CN1151062C - Method for preparing porous carbon material with phenolic resin gel - Google Patents

Abstract

The present invention relates to a method for preparing porous carbon materials, which has the steps: using linear phenolic resin as base, and hexamethylenetetramine as cross-linking agents; adding the catalyst of phosphoric acid into methanol solution for solidification, gel forming and drying at room temperature; soaking and drying the gel in potassium hydroxide solution, and then carbonizing and activating the gel in nitrogen atmosphere; finally, washing the gel by water to obtain porous carbon materials after drying. The porous carbon materials obtained by the present invention have a plurality of micro-holes and high specific surface area, and have favorable adsorbability. The present invention has the advantages of short time of gel forming in preparation, high yield and low cost.

Description

The method for preparing porous carbon material with phenolic resin gel

The present invention relates to a kind of preparation method of porous carbon material.

Porous charcoal has bigger pore volume and specific surface area, is subjected to people's attention deeply as application such as the adsorption and separation material of excellence and support of the catalyst for a long time.As far back as earlier 1900s, the most frequently used porous charcoal-gac has entered industrialization and commercialization, particularly in the World War I, for the research that gac is carried out a large amount of preparations and applied research and ejects after the war as the safety guard of chemical warfare to the gac peaceful use, as gas delivery, purification and purifying, aqueous solution decolouring, deodorizing, drink water purifying, make the theory and the practical application of gac obtain very big development [1,2].Along with fields such as the progress of raw material of wood-charcoal material technology of preparing and environment protection to improving constantly that sorbing material requires, nineteen sixties begins to occur novel porous charcoal filamentary material-activated carbon fiber.Activated carbon fiber is to be raw material with the high polymer fibre, through high temperature cabonization and activation and a kind of micro-pore carbon material for preparing.Different with macropore-mesopore-microvoid structure that gac is had, activated carbon fiber has abundant and micropore uniformly, and the aperture is 0.5 to 2nm, and pore size distribution is narrow, and specific surface area is big, thereby adsorptive capacity is big, and rate of adsorption is fast, and regeneration easily.And it can use with forms such as yarn, line, cloth, felts, and is more flexible on engineering is used, and demonstrates good prospects for application [2,3] in fields such as chemical, environment protection, energy resource, health care, electrical equipment, military projects.So far, the annual new results that preparation, structure, performance and the application of a large amount of research papers and patent report activated carbon fiber are all arranged.In recent years, a kind of work of novel porous charcoal-charcoal-aero gel causes that people pay close attention to greatly.So-called charcoal-aero gel is the nanometer porous raw material of wood-charcoal material of a kind of novel light, it is finished through formation, supercritical drying and three operations of carbonization of organogel, the product porosity is up to 80%～90%, typical case's pore dimension is less than 50nm, network colloidal solid size 3～20nm, specific surface area 600～1000m ²/ g, density is 0.05～0.8g/cm ³, be a kind of raw material of wood-charcoal material with electroconductibility, photoconductivity and good mechanical properties, at aspects such as support of the catalyst, super capacitor material and lagging materials applications well [4] is arranged.At present, porous charcoal such as gac, activated carbon fiber and charcoal-aero gel each have its production technique and play a role with performance characteristics and in different fields, they exist relative merits separately, simple as general active charcoal preparing process, low price, but the micropore ratio is lower, and adsorption/desorption speed is slower.The activated carbon fiber micropore is abundant, and adsorptive capacity is big, adsorption desorption speed height, but production cost height.Though charcoal-aero gel has nano level network particle and nano level hole, high porosity, gelation time is long during preparation, need time a couple of days usually, and the supercritical drying cost is also higher., develop new porous charcoal preparation technology and have theory and application value in the problem that preparation, structure and performance exist at existing various porous carbon materials.

The object of the present invention is to provide a kind of method for preparing porous carbon material, the porous carbon material of gained has and enriches micropore and high specific surface area, and preparation time is short, and cost is low.

To achieve these goals, the present invention is raw material with the linear phenolic resin, and through be cross-linked into glue in solution, drying and moulding adds the potassium hydroxide dip treating again, heats the novel process of the preparation porous charcoal of carbonization-activation then.Concrete preparation method was divided into for three steps: first, hexamethylenetetramine is dissolved in the methyl alcohol, concentration is 0.01～0.1 grams per milliliter, line taking resol is put into above-mentioned solution and is treated its dissolving, and making concentration is 0.05～0.5 grams per milliliter, slowly splash into phosphoric acid solution afterwards, making concentration is 0.02～0.11V%, and sealing and standing treats that it forms phenolic resin gel; The second, phenolic resin gel can adopt 50～70 ℃ of oven drying at low temperatures, and dry is the potassium hydroxide methanol solution immersion treatment of 0.16～1 grams per milliliter with concentration afterwards, boils off methyl alcohol, or adopts the CO 2 supercritical drying; The 3rd, gel resin is placed carbide furnace, under the purity nitrogen protection, heat carbonization, 600～900 ℃ of the carbonization temperatures of resin, carbonization time 60～120 minutes, product is taken out in cooling cooling naturally afterwards, water thorough washing, oven dry.In aforesaid method, the phenolic resin gel that makes through the method the first step can adopt the condition supercritical drying of carbonic acid gas at 45 ℃ of 7.4Mpa.Method second is used to soak the potassium hydroxide methanol solution of phenolic resin gel in the step amount is every milliliter 0.2～1 gram glue, soak time 12～24 hours.

Because the present invention has comprehensively drawn the preparation technology and the constructional feature of porous carbon materials such as gac, activated carbon fiber and charcoal-aero gel, use resol to be cross-linked into glue and prepare porous carbon material, as long as gelation time is generally one to two day, gelation time when producing than charcoal-aero gel shortens greatly that (charcoal-aero gel production is now used Resorcinol and formaldehyde monomers to carry out solution polymerization to become glue, general about seven days of gelation time), made porous carbon material productive rate height, cost is low, micropore is abundant, specific surface area is bigger, has the good adsorption performance.Lot of experiment results shows that the productive rate of the made porous charcoal of the technology of the present invention reaches 43%～70%, about 5 to 20 dusts in aperture, and specific surface area reaches 200～1400 meters ²/ gram reaches 130～640 milligrams/gram to the adsorptive capacity of benzene vapour.

Fig. 1 is the nitrogen adsorption isothermal line with the porous charcoal of phenolic resin gel preparation.

Fig. 2 is the micropore size distribution curve with the porous charcoal of phenolic resin gel preparation.

As can be seen, the porous charcoal for preparing with the art of this patent is the micropore carbon structure from Fig. 1, Fig. 2, and most micropore sizes are at 5 to 20 dusts.

The invention will be further described by the following examples:

Embodiment 1,5 gram hexamethylenetetramines are dissolved in (0.063 grams per milliliter) in 80 ml methanol, put into (0.5 grams per milliliter) after the 40 gram linear phenolic resins dissolvings, the phosphoric acid of Dropwise 5 milliliter (0.059V%), sealing and standing became glue in 24 hours.Oven dry is 12 hours in 60 ℃.The potassium hydroxide methanol solution dipping 24 hours (every milliliter 0.41 gram glue) that adds 120 milliliter of 0.5 grams per milliliter; methyl alcohol is removed in evaporation; afterwards resin is placed vertical heater, the speed with 6 ℃/minute under the protection of high pure nitrogen is warming up to 800 ℃, constant temperature carbonization 90 minutes.Naturally product is taken out in cooling cooling, with washing to neutral oven dry.The yield that records product is 59.7wt%, and specific surface area is 791 meters ²/ gram is to the 402 milligrams/gram of adsorptive capacity of benzene vapour.

Embodiment 2,2 gram hexamethylenetetramines are dissolved in (0.025 grams per milliliter) in 80 ml methanol, put into (0.25 grams per milliliter) after the 20 gram linear phenolic resins dissolvings, drips 3 milliliters phosphoric acid (0.036V%), 30 hours one-tenth of sealing and standing glue.Oven dry is 12 hours in 60 ℃.The potassium hydroxide methanol solution dipping 15 hours (every milliliter 0.42 gram glue) that adds 60 milliliter of 0.7 grams per milliliter; methyl alcohol is removed in evaporation; afterwards resin is placed vertical heater, the speed with 6 ℃/minute under the protection of high pure nitrogen is warming up to 800 ℃, constant temperature carbonization 90 minutes.Naturally product is taken out in cooling cooling, with washing to neutral oven dry.The yield that records product is 52.5wt%, and specific surface area is 891 meters ²/ gram is to the 379 milligrams/gram of adsorptive capacity of benzene vapour.

Embodiment 3,5 gram hexamethylenetetramines are dissolved in (0.1 grams per milliliter) in 50 ml methanol, put into (0.5 grams per milliliter) after the 25 gram linear phenolic resins dissolvings, the phosphoric acid of Dropwise 5 milliliter (0.09V%), sealing and standing became glue in 30 hours.Oven dry is 12 hours in 60 ℃.The potassium hydroxide methanol solution dipping 24 hours (every milliliter 0.35 gram glue) that adds 100 milliliter of 0.16 grams per milliliter; methyl alcohol is removed in evaporation; afterwards resin is placed vertical heater, the speed with 6 ℃/minute under the protection of high pure nitrogen is warming up to 800 ℃, constant temperature carbonization 90 minutes.Naturally product is taken out in cooling cooling, with washing to neutral oven dry.The yield that records product is 63wt%, and specific surface area is 240 meters ²/ gram is to the 180 milligrams/gram of adsorptive capacity of benzene vapour.

Embodiment 4,5 gram hexamethylenetetramines are dissolved in (0.0625 grams per milliliter) in 80 ml methanol, put into (0.5 grams per milliliter) after the 40 gram linear phenolic resins dissolvings, the phosphoric acid of Dropwise 5 milliliter (0.0625V%), sealing and standing became glue in 24 hours.Oven dry is 12 hours in 60 ℃.Add the potassium hydroxide methanol solution dipping 12 hours (every milliliter 0.45 gram glue) of 100 milliliter of 1 grams per milliliter, methyl alcohol is removed in evaporation, afterwards resin is placed vertical heater, and the speed with 6 ℃/minute under the protection of high pure nitrogen is warming up to 800 ℃, constant temperature carbonization 90 minutes.Naturally product is taken out in cooling cooling, with washing to neutral oven dry.The yield that records product is 41.7wt%, and specific surface area is 1400 meters ²/ gram is to the 640 milligrams/gram of adsorptive capacity of benzene vapour.

Embodiment 5,3 gram hexamethylenetetramines are dissolved in (0.0375 grams per milliliter) in 80 ml methanol, put into (0.375 grams per milliliter) after the 30 gram linear phenolic resins dissolvings, drips 3 milliliters phosphoric acid (0.036V%), 24 hours one-tenth of sealing and standing glue.Oven dry is 12 hours in 60 ℃.Add the potassium hydroxide methanol solution dipping 24 hours (every milliliter 0.6 gram glue) of 60 milliliter of 0.6 grams per milliliter, methyl alcohol is removed in evaporation, afterwards resin is placed vertical heater, and the speed with 6 ℃/minute under the protection of high pure nitrogen is warming up to 800 ℃, constant temperature carbonization 90 minutes.Naturally product is taken out in cooling cooling, with washing to neutral oven dry.The yield that records product is 43wt%, and specific surface area is 700 meters ²/ gram is to the 350 milligrams/gram of adsorptive capacity of benzene vapour.

Embodiment 6,3 gram hexamethylenetetramines are dissolved in (0.05 grams per milliliter) in 60 ml methanol, put into (0.5 grams per milliliter) after the 30 gram linear phenolic resins dissolvings, drips 4 milliliters phosphoric acid (0.0625V%), 30 hours one-tenth of sealing and standing glue.Oven dry is 12 hours in 60 ℃.Add the potassium hydroxide methanol solution dipping 24 hours (every milliliter 1 gram glue) of 37 milliliter of 0.6 grams per milliliter, methyl alcohol is removed in evaporation, afterwards resin is placed vertical heater, and the speed with 6 ℃/minute under the protection of high pure nitrogen is warming up to 800 ℃, constant temperature carbonization 90 minutes.Naturally product is taken out in cooling cooling, with washing to neutral oven dry.The yield that records product is 56wt%, and specific surface area is 200 meters ²/ gram is to the 170 milligrams/gram of adsorptive capacity of benzene vapour.

Embodiment 7,5 gram hexamethylenetetramines are dissolved in (0.0625 grams per milliliter) in 80 ml methanol, put into (0.5 grams per milliliter) after the 40 gram linear phenolic resins dissolvings, the phosphoric acid of Dropwise 5 milliliter (0.059V%), sealing and standing became glue in 24 hours.Oven dry is 12 hours in 60 ℃.The potassium hydroxide methanol solution dipping 24 hours (every milliliter 0.83 gram glue) that adds 60 milliliter of 0.6 grams per milliliter; methyl alcohol is removed in evaporation; afterwards resin is placed vertical heater, the speed with 6 ℃/minute under the protection of high pure nitrogen is warming up to 600 ℃, constant temperature carbonization 90 minutes.Naturally product is taken out in cooling cooling, with washing to neutral oven dry.The yield that records product is 70.7wt%, and specific surface area is 300 meters ²/ gram is to the 402 milligrams/gram of adsorptive capacity of benzene vapour.

Embodiment 8,2 gram hexamethylenetetramines are dissolved in (0.025 grams per milliliter) in 80 ml methanol, put into (0.19 grams per milliliter) after the 15 gram linear phenolic resins dissolvings, drips 9 milliliters phosphoric acid (0.10V%), 24 hours one-tenth of sealing and standing glue.Oven dry is 12 hours in 60 ℃.The potassium hydroxide methanol solution dipping 12 hours (every milliliter 0.43 gram glue) that adds 60 milliliter of 0.5 grams per milliliter; methyl alcohol is removed in evaporation; afterwards resin is placed vertical heater, the speed with 6 ℃/minute under the protection of high pure nitrogen is warming up to 900 ℃, constant temperature carbonization 120 minutes.Naturally product is taken out in cooling cooling, with washing to neutral oven dry.The yield that records product is 53.4wt%, and specific surface area is 893 meters ²/ gram is to the 422 milligrams/gram of adsorptive capacity of benzene vapour.

Embodiment 9,1 gram hexamethylenetetramine is dissolved in (0.01 grams per milliliter) in 100 ml methanol, puts into (0.05 grams per milliliter) after the 5 gram linear phenolic resins dissolvings, drips 2 milliliters phosphoric acid (0.02V%), 30 hours one-tenth of sealing and standing glue.The potassium hydroxide methanol solution dipping 12 hours (every milliliter 0.2 gram glue) that adds 40 milliliter of 0.3 grams per milliliter.With Liquid carbon dioxide exchange and soaked 24 hours, afterwards at 45 ℃, the condition supercritical drying of 7.4Mpa.Afterwards resin is placed vertical heater, the speed with 6 ℃/minute under the protection of high pure nitrogen is warming up to 800 ℃, constant temperature carbonization 90 minutes.Naturally product is taken out in cooling cooling, with washing to neutral oven dry.The yield that records product is 49.3wt%, and specific surface area is 568 meters ²/ gram.

Claims (2)

1. A method for preparing porous carbon material with phenolic resin gel is characterized in that the preparation method is divided into three steps: the first, hexamethylenetetramine is dissolved in methanol, and the concentration is 0.01～0.1 g/ml , take the novolac resin, put it into the above solution and wait for it to dissolve so that the concentration is 0.05-0.5 g/ml, then slowly drop into the phosphoric acid solution to make the concentration 0.02-0.11V%, seal it and let it stand until it forms a gel Gel; second, the gel is dried at a low temperature of 50-70°C, and after drying, it is soaked in a methanol solution of potassium hydroxide with a concentration of 0.16-1 g/ml, and the methanol is evaporated, or supercritically dried with carbon dioxide, which is used for soaking The amount of potassium hydroxide methanol solution of phenolic resin gel is 0.2 to 1 gram of glue per milliliter, and the soaking time is 12 to 24 hours; thirdly, the gel resin is placed in a carbonization furnace, heated and carbonized under the protection of pure nitrogen, the temperature 600-900°C, carbonization time 60-120 minutes, then cool down naturally, take out the product, wash fully with water, and dry. 2. a method for preparing porous carbon material with phenolic resin gel as claimed in claim 1, is characterized in that the phenolic resin gel that the first step makes adopts the condition supercritical drying of carbon dioxide at 45 ℃ of 7.4Mpa.

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