Algae-based biomass material for effluent gas stream, and associated method and apparatus

Abstract

To provide a biomass material for treating an effluent gas which can treat harmful substances still remaining in treated gas processed by a conventional effluent gas treatment apparatus.SOLUTION: A biomass material for treating an effluent gas contains algae biomass in an amount from 40 wt.% to 90 wt.%, and zeolite in an amount from 10 wt.% to 60 wt.%, where the contents are based on the total weight of the biomass material. The biomass material 320 molded into porous pellets is packed into a housing 310 and brought into contact with an effluent gas stream for treating the effluent gas.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to gas treatment technology, and more particularly to algal biomass materials, including algal biomass and zeolites, for adsorbing gaseous pollutants in exhaust gas streams. [Background technology]

[0002] Various gaseous pollutants, including harmful chemicals, are generated in industrial fields such as manufacturing, electronics, and chemistry, including the production of semiconductors, display devices, solar panels, and thin films. Common treatment methods include combustion, plasma, water washing, and catalytic treatment. Of these, combustion and plasma treatments have high decomposition efficiency, but conventional exhaust gas treatment devices, including the technologies disclosed in Patent Documents 1 to 6, all have limitations.

[0003] For example, in semiconductor manufacturing processes, various gases such as silane (SiH4), chloride gases, and perfluorinated compounds (PFCs) are used, and these compounds have a significant impact on the global environment. If the exhaust gas to be treated contains silane, treatment equipment such as thermal decomposition, combustion, or chemical reaction equipment can be used. If the exhaust gas to be treated contains chloride gases, wet treatment equipment can be used. If the exhaust gas to be treated contains PFCs, catalytic, thermal reaction, thermal decomposition, combustion, or plasma treatment equipment can be used.

[0004] However, no matter which method is adopted, harmful substances still remain in the treated gas that has been treated by the exhaust gas treatment device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent No. US12,161,964B2 [Patent Document 2] US Patent No. US12,158,266B2 [Patent Document 3] US Patent No. US11,985,754B2 [Patent Document 4] U.S. Patent Application Publication No. US2024 / 0375158A1 [Patent Document 5] U.S. Patent Application Publication No. US2024 / 0381519A1 [Patent Document 6] US Patent Application Publication US2024 / 0082782A1 Summary of the Invention

[0006] One aspect of the present disclosure provides a biomass material for treating an exhaust gas stream, the biomass material comprising: an algal biomass content of 40 wt.% to 90 wt.%, based on the total weight of the biomass material; and a zeolite content of 10 wt.% to 60 wt.%, based on the total weight of the biomass material.

[0007] One aspect of the present disclosure provides a method for treating an exhaust gas stream, the method comprising: providing a biomass adsorbent downstream of the exhaust gas stream from one or more processes, the biomass adsorbent comprising algal biomass in an amount of 40 wt.% to 90 wt.%, based on the total weight of the biomass material, and zeolite in an amount of 10 wt.% to 60 wt.%, based on the total weight of the biomass material; and contacting the exhaust gas stream with the biomass adsorbent, wherein the biomass adsorbent absorbs at least one target component in the exhaust gas stream, the target component comprising tetrafluoromethane, carbon dioxide, methane, sulfur dioxide, nitrogen oxides, volatile organic compounds, and / or hydrogen sulfide.

[0008] One aspect of the present disclosure provides an apparatus for treating an exhaust gas stream, comprising: a reactor connected to a process chamber by one or more gas inlet lines, the reactor configured to reduce exhaust gases from one or more processes; and a biomass adsorbent downstream of the reactor, the biomass adsorbent comprising: algal biomass in an amount of 40 wt.% to 90 wt.%, based on the total weight of the biomass material; and zeolite in an amount of 10 wt.% to 60 wt.%, based on the total weight of the biomass material. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram of a semiconductor processing system according to an embodiment of the present disclosure; [Figure 2] FIG. 1 is a block diagram of a semiconductor processing system configuration according to another embodiment of the present disclosure. [Figure 3] 1 is a flowchart of a method for producing biomass material provided in one embodiment of the present disclosure. [Figure 4] 1 is a schematic diagram of an exhaust gas reduction device according to an embodiment of the present disclosure. [Figure 5] FIG. 2 is a schematic diagram of an exhaust gas reduction device according to another embodiment of the present disclosure. [Figure 6] 1 is a method for treating an exhaust gas stream according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] This disclosure relates to biomass materials used as bio-based adsorbents for treating effluent gas streams containing gaseous pollutants, including perfluorinated compounds (PFCs), silanes and their derivatives, chlorinated compounds, nitrogen-containing compounds, volatile organic compounds (VOCs), and metallo-organic compounds, among other waste gas pollutants harmful to the environment and human health.

[0011] This disclosure utilizes algae and zeolite as bio-based adsorbents, providing a sustainable and cost-effective solution to the problem of conventional scrubbers sometimes failing to completely remove gases. The bio-based adsorbents offer advantages such as high adsorption capacity, low operating costs, and no risk of secondary pollution. The bio-based adsorbents utilize natural and renewable materials, which can increase adsorption efficiency and reduce the environmental footprint, making them a more sustainable solution for gas processing.

[0012] The bio-based sorbents can be manufactured as adsorption units and used as stand-alone exhaust gas treatment devices, i.e., they do not receive a treated exhaust gas stream from another exhaust gas treatment device, but instead directly and independently treat the exhaust gas stream, without the need for cooperation with another exhaust gas treatment device. Alternatively, the adsorption units can be incorporated as a component into an exhaust gas treatment device, e.g., the adsorption unit can be part of a combustion and scrubbing system or a combustion system.

[0013] 1 shows a block diagram of a semiconductor processing system configuration of the present disclosure. The system includes a semiconductor processing apparatus 100, such as a semiconductor processing chamber capable of performing one or more lithography, deposition, and / or etching steps using various gas-phase precursor chemistries, which may be connected to a vacuum pump 120 by a front conduit 110, and from which exhaust gases from processes in the semiconductor processing apparatus 100 are exhausted via an exhaust conduit 130.

[0014] The exhaust gas can be transported via exhaust line 130 to exhaust gas abatement apparatus 140 where it is treated. The treatment process involves exposing the exhaust gas to a bio-based adsorbent material in exhaust gas abatement apparatus 140. The treated exhaust gas then leaves exhaust gas abatement apparatus 140 via gas outlet 150.

[0015] In one example, the exhaust gas is treated solely by the bio-based adsorbent material of the exhaust gas reduction device 140, and is not treated by any type of method other than adsorption, such as combustion, pyrolysis, wet, catalytic, or plasma decomposition.

[0016] In another example, the bio-based sorbent material can be combined with combustion, pyrolysis, wet, catalytic, and / or plasma decomposition scrubbers to form an emission abatement device 140 .

[0017] 2 shows a block diagram of a configuration of a semiconductor processing system of the present disclosure, and discloses an exhaust gas abatement device 160. Compared to the configuration of FIG. 1, the exhaust gas abatement device 160 includes a reactor 160a and a biomass adsorbent 160b, where the reactor 160a is connected to the semiconductor processing apparatus 100 by one or more gas inlet pipes, the reactor 160a is configured to reduce exhaust gases from one or more processes, and the reactor 160a may be a combustion-type, pyrolysis-type, wet-type, catalytic-type, and / or plasma-decomposition-type scrubber.

[0018] Referring to Figure 3, one embodiment of a method for producing biomass material is shown. First, algal biomass and zeolite are provided (step 200). The algal biomass and zeolite are then mixed in a specific ratio (step 210), which can be achieved by mechanical stirring, granulation, or other suitable methods to ensure uniform distribution. The mixture is then dried to remove moisture and activate the adsorption sites (step 220). Drying can be accomplished using various methods, such as air drying, vacuum drying, or drying at a suitable temperature.

[0019] In one example, the algae biomass is carbonized algae. Algae collected from natural sources or artificial cultivation must be dried before carbonization. Carbonization is ensured by heating the algae to high temperatures and maintaining them under a protective atmosphere. After cooling, the carbonized algae is collected and mixed with zeolite to obtain a mixture, which is then homogenized by blending to ensure uniform distribution. After blending, pellets are formed from the mixture, and a solvent may be added during the pellet formation process. The pellets are then dried to remove the solvent and improve structural stability for further shaping. After this, the pellets can be loaded into a column for adsorption testing. This configuration can be used in fixed-bed setups to ensure uniform gas flow, reliable surface contact with the adsorbent, and consistent performance evaluation under controlled conditions.

[0020] 4 shows an example of an exhaust gas reduction device 300. The exhaust gas reduction device 300 includes a housing 310 and a plurality of pellets 320. The pellets 320 are packed inside the housing 310, and the housing 310 is connected to an upstream exhaust pipe 330 that guides exhaust gas to the packed pellets 320 and a downstream exhaust pipe 340 that discharges the treated exhaust gas.

[0021] In this example, each pellet 320 is made of the biomass material without any other additives or additional components, and the pellets 320 have a porous structure 321. In this example, the pore size of the porous structure 321 is within a range sufficient to capture gas molecules in the exhaust gas. In other examples, the pellets 320 may be a composition or composite of the biomass material and another material.

[0022] 5 shows an example of an exhaust gas abatement device 400. The exhaust gas abatement device 400 includes a housing 410 and a bio-based adsorbent material 420 disposed inside the housing 410. The housing 410 is connected to an upstream exhaust line 430 that guides exhaust gas to the bio-based adsorbent material 420 and a downstream exhaust line 440 that discharges the treated exhaust gas. In this example, the bio-based adsorbent material 420 may be in the form of a block rather than a pellet.

[0023] In this example, bio-based sorbent 420 is comprised of biomass material and does not include any other additives or additional materials, and bio-based sorbent 420 has a porous structure 421. In this example, the pore size is in a range sufficient to capture gas molecules in the flue gas. In other examples, bio-based sorbent 420 may be a composition or composite of biomass material and other materials.

[0024] Referring to Figure 6, a method for treating an exhaust gas stream is shown. A biomass sorbent material is provided downstream of an exhaust gas stream from one or more processes (step 500), the biomass sorbent material comprising algal biomass in an amount of 40 wt.% to 90 wt.%, based on the total weight of the biomass material, and zeolite in an amount of 10 wt.% to 60 wt.%, based on the total weight of the biomass material. The exhaust gas stream is then contacted with the biomass sorbent material (step 510), which absorbs at least one target component in the exhaust gas stream, the target component including tetrafluoromethane, carbon dioxide, methane, sulfur dioxide, nitrogen oxides, volatile organic compounds, and / or hydrogen sulfide. In one example, the target component is selected from the group consisting of tetrafluoromethane, carbon dioxide, methane, sulfur dioxide, nitrogen oxides, volatile organic compounds, and hydrogen sulfide.

[0025] The biomass material for treating an exhaust gas stream includes an algal biomass in an amount of 40 wt.% to 90 wt.%, based on the total weight of the biomass material, and a zeolite in an amount of 10 wt.% to 60 wt.%, based on the total weight of the biomass material. In one example, the biomass material consists of the algal biomass and the zeolite, without any other additional components, although in some examples, the biomass material may further include other additional components.

[0026] In some embodiments, the algal biomass content may be 40 wt.%, 45 wt.%, 50 wt.%, 55 wt.%, 60 wt.%, 65 wt.%, 70 wt.%, 75 wt.%, 80 wt.%, 85 wt.%, or 90 wt.% of the total weight of the biomass material, and in some embodiments, the zeolite content may be 10 wt.%, 15 wt.%, 20 wt.%, 25 wt.%, 30 wt.%, 35 wt.%, 40 wt.%, 45 wt.%, 50 wt.%, 55 wt.%, or 60 wt.% of the total weight of the biomass material.

[0027] In one embodiment, the gas adsorption capacity of the biomass material is greater than 0.029 mol / g, for example, the gas adsorption capacity may be in the range of 0.029 mol / g to 5 mol / g.

[0028] The algal biomass may be a single species or a mixture of two or more species, preferably a protein-rich algae with a protein content of at least 30 wt.%, such as Spirulina sp., Chlorella sp., or Nannochloropsis sp. These species were selected because they have a very large surface area, abundant functional groups (e.g., hydroxyl groups, carboxyl groups, and amines), and a high carbon content, which improve their contaminant binding capacity. Because algae have a porous cell wall structure, they can be further modified by carbonization to increase adsorption efficiency. Their fast growth, sustainability, and cost-effectiveness make them an environmentally friendly alternative for constructing adsorbents. In one example, the algal biomass used in the present disclosure is cultivated under controlled conditions and thus is artificially harvested algal biomass, as opposed to wild algae collected from natural environments. However, in another example, the algal biomass may be naturally occurring algae.

[0029] The algal biomass in this material has a large surface area, a complex cellular morphology with a precise structure, and a diverse composition, including abundant biopolymer components such as proteins, lipids, and polysaccharides with large polymeric structures. These characteristics provide numerous functional groups (e.g., hydroxyl, carbonyl, and amino groups) that act as active sites for adsorbing gas molecules through physical and chemical interactions. Furthermore, the biological properties of algae allow dynamic interactions with gas atoms, such as dipole-dipole interactions, electrostatic interactions, and π-π electron donor-acceptor mechanisms, thereby improving overall adsorption performance. In addition to its adsorption capacity, algal biomass is renewable, abundant, and environmentally friendly, making it a promising material for fields such as carbon capture and methane gas purification, where it can effectively remove contaminants such as carbon dioxide, methane, and hydrogen sulfide from gas streams.

[0030] Zeolites are microporous crystalline solids with well-defined structures that can be used as the framework for the biomass material. Zeolites generally consist of silicon, aluminum, and oxygen, with aluminum and silicon atoms located at the center of oxygen tetrahedra, and the pores in the zeolite structure can accommodate cations, water, and other molecules, which may be metal ions and are generally loosely bound to the zeolite.

[0031] Zeolites have a highly porous structure and a well-defined crystalline structure, both of which provide a large surface area suitable for adsorption. These structural characteristics allow them to selectively capture gas molecules and ions depending on parameters such as molecular size, shape, and charge. In certain embodiments, zeolites exhibit ion-exchange capabilities, allowing for substitution of cations within the framework to facilitate or improve adsorption of target substances. Some gas molecules can also chemically interact with the zeolite surface, further enhancing adsorption efficiency. Due to their uniform pore distribution, molecular sieving properties, and tunable chemical properties, zeolites are particularly well suited for use in gas storage, separation, and purification. Zeolites can also be regenerated and reused, offering cost advantages and long-term use in industrial and environmental fields. Suitable choices for zeolites of the present disclosure include, but are not limited to, zeolite 13X, A-type zeolite, zeolite beta, and H-ZSM-5, which have large surface areas, well-defined pore structures, and high affinities for gas molecules; these properties make them effective candidates for adsorbing small gas molecules through physical adsorption and selective pore interactions.

[0032] For example, H-ZSM-5 can be selected for CF4 adsorption due to its fine pore size, which allows it to effectively capture CF4 molecules while preventing interference from larger substances. Its inherent hydrophobicity improves adsorption performance in practical use and reduces other influences, such as moisture, that can decompose zeolites. Furthermore, H-ZSM-5 exhibits excellent thermal stability, making it suitable for long-term use and repeated adsorption-desorption cycles without significant structural degradation. Furthermore, its adsorption capacity and selectivity can be improved by modification (e.g., metal doping or composite with carbonized algae), making it a versatile and effective adsorbent for CF4 removal.

[0033] When combining algal biomass and zeolite, the algal biomass creates a synergistic effect to enhance gas adsorption efficiency, while the zeolite provides a well-defined crystalline framework and uniform pore structure, which are beneficial for structural stability and molecular sieving performance. The algal biomass introduces additional surface area and bioactive adsorption sites. This combination fully utilizes the advantages of the two materials, resulting in a composite with higher gas adsorption performance than either material used alone.

[0034] Biomass adsorbents are capable of absorbing carbon dioxide (CO2), methane (CH4), sulfur dioxide (SO2), and nitrogen oxides (NO x The synergistic combination of zeolite and algal biomass enhances its adsorption performance due to the unique properties of each component.

[0035] The present invention will be described in more detail below through specific experimental examples. The following experimental examples are merely examples for facilitating understanding of the contents of the present disclosure, and the scope of the contents of the present disclosure is not limited thereto.

[0036] (example) Several experimental examples according to the present invention and comparative examples are prepared and evaluated as follows.

[0037] Table 1 summarizes the compositions of the adsorbents in the experimental examples (Examples A-1 to A-5, and Examples B-1 to B-5) and comparative examples (Examples C-1 and C-2). Experimental examples A-1 to A-5 used uncarbonized algae, while experimental examples B-1 to B-5 used carbonized algae. The difference between the experimental examples and comparative examples lies in the algae and zeolite content. Finally, the adsorption capacity of each sample was evaluated using a gas containing CF4, and the results of the adsorption capacity and structural stability are shown in Table 2.

[0038] (Experimental Examples A-1 to A-5 and Comparative Example C-1) Uncarbonized spirulina was used as the algae. After collection, it was dried. Then, the algae and H-ZSM-5 were mixed in different ratios as shown in Table 1. After mixing, the mixture was made into pellets by adding a small amount of water. The pellets were then dried at 110°C for 12 hours.

[0039] (Experimental Examples B-1 to B-5 and Comparative Example C-2) The collected algae was carbonized in a reactor at 500 °C under a nitrogen (N2) atmosphere, and the heating process was continued for 2 hours to ensure sufficient carbonization. After cooling, the algae and H-ZSM-5 were mixed in different ratios as listed in Table 1. After mixing, the mixture was made into pellets by adding a small amount of water, and then the pellets were dried at 110 °C for 12 hours. [Table 1] [Table 2]

[0040] The results show that experimental carbonized algae have better adsorption capacity than uncarbonized algae. Carbonization can change the natural structure of algae, enlarging the pore size and porosity, which is advantageous for adsorbing gas molecules (such as CF4) in gas streams. Carbonized algae outperforms pure (uncarbonized) algae because its surface area and porosity are significantly higher, providing more active sites for gas adsorption. The carbonization process also improves the algae's thermal stability and mechanical strength, ensuring better long-term performance. Furthermore, carbonized algae can be customized to specific pore sizes and surface properties, making it a more effective adsorbent than pure algae.

[0041] The adsorption capacity of an adsorbent is a value that indicates how much gas an adsorbent can absorb per unit mass. When gas molecules are adsorbed by an adsorbent, they interact with the pore surface and are captured through weak physical interactions or strong chemical bonds. The higher the adsorption capacity, the more gas molecules the adsorbent can effectively capture and accommodate. This ability is affected by factors such as the surface area and pore structure of the adsorbent. The larger the surface area, the more space there is for gas molecules to attach. Essentially, a high adsorption capacity indicates that the adsorbent has a strong ability to remove gases from the surrounding environment, and also proves that the adsorption process is occurring.

[0042] Experimental Examples B1-B5 demonstrate high CF4 gas adsorption capacity, indicating that adsorption is not determined solely by porosity or surface area. Rather, this performance may be due to the presence of heteroatom (e.g., N, O)-containing functional groups and surface defects generated during the carbonization process, which promote specific interactions with CF4 molecules. Furthermore, the large pore size and outer surface area may enable their use for gas adsorption. This is evident from the fact that for some carbonized algae, surface chemistry and morphology play a larger role than surface area alone in determining gas adsorption efficiency, especially for weakly interacting gases such as CF4.

[0043] Compared to the values ​​reported in the literature, the carbonized algae adsorbents containing zeolite (Examples B1-B5) show a significantly higher CF4 adsorption capacity of 2.0627 mol / g. As shown in Table 3 below, the capacities of several other adsorbents are relatively low. [Table 3]

[0044] The literature citations in Table 3 refer to Table 4. [Table 4]

[0045] Furthermore, pure uncarbonized algae without zeolite (Example C-1) showed a very low adsorption capacity of 0.0013 mol / g, while pure carbonized algae without zeolite (Example C-2) showed an adsorption capacity of 1.0226 mol / g. Although carbonized algae without zeolite exhibited good CF4 adsorption performance, the absence of zeolite resulted in poor structural stability and little moldability, making it unusable for practical use. Furthermore, in mixed gas environments, the selectivity of its adsorption performance may be low. Adding zeolite to carbonized algae increases structural stability, improves selectivity, and provides additional active adsorption sites, making the material more suitable for long-term use.

[0046] As a result, the combination of carbonized algae and zeolite provides higher gas adsorption efficiency, utilizing physical adsorption and chemical interactions to capture and remove pollutants in industrial exhaust gases. By incorporating this material into conventional gas treatment systems such as scrubbers and plasma reactors, it can provide a sustainable, economical, and efficient alternative to conventional adsorbents. The present invention provides an environmentally friendly method for reducing industrial emissions while ensuring high adsorption performance and operational viability.

[0047] Throughout the specification and claims, the articles "a," "an," "the," and similar terms are understood to cover both the singular and the plural unless the context clearly dictates otherwise. Unless otherwise clearly stated, the terms "comprise," "have," and "containing" are used herein open-ended, meaning "including, but not limited to." While these open-ended terms are generally used to describe compositions and methods, in some cases, alternative embodiments may be described with the more restrictive terms "consisting essentially of" or "consisting of." Additionally, for purposes of the present disclosure, the term "X and / or Y" refers to (X), (Y), or (X and Y), and the term "X, Y, and / or Z" refers to (X), (Y), (Z), (X and Y), (X and Z), (Y and Z), or (X, Y, and Z).

[0048] Unless otherwise indicated, all values ​​relating to quantities of ingredients, material properties (e.g., weight or concentration), reaction conditions, and the like, set forth in the present disclosure and the claims that follow are understood to be modified in all instances by the term "about." Accordingly, unless expressly indicated otherwise, the numerical parameters set forth herein are understood to be approximations that may vary depending on the specific function of the example. At least except as limited by the application of the rules of identity, each value is understood to be in accordance with the value of significant digits and ordinary application of rounding techniques.

[0049] All methods described herein can be performed in any suitable order, unless expressly stated otherwise or the context clearly dictates a particular order. The use of enumerated or exemplary language, such as "for example," is intended to describe particular embodiments of the invention and is not intended to limit the scope of the invention, unless expressly stated otherwise in the claims. No language herein should be construed as designating any non-claimed element or component as essential to the practice of the invention.

[0050] The above embodiments are described to enable one skilled in the art to make and use the present invention. It is understood that modifications and variations of these embodiments will be apparent to those skilled in the art given the teachings herein, and that the generic principles and examples disclosed may be applied to other embodiments without departing from the scope of the present invention. The present invention is not limited to the specific embodiments described, but is intended to be accorded the widest scope consistent with the claims and applicable legal rules. [Explanation of symbols]

[0051] 100 Semiconductor processing equipment 110 Front conduit 120 Vacuum Pump 130 Exhaust pipe 140 Exhaust Gas Reduction Device 150 Gas outlet 160 Exhaust Gas Reduction Device 160a Reactor 160b Biomass adsorbent 200, 210, 220 processes 300 Exhaust Gas Reduction Device 310 Housing 320 pellets 321 Porous structure 330 Upstream exhaust pipe 340 Downstream exhaust pipe 400 Exhaust Gas Reduction Device 410 Housing 420 Bio-based Adsorbents 421 Porous structure 430 Upstream exhaust pipe 440 Downstream exhaust pipe 500, 510 processes

Claims

1. 1. A biomass material for treating an exhaust gas stream, comprising: Algal biomass having a content of 40 wt. % to 90 wt. % based on the total weight of the biomass material; and a zeolite content of 10 wt. % to 60 wt. % based on the total weight of the biomass material.

2. 10. The biomass material of claim 1, wherein the biomass material absorbs at least one component of interest in the exhaust gas stream, the component of interest comprising tetrafluoromethane, carbon dioxide, methane, sulfur dioxide, nitrogen oxides, volatile organic compounds, and / or hydrogen sulfide.

3. 10. The biomass material of claim 1, wherein the algal biomass is carbonized algae.

4. 2. The biomass material of claim 1, wherein the zeolite is selected from the group consisting of 13X zeolite, A-type zeolite, beta zeolite, H-ZSM-5, and combinations thereof.

5. 10. The biomass material of claim 1, wherein the algal biomass is a mixture having two or more species.

6. 10. The biomass material of claim 1, wherein the algal biomass is protein-rich algae.

7. 2. The biomass material of claim 1, wherein the algal biomass is selected from the group consisting of Spirulina, Chlorella, Nannochloropsis, and combinations thereof.

8. 2. The biomass material of claim 1, consisting of the algal biomass and the zeolite.

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