Description:TECHNICAL FIELD
The present disclosure relates to a method of extraction of fibers and pulp. More particularly, the present disclosure relates to the method of extraction of fibers and pulp from banana stems by way of vibrational energy and chemicals.
BACKGROUND
With the change in lifestyle, the demand for sustainable approaches is increasing exponentially. Among the known sustainable materials such as bamboo, coconut, clay, wood, hemp, and others banana has caught the major attention since every single part of banana is found to be functional and applicable for use.
Several research are being conducted globally to discover and improve the existing methods for the extraction of natural fibers to make biodegradable products thereby conserving the environment. Major attention is being given to the extraction of fibers from banana pseudo stem and the obtained scutcher (short fibers) as they are discarded as waste or burnt post drying thereby increasing pollution levels.
The available technologies as of now for the extraction of banana fibers use traditional mechanical and manual methods. The common practice for extraction of fibers and pulp from banana pseudo stem involves the use of some machines, for example-a decorticator machine. In the available methods, the obtained separated fibers are then combed using a metallic comb to remove the remnants of the pseudo stem. However, there are certain disadvantages to the available methods. The power requirement of the machine used in the method is high and that increases the capital investment. Further, the resulting yield is low up to 0.5-1% weight. An additional amount of 2-3 % of scutcher (short fibers) is obtained which are generally not used and discarded as waste.
Hence, there is a need to develop a method that overcomes the problems of the existing methods and utilizes the waste generated in the method itself to enhance the yield of the obtained product.

SUMMARY OF THE INVENTION
One aspect of the present disclosure is a method for extraction of fibers and pulp from a banana stem. The method comprises separating an outer bark from the banana stem, cutting the separated outer bark to obtain a fragmented long outer bark, hydrolyzing the fragmented outer bark to remove impurities, treating the obtained hydrolyzed outer bark by way of vibrational/ultrasonic energy in a frequency ranging from 20-40KHz, soaking the obtained sonicated outer bark in an alkali solution to further obtain defibrillated fibers; extracting the obtained defibrillate fibers from the soaked outer bark to obtain fiber and scutchers, delignification of the obtained scutchers in an alkali peroxide solution to obtain a lignin-free short fiber, washing the obtained lignin-free fiber to remove impurities and further obtaining a pure fiber and beating the obtained pure fiber to obtain pulp from banana stem.
In some aspects of the present disclosure, the fibers are selected from a group comprising long fibers and short fibers.
In some aspects of the present disclosure, the fragmented outer bark obtained is 200-1000mm long.
In some aspects of the present disclosure, cutting is carried out by pulverizing or shredding.
In some aspects of the present disclosure, ultra-Sonication is performed with a temperature ranging from 30 ? to 60 ?
In some aspects of the present disclosure, the vibration/Ultrasonic energy is provided by way of a vibration energy generator selected from a group comprising an Ultra- sonicator, a piezoelectric transducer, an ultrasonic generator, or a vibrational screen.
In some aspects of the present disclosure, the sonicator is selected from a group comprising probe Ultra-Sonicator or bath Ultra-Sonicator.
In some aspects of the present disclosure, the alkali reagent is selected from a group comprising sodium hydroxide, calcium hydroxide, potassium hydroxide or magnesium hydroxide.
In some aspects of the present disclosure, the reagents used for pulping are selected from a group comprising alkali peroxide solution, kraft solution, polysulfide, sodium hydroxide, acid sulfite, or bisulfite.
In some aspects of the present disclosure, the mechanism for extracting fibers from soaked outer bark is selected from a group comprising brushing, sweeping, scraping or combing.
BRIEF DESCRIPTION OF DRAWINGS
The drawings mentioned herein disclose exemplary embodiments of the claimed invention. Other objects, features, and advantages of the present invention will be apparent from the following description when read with reference to the accompanying drawing:
FIG.1 illustrates a method for extraction of fibers and pulp from banana stem, according to an embodiment herein.
FIG.2 illustrates a method of alkali recovery from obtained spent solution, according to an embodiment herein.
FIG. 3 is a graphical representation that illustrates a comparative analysis of fiber yields post-extraction by way of present method with a sonicator chamber and existing methods with a decorticator machine, according to an embodiment herein.
FIG. 4 is a SEM images that illustrated the long and short fiber morphological analysis including measurements of fiber diameter, length as well as observations of the fiber surface, according to an embodiment herein.
FIG.5 is a graphical representation that illustrates the extraction of pulp from banana scutches by way of a sonicator chamber and a decorticator machine, according to an embodiment herein.
FIG. 6 is a graphical representation that illustrates the recovery of alkali and its purity from concentrated spent by varying smelting temperature, according to an embodiment herein.
DETAILED DESCRIPTION
This section is intended to provide an explanation and description of various possible embodiments of the present invention. The embodiments used herein, and the various features and advantageous details thereof are explained more fully with reference to non-limiting embodiments illustrated in the accompanying drawing/s and detailed in the following description. The examples used herein are intended only to facilitate an understanding of ways in which the embodiments may be practiced and to enable the person skilled in the art to practice the embodiments used herein. Also, the examples/embodiments described herein should not be construed as limiting the scope of the embodiments herein.
As mentioned, there is a need for development of a method for extraction of fibers and pulp from banana stem with higher yields.
The present aspect provides a method for extraction of fiber and pulp from banana by way of vibrational/ultrasonic energy and chemicals resulting in higher yields of fiber and pulp.
The banana stem was procured from a village called Tenelagudem near Venkatapur, Hyderabad.
FIG.1 illustrates a method for extraction of fibers and pulp from the banana stem, according to an embodiment herein. The method (100) includes separating (102) an outer bark from a banana stem, cutting (104) the separated outer bark to obtain a fragmented longer outer bark, hydrolyzing (106) the fragmented outer bark to remove impurities, treating (108) the obtained hydrolyzed outer bark by way of vibrational/ultrasonic energy in a frequency ranging from 20-40KHz which is absorbed by the liquid molecules, leading to the generation of mechanical oscillating power, which results in the formation, expansion, and implosion of microscopic gas for extraction fiber, soaking (110) the obtained sonicated outer bark in an alkali solution to further obtain defibrillated fibers, extracting (112) the obtained defibrillate fibers from the soaked outer bark to obtain fiber and scutchers, delignification (114) of the obtained scutchers in an alkali peroxide solution to obtain a lignin-free fiber, washing (116) the obtained lignin-free fiber to remove impurities and further obtaining a pure fiber, and beating (118) the obtained pure fiber to obtain a pulp.
In another embodiment, the fibers and pulp are extracted from banana stem. In another embodiment, the pulp is extracted from banana leaf. In another embodiment, the fibers and pulp are extracted from banana tree bark.
In another embodiment, the method (100) comprises separating (102) an outer bark from the banana stem. In another embodiment, the separation is performed by manual peeling. In another embodiment, the separation is achieved by crushing. In another embodiment, the separation is achieved by smashing.
In another embodiment, the method (100) comprises cutting (104) the separated outer bark to obtain a fragmented long outer bark. In an embodiment, the fragmented outer bark obtained is 200-1000mm long. In another embodiment, the cutting is carried out by pulverizing or shredding.
In another embodiment, the method (100) comprises hydrolysing (106) the fragmented outer bark to remove impurities. In another embodiment, the fragmented outer bark is hydrolyzed in hot water. In another embodiment, the fragmented outer bark is hydrolyzed in cold water.
In another embodiment, the impurities are removed by sterilizing the obtained fragmented outer bark. In another embodiment, the sterilizing agent is selected from a group, but not limited to, a mercury chloride, sodium hypochlorite, sodium chlorite, lactic acid, or sodium benzoate.
In another embodiment, the impurities are removed by disinfecting the obtained fragmented outer bark. In another embodiment, the fragmented outer bark is disinfected by ultraviolet irradiation.
In another embodiment, the method (100) further includes hydrolyzing (108) treating the obtained outer bark by way of vibrational / ultrasonic energy in a frequency ranging from 20-40KHz.
In another embodiment, the vibration / ultrasonic energy is provided by way of a vibration energy generator comprising, but not limited to, an Ultra-Sonicator, piezoelectric transducer, Ultrasonic generator, or vibrational screen.
In another embodiment, the sonicator is selected from a group comprising probe ultra-Sonicator or bath Ultra-Sonicator.
In another embodiment, the vibration generated is measured by way of sensors selected from a group comprising an accelerometer, velocity sensors, laser displacement sensor or a proximity probe.
In another embodiment, wherein the treatment of outer bark by way of vibrational energy is accompanied by a temperature ranging from 30 ? to 60 ?.
In another embodiment, the method (100) comprises soaking (110) the obtained sonicated outer bark in an alkali solution to further obtain defibrillated fibers and scutchers. In another embodiment, the alkali reagent is selected from a group comprising sodium hydroxide, calcium hydroxide, potassium hydroxide, or magnesium hydroxide.
In another embodiment, method (100) includes extracting (112) the obtained defibrillate fibers from the soaked outer bark to obtain fiber and scutchers.
In another embodiment, the extracted fiber is fabricated into textile materials. In another embodiment, the extracted fiber is fabricated into paper and air-laid paper. In another embodiment, the extracted fiber is fabricated into the cardboard. In another embodiment, the extracted fiber is fabricated into a face mask.
In another embodiment, the extracted fiber is reinforced to fabricate bio-degradable and durable cutlery. In another embodiment, the bio-degradable article is selected from a group comprising plates, cups, bowls, spoons, forks, butter knives, and mugs.
In another embodiment, the extracted fiber is converted into Crystalline Cellulose. In another embodiment, the crystalline cellulose is selected from a group comprising Micro Crystalline Cellulose (MCC), Nano Crystalline Cellulose (NCC), and Cellulose Nano-Fiber (CNF).
In another embodiment, the method (100) comprises delignification (114) of the obtained scutchers in an alkali peroxide solution to obtain a lignin-free short fiber. In another embodiment, the reagents used for delignification are selected from a group, comprising alkali peroxide solution, kraft solution, polysulfide, sodium hydroxide, acid sulfite or bisulfite.
In another embodiment, the method (100) includes washing (116) the obtained lignin-free short fiber to remove impurities to obtain a pure fiber followed by beating (118) the obtained pure fiber to obtain a pulp. In another embodiment, the mechanism of beating is selected from a group consisting of wet beating or free beating.
In another embodiment, the pulp is fabricated as a sanitary article. In another embodiment, the sanitary article is selected from a group comprising sanitary pads, sanitary cloth, diapers, pantyliners, menstrual cups, and tampons. In another embodiment, the extracted pulp is fabricated into paper selected from a group, but not limited to, writing paper, printing paper, packaging paper, and tissue paper. In another embodiment, the extracted pulp is fabricated into building materials selected from a group, but not limited to, insulation, ceiling tiles, and wallboard. In another embodiment, the extracted pulp is fabricated into biofuels selected from a group, but not limited to ethanol and butanol.
In some embodiments, the recovery reboiler is accompanied with a temperature ranging from 600 ?- 800 ? to recover alkali as smelt and remove dissolved lignin and hemi cellulose from concentrated spent.
In some embodiments, the reboiler is selected from a group comprising a kettle type reboiler, fired reboiler, thermosphon reboiler or forced circular reboiler.
In some embodiments, the causticizing is selected from a group comprising autoclave or high-pressure reactors.
In some embodiments, the alkali reagent is selected from a group comprising calcium hydroxide, potassium hydroxide or magnesium hydroxide.
In some embodiments, the alkali recovery is selected from a group comprising rotary evaporator or mutli-stage evaporator.
In another embodiment, a method for alkali recovery is provided. The method includes collecting concentrated spent post pulp extraction. The method further includes boiling the concentrated spent in a recovery reboiler. The method further includes causticizing the boiled concentrated to remove inorganic salts followed by regeneration of inorganic salts to recover the alkali solution.
In an embodiment, the boiling in reboiler may be accompanied with a temperature ranging from 600 ?- 800 ? to recover alkali as smelt and remove dissolved lignin and hemi cellulose from concentrated spent.
In an embodiment, the reboiler may be selected from a group comprising a kettle type reboiler, fired reboiler, thermosphon reboiler or forced circular reboiler.
In an embodiment, the causticizing agent may be selected from a group comprising an autoclave or high-pressure reactors.
In an embodiment, the inorganic salt may be selected from a group comprising a calcium carbonate, potassium carbonate or magnesium carbonate.
Advantages of the present method:
1. The extracted fiber is fabricated into textile materials, paper and air-laid paper, cardboard and face mask.
2. The extracted fiber is reinforced to fabricate fiber reinforced durable and compostable plastic
3. The extracted pulp is fabricated as a sanitary article, building materials, bio medical devices, biodegradable packaging films.
Examples
The disclosure will now be illustrated with working examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar to or equivalent to those described herein can be used in the practice of the disclosed methods and compositions, the exemplary methods, devices, and materials are described herein. It is to be understood that this disclosure is not limited to methods, and experimental conditions described, as such methods and conditions may vary.
Example 1: Fibre extraction from banana stem
A comparative study was conducted to compare the yields of fibers obtained from sonication process (present methodology) and decorticator machine (existing methodology). The fibers were extracted from the banana stem through vibrational/ultrasonic energy and chemical. The outer bark was separated from the inner core to obtain sheaths. Further, the obtained sheaths were subjected to ultra-sonication with an alkali solution to obtain fibers and yield were calculated. The fiber yield obtained from the decorticator machine was also recorded.
Observation: During fiber extraction, alkali solution of different strength was added to subsequent batches for extraction.
The x-axis represents the subsequent batches and the y-axis represents yield %. It was observed, that as the number of batches increased the strength of the alkali solution decreased that further resulted in a reduction in yield. The yields were calculated with respect to the initial weight of banana sheath (moisture was taken into consideration). The recorded results are depicted in FIG.3.
The present method using sonication enhances the absorption of chemical molecules into the inner core of the sheath, and mechanical power results in expansion, and implosion of microscopic gas for extraction fiber. Thereby increasing the yield of defibrillated fiber and overall efficiency.
The morphological analysis for the obtain fibers were observed through SEM analysis depicted in the FIG.4. The fibers extracted from the sonication chamber shows reduced pith or contamination on the surface and non-fragile over the fiber surface when compared to the fiber extracted from a decorticator machine that has seen more pith or contamination with intermediate fragile over the fiber surface.
Results: The fibers extracted from the sonication chamber recorded an average tensile strength of 78.07 Mpa for different batches and resulted in better yield (2-3%) depicted in FIG.3 and when compared to the fibers extracted from a decorticator machine (that recorded an average tensile strength of 67.97 Mpa as depicted in Table 1 below.
Table 1
Batches Average Tensile
(MPa) Average Diameter (mm) Average young modulus
(Gpa) Cellulose (%) Hemi cellulose (%) Lignin (%)
S. F D.F S. F D.F S. F D.F S. F D.F S. F D.F S. F D.F
1 81.28 67.97 0.50 1.2 4 5 52 48 12 15 12 20
2 79.98 0.75 3.1 55 11 10
3 76.21 0.79 3.5 57 10 11
4 74.82 0.81 3 59 12 10
DF- Decorticator fiber, SF-Sonicated fiber
Higher tensile strength material can be used to fabricate high performance fibers. The reduction in lignin is a possible reason for improved properties. Thus, the extraction of fibers by providing present treatment resulted in good quality (higher cellulosic content) with higher yield when compared to existing methodologies.
Example 2. Pulp extraction from banana scutchers
Residue or scutchers were obtained from post extraction of fibers in the sonication treatment and decorticator machine. The obtained scutchers from the Sonication treatment and decorticator machine were further subjected to alkali peroxide treatment followed by bleaching. Further, the efficiency of alkali-peroxide method and conventional kraft-sulfide pulping process were compared for preparation of pulp from sonicator obtained scutchers. The leftover liquid obtained after alkali-peroxide treatment of scutchers is called as spent solution.
Observation: It was observed that the scutchers obtained from the sonication chamber recorded better yield when compared to the decorticator machine, as indicated in FIG.5. The x-axis represented amount of alkali concentration was used in the reaction and the y-axis represented the pulp yield. The yields were calculated with respect to the dry weight of scutchers. The lesser yield in decorticator obtained scutchers mainly due to the inherent impurities which otherwise are removed in case of present method. The scutchers obtained from sonication treatment subjected to alkali-peroxide method and conventional kraft-sulfide pulping process were carried out as indicated in Table 2, with varying chemical composition and feed with 90% moisture content. The concentration is in accordance with stoichiometric balance for preparation of pulping chemical. The recorded result depicts in Table 2, that shows scutchers obtained from sonication treatment has better efficiency and quality in the pulping process than conventional method.
Results: The pulp obtained from the scutchers subjected to alkali peroxide treatment recorded an optimum absorption capacity of max 7.0 ml/gm with holocellulose (Cellulose and hemicellulose) content of 76 % as depicted in table 2 below.
Table 2
S.no Chemical consumption
(wrt water) Pulp yield Fibre Constituents Absorption capacity
(ml/gm)
Cellulose Hemi Cellulose Lignin
APP CP APP CP APP CP APP CP APP CP
1 2 % 2.9 2.5 61.3 61 12 10.2 10.1 13 6.8 6.1
2 4 % 2.7 2.3 70.0 65.3 10 9.7 7 10.5 7.0 6.4
3 6 % 2.3 2.0 67.5 63 12 11 6 9 7.1 6.7
APP-Alkali peroxide pulp, CP- Conventional pulp

EXAMPLE 3: Alkali Recovery after pulp Extraction:
Spent solution was obtained in the post extraction of pulp from scutchers in the mentioned embodiment herein. The obtained spent solution was further subjected to recovery reboiler for reuse alkali in sonication process for long fiber extraction and in pulping process. The recovery yield and purity varied with temperature were recorded.
Observation: It was observed that the recovery decreases with increasing temperature in recovery reboiler but on expense of purity level as illustrated FIG.6, The x-axis represented smelting temperature in recovery reboiler and the double y-axis represented the percentage recovery and purity of recovered alkali from the mentioned embodiments FIG.2. The recovery were calculated with respect to the fresh alkali used in the embodiments.
Results: The recovery obtained from the concentrated spent subjected to range of 60% - 85.71% with purity range of 65% - 85% resulted in better yield in the range of 700? - 750? and when compared to the recovery from other temperature profile that were recorded as depicted in FIG.6. This recovered alkali can be reuse again in mentioned embodiment.
The foregoing discussion of the present disclosure has been presented for purposes of illustration and description. It is not intended to limit the present disclosure to the form or forms disclosed herein. In the foregoing Detailed Description, for example, various features of the present disclosure are grouped together in one or more aspects, configurations, or aspects for the purpose of streamlining the disclosure. The features of the aspects, configurations, or aspects may be combined in alternate aspects, configurations, or aspects other than those discussed above. This method of disclosure is not to be interpreted as reflecting an intention, the present disclosure requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed aspect, configuration, or aspect. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate aspect of the present disclosure.
Moreover, though the description of the present disclosure has included a description of one or more aspects, configurations, or aspects and certain variations and modifications, other variations, combinations, and modifications are within the scope of the present disclosure, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights that include alternative aspects, configurations, or aspects to the extent permitted, including alternate, interchangeable, and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter. , Claims:1. A method (100) for extraction of fibers and pulp from a banana stem, the method comprising:
a) separating (102) an outer bark from the banana stem;
b) cutting (104) the separated outer bark to obtain a fragmented longer outer bark;
c) hydrolyzing (106) the fragmented outer bark to remove impurities;
d) treating (108) the obtained outer bark by way of vibrational/ultrasonic energy in a frequency ranging from 20-40KHz;
e) soaking (110) the obtained sonicated outer bark in an alkali solution to further obtain defibrillated fibers;
f) extracting (112) the obtained defibrilled fibers from the soaked outer bark to obtain fiber and scutchers;
g) delignification (114) of the obtained scutchers in an alkali peroxide solution to obtain a lignin-free fiber;
h) washing (116) the obtained lignin-free fiber to remove impurities to obtain a pure fiber; and
i) beating (118) the obtained pure fiber to obtain pulp from the banana stem.

2. The method (100) as claimed in claim 1, wherein the fibers are selected from a group comprising long fibers and short fibers.

3. The method (100) as claimed in claim 1, wherein the fragmented outer bark obtained at step (b) is 200-1000mm long.

4. The method (100) as claimed in claim 1, wherein cutting at step (b) is carried out by pulverizing or shredding.

5. The method (100) as claimed in claim 1, wherein vibrational/ultrasonic energy is accompanied with a temperature ranging from 30 ? to 60 ?.

6. The method (100) as claimed in claim 1, wherein the vibration/ultrasonic energy is provided by way of a vibration/ultrasonic energy generator selected from a group comprising a ultra-sonicator, piezoelectric transducer, ultrasonic generator, or vibrational screen.

7. The method (100) as claimed in claim 6, wherein the sonicator is selected from a group comprising probe ultra-sonicator or bath Ultra-Sonicator.

8. The method (100) as claimed in claim 1, wherein the alkali reagent is selected from a group comprising sodium hydroxide, calcium hydroxide, potassium hydroxide or magnesium hydroxide.

9. The method (100) as claimed in claim 1, wherein the reagents used for pulping are selected from a group comprising alkali peroxide solution, kraft solution, polysulfide, sodium hydroxide, acid sulfite or bisulfite.

10. The method (100) as claimed in claim 1, the mechanism for extracting fibers from soaked outer bark is selected from a group comprising brushing, sweeping, scraping, or combing.