COMPOSITE TEXTILE CONSISTING OF NATURAL AND/OR SYNTHETIC AND/OR ARTIFICIAL FIBRES AND LIGNOCELLULOSIC PARTICLES

Abstract

The invention relates to a composite textile consisting of natural and/or synthetic and/or artificial fibres and lignocellulosic particles entangled between said fibres, comprising more than 30 wt. % of said lignocellulosic particles. The invention also relates to the method for the production thereof and to the uses of same.

Claims

1. A composite textile consisting of natural and/or synthetic and/or artificial fibres and lignocellulosic particles entangled between said fibres comprising more than 30% by weight of said lignocellulosic particles characterised in that it is a nonwoven material that can be obtained by a process comprising the following steps: a) napping a card web of said fibres with deposition of lignocellulosic particles between each card web layer, b) pressing the whole obtained in step (a), and c) consolidating the whole obtained in step (b) by needling and/or thermobonding, or a woven material that can be obtained by a process wherein the lignocellulosic particles are deposited in the card web which is then spun then woven.

2. (canceled)

3. The textile according to claim 1, the size of the particles being between 0.1 and 10 mm, preferably less than 1 mm.

4. The textile according to claim 1, comprising 30 to 80%, preferably 40 to 75%, by weight of particles in relation to the total weight of the textile.

5. The textile according to claim 1, comprising 20 to 80%, preferably 30 to 50%, by weight of fibres in relation to the total weight of the textile.

6. The textile according to claim 1, the thickness thereof being between 3 and 20 mm, preferably between 8 and 15 mm.

7. The textile according to claim 1, the weight thereof being between 0.1 and 2 kg/m.sup.2, preferably between 0.8 and 1.5 kg/m.sup.2.

8. The textile according to claim 1, said fibres consisting of plant fibres.

9. The textile according to claim 1, characterised in that it is biodegradable.

10. The textile according to claim 1, said fibres consisting of natural and/or artificial fibres.

11. The textile according to claim 1, said fibres consisting of synthetic fibres.

12. A process for manufacturing a nonwoven textile according to claim 1, comprising the following steps: a) napping a card web of said fibres with deposition of lignocellulosic particles between each card web layer, b) pressing the whole obtained in step (a), and c) consolidating the whole obtained in step (b) by needling and/or thermobonding.

13. A process for manufacturing a woven material according to claim 1, wherein the lignocellulosic particles are deposited in the card web which is then spun then woven.

14. A method for treating water in order to trap metals and/or metalloids and/or radionuclides and/or biocides contained therein, said method comprising employing the textile according to claim 1.

15. The method according to claim 14, said metals being selected from the group consisting of lead, nickel, chromium, zinc, copper, gold, silver, and iron.

16. The method according to claim 14, said radionuclides being selected from the group consisting of uranium, plutonium, palladium, and americium.

17. A method for trapping metals and/or metalloids and/or radionuclides and/or biocides, said method comprising employing a woven or nonwoven textile of lignocellulosic particles in a quantity of 30 to 80% by weight of said textile.

Description

FIGURES

[0032] FIG. 1: Monitoring of copper concentrations as a function of the volume of solution passed through each product:

[0033] Lignocellulosic particles alone

[0034] Bagged lignocellulosic particles

[0035] Fibres alone

[0036] Nonwoven material accoring to the invention

[0037] Y-axis: Copper concentration at the column outlet (mg/L)

[0038] X-axis: Volume of solution passed through the column (L)

[0039] FIG. 2: Percentage of copper not retained at the column outlet as a function of the volume of solution passed through each product:

[0040] Lignocellulosic particles alone

[0041] Bagged lignocellulosic particles

[0042] Fibres alone

[0043] Nonwoven material according to the invention

[0044] Y-axis: Percentage of copper not retained at the column outlet

[0045] X-axis: Bed volume passed

[0046] FIG. 3: Percentage of copper retained at the column outlet as a function of the volume of solution passed through each product:

[0047] Lignocellulosic particles alone

[0048] Bagged lignocellulosic particles

[0049] Fibres alone

[0050] Nonwoven material according to the invention

[0051] Y-axis: Percentage of copper retained at the column outlet

[0052] X-axis: Bed volume passed

[0053] FIG. 4: Average percentage of copper not retained at the column outlet as a function of the volume of solution passed through each product:

[0054] Lignocellulosic particles alone

[0055] Bagged lignocellulosic particles

[0056] Fibres alone

[0057] Nonwoven material according to the invention

[0058] Y-axis: Average percentage of copper not retained

[0059] X-axis: Bed volume passed

[0060] FIG. 5: Average percentage of copper retained at the column outlet as a function of the volume of solution passed through each product:

[0061] Lignocellulosic particles alone

[0062] Bagged lignocellulosic particles

[0063] Fibres alone

[0064] Nonwoven material according to the invention

[0065] Y-axis: Average percentage of copper retained

[0066] X-axis: Bed volume passed

DETAILED DESCRIPTION

[0067] A first object of the invention relates to a composite textile consisting of natural and/or synthetic and/or artificial fibres and lignocellulosic particles entangled between said fibres comprising more than 30% by weight of said particles.

[0068] Advantageously, the textile according to the invention is biodegradable.

[0069] Preferentially, the particles are entangled in said fibres only thanks to the mechanical steps of manufacture of said textile. No binder- or resin-type additive is used to create bonds between the particles and the fibres. The size of the particles is sufficiently small to offer a large contact surface for adsorption and thus to generate an optimal treatment capacity.

[0070] The size of the particles is sufficiently large to allow them to be held between the fibres.

[0071] The size of the particles is thus between 0.1 and 10 mm, preferably between 0.2 and 4 mm, in a particularly preferred manner between 0.4 and 3 mm. Advantageously, the size of the particles is less than 1 mm.

[0072] Advantageously, the textile according to the invention comprises 30 to 80%, preferably 40 to 75% by weight of lignocellulosic particles in relation to the total weight of the textile, in a particularly preferred manner 50% to 70%.

[0073] Advantageously, the textile according to the invention comprises 20 to 80%, preferably 20 to 60% by weight of fibres in relation to the total weight of the textile, in a particularly preferred manner 30 to 50%.

[0074] The thickness of the textile according to the invention is between 3 and 20 mm, preferably between 8 and 15 mm.

[0075] The weight of the textile according to the invention is between 0.1 and 2 kg/m.sup.2, preferably between 0.8 and 1.5 kg/m.sup.2.

[0076] Preferably, the textile according to the invention is nonwoven.

[0077] According to an embodiment, the fibres of the textile according to the invention are natural and/or artificial fibres.

[0078] According to an embodiment, all the fibres of the textile according to the invention consist of plant fibres.

[0079] Preferably, the fibres of the textile according to the invention are exclusively flax fibres and PLA fibres. The material used for the manufacture of PLA fibres is corn starch. The latter is transformed into sugar which, by decomposition thanks to microorganisms, becomes the acid lactide. This acid is polymerized to become polylactide then extruded to manufacture PLA fibre.

[0080] According to another embodiment, the fibres of the textile according to the invention are natural fibres, preferably natural plant fibres, and preferentially exclusively flax fibres.

[0081] According to an embodiment, the textile according to the invention is functionalized, for example by manganese permanganate or manganese dioxide MnO.sub.2.

[0082] According to another embodiment, the fibres of the textile according to the invention are synthetic fibres.

[0083] Advantageously, the synthetic fibres may be selected from the group consisting of polyesters, polyamides, polypropylenes, and mixtures thereof.

[0084] According to another embodiment, the fibres of the textile according to the invention are artificial fibres.

[0085] Advantageously, the artificial fibres may be of animal origin, of plant origin or of mineral origin.

[0086] Advantageously, the artificial fibres may be selected from the group consisting of viscoses such as soy viscose, PLA fibres, fibres based on cellulose, fibres based on crustacean shell chitin, fibres based on bamboo, fibres based on wood pulp, fibres based on dried algae, and mixtures thereof, and preferably the artificial fibres are selected from viscoses.

[0087] Advantageously, the synthetic and/or artificial fibres are biodegradable, partially biodegradable or non-biodegradable.

[0088] According to an embodiment, part of the natural and/or artificial fibres of the textile may be mineral fibres.

[0089] Advantageously, the mineral fibres may be natural mineral fibres such as asbestos, or artificial mineral fibres such as ceramic fibre, glass fibre, or metal fibres.

[0090] According to an embodiment, the textile comprises at least 50% by weight of natural fibres, in relation to the total weight of fibres in the textile according to the invention, preferably at least 70% by weight, more preferentially at least 80% by weight.

[0091] According to an embodiment, the textile comprises at least 50% by weight of synthetic fibres, in relation to the total weight of fibres in the textile according to the invention, preferably at least 70% by weight, more preferentially at least 80% by weight.

[0092] According to an embodiment, the textile comprises at least 50% by weight of artificial fibres, in relation to the total weight of fibres in the textile according to the invention, preferably at least 70% by weight, more preferentially at least 80% by weight.

[0093] According to an embodiment, the textile comprises at least 50% by weight of natural and/or artificial fibres, in relation to the total weight of fibres in the textile according to the invention, preferably at least 70% by weight, more preferentially at least 90% by weight.

[0094] According to an embodiment, the textile comprises at least 50% by weight of plant fibres, in relation to the total weight of fibres in the textile according to the invention, preferably at least 70% by weight, more preferentially at least 80% by weight.

[0095] A second object of the invention relates to a process for manufacturing the textile according to the invention comprising the following steps.

[0096] According to the following first embodiment, the manufacturing process according to the invention is suitable for the manufacture of a nonwoven according to the invention.

[0097] The fibres are first disentangled by the carding process.

[0098] The web thus obtained is then stacked by a napping operation then pressed then consolidated by needling and/or thermobonding.

[0099] The napping operation consists in stacking the webs of carded fibres to obtain the desired sheet thickness.

[0100] Thermobonding consists in passage in an oven after passage in a press. Thermobonding requires the presence of thermofusible fibres in the web. Thermobonding is a process for consolidating the sheet which calls upon the thermoplastic properties of certain fibres in the composition of the web. Under the effect of heat, the thermofusible fibres (the melting point of which is lower than that of the other fibres constituting the sheet) melt and thus bond all the fibres together.

[0101] Needling consists in entangling the textile fibres together and potentially into a fabric, by means of special needles bearing barbs or by means of hydraulic jets (hydraulic needling). Needling makes it possible to entangle the fibres constituting the nonwoven sheet by means of special needles or hydraulic jets which create vertical fibre bridges between the various webs in order to keep them together and thus ensure the performance of the finished product.

[0102] In the case of needling, the number of perforations generally made is in a range of 30 to 200 perforations per cm.sup.2, and commonly around 150 perforations per cm.sup.2.

[0103] The lignocellulosic particles are deposited between two layers of nonwoven carded fibre webs during napping.

[0104] In the presence of thermofusible fibres, the process of the invention will favour thermobonding rather than needling.

[0105] In the absence of thermofusible fibres, needling is used, optionally followed by a high-temperature passage. This high-temperature passage may last from a few minutes to about 30 minutes, preferably from 5 to 15 minutes. By “high temperature” is meant a temperature above 100° C.

[0106] According to the following second embodiment, the manufacturing process according to the invention is suitable for the manufacture of a woven textile according to the invention.

[0107] The lignocellulosic particles are then either: [0108] deposited in the card web which is then spun then woven or knitted [0109] incorporated into the yarn at the time of spinning, then the yarn is woven or knitted [0110] incorporated at the time of weaving or knitting.

[0111] According to a particular embodiment of the invention, the lignocellulosic particles are treated before being incorporated into the woven or nonwoven material according to the invention to optimize their capacity to trap metals and/or metalloids and/or radionuclides and/or biocides.

[0112] The steps of this embodiment are as follows.

[0113] The first particle treatment step is a step consisting of rinsing, washing, and removing residual fines after the grinding step and the various transfer and storage steps. Certain water-soluble compounds such as tannins or others phenolic compounds are partially released into the wash water, and simultaneously the bark absorbs water, causing swelling by hydration. The particles thus pre-prepared are then activated to give them ion-exchange functionalities. A solution for solubilization of tannins and phenolic compounds is employed, with the order of these two treatments being unimportant. The activation of the particles is obtained in a known manner by an acid treatment, in this case nitric acid at 0.1 M, i.e., at 0.1 mole per litre). The acid causes exchanges of the salts Na, K, Ca and P, to cite the primary compounds of the ion-exchange sites by H protons. The monitoring consists in measuring conductivity as a function of pH.

[0114] The treatment time is defined when the conductivity reaches a horizontal asymptote, generally when the solution reaches a maximum acidity, i.e., a pH on the order of 1, with the conductivity able to reach values of about 40 μs/cm. The particles are then rinsed again to remove the acid solution. Hence, the particles regain a pH close to 7 and therefore neutrality. Simultaneously, the conductivity returns to the conductivity of distilled water. During this phase, the water-soluble compounds are again removed. Nevertheless, water-soluble compounds remain, and the latter should no longer be released subsequently during the use of the finished product for purposes of treating fluids, notably water, with a view to recovering metals, preferably heavy metals and/or metalloids and/or radionuclides and/or biocides. Thus, it is necessary to stabilize the particles thus activated and ready to be used to prevent any subsequent release of water-soluble compounds.

[0115] A solubilization solution consists in treating said particles by making them undergo an oxidation reaction known as Fenton oxidation. This oxidation reaction causes a decrease in the size of tannins or other phenolic compounds, thus making them easily soluble. These soluble compounds are then removed from the wash water, preventing their subsequent solubilization during the filtration phases with a view to retaining radionuclides and/or heavy metals and/or metalloids and/or biocides since these water-soluble compounds are absent. This solubilization treatment relies on the Fenton oxidation reaction. This reaction is illustrated below:

Fe.sup.2++H.sub.2O.sub.2=Fe.sup.3++OH.sup.−+OH

[0116] Thus, it is noted that this reaction makes possible the opening of rings and a decrease in the size of molecules, thus enabling their solubilization in and removal from the wash water during preparation of the bark. Moreover, this reaction causes the opening of the benzene rings of lignins to form carboxyl groups and thus to increase the number of sites available for adsorption.

APPLICATIONS

[0117] The textile according to the invention may be used to treat water with the aim of trapping metals and/or metalloids and/or radionuclides and/or biocides contained therein.

[0118] These metals and/or metalloids and/or radionuclides and/or biocides may be present in the water in any quantity, even trace quantities.

[0119] Metals include lead, nickel, chromium, zinc, copper, gold, silver, iron, mercury, cadmium.

[0120] Metalloids include boron, silicon, germanium, arsenic, antimony, tellurium and astatine, preferably arsenic.

[0121] Radionuclides include uranium, plutonium, palladium, americium, polonium, radium, caesium in their various isotopic forms.

[0122] Biocides include pesticides, antiparasitics and antibiotics.

[0123] Among pesticides, particular mention may be made of insecticides, fungicides, herbicides, parasiticides, antimicrobials, algicides, acaricides, antimicrobials, bactericides, crow toxicants, molluscicides, nematicides, ovicides, rodenticides, mole toxicants, virucides, repellent products, and biopesticides.

[0124] Among herbicides, particular mention may be made of selective weed killers, total weed killers, bush killers, top killers, sprout inhibitors, and silvicides.

[0125] The use can take place in certain extraction mines or in certain metal or metalloid processing industries or in sites where radionuclides or biocides are used.

[0126] The use relates to drinking water as well as to water arising from oceans, seas, rivers, lakes, ponds, reservoirs, streams and watercourses, ground seepage water at industrial pollution sites and leachates.

[0127] The use consists in using the textile according to the invention as a filter. For each application, the textile according to the invention is placed in such a way that the water to be treated passes through it and the metals and/or metalloids and/or radionuclides and/or biocides contained therein are trapped.

[0128] By way of example, certain applications are as follows: [0129] Fixation of radionuclides in nuclear plant decontamination tanks. Here, the textile according to the invention is located in the decontamination tanks. [0130] Fixation of copper before penetration of the soil in vineyards after copper treatment, for example with Bordeaux mixture. Here, the textile according to the invention is deposited on or in the soil. [0131] Fixation of metal, for example precious metal such as gold in ground seepage water of extraction mines. [0132] Fixation of metal, particularly of iron in discharge purification leachates. [0133] Recovery of agricultural phytosanitary products either from runoff after manuring or when the material is washed.

[0134] The woven or nonwoven textile consisting of lignocellulosic particles according to the invention may be used in a quantity of 30 to 80% by weight of said textile in order to trap metals and/or metalloids and/or radionuclides and/or biocides.

[0135] The following examples illustrate the invention without limiting its scope.

EXAMPLES

Example 1: Preparation of Bark Particles

[0136] Douglas pine bark is ground into granules having a size of less than 10 mm.

Example 2: Manufacture of a Nonwoven Composite According to the Invention

[0137] Flax fibres are carded. The web thus obtained is then stacked by napping. Between each web layer, granules obtained according to Example 1 are deposited in a ratio of 50% flax fibres and 50% granules by weight.

[0138] The whole is then pressed then needled then passed in a 160° C. oven for 10 min.

Example 3: Manufacture of a Nonwoven Composite According to the Invention

[0139] Fibres of flax and of PLA are carded. The web thus obtained is then stacked by napping. Between each web layer, granules obtained according to Example 1 are deposited in a ratio of 25% flax fibres, 25% PLA fibres and 50% granules by weight.

[0140] The whole is then pressed then consolidated by thermobonding.

[0141] The nonwoven composite obtained has a thickness of 5 mm and a weight of 600 g/m.sup.2.

Example 4: Characterisation of the Copper Adsorption Capacities of the Product of Example 3

[0142] Aim

[0143] The aim is to characterise the capacities to adsorb trace metal elements (TMEs) of the material as a function of its packing. Three configurations are tested: loose bark, bagged bark and the composite nonwoven fabric according to the invention.

[0144] Principle

[0145] In the 3 cases tested, 20 mL (bulk volume of the product), or about 3 g of product, is packed in a column. A solution, whose TME concentration to be tested is known, is percolated through this column and a measurement is taken regularly at the outlet to confirm the efficiency of the treatment.

[0146] Test Protocol on Copper

[0147] The TME solution used here has an initial copper concentration of 3 mg/L. This element, in addition to being a potential pollutant to be treated, has the advantage of being easily assayable and is representative of a number of other divalent cationic pollutants. A measurement at the column outlet is carried out every 25 bed volumes (BV), i.e., every 500 mL in this case, the bed volume being equal to 20 mL.

[0148] The results are compared with those obtained for the adsorption of uranium, the concentration of which was 0.3 mg/L.

[0149] For reasons of homogeneity, all the results are presented as if they had been carried out at a concentration of 0.3 mg/L, i.e., the volumes passed with copper were multiplied by 10 to compensate for the 10 times greater concentration in solution, which is equivalent to the same quantity of fixed element.

[0150] The fixation efficiency results are presented in FIGS. 1 to 5:

[0151] The loose configuration is represented by a double line, the bagged configuration by a dotted line, and the configuration according to the invention by a dashed line.

[0152] It is observed that if one refers to the fixation efficiency as the efficiency criterion, the configuration according to the invention makes it possible to treat a volume of effluent at least 2 times greater for an identical water quality at the outlet.