzed in the gases chromatograph with a Hewlett Packcard mass selector 5890 serie II with technique 8015 EPA during 78 days. The mix of diesel and distillate water was carried out in a precipitate vessel of 500 mL with a continuous agitation since the solution was homogenized. The columns were built in transparent acrylic with length 20 cm and diameter 10.7 cm. The gasket was silica sand.

RESULTS

Batch:

Table 1. Results of diesel oxidation by hydrogen peroxideTime

(h)C 1

(mg/L)C 2

(mg/L)C 3

(mg/l)C

(mg/L) averagelnC/Co

0 43,472 45,505 45,336 44682 -0.01198103

1 40,738 43,368 44,136 43459 -0.02775405

2 37,408 42,631 43,575 41,450 -0.07508807

3 38,272 42,297 43,007 41,303 -0.07864127

4 34,212 41,694 41,489 39,332 -0.12752837

8 29,320 39,760 41,785 37,599 -0.17258637

12 28,298 35,002 37,942 35,333 -0.23475612

24 34,186 32,380 33,309 34,165 -0.26836287

28 31,921 31,746 34,359 32,886 -0.3065199

32 28,581 34,942 30,633 30,320 -0.38777728

49 30,150 29,863 34,359 34,650 -0.2542763

54 28,850 30,061 28,390 29,126 -0.42793395

78 25,930 24,990 27,679 28,870 -0.43678038

114 24,551 24,990 24,235 24,612 -0.59632881

y = 0.0047x + 0.1063R2 = 0.8374

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 20 40 60 80 100 120

Time (h)

lnC

/Co

Columns:

30cm

Add of H2O2

=10.7 cm

Silica sand0.85-0.60mm

Inflow

Outflow

Gravel

Gravel

Fig 2. Diagram and photography of the used columns

Fig 1. Oxidation Kinetic of diesel with H2O2

The columns 1 y 2 be operated with diesel add and

the 3 y 4 diesel only.

Table 2. Average results of oxidation diesel in columnsTime (days) Columns 1-2 (mg/L) Columns 3-4 (mg/L)

Diesel + H 2 O 2 Diesel6 552 69812 517 71818 708 83824 638 86730 1091 104336 1505 386242 1581 368448 2086 336254 3835 981860 1515 533466 763 733372 2618 650878 1217 6130

CONCLUSIONSThe kinetics of diesel oxidation with hydrogen peroxide could be obtained with a first order equation. The results obtained in batch and in columns allow to conclude that diesel can be oxidable with H202. The speed of reaction can permit the application of the oxidant agent to the remediation of contaminated soils and aquifers. The diesel volatilization test was made where it gave less than 1 mg/L of lost diesel. The data achieved conclude that the hydrogen peroxide due to its low cost, major dissolution in water and oxidative strength makes to it a good candidate to be used in cleaning systems.

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Grigoropoulou, H. et al (1997) Homogeneous oxidation of phenols in aqueous solution with hydrogen peroxide and ferric ions. Water Science Technology, Vol. 36, No. 2-3-, pp. 151-154.

Ince, N. H. et al (2000) Combination of activated carbon adsorption with light-enhanced chemical oxidation via hydrogen peroxide. Water Research, Vol. 34, No. 17, pp. 4169-4176.

Siegrist, Robert L. (2000) In situ chemical oxidation. Technology features & applications. Advances in innovation ground water remediation technologies. GWRTAC and EPA-TIO. June 6. Boston.

Siegrist, Robert L., et al. (2001) Principles and practices of in situ chemical oxidation using permanganate. Battelle Press. Columbus, Ohio, USA.

Lee, Byung-Tae and Kim, Kyoung (2002) Ozonation of diesel fuel in insaturated poeous media. Applied Geochemistry, vol. 17, pp. 1165-1170.

Kong, Sung-Ho, Watts, Richard J., Choi, Jin-Ho (1998) Treatment of petroleum-contaminated soils using iron mineral catalyzed hydrogen peroxide. Chemosfere, Vol. 37, No. 8, pp. 1473-1482.

Choi, H., Lim, H-N., Kim, J., Hwang, T-M., Kang, J-W. (2002) Transport characteristics of gas phase ozone in unsaturated porous media for in-situ chemical oxidation. J. Contaminant Hydrology, vol. 57, pp. 81-98.

Yin, Yujun and Allen, Herbert E. (1999) In situ chemical treatment. Groud-Water Remediation Technologies Analysis Center, GWRTAC. Technology evaluation report. Series TE-99-01