CN116516706A - Organic alkali extraction method of bamboo cellulose - Google Patents

Abstract

The invention provides a simple method for extracting cellulose from bamboo. In the method, organic alkali is used to treat bamboo biomass, and the extract can reach a bamboo cellulose content of more than 95%. At the same time, bamboo lignin and hemicellulose components can be obtained. The method provided by the invention has the advantages of simple process, good extraction effect, recyclable and reusable organic solvent, and environmental friendliness.

Description

A kind of organic alkali extraction method of bamboo cellulose

technical field

The invention belongs to the technical field of biomass utilization, and in particular relates to an effective method for extracting cellulose from bamboo.

Background technique

Cellulose is the most widely distributed and abundant renewable polysaccharide organic polymer in nature, which can be widely used in papermaking, textiles, building materials, adhesives, new materials, chemicals and other fields. Extracting cellulose from substances has important application value.

Paper pulping is one of the typical industrial applications for cellulose extraction from biomass. At present, the methods for separating and extracting cellulose from biomass (such as wood, wheat straw and bamboo, etc.) mainly include methods such as sulfate method, sulfite method, caustic soda method, organic acid method and organic solvent method. The extraction effect of cellulose is poor (generally less than 85% content), the loss of cellulose is large, the operation is complicated, the pollution is serious, and the cost is high. Bamboo is a type of biomass with high cellulose content. It has the characteristics of rapid growth, short growth cycle, wide distribution, and rich resources. It is also widely used in papermaking and pulping.

Therefore, a process route for extracting cellulose from bamboo is invented, which makes the extraction rate high, the process is simple and easy, green, environmentally friendly and pollution-free, and the cost is low. It has important industrial applications in the fields of paper pulping, dissolving pulp pulping, and textiles. value.

Contents of the invention

The purpose of the present invention is to propose a method for obtaining bamboo cellulose by treating bamboo with an organic alkali, and by further bleaching treatment, high-content (95%) cellulose can be obtained. Moreover, it has the advantages of small loss of cellulose, recyclable and reusable solvent, simple treatment, and environmental protection. It can be completely used in technical fields such as paper pulping and dissolving pulp pulping. In the present invention, bamboo refers to various kinds of bamboos such as Cizhu, moso bamboo and hard-headed yellow.

Bamboo cellulose extraction method provided by the invention comprises the following steps:

(1) bamboo is washed and dried, and cut into bamboo pieces;

(2) the bamboo piece that step (1) is obtained is put into reactor and carries out lignin and hemicellulose in the bamboo wood that organic alkali solution removes;

(3) extruding the mixture obtained in step (2) into pulp, separating and washing to obtain crude fiber and filtrate;

(4) the crude fiber obtained in step (3) is bleached, and then separated to obtain bamboo cellulose;

(5) The filtrate obtained by step (3) separation is subjected to vacuum distillation and rectification to reclaim the organic base and the solvent.

(6) Drying the solid obtained by distillation under reduced pressure in step (5), washing with water, and then centrifuging, the upper liquid is dissolved hemicellulose, and the lower sediment is lignin.

Within the scope of the invention, the loss rate of cellulose is low, while the corresponding removal rate of lignin and hemicellulose is high, and the organic base and solvent can be recycled and reused, the treatment is simple, and the method is environmentally friendly. Before bleaching, the removal rate of hemicellulose and lignin can reach 80%-90%; after bleaching, the removal rate of hemicellulose and lignin can reach more than 90%, while the loss rate of cellulose is basically less than 5%. The extraction rate can reach more than 95%.

In the technical invention, the bleaching process is simple and effective. Compared with the current traditional bleaching process of 4-5 stages, this method only needs one stage of bleaching to achieve good results, and uses less material, and the process is convenient and low in cost.

In the invention of this technology, since lignin and hemicellulose can be separated and recovered, on the one hand, the discharge of pollutants is greatly reduced, and full recovery and pollution-free can be achieved in the pulping process; on the other hand, the recovered lignin and hemicellulose can also be recovered Hemicellulose is further modified and processed to produce high value-added products.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the above-mentioned examples, and any combination of various embodiments of the present invention is also possible, as long as they do not violate the idea of the present invention, they should be regarded as It is the disclosed content of the present invention.

Description of drawings

Fig. 1 is the bamboo cellulose finally extracted of the present invention.

Detailed ways

In order to better understand the technical solutions and advantages of the present invention, the present invention will be described in more detail below in conjunction with specific examples.

Example 1: Wash and dry the bamboo, cut into bamboo pieces, put 5g of bamboo pieces into an airtight container, add 25ml of N-methylformamide and 25ml of water respectively, and react at a high temperature of 150°C for 3h to obtain a mixture, The reacted mixture was stirred, filtered and washed. The filtered solids were put into 50ml aqueous solution containing 0.3% hydrogen peroxide, 0.4% sodium hydroxide, 0.04% magnesium sulfate and 0.3% sodium silicate, and bleached at 50°C for 6h. Then the bamboo cellulose is separated and obtained, the yield is 45.4%, and the extracted solid cellulose content is 93.6%. The filtrate (organic lye) can be recycled by vacuum distillation to recycle the organic base and solvent, and the solid obtained by vacuum distillation is dried, washed three times with 30ml of water, centrifuged, the upper liquid is dissolved hemicellulose, and the precipitate is lignin , and then separate the lignin, and the recovery rate of the lignin obtained after drying is 30.4%.

Embodiment 2: Bamboo is cleaned and dried, cut into bamboo pieces, 5g bamboo pieces are put into airtight container, add 35ml tetramethylguanidine, 20ml N,N-dimethylformamide and 20ml water respectively, at 170 The mixture was reacted at high temperature for 2 h, and the reacted mixture was stirred, filtered and washed. The solid after filtration is put into the aqueous solution that contains 50ml mass concentration and is respectively 0.6% hydrogen peroxide, 0.3% sodium hydroxide, 0.05% magnesium sulfate and 0.3% sodium silicate, bleaches 5h at 60 ℃, then separates to obtain bamboo fiber The yield is 47.2%, and the extracted solid cellulose content is 97.3%. The filtrate (organic lye) can be recycled by vacuum distillation and rectification, and the organic base and solvent can be reused. The solid obtained by distillation under reduced pressure was dried, washed three times with 30ml of water, and centrifuged. The upper liquid was dissolved hemicellulose, which was precipitated as lignin, and then the lignin was separated. The recovery rate of lignin obtained after drying was 82.3%.

Example 3: Wash and dry the bamboo, cut into bamboo pieces, put 5g of bamboo pieces into an airtight container, add 35ml of dibutylamine and 15ml of water respectively, and react at a high temperature of 150°C for 5h to obtain a mixture. After the reaction, The mixture was stirred, filtered and washed. The solid after filtration is put into the aqueous solution that contains 50ml mass concentration and is respectively 0.5% hydrogen peroxide, 0.5% sodium hydroxide, 0.03% magnesium sulfate and 0.1% sodium silicate, bleaches 5h at 60 ℃, then separates to obtain bamboo fiber The yield is 45.5%, and the extracted solid cellulose content is 93.7%. The filtrate (organic lye) can be recovered and reused through vacuum distillation and rectification. The solid obtained by vacuum distillation was dried, washed three times with 30ml of water, and centrifuged. The upper liquid was dissolved hemicellulose, which was precipitated as lignin, and then the lignin was separated. The recovery rate of lignin obtained after drying was 25.3%.

Example 4 Wash and dry the bamboo, cut into bamboo pieces, put 3g of bamboo pieces into an airtight container, add 10g of pyrrolidone, 10ml of tetrahydrofuran and 30ml of water respectively, and react at a high temperature of 160°C for 2h to obtain a mixture. The resulting mixture was stirred, filtered and washed. The solid after filtration is put into the aqueous solution containing 30ml mass concentration of 0.5% hydrogen peroxide, 0.5% sodium hydroxide, 0.02% magnesium sulfate and 0.2% sodium silicate, bleached at 50°C for 7h, and then separated to obtain bamboo cellulose , the yield was 46.1%, and the extracted solid cellulose content was 95.1%. The filtrate (organic lye) can be recycled by vacuum distillation and rectification, and the organic base and solvent can be reused. The solid obtained by distillation under reduced pressure was dried, washed three times with 30ml of water, and centrifuged. The upper liquid was dissolved hemicellulose, which was precipitated as lignin, and then the lignin was separated. The recovery rate of lignin obtained after drying was 4.9%.

Example 5 Wash and dry the bamboo, cut it into bamboo pieces, put 2g of bamboo pieces into a closed container, add 7g of ethyl urea, 5ml of acetone and 30ml of water respectively, and react at a high temperature of 140°C for 4h to obtain a mixture, The reacted mixture was stirred, filtered and washed. The solid after filtration is put into the aqueous solution that contains 20ml mass concentration and is respectively 0.4% hydrogen peroxide, 0.3% sodium hydroxide, 0.05% magnesium sulfate and 0.3% sodium silicate, bleaches 5h at 60 ℃, then separates to obtain bamboo fiber The yield is 47.0%, and the extracted solid cellulose content is 96.9%. The filtrate (organic lye) can reclaim the organic base and solvent for reuse through vacuum distillation and rectification. The solid obtained by vacuum distillation was dried, washed three times with 30ml of water, and centrifuged. The upper liquid was dissolved hemicellulose, which was precipitated as lignin, and then the lignin was separated. The recovery rate of lignin obtained after drying was 26.3%.

Claims (5)

1. A method for extracting cellulose from bamboo, the method comprising the steps of:

(1) Cleaning bamboo, oven drying, and cutting into bamboo blocks;

(2) Placing bamboo blocks into a closed container, respectively adding organic alkali A and solvent B, and reacting at high temperature to obtain a mixture;

(3) Pulping, separating and washing the mixture obtained in the step (2) to obtain crude fibers and filtrate;

(4) Bleaching the crude fiber obtained in the step (3), and then separating to obtain bamboo cellulose;

(5) And (3) carrying out reduced pressure distillation and rectification on the filtrate obtained in the step (3) to recover organic alkali and solvent, and simultaneously obtaining lignin and hemicellulose.

2. The method according to claim 1, wherein the organic base a is at least one of dipropylamine, dibutylamine, diethanolamine, tetramethylguanidine, N-methylamide, ethylurea, pyrrolidone.

3. The method according to claim 1, characterized in that the solvent B is at least one of toluene, ethanol, acetone, dioxane, tetrahydrofuran, N-dimethylformamide and water.

4. The process according to claim 1, wherein the reaction temperature is 130-170 ℃ and the reaction time is 1-5 hours.

5. The method according to claim 1, wherein the bleaching treatment method comprises: adding the crude fiber obtained in the step (3) into an aqueous solution containing sodium hydroxide with the mass concentration of 0.2-0.5%, hydrogen peroxide with the mass concentration of 0.3-1%, magnesium sulfate with the mass concentration of 0.02-0.05% and sodium silicate with the mass concentration of 0.05-0.3%, and keeping the temperature at 50-70 ℃ for 3-8 hours.