COMPOSITION AND METHOD FOR RECOVERY AND/OR BIOREMEDIATION OF OIL SPILLS AND/OR HYDROCARBONS

Abstract

A composition and method for recovery and/or bioremediation of oil spills and/or hydrophobic hydrocarbons includes (a) cellulosic material, (b) a charged polymer adsorbed to the cellulosic material, and optionally (c) microorganisms combined with the polymer and/or cellulosic material.

Claims

1.-15. (canceled)

16. An absorbent composition for recovery and/or bioremediation of oil spills and/or hydrophobic hydrocarbons, the composition comprising: cellulosic material, comprising semi-chemical pulp, mechanical pulp, thermomechanical pulp (TMP) or chemithermomechanical pulp (CTMP); at least one layer of a charged polymer adsorbed to said cellulosic material, wherein the charged polymer is a polyelectrolyte selected from polyvinylamine (PVAm), polyacrylamide, polyacrylic acid (PAA), polymethacrylic acid, chitosan, cationic gelatin, poly DADMAC, polyallylamine, polyethylenimine, anionic nanocellulose, sodium lignin sulfonate, sodium polyacrylate, anionic polyacrylamide, anionic glyoxalated polyacrylamide, poly-(sodium styrene sulphonate) and/or poly(vinylphosphonic acid); and optionally microorganisms combined with said polymer and/or cellulosic material.

17. The absorbent composition according to claim 16, wherein at least one polyelectrolyte is polyvinylamine (PVAm) including unmodified PVAm or PVAm modified with, straight or branched and optionally substituted alkyl chains, preferably PVAm is unmodified.

18. The absorbent composition according to claim 17, comprising a first layer of polyvinylamine (PVAm).

19. The absorbent composition according to claim 17, comprising a single of layer of polyvinylamine (PVAm).

20. The absorbent composition according to claim 18, comprising multiple layers of consecutive cationic and anionic polyelectrolytes, such as three layers of PVAm-PAA-PVAm.

21. The absorbent composition according to claim 16, comprising microorganisms selected from bacteria, fungi and archaea, preferably the microorganisms comprise archaea.

22. The absorbent composition according to claim 16, wherein said composition has higher affinity for oil than water.

23. A method for recovery and/or bioremediation of oil spills and/or hydrophobic hydrocarbons, comprising the steps of: contacting oil spills and/or hydrophobic hydrocarbons with the composition according to claim 16; admitting the composition to absorb the oil spills and/or hydrophobic hydrocarbons; and optionally collecting the composition.

24. The method according to claim 23, wherein the composition absorbs at least its double weight following as a result of the contacting step.

25. The method according to claim 23, performed in water or on a wet surface.

26. The method according to claim 23, performed on a dry surface.

27. The method according to claim 23, comprising collecting the composition; and compressing the composition to recover said oil spill and/or hydrophobic hydrocarbons.

28. The method according to claim 23, comprising retaining the absorbed oil spills and/or hydrophobic hydrocarbons in the composition for at least on day before collecting the composition.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0039] FIG. 1 shows the amount (g/g pulp) of diesel and diesel/H.sub.2O (diesel mixed with water) which is absorbed by unmodified kraft pulp and mechanical pulp.

[0040] FIG. 2 shows from left to right the behavior unmodified mechanical pulp (Ref), 1L-PVAm layered kraft pulp (1L) and 3L-PVAm/PAA/PVAm layered kraft pulp (3L) in water.

[0041] FIGS. 3 and 3b show absorption of water and oil, respectively.

[0042] FIG. 4 shows the filtration of a mixture comprising 10 ml hydraulic oil and 30 ml water through 0.5 g unmodified mechanical pulp (REF) and 1L-PVAm layered mechanical pulp (1L).

EXAMPLES

Example 1

[0043] Fiber Disintegration

[0044] Dried bleached kraft pulp (KRAFT) and dried unbleached mechanical pulp (MP) were resuspended in deionized water and disintegrated. One layer of PVAm or three layers of PVAm/PAA were adsorbed onto the resulting fiber products as described below.

[0045] Fiber Modification—1 Layer (i.e. Example of Single Layer)

[0046] A single layer of the polyelectrolyte PVAm was adsorbed onto the fiber products at a fiber consistency of 0.25% w/w, i.e. a 0.25% polymer w/w was added to the cellulose. The single layer of PVAm were adsorbed onto the fibers at a polymer concentration of 0.10 g/L and a NaCl concentration of 100 mM under constant stirring at pH 9.5. Excess polymer was removed by rinsing the sample with deionized water. Finally, the fibers were rinsed with acidic water (pH<3.5) prior to drying.

[0047] Fiber Modification—3 Layers (i.e. Example of Multi-Layer)

[0048] Three layers of the PVAm/PAA/PVAm were adsorbed onto the fiber products at a fiber consistency of 0.5% WW. The polyelectrolyte multilayer of PVAm were adsorbed onto the fibers at a polymer concentration of 0.10 g/L and a NaCl concentration of 100 mM under constant stirring. The adsorption scheme was as follows: PVAm (pH 9.5), PAA (pH 3.5) and PVAm (pH 9.5). After each step, excess polymer was removed by rinsing the sample with deionized water. Finally, the fibers were rinsed with acidic water (pH<3.5) prior to drying.

[0049] Hence in summary, the cellulosic material (i.e. pulp) is modified by adding polymer, salt and adjusting pH for adsorption of the polyelectrolyte to the cellulosic material.

[0050] The fiber samples resulting from the above described 1- and 3-layer modifications are in FIGS. 1-5, designated according to the number of layers they contained, e.g. 3L fibers possess three layers of polymers, i.e. PVAm/PAA/PVAM. Similarly, 1L fibers possess one layers of polymers, i.e. PVAm.

Results

[0051] FIG. 1 shows the amount (g/g pulp) of diesel and diesel/H.sub.2O (diesel mixed with water) which is absorbed by unmodified kraft pulp and mechanical pulp. Both pulps have similar absorptions. Similar results were observed for 3-layered kraft pulp (data not shown).

[0052] FIG. 2 shows from left to right the behavior unmodified mechanical pulp (Ref), 1L-PVAm layered kraft pulp (1L) and 3L-PVAm/PAA/PVAm layered kraft pulp (3L) in water. FIG. 2a shows the behavior after 0 minutes, i.e. at the start of the test, while FIG. 2b shows the behavior after 1 day. The results clearly show that most of the 1-PVA layered kraft pulp and 3L-PVAm/PAA/PVAm layered kraft pulp float on the surface of water while most of the unmodified mechanical pulp is below water-level. Hence, due to the surprising and unexpected technical effects of 1-PVAm layered kraft pulp and 3L-PVAm/PAA/PVAm layered kraft pulp, these modified kraft pulps will be easier to collect after recovery and/or bioremediation of oil spills in water. The collected pulps comprising recovered oil can be used for e.g. producing energy.

[0053] Table 1 relates to absorption of three types of oils and hydrocarbons using unmodified mechanical pulp (Ref pulp), 1L-PVAm layered kraft pulp (1L pulp) and 3L-PVAm/PAA/PVAm layered kraft pulp (3L pulp) during an absorption time of 1 minute. The results clearly show that modified pulps surprisingly absorb more than twice as much petroleum diesel, hydraulic oil and motor oil when compared to unmodified pulp.

TABLE-US-00001 TABLE 1 Ref pulp 1L pulp 3L pulp Oil (g/g pulp) (g/g pulp) (g/g pulp) Petrol diesel 2.0 ± 0.3 5.9 ± 0.3 6.2 ± 0.4 Hydraulic oil 3.0 ± 0.1 6.7 ± 0.4 6.7 ± 0.3 Motor oil 3.2 ± 0.4 7.2 ± 0.5 7.7 ± 0.7

[0054] Table 2, below shows the average absorption of liquid per gram of kraft pulp in different oil and water mixtures.

TABLE-US-00002 TABLE 2 Diesel/water Hydraulic oil/water Motor oil/water Pulp mixture mixture mixture sample [g/g pulp] [g/g pulp] [g/g pulp] REF 3.9 ± 0.8 4.3 ± 0.1 5.0 ± 0.4 L1 9.0 ± 0.3 9.4 ± 0.4 8.6 ± 0.8 L3 9.7 ± 0.2 8.3 ± 0.8 8.9 ± 0.8

[0055] FIG. 3a shows absorption of water by unmodified mechanical pulp (REF MP) and 1L-PVAm layered mechanical pulp (1L MP). The graph indicates that unmodified mechanical pulp (REF MP) absorbs more water than 1L-PVAm layered mechanical pulp (1L MP). The graph further indicates that unmodified mechanical pulp (REF MP) absorbs water with a higher rate than 1L-PVAm layered mechanical pulp (1L MP).

[0056] FIG. 3b shows absorption of oil after the pulps have been exposed to water for X minutes when using unmodified mechanical pulp (REF pulp) and 1L-PVAm layered mechanical pulp (1L pulp). The graph indicates that 1L-PVAm layered mechanical pulp (1L pulp) which has first been in water surprisingly and unexpectedly absorbs more oil than unmodified mechanical pulp (REF pulp).

[0057] FIGS. 3a and 3b clearly and unambiguously shows that 1L-PVAm layered mechanical pulp is more advantageous than unmodified mechanical pulp as a composition for recovery of oil and hydrocarbons since the 1L-PVAm layered mechanical pulp has more affinity for oil than water. Hence, the modified kraft pulps can recover more oil spills and hydrocarbons than unmodified pulps. In other words, the recovery of oil spills and hydrocarbons will be more efficient with 1L-PVAm layered mechanical pulp when compared to unmodified mechanical pulp. This surprising and unexpected effect has not been described in any prior art documents. As already indicated, collected pulps which comprise recovered oil can be used for e.g. producing energy.

[0058] FIG. 4 shows the filtration of a mixture comprising 10 ml hydraulic oil and 30 ml water through 0.5 g unmodified mechanical pulp (REF) and 1L-PVAm layered mechanical pulp (1L). The figure shows that the mixture which has been filtered through the unmodified mechanical pulp (REF) has about 3 mm thickness of hydraulic oil at the surface of the water. As a contrast, the mixture which has been filtered through the 1L-PVAm layered mechanical pulp (1L) has about 1 mm thickness of hydraulic oil at the surface of the water. Consequently, the results clearly show that modified pulp (i.e. 1L-PVAm layered mechanical pulp) surprisingly has more affinity for oil than unmodified pulp since more oil has been captured by the modified pulp. In other words, the recovery oil spills and hydrocarbons will be more efficient with 1L-PVAm layered mechanical pulp when compared to unmodified mechanical pulp.

Example 2

[0059] CTMP Pulp Absorption Test in Oil/Water

[0060] Chemo-thermo mechanical pulp (CTMP) fibers were modified with one layer of PVAm (L1) and with three layer PVAm-PAA-PVAm (L3) according to the method described in Example 1. The reference pulp, L1 and L3, 0.5 g of each, were immersed into the motor oil (10 ml) and motor oil/water mixture (15 ml H.sub.2O and 6 ml motor oil) for 1 minute for each absorption test. The samples were then weighted after absorption. All the tests were conducted in triplicates.

[0061] Table 3, below show that the unmodified CTMP pulp absorbed 7.4 g motor oil per gram of pulp while both the modified pulps, L1 and L2, absorbed twice as much pure motor oil. This is a doubled absorption capacity compared to the kraft pulp tested in the previous absorption test. The reason might be that the lignin in mechanical pulp increased the hydrophobicity of the pulp, which gives the pulp a higher affinity for hydrophobic products like oil. The modified pulps, L1 and L3, absorbed almost the same amount of motor oil. This test showed that the CTMP pulps had a higher affinity for oil compared to kraft pulp and that a single layer of PVAm enables a suitable absorbent.

TABLE-US-00003 TABLE 3 Motor oil/Water Pulp Motor oil mixture sample [g/g pulp] [g/g pulp] REF  7.4 ± 0.4 4.9 ± 2.2 L1 14.4 ± 0.9 9.0 ± 0.3 L3 14.2 ± 0.5 9.9 ± 0.3

Example 3

[0062] Combination of Microorganisms and Absorbent

[0063] The modified pulp from Example 2 was used (L1 CTMP in Example 2) together with reference pulp (CTMP). The microorganisms used comprise natural oil consuming Archaea and were obtained from Oppenheimer Biotechnology, Inc., (https://www.obio.com/index.htm) as the product Piranha®. The microorganisms was added to the pulp absorbent by shaking 1 g of pulp 1 g with 100 mg grinded nutrient mixture and 100 mg microorganism fixated on starch. The microorganism containing absorbent was added to a mixture of 10 ml hydraulic oil and 90 ml water. Six different combinations of the experiment were tested in duplicates, see Table 4, below for setup. The bottles were shaken and sealed. After 2 weeks of incubation at room temperature the solution was analyzed for hydrocarbons. The absorbent was removed from the mixture and dried for 2 days in the fume hood before it was weighted.

TABLE-US-00004 TABLE 4 Experiment group 1 2 3 4 5 6 Hydraulic oil & water X X X X X X (1:9) Microorganism/starch X X X 100 mg Nutrients 100 mg X X X REF CTMP 1 g X X L1 CTMP 1 g X X

[0064] After 2 weeks incubation there was a difference in the flasks containing pulp with and without microorganisms added. The pulp in flask 4 and 6, with microorganisms added in the pulp, had started to fall apart and fibers were seen in the bottom of the flasks. The L1 pulp without added microorganisms was still floating collected in lumps. The microorganisms might affect the structure of the pulp, perhaps it starts to degrade the pulp and the absorbed hydrocarbons as well as the added polymers in the modification.

[0065] The results of the hydrocarbon analysis indicated that the toluene concentration decreased as a result of the addition of microorganisms (flasks 2, 4 and 6) and that the lowest toluene concentration was found in the L1-modified pulp (flask 6).