Bio-based filters for removal of contaminants from fluids

Abstract

A hybrid filter material includes a multiplicity of plastic fibers and a coating including biochar on a surface of each plastic fiber of the multiplicity of plastic fibers, wherein the multiplicity of plastic fibers are in the form of a woven or nonwoven mat. Making a hybrid filter material includes treating plastic fibers with bio-oil to yield bio-treated plastic fibers, combining the bio-treated plastic fibers with biochar and a solvent to yield a mixture, and drying the mixture to yield biochar-coated plastic fibers.

Description

BIO-BASED FILTERS FOR REMOVAL OF CONTAMINANTS FROM FLUIDSCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Patent Application No. 63 / 570,371 filed on March 27, 2024, which is incorporated by reference herein in its entirety.TECHNICAL FIELD

[0002] This invention relates to bio-based filters for removal of contaminants such as metals and volatile organic compounds from fluids, as well as method of making the filters.BACKGROUND

[0003] Contaminants such as metals and volatile organic compounds in air and water can have negative impacts on health. For example, airborne manganese exposure can lead to neurotoxic consequences, and has been linked to deficits in certain neuropsychological domains such as cognition. Exposure to copper fume and zinc oxide is known to cause upper respiratory tract irritation, metallic taste, nausea, and metal fume fever.BRIEF DESCRIPTION OF DRAWINGS

[0004] FIG. 1A is a top view of a hybrid filter. FIG. IB is a cross-sectional view of the hybrid filter of FIG. 1A.SUMMARY

[0005] This disclosure describes a hybrid filter material including a multiplicity of plastic fibers, and a coating including biochar on a surface of each plastic fiber of the multiplicity of plastic fibers. Each plastic fiber of the multiplicity of plastic fibers is coated with bio-oil. The multiplicity of plastic fibers can be in the form of a woven or nonwoven mat. Making the hybrid filter material includes treating plastic with bio-oil to yield bio-treated plastic, combining the biotreated plastic with biochar and a solvent to yield a mixture, and drying the mixture to yield biochar-coated plastic fibers. The plastic can be in the form of fibers or granules.

[0006] In a first general aspect, a hybrid filter material includes a multiplicity of plastic fibers and a coating including biochar on a surface of each plastic fiber of the multiplicity of plastic fibers. The multiplicity of plastic fibers are in the form of a woven or nonwoven mat.

[0007] Implementations of the first general aspect can include one or more of the following features. In some cases, the hybrid filter material can further include wood fiber. In some implementations, each plastic fiber of the multiplicity plastic fibers is coated with bio-oil. The multiplicity of plastic fibers can include waste plastic fibers. The waste plastic fibers can include polyethylene terephthalate, polyethylene terephthalate glycol, or a combination thereof. In one example, the biochar includes biogenic carbon. In certain implementations, the hybrid filter material further includes a photocatalyst. The biochar can adsorb metal particles. The biochar can absorb volatile organic compounds. In some cases, a weight ratio of the biochar to the multiplicity of plastic fibers is in a range of about 1 :4 to about 1 : 1.

[0008] In a second general aspect, making a hybrid filter material includes treating plastic fibers with bio-oil to yield bio-treated plastic fibers, combining the bio-treated plastic fibers with biochar and a solvent to yield a mixture, and drying the mixture to yield biochar-coated plastic fibers.

[0009] Implementations of the second general aspect can include one or more of the following features. In some cases, the plastic fibers include waste plastic. The waste plastic can include polyethylene terephthalate, polyethylene terephthalate glycol, or any combination thereof. In certain implementations, treating the plastic fibers includes contacting the plastic fibers with the bio-oil to coat the plastic fibers and heating the coated plastic fibers. The solvent can include water, organic solvent, or a mixture thereof. Making a hybrid filter material can further include sonicating the mixture before drying the mixture. In some cases, biochar and the plastic fibers are present in a weight ratio of about 1 :4 to about 1 : 1. Making a hybrid filter material can further include forming a woven or non-woven filter material with the biochar- coated plastic fibers. In one example, making a hybrid filter material can further include combining wood fibers with the biochar-coated plastic fibers. In certain implementations, making a hybrid filter material can further include forming a woven or nonwoven hybrid material from the biochar-coated plastic fibers and the wood fibers.

[0010] The details of one or more embodiments of the subject matter of this disclosure are set forth in the accompanying drawings and the description. Other features, aspects, andadvantages of the subject matter will become apparent from the description, the drawings, and the claims.DETAILED DESCRIPTION

[0011] This disclosure describes hybrid filter materials made from components including plastic and functional biogenic carbon (biochar), in which the plastic is treated with bio-oil, coated with the biochar, and then spun or woven alone or in combination with additives (e.g., wood fiber, photocatalytic particles). The plastic can be waste plastic (e.g., in the form of fibers or granules). The hybrid filter materials can be formed into mats for use as filters suitable for trapping particulate matter as well as metals (e.g., copper and iron) and select volatile organic compounds (e.g., benzene) through physisorption and chemisorption. Hybrid filter materials that include photocatalytic particles (e g., titania) can be used to form filters that are regenerable.

[0012] Suitable waste plastics include, for example, polyethylene terephthalate and polyethylene terephthalate glycol. Suitable bio-oils include, for example, waste vegetable oils and other plant-based oils. Biochar is obtained from thermal decomposition under low-oxygen conditions of organic material such as algae, plant material, and agricultural waste.

[0013] A method of making the hybrid filter materials includes preparing plastic fibers from waste plastics (e.g., polyethylene terephthalate, polyethylene terephthalate glycol). Suitable methods of preparing the plastic fibers include extrusion and electrospinning. The plastic fibers are treated with bio-oil, followed by heating (e g., with microwave radiation). The biochar is soaked in a solvent, and the resulting biochar mixture is then agitated to inhibit agglomeration of the biochar. The plastic fibers are combined with the biochar mixture at a biocharplastic fiber weight ratio of about 1 :4 to about 1 : 1 (e.g., 1 :2), and the resulting hybrid mixture is stirred, allowed to age (e.g., at ambient temperature), and then agitated. The hybrid mixture is then dried to yield biochar-coated plastic fibers. The biochar-coated plastic fibers are then spun and woven alone or in combination with additive (e.g., wood fiber) to yield a hybrid fiber filter material. The hybrid fiber filter material can be used to remove contaminants (e.g., metals and volatile organic compounds) from fluids such as air and water.

[0014] Preparing biochar-coated plastic granules includes combining the plastic with bio-oil (e.g., in a weight ratio of about 1 :1), heating the mixture, removing the excess bio-oil, and drying the plastic to yield treated plastic. One example of a suitable bio-oil is waste vegetable oil.Biochar is combined with the treated plastic (e.g., in a weight ratio of 1 :2 biochar to treated plastic) in an aqueous solution to yield a mixture. The mixture is agitated and then dried to yield the biochar-coated plastic.

[0015] Referring now to FIG. 1 A, a front view of hybrid filter 100 is illustrated. As described herein, the hybrid filter 100 includes bio-oil (e.g., plant-based oil) coatings and recycled materials to increase sustainable aspects. The air filtration apparatus 100 includes a frame 110 and a hybrid filter material 120.

[0016] The frame 110 structurally supports the hybrid filter material 120. In various embodiments, the frame 110 may contribute to filtering functions of the hybrid filter 100. The frame 110 may be manufactured from a variety of materials, such as paper or metal. The frame 110 can surround and enclose the hybrid filter material 120. In this regard, frame 110 may create a border around the hybrid filter material 120, in accordance with various embodiments.Although described herein as including frame 110, the filter 100 is not limited in this regard. For example, any air filtration apparatus includes a hybrid filter material 120 as described herein that is configured to capture (e.g., adsorb or absorb) metal particles or volatile organic compounds, with or without a frame 110, is within the scope of this disclosure.

[0017] The hybrid filter material 120 includes a multiplicity of biochar-coated plastic fibers. The multiplicity of plastic fibers can be woven or non-woven. In some cases, the hybride filter material also includes wood fibers. The thickness, width and height of the filter 100 may vary, depending on the size of the system the filter may be intended to be installed into.

[0018] FIG. IB shows a cross-sectional view of the filter 100 . The hybrid filter material 120 defines an air inlet 122 and an air outlet 124 (e.g., a first side and a second side, respectively). In this regard, “dirty air” or “unpurified air” may be configured to enter the hybrid filter material 120 through the air inlet 122. The hybrid filter material 120 then removes (e.g., adsorbs or absorbs) volatile organic compounds or metal particles from the unpurified air, and outputs purified air through the air outlet 124.Example

[0019] Plastic fibers were made from waste plastics (e.g., polyethylene terephthalate, polyethylene terephthalate glycol), either through extrusion or electrospinning. The resulting plastic fibers were treated with bio-oil, and the mixture was left at ambient temperature for 12hours. The mixture was irradiated with microwave irradiation at 400 watts for 5 minutes. The mixture was taken out to be stirred for 10 minutes using a stainless-steel lab spoon. The mixture was irradiated again, stirred for 10 minutes, and washed with acetone to remove the excess biooil for 5 minutes. The mixture was dried at a temperature of 60 °C to yield bio-treated plastic fibers. Biochar was soaked in a beaker in a solution of 60 wt% acetone and 40 wt% distilled water. The biochar mixture was stirred using a stainless steel spatula for 10 minutes, then sonicated using a Branson CPX2800H Ultrasonic Digital Bench Top Cleaner with Timer and Heater at 50 °C for 15 minutes. After sonication, the bio-treated plastic fibers were combined with the biochar mixture to yield a hybrid mixture, and the hybrid mixture was stirred for 10 minutes. The hybrid mixture was then left at ambient temperature for 24 hours, followed by another sonication procedure for 90 minutes. The hybrid mixture was then dried at a temperature of 100 °C for 1 hour, resulting in biochar-coated plastic fibers. The biochar-coated plastic fibers were then spun and woven alone or in combination with wood fibers to yield a hybrid fiber filter material.

[0020] Although this disclosure contains many specific embodiment details, these should not be construed as limitations on the scope of the subject matter or on the scope of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in this disclosure in the context of separate embodiments can also be implemented, in combination, in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments, separately, or in any suitable sub-combination. Moreover, although previously described features may be described as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can, in some cases, be excised from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination.

[0021] Particular embodiments of the subject matter have been described. Other embodiments, alterations, and permutations of the described embodiments are within the scope of the following claims as will be apparent to those skilled in the art. While operations are depicted in the drawings or claims in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order,or that all illustrated operations be performed (some operations may be considered optional), to achieve desirable results.

[0022] Accordingly, the previously described example embodiments do not define or constrain this disclosure. Other changes, substitutions, and alterations are also possible without departing from the spirit and scope of this disclosure.

Claims

WHAT IS CLAIMED IS:

1. A hybrid filter material comprising: a multiplicity of plastic fibers; and a coating comprising biochar on a surface of each plastic fiber of the multiplicity of plastic fibers, wherein the multiplicity of plastic fibers is in the form of a woven or nonwoven mat.

2. The hybrid filter material of claim 1, further comprising wood fiber.

3. The hybrid filter material of claim 1, wherein each plastic fiber of the multiplicity plastic fibers is coated with bio-oil.

4. The hybrid filter material of claim 1, wherein the multiplicity of plastic fibers comprises waste plastic fibers.

5. The hybrid filter material of claim 4, wherein the waste plastic fibers comprise polyethylene terephthalate, polyethylene terephthalate glycol, or a combination thereof.

6. The hybrid filter material of claim 1, wherein the biochar comprises biogenic carbon.

7. The hybrid filter material of claim 1, further comprising a photocatalyst.

8. The hybrid filter material of claim 1, wherein the biochar adsorbs metal particles.

9. The hybrid filter material of claim 1, wherein the biochar adsorbs volatile organic compounds.

10. The hybrid filter material of claim 1, wherein a weight ratio of the biochar to the multiplicity of plastic fibers is in a range of about 1 :4 to about 1 : 1.

11. A method of making a hybrid filter material, the method comprising: treating plastic fibers with bio-oil to yield bio-treated plastic fibers; combining the bio-treated plastic fibers with biochar and a solvent to yield a mixture; and drying the mixture to yield biochar-coated plastic fibers.

12. The method of claim 11, wherein the plastic fibers comprise waste plastic.

13. The method of claim 12, wherein the waste plastic comprises polyethylene terephthalate, polyethylene terephthalate glycol, or any combination thereof.

14. The method of claim 11, wherein treating the plastic fibers comprises contacting the plastic fibers with the bio-oil to coat the plastic fibers and heating the coated plastic fibers.

15. The method of claim 11, wherein the solvent comprises water, and organic solvent, or a mixture thereof.

16. The method of claim 11, further comprising sonicating the mixture before drying the mixture.

17. The method of claim 11, wherein biochar and the plastic fibers are present in a weight ratio of about 1 :4 to about 1: 1.

18. The method of claim 11, further comprising forming a woven or non-woven filter material with the biochar-coated plastic fibers.

19. The method of claim 11, further comprising combining wood fibers with the biochar- coated plastic fibers.

20. The method of claim 19, further comprising forming a woven or nonwoven hybrid material from the biochar-coated plastic fibers and the wood fibers.

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