Field of the invention

This invention relates to methods of preliminary treatment of the plant feedstock containing cellulose and other concurrent polysaccharides and lignines. The method lies in intensifying subsequent shredding and enzymatic hydrolysis of high molecular carbohydrides into water-soluble carbohydrides. Improvement of efficiency of enzymatic hydrolysis is achieved at the cost of combination of preliminary feedstock treatment with hot water and weak solution of hydrochloric acid (pH 1-2), solutions of cellulolytic enzyme preparation, drying and subsequent mechanical shredding of the feedstock. Extraction of the feedstock components is achieved by processing of the starting feedstock with hot water and weak solution of hydrochloric acid and formation of inner cavities and pores wich further may be filled with cellulolytic preparations. The method accounts for morphologic peculiarities of EFB structure and allows treatment not only outer surfaces of the feedstock but also inner surfaces. Such treatment efficiently weakens the strands strength and their efficient shredding.

Treatment with cellulolytic preparations is carried out at the temperatures from 20 to 50°C and low water duty of 1-8. Further the feedstock is dried and shredded in the mills of free or stringent impact. Preparation of the plant feedstock causes destruction of cellulose crystalline structure and increase in specific surface. In comparison with shredding which is carried out under the same conditions but without preliminary enzymatic treatment and drying the yield of fine fraction increases significantly. Saccharification of the fine feedstock is carried out up to deep degrees of conversion.

History of the invention

Below the methods are listed which can significantly increase efficiency of enzymatic hydrolysis of cellulose and concurrent polysaccharides.

Most of researchers pointed out at pronounced dependence between the grade of cellulose and its hydrolysis rate. The more cellulose is decrystallized the higher is the rate of hydrolysis. In some case the increase in the amorphous phase content from 20 to 80% cause increase in the rate by the factor of 5-6. Crystalline cellulose in biomass may be amorphous by mechanical processing of feedstock at apparatuses of different types - extruders, ball mills, centrifugal vibration mills, jet mills, roller mills and others.

Process of enzymatic hydrolysis of cellulose-containing biomass is heterogeneous Influence of the area of «solid state-liquid» interface is considerable. In this connection in the course of preliminary treatment of feedstock containing cellulose it is reasonable to obtain particles as fine as possible and provide the maximum increase in surfaces division phase.

Most of all known approaches to intensifying enzymatic hydrolysis of polysaccharides are based on mechanical processing of feedstock.

In order to obtain Fine plant feedstock containing cellulose is subjected to mechanical shredding at mills of different types; the resulting product is dried and sieved. As an example, the method for production of vegetable flour IEmil H. BaIz, Andrew W. Kassay, 1944, US 2362528, B27L 11/06/ includes desintegration of feedstock at the impact rattler, separation of fine particles and repeated desintegration of the rests of feedstock at the rotary mill. The method proposed by et al lies in moisturizing the feedstock before disintegration to moisten, then reduce to fine particles in the screw mixer heated to 120 ⁰ C under pressure of 50 MPa ISU 4260749, 1988 , D21B 1/06/.

The drawbacks of the listed methods for obtaining fine-dyspersated products from vegetable feedstock are high energy consumption for desintegration and drying of feedstock, and also low efficiency desintegration. Fiberlike structure of vegetable feedstock, presence of accompanying components such as lignines, hemicelluloses imparts particular strength to natural materials containing cellulose. Therefore various methods for obtaining fine- dyspersated products from vegetable feedstock which include preliminary chemical action on the feedstock and its subsequent chemical treatment.

Chemical treatment allows modification of the feedstock in the way that preparation of the feedstock for enzymatic hydrolysis by mechanical treatment runs more efficiently. Acid hydrolysis of cellulose and hemicelluloses inherent in plant feedstock, alkaline treatment for elimination of lignine, treatment with other agents and various solvents.

In particular, a method is proposed for obtaining fine-dyspersated products based on treatment of wood or other feedstock containing cellulose with urea solution, subsequent drying and desintegration at the ball mill /Andrew W. Kassay et al, 1942, US 2364721, C08L 97/02/.

For destruction of cellulose crystalline structure and enlarging of the specific surface of the feedstock with the aim of intensifying further enzymatic hydrolysis of polysaccarides it was proposed to threat the waste containing cellulose in twin screw extruders at elevated temperature (up to 200 ⁰ C). As a feedstock rice mash, cotton mill puffs, cotton stems etc. IRU 2223327, 2004, C13K 1/02/. G.R. Huber et al has proposed to treat feedstock containing cellulose in extruders at elevated temperatures under high pressures IG. R. Huberet al, 1992, US 5114488, B30B 11/22, C13K 1/00/. Preprocessing of the feedstock may be carried out in extruders in presence of alkaline solutions IT. Inoiet al, 1987 , US 4642287, C12P 19/00, C13K 1/00/; with that, efficiency of the subsequent enzymatic hydrolysis of saccharides in the feedstock is improved .

Pre-hydrolysis treatment of lignocellulose in the πpoTOHHOM reactor is performed with diluted acid solutions; such treatment results in isolation of hemicelliiloses and pentoses from the solid feedstock. Then cellulase enzymes are added, and hydrolysis of the bulk of the feedstock is carried out .// R.W. Torget, et al. 1984, US 5503996.

A method is proposed for mechanical processing of lignocellulose feedstock in presence of water, alkaline solutions, acid solutions and enzymes. The method is based on treatment of pulp in microcavitation installations; at the cost of intense shift loads destruction of strands of lignocellulose biomass is achieved and as a consequence, elevation in the substrate sensitivity to further enzymatic hydrolysis IE.D. Stuart et al, 1996, US 5498766, C08H 5/04, C13K 1/00/.

For separate hydrolysis of hemicellulose and cellulose a two-staged scheme of hydrolysis of lignocellulose feedstock was proposed. At the first stage hydrolysis is carried out with diluted acid with that the treatment is performed at temperature and pressure which provides preferential hydrolysis of hemicelloloses to pentoses. At the second stage temperature and pressure are elevated, and preferential hydrolysis of cellulose to hexoses takes place //FJ. Reitter. US 1984, 4427453.

Background to the invention.

Despite insignificant amounts of liquid biofuel produced (somewhat higher 1.5 % from the total volume of liquid fuel), shut down termination of biofuel production as estimated by Merrill Lynch [1] would cause the rise in oil and gas pries by 15 %. Unfortunately, growth in bioethanol production leads to growth in consumption of foodstuffs and fodders.

It is generally recognized fact that there exist solid fuels (pellets, fuel bricks), liquid fuels (bioethanol, biodiesel) and gaseous fuels (methane, hydrogen). Presently, the fuels are differentiated as fuels of first, second and third generations. It is the fuel of first generation that is manufactured of potential food stuffs. Biofuel of second generation is a product of fast pyrolysis of biomass which mar represent wood or agricultural waste (sunflower husk and gramineae plant straw). This product which differs from bioethanol or biomethanol with further processing may be a promising source for liquid fuel for engines and power plants.

The present patent is directed to obtaining liquid and solid biofuel from agricultural waste, namely, from waste from palm oil production which composition are of no food value for animals and humans due to its composition. Recovery of waste of palm oil production will also serve for solving ecologic problem in the region. Informative part of the patent is based on specific peculiarities of the structure and composition of the main part of the mentioned above waste, that is, bunches, or more precisely, empty fruit bunch fibers (EFB).

Oil palm (Elaeis guineensis) is widely cultivated in Western and Central Africa, Indonesia, Thailand, India, and Malaysia it is one of the most important crop plants. For 40 years Malaysia has been the world leader in raising oil palm and palm oil production. Acreage under oil palm continually grows. However, rapid development of production and processing oil palm leads to unwanted consequences - accumulation of large amounts of waste and arising ecologic problems.

Peculiarities of EFB composition.

Chemical composition of the material [2] is presented in the Table 1. It is seen that the total content of cellulose and hemicellulose in the products is more than 80 %, and content of lignine is about 18 %. In comparison with wheat and maize straw where cellulose content does not exceed 60%, an content of lignine achieves 35 % this lignine cellulose feedstock from palm oil production has obvious advantages.

Table 1. Chemical composition of fiber strands Oil Palm Empty Fruit Bunches.

Peculiarities of EFB structure.

The structure of fiber strands oil palm empty fruit bunches possesses some properties which in the course of mechanical activation leads to different results in comparison with straw of grain varieties. Another consequence of the differences in structure is necessity of special chemical preprocessing the feedstock of oil palm.

Photomicrographs analysis of starting feedstock of oil palm has shown that fibers of the material consist of elongated cells— vessels up to 1 mm in length and 19 μm thick. The wall thickness of the cells is 3.4 μm. In the Fig. 3 a cross cut of the fiber strand is shown. In comparison with tissues of grain varieties fibrous material of oil palm appeared to be the closest to straw conducting strands.

The obvious differences are the following. There are channels in the walls of vascular cells. Clearance of the channels is filled with electron-dense substance, distance between the channels is usually 2 or 4 μm (Fig. 1). Due to the fact that there are typical deepening where silicon dioxide are located at the output of the channels from the cell walls, it is believed that these particles take part in silicon transportation over the plant.

In the inner part of intercellular substance accumulation of starch grains are observed. In The fig.2 Photos Of The Cell Wall Are Presented Taken With High Magnification (E And B). It Is Seen That In Contrast To Maize Straw The Cell Wall Has No Distinct Periodic Structure, That Is, Distinct Alteration Of Electron-Dense And Electron-Transparent Layers Is Absent. In The Cell Wall, Layers Of 50-100 Nm Thick Are Distinguishable. In The Ultrastructure An Expressed Electron-Transparent Layer Is Traced Having The Thickness Of The Order Of 150 Nm Which Extends Along The Cell Wall.

In comparison with the straw of grain varieties feedstock of the oil palm is more mechanically resistant. There arise problem in the course of shredding the material in the strike-slip mill. Material cannot be efficiently shredded even under prolonged processing. As it was shown, particular strength of the wall is probably associated with these layers.

Thus, material of the oil palm is rather different from the straw of grain varieties; it is more resistant to mechanical action. In order to decrease strength of the material and to achieve its efficient shredding and activation for subsequent chemical and biochemical reaction, special preliminary treatment is necessary. The main new physical and chemical knowledge obtained in the course of the method development is finding out peculiarities of the structure of the cell walls of the feedstock, namely, presence of the channels in the wall, and efficient using the channels for destruction of the palm material structure. Summary of the invention.

The proposed method consists of several stages including conversion of polysaccharides (cellulose and hemicellulose) of lignocellulose feedstock into soluble sugars, biotechnological conversion of soluble sugars in methanol by microorganisms.

The first stage of saccharification of lignocellulose feedstock is a heterogeneous solid phase process consisting of chemical heterogeneous solid phase reaction of cellulose with water and diffusion stage of agents delivery to the substrate and removal of reaction products. Any heterogeneous reaction runs the faster and degree of conversion rate is the deeper the finer are the particle of solid phase.

Presence of lignine in the reaction mixture is the factor that hinders hydrolysis of carbohydrides in lignocellulose feedstock. Lignine inhibits action of enzymes— it covers cellulose fibers hindering access of enzymes to the substrate.

Therefore the first task is efficient shredding of the plant substrate consisting mainly of cell walls, and creation of defects in the form of disordered and amorphous sites of cellulose. Chemical composition of the bunches given below shows that they contain a large amount of water- and acid-soluble compounds. Their removal from the bunches should affect the structure, and, therefore, mechanical strength of the material. Actually, preliminary chemical treatment and treatment with hot water leads to partial removal of lignine and hemicellulose, and also fats and water-soluble substances.

It was proved experimentally that after removal of these substances voids are formed in the bunches. So, removal of about 30 % of substances from the bunch changes diameter of fibers by a few percent. The formed cavities decrease the strength of bunches which provides their finer shredding.

The cavities remained after removal of soluble substances are stable may be reproducibly filled with water vapor and other volatile substances, and solution of various salts and enzymes. To fill in the voids with enzyme solution more efficiently ultrasound stimulation of diffusion process is carried out. Thus, the substrate is treated with enzyme not only outside bunches but also inside bunches which provides severalfold increase in the output of fine fraction under similar conditions for shredding of starting and processed bunches.

DRAWINGS

Fig. 1. A particle vascular elements of the bunch. Magnification x 1000. Fig. 2. Cross- section of bunches of palm fibers. Semithin shear cut stained with azure-2. Fig. 3. Ultrafine shear cuts of cell walls of EFB fibers. Preparations are fixed with osmic acid. A-C starting feedstock before mechanical processing. Layers of the cell walls 50-100 nm thick are distinguishable. 'Channels' are stained; the distance between them is usually 2-4 μm (A). Fig. 4. Distribution in sizes of the particles of maize straw, wheat straw and (EFB) bunches washed off from oil and lipids after their shredding under similar conditions at the cage mill IA 28. Fig. 5. Relative increase in mass (swelling ability) in water of the samples of bunches of palm fibers (EFB): 1 - starting, and 2 - treated with diluted hydrochloric acid. Fig. 6> Quantity of fine fraction (<200μm) after preliminary chemical treatment and shredding at the stringent shock strike-slip mill APF 3. Fig. 7. Distribution in sizes of the EFB particles after acid and enzymatic treatment and their shredding at the stringent shock strike-slip mill APF- 3 - Fig. 7.1., after shredding at the stringent shock strike-slip mill CMA-2 - Fig. 7.2. Fig. 8. Distribution in sizes of the EFB particles: 1— after standard shredding (corresponds to type 1. in the histogram 6), 2 - after shredding the treated sample at the CMA-02 mill, corresponds to fine fraction shown in the Fig. 7.2. Fig. 9. Distribution in sizes of the EFB particles after chemical treatment and shredding at the CMA-02 stringent shock strike-slip mill. Fig. 10. Distribution in sizes of the EFB particles shredding at the CMA-02 mill without preliminary chemical treatment. Fig. 11. Hydrolysis of the fraction less than 200 μm which was obtained after shredding the bunches without preliminary treatments corresponds to Fig. 10. Fig. 12. Hydrolysis of the fraction less than 200 μm which was obtained after shredding of the bunches after preliminary treatment corresponds to Fig. 9. Fig. 13. Heat value with EFB combustion: 1— before hydrolysis, 2 - after partial hydrolysis (relative units). Values of combustion heat are proportional to the squares under corresponding curves 1 and 2. Fig. 14. Optical spectra of compounds extracted from the palm bunches with weak acid solution: 1— starting solution (tenfold dilution), 2 - solution after adding aluminum oxide (threefold dilution).

Description of the preferred embodiment.

Starting feedstock from palm oil production - bunches - after shredding at powerful equipment of desintegrator type with rotational speed of 1000 rpm, inflame directly inside the apparatus. This is associated with a high content of fats and lipids, up to 6 %, which in the process of shredding under heating of material oxidize intensively.

For removal of lipids and rests of oil the bunches were washed out with hot water with detergents or 2 % solution of sodium carbonate. After washing out the samples the mass loss was 6-8 %, after drying it becomes possible to perform shredding process without inflammation. The results for shredding of bunches washed out from fats and lipids obtained at the laboratory desintegrator are given in the Fig. 4. In the same figure the results for shredding another plant feedstock promising from the viewpoint of ethanol production are given for comparison. H Comparing the amount of fine fraction in shredded lignocellulose feedstock, namely, in maize straw, wheat straw and palm bunches it should be concluded that palm bunches are much stronger than maize and wheat straw and is harder for shredding. The cause of this strength lies in the peculiarities of the structure and was discussed earlier.

Analysis of the palm bunch composition, presence of substances which may be removed from the feedstock with diluted solution of hydrochloric acid are given in the Table 1. This process causes mass loss of more than 17-20% which together with substances removed with treating with hot water comprise about 30% of starting mass. This considerable mass loss is accompanied by insignifican change in the volume which indicates the pore and voids formation in the processed feedstock. The voids may be filled with water of and other volatile substances.

Bunch fibers treated with hydrochloric acid, washed out and dried were conditioned in saturate water vapor at the constant temperature. The results on sorption capacity for palm bunch fibers treated and untreated with acid are given in the figure 5. From the data it is seen that during conditioning of stating fibers for 40 hours their swelling ability achieves the saturation. Increase in mass was 20 % and may be associated with water sorption on the outer surfaces of fibers.

Sorption of water vapor on the treated fibers consists of two stages: fast sorption taking about 20 hours and quantitatively correlating with sorption of water vapor on the untreated fibers, and slow stage. The slow stage does not stop even after 140 hours and is apparently associated with diffusion of water vapor into pores and voids remained after elimination of lignine and cellulose from the bunches, Fig. 5. This pores and voids may be filled not only with water vapor but also with solutions of salts and enzymes. Formation of this porous structure was not observed in the case of preliminary chemical treatment of other lignocellulose materials: wheat and maize straw, shavings of hard- and soft-textured wood. It is probably associated with a specific tissue structure of the palm bunches and channels in the cell walls found with their microscopic investigation and shown in the Fig. 1—3.

Thus, after processing the bunches become porous which also results in reducing their strength and higher efficiency of the material shredding.

In order to speed up diffusion of the substances inside the pores ultrasound treatment was carried out for the system of 'solution-palm bunch fibers'. According to literature, enzymes are denaturated with ultrasound treatment [3]. To estimate influence of ultrasound on fermentation activity of the complex hydrolysis was carried out using the starting enzyme and the enzyme preliminary treated with ultrasound. As a model substrate, Whatman drawing paper #1 was used. The experiments showed that ultrasound of 35 kHz, dose 150- 300 J did not cause alteration in the enzyme complex within the limits of experimental error.

Treatment of the obtained porous bunch with enzyme causes 1-3 % hydrolysis of the cellulose fibers. However, such hydrolysis runs not only outside but also inside fibers which results in heavy deterioration of the structure and efficient shredding of the dried feedstock.

Efficiency of shredding may be determined by the amount of fine fraction obtained in the course of material shredding. The results are given in the histogram in the Fig. 6. feedstock being processed was undergone to preliminary treatment of different types, Table 2.

Table 2. Type of EFB chemical treatment.

Not only preliminary treatment influence the state of shredding but also the type of mechanical processing. The largest amount of fine fraction was obtained of the stringent strike mill where mainly shifting abrasive action is performed. This result is shown in the Fig. 7.

The fraction of particles less than 80 μm was determined by diffraction of laser irradiation on the particles , Fig. 8.

From the distribution shown in the Fig. 6-7, it is possible to calculate the fraction of particles of specified size for each type of shredding. For example, the fraction of particles less than 20 μm with standard shredding EFB is about 1 %, and the fraction of the same particles according to the proposed method is about 41 %. Consumption of mechanical energy for both type of shredding are equal.

Fine particles obtained after mechanical shredding of chemically treated palm bunch fibers are readily hydrolizable. The total degree of conversion in carbohydrides is achieved already 60 % after 25 - 30 hours of hydrolysis. Then the rate of hydrolysis drops significantly; this is associated with covering the remained substrate with lignine and limitation of enzyme access to the substrate At this stage additional activation of the feedstock is possible and degree of conversion of carbohydrides in soluble sugars may be brought to 90 %.

Taking into consideration that hydrolysis of carbohydrides leads to enrichment of the feedstock with lignine of a higher heat value than that of cellulose it is reasonable to use the 60 - 70% of biomass remained after hydrolysis for production of solid fuels (pellets).

With incineration of such pellets the heat release is approximately 1.5 times higher than with incineration of starting palm bunches.

Example 1. Effect of preliminary chemical treatment on changes in composition of the feedstock.

The palm bunch fibers were conditioned in hot water for about 2 hours. As the result of this process fiber swelling occurs.

Further the feedstock was treated with diluted solution of hydrochloric acid (1 %), which increases the mass percent of cellulose in the feedstock and also allows transform a part of easily hydrolizable polysaccharides in soluble state. As a result of acid hydrolysis 17 % hemicelluloses was solved which corresponds to 22.5 % of carbohydrides conversion. The mass loss after acid hydrolysis was 30 %. This indicates that a part of lignine and other substances was also solved in acids. The mass percent of these substances decreased in the feedstock

Composition of the feedstock obtained after chemical modification is given in the

Table 3.

Table 3.

Components Content, % from dry weight

Starting Elimination Of Treatment with Treatment With Feedstock Extractive HCl 1 % Enzyme

Substances Solution

Cellulose 40 45,5 68 68

Hemiculloloses 22 25 12 12

Extractive 12

Substances

Lignine 18 20,5

Others 8 9 20 20 Example 2. INFLUENCE OF PRELIMINARY CHEMICAL TREATMENT ON PALM BUNCHES SHREDDING.

After chemical treatment of palm bunches described in Example 1, they were shredded in shift action CMA-2 mill. The fraction composition of the shredded bunches is given in the Fig. 9. The fraction composition of the shredded bunches without preliminary treatment is given in the Fig. 10.

As it is seen from the data given the proposed method for chemical modification of palm waste, EFB shredding is much efficient in comparison with starting feedstock. Mass percent of the particles < 80 μm is almost 90 %. Without chemical treatment, the feedstock is shredded much worse. Mass percent of the particles > 80 μm is greater 40 %. 20 % of them

- Mass percent of the particles > 400 μm.

Example 3. Hydrolysis of palm bunches.

enzymatic hydrolysis was carried out in the reactor placed in the thermostat with water temperature of 50 C, pH 4.7 (acetate buffer). Reaction runs under permanent stirring, stirring rate was 400 rpm. In order to prevent irreversible enzyme sorption on lignines and to increase activity of cellulase enzymes, TWEEN-60 surface-active substancc(5 % from the mass of palm waste) was added to the reaction medium. In order to prevent development of microorganisms 0.5% formalin as an antiseptic for prevention of development of microorganisms in the reactionary environment as antiseptics added formalin (0.5 %) was added to the reaction medium. In certain periods of time aliquots of hydrolyzate (1-2 ml) were taken out, the solution was separated from the solid precipitate at the centrifuge (8500 rpm for 15 min). The liquid was used for determination of reducing carbohydride concentration in the solution and degree of carbohydride conversion in soluble sugars.

Reducing carbohydride concentration in the solutions was by reduction reaction of

Fe(III) in the potassium ferricyanide complex. 1 ml of hydrolyzate was mixed with 3 ml of 0.6 % Kn(Fe(CN))g solution. The solution was kept on the boiling water bath for 10 minutes. Optical density of Fe (III) solutions after interaction with enzymatic reaction products were registered at the wavelength of 419 nm. Concentration of reducing carbohydrides was determined by the calibration graph plotted by glucose solution of know concentration. So, the number of reducing chemical groups was determined according to this technique.

Effect of preliminary processing and degree of shredding is illustrated by Fig. 1 1 and 12. Example 4. Influence of degree of EFB hydrolysis on heat effect of complete oxidation (incineration).

One of the method for EFB utilization is application as a fuel for heating use as fuel for heating is boilers, reactors and heating water. Fibrillae forms the base of palm bunch fibers contain from 10 to 19 % of lignine and about 60-70 % of carbohydrides while the pine wood of contain up to 30 % of lignine, and total amount of carbohydrides is about 60 %. As combustion heat of lignine is approximately 1.5 times higher than that of cellulose, incineration of starting palm feedstock provides less heat energy than incineration of pine wood. Also the fuel produced from starting palm feedstock provides less heat energy.

In bioethanol production the rate of carbohydride conversion in sugars is high at the initial stages but as reaction runs and conversion degree deepens the amount of carbohydrides decreases, and amount of lignine increases. Along with that, inhibition of the reaction with lignine rises. At this stage of hydrolysis solid precipitate enriched with lignine may be used for production of solid fuel— pellets which in heat value are comparable with pellets of pine wood but contain smaller amount of ashes.

Incineration of the starting samples of bunches and bunches after hydrolysis to 60% conversion in carbohydrides was carried out in the derivatograph in the oxygen flow.

Temperature of incineration was about 700 C. Test portion - 100 mg. Heat rate was about 25 per minute. In the Fig. 13 kinetics of heat release is shown with incineration of bunches before hydrolysis and incineration of solid residues after partial (60 %) hydrolysis. Combustion heat of starting sample is 1.3 times less than after partial hydrolysis.

Example 5. Elimination of lignine from solution.

After palm bunches were treated with weak acid solution not only a part of hemicelluloses pass to the solution but also acid-soluble lignine. Separation of carbohydrides in penthoses and hexoses facilitate further fermentation in ethanol. Isolation of soluble penthoses from carbohydride phase simplify technology for bioethaol production. However, acid-soluble lignine inhibiting enzymatic hydrolysis of hemicelluloses also passes into solution. It is proposed to use aluminum oxide for elimination of lignine.

Aluminum oxide is obtained by baking aluminum hydroxide. Specific surface of aluminum axde is 70 m /g.

Aluminum oxide in the ratio of 1 :5 was added to the solution obtained at the stage B) of the process 1. After stirring at 25 C for one hour the solution was discolorated. The amount of lignine rests in the solution may be estimated by absorption spectra which are given in the Fig. 14. The There are bands in the optical spectra specific for lignine. Discoloration of the solution after addition of aluminum oxide is associated with lignine sorption on oxide.

The data presented show that lignine concentration after addition of sorbent agent decreases by the factor of 50.

References

1. Wall Street Journal, 24/03/2008

(http://online.wsj .com/article/SB 121728170968391097.html)

2. Law K-N., Daud W.R.W., Ghazali A. Morphological and chemical nature of fibre strands of oil palm empty-fruit-bunch (OPEFB) // BioResources, V.2, N3, 2007, p. 351-362.

3. Dubinskaya, A.M., Transformation of organic substances under action of mechanical pressure. // Successes of chemistry. - 1999. T. 68. - JYe 8. - C. 708 - 724.