THEIR PRODUCTION

1. Field of the invention

(003) The present invention relates to the production of hydrophobic super absorbent for water and ground surface cleaning and the production of the filtering material for filtration of twater emulsions, made from the natural fibers obtained from the seeds of Populus tree and to the method for their production. In particular, the present invention relates to the removal of hydrophobic organic substances from bodies of water and earth materials in an environmentally and ecologically beneficial manner.

2. Related prior art

(004) There are known solutions for using natural fibers as absorbents and filtering material. The most widely researched and used materials are cellulosic fibers and materials which contain cellulosic fibers such as wood, bark as well as different agricultural products and remains (rice straw, rice hulls, corn corb, peat moss, cotton, cotton grass, barks, milkweed, kenaf, bagasse, coconut shells and different vegetable and fruit pulps). Agricultural remains, for example rice straw, corn corb, peat moss, cotton, cotton grass, barks, milkweed and kenaf, have good oil absorbency. All listed materials have fibrous structure composed of cellulosic fibers, lignin and hemicellulose. They are cheap and usually locally available as waste. Rice straw, corn cob, cotton, milkweed floss, kenaf, and wool fibers have already been used as sorbents in oil spill cleanup. However, rice straw, corn cob, and wood fiber have poor buoyancy, relatively low oil sorption capacity and low hydrophobicity. Milkweed and cotton have greater potential for oil spills cleanup because they absorb significantly more oil compared to commercial synthetic sorbent materials. This is because of cellulose high affinity to bind hydrophobic substances but on the other hand they express high deterioration due to the water absorption. For this reason many attempts have been made to overcome the wetting characteristics of the lignocellulosic materials. In U.S. Patent No. 3,607,741 Sohnius used the mixture of cellulosic fibers and water repellent substances such as silicone, paraffin, stearate and emulsifier for increasing the hydrophobicity of the fibers. Due to the same reason many attempts for chemical modification of the cellulose fibers have been made. For example, in U.S. Patent No. 3,464,920 Pirson et al. suggested silanisation of the cellulosic materials, in U.S. Patent No. 3,591 ,524 Eriksen et al. described the treatment of cellulose containing material with ammonia salt and different amines and Fanta et al. in U.S. Patent No. 4,605,640 proposed treatment of cellulosic fibers with fatty quaternary ammonium salts. The hydrophobicity of cellulosic materials has also been increased by reaction of cellulosic material with organic isocyanates (Hoist et al., German Often. 2,358,808) and with fatty acid derivatives, such as anhydrides (Ball et al, U.S. Patent No. 3,770,575) and acid chlorides (Teng et al., U.S. Patent No. 3,874,849). Coating cellulosic fibers with hydrophobic compounds, such as paraffin wax (Peterson et al., U.S. Patent No. 3,630,891 ; Matsuda et al., Japanese Kokai 77/76,285; and Orth, German Often. 2,301 ,176), insoluble fatty acid salts (Aoso et al., Japanese Kokai 74/64,577), or low melting polymers, such as polyolefins (Kunitomo et al., German Often. 2,621 ,961 ; and Saida et al., Japanese Kokai 78/04,760) is another technique used to increase the hydrophobicity of the fibers; some polymers (e.g., ethylene-vinyl acetate copolymer) have also been deposited onto fibers from aqueous emulsions (Sato et al., Japanese Kokai 77/89,244; and Sato et al., Japanese Kokai 77/90,486). Other authors simply used mixtures of different cellulosic materials, for example Raible et al. in US Patent No. 4,925,343, who used mixture of wood fibers with organophilic water wettable cotton liners.

(005) US Patent 4,061 ,567 published by Kobayashi et al. on December 6, 1977 (Method for adsorption of oils) describes a method of using kapok fibers as natural super absorbent for oil spilling sanitation. The kapok fibers have been described as micro-tubes whose cell walls are composed of 64 % of cellulose, 13 % of lignin, 23 % of pentosans and they are naturally coated by plant waxes. They have high affinity to hydrophobic substances and they expressed good buoyancy.

3. Background of the invention

(007) Because of the worldwide expansion of oil consumption and ecological awareness of oil production, a lot of extended researches have been made on the development of efficient absorbents for hydrophobic/oleophilic substance spilling sanitation. By definition, super absorbents are substances that absorb and retain from 10 to 100 times the mass of the substance as to their own weight. Usually they are a mixture of fibers containing super absorbing particles, made from various natural or synthetic polymers such as agar, carboxy-alkyl cellulose, resin, pectin, carboxy alkyl starch, cellulose sulphate, products of hydrolysis of starch, polyacrylates, sulphonated polystyrene, polyvinyl alcohols, polyethylene oxide polivinilpirolidin, polyacrylonitrile, polyacrylamide and hydrolyzed polyacrylamide. Due to their hydrophilic nature natural super absorbents normally do not float on water surface while on the other hand synthetic absorbents are expensive because of demanding and environmentally questionable production processes. Natural super absorbents tend to form soft, jelly products swelled with the absorbed liquid. The occurrence of swelling and formation of gels reduces the transport and distribution of absorbing substance throughout the absorption medium. This phenomenon is known as gel blocking. Gel blocking reduces the ability of absorbing next quantity of substance and absorbent leakage occurs. In contrast, synthetic super absorbents, despite the absorbed substances, retain their mechanical structure, which prevents gel blockage due to swelling of the material. Maintaining the gap between the particles or fibers allows penetration of substances into the space between them, thereby increasing the absorption capacity of the absorbent and preventing leakage.

(008) Agricultural products and their production remains, for example kapok fibers, cotton fibers, rice husks, forage from corn mixture, fibers from sugar cane and peat, have been the subject of extensive research for producing cheap and effective natural absorbents. Among them, only kapok and cotton fibers can be classified as super absorbent, but the latter does not float on water without additional chemical treatment. Kapok fibers are obtained from fruits of Ceiba pentandra (L.) Gaertn. trees which belong to the family of the Malvaceae plants. Kapok fibers are natural hydrophobic/oleophilic micro tubes with 25 ± 5 mm in length, outside diameter of 16.5 ± 2.4 mm and with an average wall thickness of 2.0 Mm. Tube walls are composed of cellulose, hemicelluloses and lignin. Bulk density of kapok fibers is 0.0013 g/cm ³ as 77 vol. % of the fibers is empty lumen. Hydrophobicity is enhanced due to acetylation of the wall saccharides and due to the coating of the tube wall surface with natural waxes. This lumen tends to be filled with hydrophilic/oleophilic substance when fibers come to contact with it. Absorption capacity of the kapok fiber, measured according to standard ASTM F726 - 06, at a package density of 0.02 g/cm ³ , is 41 g/g to 45 g/g for engine oil HD 40 and 31 g/g to 36 g/g for diesel fuel D2 (Hori et al 2000, Mungasatkit 2004, Lim and Huang 2007). The fibers fully passed the degradation test according to ASTM standard F726 - 06. Kapok fibers can be characterized as a natural super absorbent for water and hard surface cleaning.

(009) The disadvantage of kapok fiber is reflected in their mechanical instability due to the high ratio of fiber length versus their external diameter. This results in decrease of the absorption capacity with increasing of package density. Gel blockage appears at absorption of large quantities of substance.

(010) The origin of the Ceiba pentandra (L.) Gaertn. tree is in South America but it can be found in tropical areas of Southeast Asia, Sri Lanka and other parts of eastern Asia and Africa. Ceiba pentandra (L.) Gaertn. trees are planted on purpose to produce fibers which are used for producing lifejackets, fillers for toys, and recently also for manufacturing absorbents. Intentional cultivation of trees reduces the extent of cultivable land. Manufacturing is hard work because it is limited to manual collection of open flowers. Due to the low bulk density, transport of the fibers to the point of final use in North America and Europe is complex and relatively expensive.

BRIEF SUMMARY OF THE INVENTION

(01 1 ) The present invention relates to the use of natural fibrous material for the absorption of oil floating on or suspended in water, the method and machine for producing it.

(012) Poplars and aspen are angiosperm trees genus Populus which originates from Salicaceae plant family. These trees of different subgenres are widespread in western and central Europe and most parts of North America. They are planted purposely as earth erosion protectors or protection against noise. The wood is used in furniture, for package material and pulp production. Due to their fast growing nature, trees quickly spread throughout urban areas where they are unwanted because they generate large quantities of fibrous seeds which appear due to blooming in spring time.

(013) The method described in this invention comprises an innovative approach for using invaluable waste natural material, such as poplar seeds fibers, as a product with high added value. On average, one Populus tree produces 0.9 kg of seeds per year, which is approximately 54 million seeds per tree. The possibility of capturing and processing fibers derived from the seeds of Populus trees in super absorbent, which is basically a high-tech product, presents an ecologically, economically and technologically progressive manufacturing method for production of absorbents and filtering materials. A produced absorbent is natural material with oil absorbing capacity twice as high as the most abundant synthetic, water floating absorbents which are available on the market today. At the same time it also presents a sustainable solution for seeds management as seeds are usually treated as waste.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(014) The morphological structure of the fiber obtained from the seeds of Populus nigra italica tree is shown in Figure 1 , the schematic description of the method is shown in Figure 2, the schematic description of the device for collecting fibers lying on the ground in Figure 3, the schematic description of the device for collecting airborne fibers in Figure 4, the schematic description of the fiber concentration device in Figure 5 and the schematic description of the fiber cleaning device in Figure 6.

DETAILED DESCRIPTION OF THE INVENTION

(015) This invention is related to the use of fiber obtained from the seeds of Populus trees to produce super absorbent and filtering materials as well as to the method and machine for their production. (016) Super absorbent will consist of fibers derived from the seeds of Populus trees which are, by their nature, hydrophobic/oleophilic micro tubes with 8.74 ± 5.75 mm of outer diameter, 8.24 ± 4.79 mm of internal diameter and 4 ± 1 mm in length. Micro-tubes have an average wall thickness of 500 ± 30 nm and are composed of 33-37 % of cellulose, 19- 22 % of hemicelluloses (manly pentosans), 10-12 % of lignin and 1 -2 % of inorganic substances. Fibers have a high acetyl groups content (approximately 19-22 %), suggesting a degree of acetylation of the saccharides from 1 .3 to 1 .4 of acetyl groups per monosaccharide unit. Bulk density of the fibers is 0.0036 g/cm ³ as 89 vol. % of the fiber is empty lumen. This lumen tends to be filled with hydrophobic/oleophilic substance when the fiber comes into contact with this substance. Hydrophobicity of the fibers is increased due to a coat of fiber surface with natural waxes. The absorption capacity of the fibers obtained from the seeds of Populus trees at a package density of 0.02 g/cm ³ , measured according to standard methods (ASTM F726 - 06) ranges from 55 g/g to 60 g/g for engine oil HD and from 40 g/g to 44 g/g for diesel fuel D2. Fibers fully passed the degradation test according to standard methods (ASTM F726 - 06). Due to their low ratio between length and external diameter, fibers express improved resistance to gel blockage and higher mechanical resistance against collapse or clumping and thus against clogging the filters. Table 1. Comparison of the absorption capacity of poplar seed fibers with other natural and synthetic absorbing materials.

Own measurements according to standard ASTM 726-06 at package density 0.02 g/cm ³ .

HD40 - motor oil SAE 15W-40

D2 - diesel fuel

(017) The invention describes a method and machine for the production of hydrophobic/oleophilic super absorbent and filtering materials based on usage of the fibers obtained from the seeds of Populus trees, which are considered as undesirable in urban areas and they are treated as waste. The method for the preparation of a super- absorbent and filtering material from the seeds of Populus trees is divided into a method for collecting released fibers and a method for cleaning and packing acquired fibers into the final product. The applicative use of the final super absorbent is described as well. (018) Related to the invention, released fibers are collected and cleaned of the unwanted contaminants (remnants from envelopes and leaves, dust and debris) which reduce absorptivity and prevent the manufacture of filters. Fibers are packaged in permeable polyethylene or polypropylene nets with a mesh from 1.00 mm to 2.81 mm in diameter (mesh 16 to 7 according to Tyler). The optimum package density for the achievement of desired absorption efficiency ranges from 0.02 g/cm ³ to 0.09 g/cm ³ .

(019) Related to the invention, fibers obtained from the seeds of Populus tree can be used as such or can be further blended with other absorption materials such as natural or chemically treated cellulose fibers, cellulosic nano-fibers, organoclay nano composites, treated papermill sludge, peat or expanded polypropylene within the ratios from 1 % to 99 % by weight in order to reduce production costs and achieve the optimal ratio between the price of the absorbent and its effectiveness.

(020) The method for producing absorbent or filtering material is characterized by the collection of the airborne or ground lying fibers, cleaning the collected fibers and using them as an absorbent for absorption of the hydrophobic/oleophilic liquids from water and ground surfaces or for making the filtering material for extracting hydrophobic/oleophilic substances from their aqueous emulsions. The method and machine for the manufacture of absorbent and filtering material are shown in Figure 2.

1. Detailed description of drawings

(021) Ground lying fibers 1 are collected a by vacuum suction device 2, which is shown in detail in Figure 3. The bristle roller 4, which rotates in the direction of the air flow 3, is driven by a gear or rod system 5, optionally by a separated power unit; it lifts the fibers from the ground. Lifted fibers are caught into the air flow 3 generated by a vacuum pump 17. The speed of the air flow containing collected fibers increases inside the venturi chamber 6 and thus the concentration of fiber inside the air flow increases. The fibers are sucked into the drainage system 8 through the valve 7.

(022) Airborne fibers 9 are collected with a network system 10. This system consists of hollow tubes 11 which have a suction slot built-in as is shown in detail in Figure 4. Tubes with the diameter from 6 mm to 10 mm are fitted with suction slots with heights from 1 mm to 5 mm in a way that the ratio between the height and width of the suction slots is lower than 0.005. The tubes are linked into the intake system via sucking pipes 12 which are further connected to the drainage system 8.

(023) The drainage system 8 is drawn into a device for extracting fibers from the air stream 13. The device is shown in detail in Figure 5. It works on the principle of the cyclone, where crude mixture of fibers and foreign materials (remnants of envelopes and leaves, dust and debris) hits against the wall 14 due to the circulation of the air flow inside device 13. Due to the friction of fibers and foreign bodies with the chamber wall 14, their speed is reduced, which allows them to drop out from the air flow and accumulate at the conical bottom of the chamber 15. The air is sucked from the chamber through the vertical venturi tube, with a mouth diameter of less than 3 mm, and the air flow 16 is created inside the pipe driven by the vacuum pump 17. The collected fibers contaminated with foreign bodies are removed from the chamber by a jagged roller 21 , driven by the force of the pressurized air flow 18. The air flow 18 is generated by the vacuum pump 17, and their forces are transferred onto the roller 21 through the rotor with blades 19 and the transmission axis 20. Due to the friction and shear forces within the fibers and foreign bodies which are the result of the rotation of the jagged rotor against static housing, grinding of foreign bodies occurs. The mixture of fibers and ground foreign bodies are collected inside the collecting container 22.

(024) The mixture of fibers and ground foreign bodies is baled under mechanical pressure inside the baler 24. The baled mixture 25 is transported to a location where the device for cleaning and confectioning the final product is located.

(025) The ground foreign bodies are removed from fibers on the cleaning device described by Baker et al. in 1994. The device is schematically shown in figure 6. The cleaning process starts with opening bales and flocking the fibers on the roller 28. Meanwhile the rotary compressor 30 creates an air flow which transfers the mixture of the flocking fibers and ground foreign bodies 29 to a system of toothed rollers. The toothed roller 31 kneads the mixture of fibers and ground foreign bodies against the sieve 32. The size of the sieve openings must be from 1.00 mm to 2.81 mm in diameter (mesh 16 to 7 according to Tyler). The roller 33 removes cleaned fibers from the device 26. This generates the flow of purified fibers 34 which can be packaged as the product for further use in bulk 35 or can be led to the device for confectioning the final product 38.

(026) The ground remnants and fibers smaller than 1 mm in length drop through the sieve 32 and create a flow of organic biomass 36. Organic biomass is concentrated on the bottom of the device 26 from where it is removed by rotating cylinders 37. Organic biomass can be used as highly calorific fuel.

(027) Fibers 35 can be used for absorbent in bulk or for the production of filtering systems for the separation of hydrophobic/oleophilic liquids from aqueous emulsions.

(028) Cleaned fibers 34 are transferred on the device for confectioning the final product 38. Fibers are packaged in the shape of cushions or booms. The package density must exceed 0.02 kg/I and must be lower than 0.09 kg/I. A polyethylene or polypropylene net with rectangular or hexagonal mesh from 1.00 mm to 2.81 mm in diameter (mesh 16 to 7 according to Tyler) can be used as package material. The cushion size is limited by application needs, while the diameter of the booms which compose the barrage is limited from 12 cm to 20 cm with a view to simplified handling.

The present invention will be described more specifically with reference to working examples, which are cited solely for illustration and are not limitative of the invention in any sense.

EXAMPLE 1

(029) Hand-harvested fibers from the seeds of trees Populus nigra italica contaminated by foreign matter ( envelopes, leaves, branches and debris particles) were put into a glass dish with 14 cm in diameter. The container was equipped with an anchor type stirrer with pointed edges 13.9 cm in diameter. The fibers were blended for 60 seconds at 5600 rpm. Fibers with ground foreign bodies were passed onto a vibrating sieve with a mesh 16. The sieve vibrated at 300 rpm with the amplitude of oscillation of about 1 cm. The rate of foreign bodies removal was higher than 95%.

EXAMPLE 2

(030) 1 g of purified fibers from the seeds of trees Populus nigra italica were put onto a net in accordance with standard ASTM F726 - 06. The bulk density of the fibers on the net was 0.0036 g/cm ³ . In a 600 ml glass beaker 400 ml of engine oil SAE 15W-40 were poured. The net with fibers was dipped into the oil. The fibers were totally imbibed with oil after 4 minutes. The rate absorption after 15 minutes was 1 15 g of motor oil per 1 g of fiber.

EXAMPLE 3

(031 ) 1 g of purified fiber from the seeds of trees Populus nigra italica was put onto a net, in accordance with standard ASTM F726 - 06. The bulk density of the fibers on the net was 0.0036 g/cm3. In a 600 ml glass beaker 400 ml of diesel fuel D2 were poured. The net with fibers was dipped into the diesel fuel. The fibers were totally imbibed with diesel fuel after 1 minute. The rate absorption after 15 minutes was 82 g of diesel fuel per 1 g of fiber.

EXAMPLE 4

(032) 1 .3 g of purified fibers from the seeds of trees Populus nigra italica was packaged into a net shaped as a sphere in accordance with standard ASTM F726 - 06. The bulk density of the fibers inside the net was 0.02 g/cm ³ . In a 600 ml glass beaker 400 ml of engine oil SAE 15W- 40 were poured. The net with fibers was dipped into the oil. The absorption rate after 15 minutes was 56 g of motor oil per 1 g of fiber.

EXAMPLE 5

(033) 1 .3 g of purified fibers from the seeds of trees Populus nigra italica was packaged into a net shaped as a sphere in accordance with standard ASTM F726 - 06. The bulk density of the fibers inside the net was 0.02 g/cm3. In a 600 ml glass beaker 400 ml of diesel fuel D2 were poured. The net with fibers was dipped into the diesel fuel. The rate of absorption after 15 minutes was 44 g of diesel fuel per 1 g of fiber.

EXAMPLE 6

(034) 2 liters of water were poured into a 5 liter glass container with the diameter of 18 cm. On the water surface 1 g of purified fibers with the bulk density 0.0036 g/cm ³ was weighed. The beaker was mounted on the shaker and the contents were shaken for 15 minutes at the frequency 150 rpm and amplitude 3 cm. After 15 minutes of shaking 100% of fibers hovered on the surface.

EXAMPLE 7

(035) 2 liters of water were poured into a 5 liter glass container with the diameter of 18 cm. On the water surface 10 ml of motor oil SAE 15W-40 were poured. 1 g of the purified fibers was placed in the center of the oil spot. The beaker was mounted on the shaker and the contents were shaken for 15 minutes at the frequency 150 rpm and amplitude 3 cm. After 15 minutes of shaking, the water surface was clean and 100% of fibers hovered on the surface

EXAMPLE 8 (036) Into a glass tube with the diameter of 2 cm and height of 10 cm and with the bottom fitted with mesh 2.82 g of purified fibers were placed. The packing density was 0.09 g/cm ³ . 100 ml of 10 % emulsion of motor oil SAE 15W-40 in water flowed through the column. The flow rate was 1 ml/min. The cleaning rate was higher than 97.5%.