Wood-based water-resistant charcoal and method for producing the same
By using materials such as CMC, zinc salt, and 4,4'-oxobisbenzenesulfonyl hydrazine as binders and pore-forming agents, the problem of easy clogging of wood-based activated carbon in water was solved, and wood-based activated carbon with high strength and water resistance was prepared, thus improving its adsorption performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- FUJIAN XINSEN CARBON
- Filing Date
- 2026-04-21
- Publication Date
- 2026-07-28
AI Technical Summary
Existing wood-based activated carbon is prone to pore blockage when exposed to water, leading to a decrease in adsorption performance. Furthermore, traditional additives can cause pore blockage or reduced adsorption capacity.
Using CMC as a binder, zinc salt as a crosslinking agent, ammonium oxalate as a microporous pore-forming agent, and 4,4'-oxobisbenzenesulfonyl hydrazine as a mesoporous and macroporous pore-forming agent, water-resistant wood-based carbon was prepared by stirring and drying, forming a three-dimensional network sol that is insoluble in water, opening up micropores, mesopores, and macropores.
The prepared wood-based activated carbon maintains high strength while exhibiting good water resistance and less pore blockage, thus improving its adsorption performance.
Abstract
Description
Technical Field
[0001] This invention belongs to the field of activated carbon technology, specifically relating to a wood-based water-resistant charcoal and its preparation method. Background Technology
[0002] Activated carbon made from woody raw materials such as sawdust and coconut shells through processes including crushing, drying, carbonization, and activation. It features a large specific surface area, strong adsorption capacity, and well-developed pore structure, and is widely used in solvent recovery, water purification, and air purification. When preparing shaped activated carbon, adhesives are usually added. The addition of adhesives not only facilitates the shaping process but also improves the strength and stability of the product while ensuring adsorption performance. Currently, there are two common methods for bonding wood-based activated carbon: 1) using wood powder as raw material and CMC (sodium carboxymethyl cellulose) as binder to form shaped activated carbon, followed by drying; 2) using wood powder as raw material and CMC as binder, adding crosslinking agents (such as water glass) and pore-forming agents (starch, ammonium bicarbonate, etc.) to form shaped activated carbon, followed by drying.
[0003] Regarding the two commonly used methods, the first method produces a finished product with less pore blockage, but it is not water-resistant; the adhesive dissolves and becomes ineffective when the activated carbon comes into contact with water, resulting in a limited range of applications for the molded activated carbon. The second method uses many additives, leading to severe pore blockage and a significant reduction in the adsorption capacity of the molded activated carbon (and the higher the adsorption capacity of the powdered carbon, the greater the reduction in adsorption capacity after molding). Organic pore-forming agents such as starch can be added, but the decomposition of starch leaves residual carbon that blocks some pores. Inorganic pore-forming agents such as ammonium bicarbonate can also be added, but they can only open some of the blocked micropores, having little effect on the blocked mesopores and macropores. Therefore, the improvement in the adsorption capacity of the molded activated carbon is not significant. How to prepare water-resistant wood-based activated carbon while avoiding pore blockage has become an urgent problem to be solved. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide a wood-based activated carbon with less pore blockage and water resistance, and a method for preparing the same.
[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A method for preparing wood-based water-resistant charcoal, comprising the following steps: mixing wood charcoal powder, CMC, ammonium oxalate and 4,4'-oxobisbenzenesulfonyl hydrazine, adding soluble zinc salt solution and stirring, and then obtaining the wood-based water-resistant charcoal after molding and drying.
[0006] The technical solution adopted in this invention is: a wood-based water-resistant charcoal prepared by the above preparation method.
[0007] The beneficial effects of the present invention are as follows: The preparation method provided by the present invention uses CMC as a binder, zinc salt as a crosslinking agent, ammonium oxalate as a microporous pore-forming agent, and 4,4'-oxobisbenzenesulfonyl hydrazine as a mesoporous and macroporous pore-forming agent, which can prepare wood-based activated carbon with less pore blockage and water resistance. Detailed Implementation
[0008] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments.
[0009] A method for preparing a water-resistant wood-based charcoal includes the following steps: mixing wood charcoal powder, CMC, ammonium oxalate and 4,4'-oxobisbenzenesulfonyl hydrazine, adding a soluble zinc salt solution and stirring, and then molding and drying to obtain the water-resistant wood-based charcoal.
[0010] As can be seen from the above description, the beneficial effects of the present invention are as follows: The preparation method provided by the present invention involves zinc ions in a soluble zinc salt solution crosslinking with CMC to form a three-dimensional network sol that is insoluble in water, giving the formed activated carbon high strength and water resistance. During the subsequent drying process, ammonium oxalate decomposes upon heating to reopen the micropores without producing residue. 4,4'-oxobisbenzenesulfonyl hydrazine decomposes upon heating to release a large amount of gas, opening up the blocked mesopores and macropores, and its residue rate is low. At the same time, due to the high valence of zinc ions, the crosslinking effect on CMC is stronger, resulting in less pore blockage of the formed activated carbon compared to activated carbon prepared by traditional processes, while maintaining the same strength.
[0011] Furthermore, the soluble zinc salt solution is prepared by mixing soluble zinc salt with water. The zinc salt can be zinc sulfate, zinc chloride, zinc nitrate, zinc acetate, etc.
[0012] Furthermore, the mass ratio of wood charcoal powder, CMC, ammonium oxalate, 4,4'-oxobis(benzenesulfonyl)hydrazine and zinc salt solution is 150~250:10~20:5~15:2~8:120~400.
[0013] Furthermore, the mass concentration of the soluble zinc salt solution is 1~10%.
[0014] Furthermore, the drying temperature is 190~250℃, preferably 190~220℃.
[0015] Furthermore, the wood charcoal powder is a highly adsorbent wood charcoal powder.
[0016] Furthermore, shaping is performed during granulation. The specific steps of shaping can be adjusted as needed, and it can be carried out in a kneader or using a mold.
[0017] The water-resistant wood-based activated carbon prepared using the above method has the following properties: iodine value >1000 mg / g, BWC >12 g / dl, A-method caramel content >90%, softening coefficient >0.95, pH value 6-8, and strength >90%.
[0018] Iodine value (iodine adsorption value): A quantitative indicator measuring the adsorption capacity of activated carbon for iodine molecules in liquids. It is characterized by the mass of iodine adsorbed per unit mass of activated carbon (mg / g), directly reflecting the degree of development of micropores with a diameter greater than 1.0 nm within the activated carbon. It is particularly suitable for evaluating the adsorption performance of small molecules (iodine molecules with a diameter of 0.335~0.6 nm). This invention uses the iodine solution shaking adsorption combined with sodium thiosulfate titration method specified in national standard GB / T 12496.8 for detection.
[0019] BWC (Butane Working Capacity of Activated Carbon): The amount of butane that can be released by purging with dry air after a unit volume or unit mass of activated carbon has adsorbed butane to saturation under specified conditions. It reflects the dynamic adsorption-desorption capacity of activated carbon in practical applications, not just the total static adsorption. This invention uses GB / T 20449-2006 "Test Method for Butane Working Capacity of Activated Carbon" for testing.
[0020] A-method caramel (A-method caramel decolorization rate): This method evaluates the decolorization ability of activated carbon for caramel pigments, indirectly reflecting its macroporous and mesoporous adsorption performance. The present invention uses the national standard GB / T 12496.9-2015 for testing.
[0021] Softening coefficient: The ratio of a material's strength after immersion in water for a certain period to its initial strength, used to characterize its water resistance. The value ranges from 0 to 1; a higher value indicates stronger strength retention after immersion in water. The softening coefficient testing method of this invention is as follows: Take an activated carbon sample with less than 1% moisture content, measure its initial strength f0, then immerse it completely in water at 25±2℃ for 30 days. After removal, dry it at 100℃ until the moisture content is <1%, and measure its strength f1. The softening coefficient = f1 / f0.
[0022] Strength (physical strength): An important physical performance indicator for measuring wear resistance and breakage resistance, expressed as a percentage. A higher value indicates stronger particles and less likelihood of dust generation during use and transportation. This invention uses the national standard GB / T 12496.6-1999 for testing.
[0023] Embodiment 1 of the present invention is as follows: A method for preparing a water-resistant wood-based charcoal: wood charcoal powder, CMC, ammonium oxalate and 4,4'-oxobisbenzenesulfonyl hydrazine are mixed, 3wt% zinc sulfate solution is added and stirred for 30 min, then granulated by a granulator, and dried at 195℃ to obtain columnar water-resistant wood-based charcoal with an average particle size of about 5 mm. The mass ratio of wood charcoal powder, CMC, ammonium oxalate, 4,4'-oxobis(benzenesulfonyl)hydrazine and zinc sulfate solution was 200:16:10:5:340.
[0024] The performance of the wood-based water-resistant charcoal prepared by the method in Example 1 was tested. The results showed that the iodine value was 1150 mg / g, the softening coefficient was 0.79, the BWC was 13.98 g / dl, the A-method caramel content was 95%, and the strength was 93%.
[0025] Embodiment 2 of the present invention is as follows: A method for preparing a water-resistant wood-based charcoal: wood charcoal powder, CMC, ammonium oxalate and 4,4'-oxobisbenzenesulfonyl hydrazine are mixed, 5wt% zinc sulfate solution is added and stirred for 400 min, then granulated by a granulator, and dried at 200℃ to obtain columnar wood-based water-resistant charcoal with an average particle size of about 3 mm. The mass ratio of wood charcoal powder, CMC, ammonium oxalate, 4,4'-oxobis(benzenesulfonyl)hydrazine and zinc sulfate solution was 220:17:11:6:380.
[0026] The performance of the wood-based water-resistant charcoal prepared by the method in Example 2 was tested. The results showed that the iodine value was 1100 mg / g, the softening coefficient was 0.83, the BWC was 13.31 g / dl, the A-method caramel content was 92%, and the strength was 95%.
[0027] Embodiment 3 of the present invention is as follows: A method for preparing a water-resistant wood-based charcoal: wood charcoal powder, CMC, ammonium oxalate and 4,4'-oxobisbenzenesulfonyl hydrazine are mixed, 6wt% zinc sulfate solution is added and stirred for 50 min, then granulated by a granulator, and dried at 190℃ to obtain spherical water-resistant wood-based charcoal with an average particle size of about 0.5 mm. The mass ratio of wood charcoal powder, CMC, ammonium oxalate, 4,4'-oxobis(benzenesulfonyl)hydrazine and zinc sulfate solution was 240:18:13:8:390.
[0028] The performance of the wood-based water-resistant charcoal prepared by the method in Example 3 was tested. The results showed that the iodine value was 1070 mg / g, the softening coefficient was 0.88, the BWC was 13.02 g / dl, the A-method caramel content was 93%, and the strength was 97%.
[0029] Embodiment four of the present invention is as follows: A method for preparing a water-resistant wood-based charcoal: wood charcoal powder, CMC, ammonium oxalate and 4,4'-oxobisbenzenesulfonyl hydrazine are mixed, 1wt% zinc chloride solution is added and stirred for 35 min, then granulated by a granulator, and dried at 250℃ to obtain spherical water-resistant wood-based charcoal with an average particle size of about 1 mm. The mass ratio of wood charcoal powder, CMC, ammonium oxalate, 4,4'-oxobis(benzenesulfonyl)hydrazine and zinc sulfate solution is 150:10:5:2:400.
[0030] Embodiment five of the present invention is as follows: A method for preparing a water-resistant wood-based charcoal: wood charcoal powder, CMC, ammonium oxalate and 4,4'-oxobisbenzenesulfonyl hydrazine are mixed, 10wt% zinc sulfate solution is added and stirred for 60 min, then granulated by a granulator, and dried at 210℃ to obtain columnar water-resistant wood-based charcoal with an average particle size of about 2 mm. The mass ratio of wood charcoal powder, CMC, ammonium oxalate, 4,4'-oxobis(benzenesulfonyl)hydrazine and zinc sulfate solution is 250:20:15:7:350.
[0031] Comparative Example 1 is: Based on Example 1, an equal amount of ammonium bicarbonate was used to replace ammonium oxalate.
[0032] The performance of the wood-based water-resistant charcoal prepared by the method of Comparative Example 1 was tested. The results showed that the iodine value was 927 mg / g, the softening coefficient was 0.78, the BWC was 12.85 g / dl, the A-method caramel content was 92%, and the strength was 96%.
[0033] Comparative Example 2 is: Based on Example 1, an equal amount of ammonium oxalate was used to replace 4,4'-oxobisbenzenesulfonyl hydrazine.
[0034] The performance of the wood-based water-resistant charcoal prepared by the method of Comparative Example 2 was tested. The results showed that the iodine value was 1047 mg / g, the softening coefficient was 0.82, the BWC was 12.63 g / dl, the A-method caramel content was 76%, and the strength was 97%.
[0035] The raw materials used in the embodiments and comparative examples of this invention are all from the same batch, and the testing methods and equipment used are all the same.
[0036] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.
Claims
1. A method for producing wood-based water-resistant charcoal, characterized by, Includes the following steps: The wood charcoal powder, CMC, ammonium oxalate and 4,4'-oxobisbenzenesulfonyl hydrazine were mixed and stirred, and then the mixture was shaped and dried to obtain the water-resistant wood charcoal.
2. The production method according to claim 1, characterized by, The mass ratio of the wood charcoal powder, CMC, ammonium oxalate, 4,4'-oxobisbenzenesulfonyl hydrazine and soluble zinc salt solution is 150~250:10~20:5~15:2~8:120~400.
3. The preparation method according to claim 1, characterized in that, The mass concentration of the soluble zinc salt solution is 1~10%.
4. The preparation method according to claim 1, characterized in that, The drying temperature is 190~250℃.
5. The preparation method according to claim 1, characterized in that, The wood charcoal powder is a highly adsorbent wood charcoal powder.
6. The preparation method according to claim 1, characterized in that, The shaping process involves granulation in a granulator.
7. The preparation method according to claim 6, characterized in that, Granulation produces columnar or spherical particles with an average particle size of 0.5~5mm.
8. A wood-based water-resistant charcoal prepared by the preparation method according to any one of claims 1 to 7.
9. The water-resistant wood-based charcoal according to claim 8, characterized in that, Iodine value > 1000 mg / g, BWC > 12 g / dl, A-method caramel > 90%.
10. The water-resistant wood-based charcoal according to claim 8, characterized in that, Softening coefficient > 0.95, pH value 6~8, strength > 90%.