Name: extraction of ramie fiber in alkali hydrogen peroxide system supported by controlled-release alkali source
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This work was supported by the earmarked fund for China Agriculture Research System for Bast and Leaf Fiber Crops (grant number CARS-19), The China Academy of Agricultural Science and Technology Innovation Project (grant number ASTIP-IBFC07), The innovation fund for graduate students in Donghua University (grant number 16D310107), The &#39;Xiaoping science and technology innovation team&#39; (industrialization integrated R &#38; D group of bast fiber biological degumming), China Scholarship Council.

1. Oxidation Degumming of Ramie
<ol>
	<li>Preparing the oxidation degumming solution
	<ol>
		<li>Dissolve 2 g H2O2, 1 g alkali (a mixture of Mg(OH)2 and NaOH), 0.4 g Na5P3O10, 0.1 g anthraquinone, and 0.2 g HEDP in 100 mL distilled water to make the degumming solution.</li>
	</ol>
	</li>
	<li>Oxidation degumming of ramie
	<ol>
		<li>Immerse 10 g raw ramie in the degumming solution and scour it under 85 &#176;C for 60 min.</li>
		<li>Raise the temperature to 125 &#176;C (with pressure of 0.6 kg) and scour for another 60 min. 
		NOTE: See the Discussion for explanation on raising the temperature.</li>
	</ol>
	</li>
	<li>Reducing the ramie fiber
	<ol>
		<li>Dissolve 0.4 g NaHSO3 in 100 mL distilled water to prepare the reducing solution. Then, treat the degummed fiber in the reducing solution at 90 &#176;C for 60 min. 
		NOTE: The carboxyl groups and aldehyde groups in cellulose generated in the oxidation reaction cause the reduction of hydrogen bonds and thus damage to the fiber property. Reducing can improve the property of the fiber by converting the carboxyl groups and aldehyde groups back to hydroxyl groups.</li>
	</ol>
	</li>
	<li>Follow-up treatment
	<ol>
		<li>Wash the degummed ramie fiber thoroughly with deionized water.</li>
		<li>Immerse the fiber in degumming oil at 90 &#176;C for 15 min and then dry the fiber in an oven (125 &#176;C) for 4 h.</li>
	</ol>
	</li>
</ol>
2. Testing of the Degumming Solution Property
<ol>
	<li>Solubility test of Mg(OH)2
	<ol>
		<li>Dissolve 2 g Mg(OH)2 in 100 mL distilled water.</li>
		<li>Separately, dissolve 2 g Mg(OH)2 in 100 mL solution with completely soluble degumming additives, including 0.4 g Na5P3O10 and 0.2 g HEDP.</li>
		<li>Raise the temperature of the solutions described in steps 2.2.1 and 2.2.2 to 85 &#176;C.</li>
		<li>Extract the undissolved Mg(OH)2 with sintered discs.</li>
		<li>Calculate the solubility of Mg(OH)2 by the following formula: 
		<img alt="Equation 2" src="/files/ftp_upload/56461/56461eq2.jpg" /> 
		NOTE: Here m (g) is the weight of the undissolved Mg(OH)2.</li>
	</ol>
	</li>
	<li>Effect of the Mg(OH)2 substitution rate on pH value, ORP value, and residual H2O2 content of the degumming solution 
	NOTE: ORP12,19 is an important water chemistry parameter and it provides a measurement tool for the oxidizing or reducing capacity of the ambient water. Solutions with stronger oxidation property have a higher ORP value. The Mg(OH)2 substitution rate refers to the mole proportion of NaOH replaced by Mg(OH)2 under the total alkali dosage of 10% (on weight of fabric).
	<ol>
		<li>Prepare the degumming solutions with Mg(OH)2 substitution rate of 0%, 20%, 40%, 60%, 80%, and 100% according to step 1.1, respectively.</li>
		<li>Immerse the raw ramie in the degumming solutions described in step 2.2.1.</li>
		<li>Start the degumming process according to step 1.2.</li>
		<li>Wash the combined ORP electrode with distilled water and dry it in the air. Then immerse the combined ORP electrode meter in the degumming solutions to read the ORP value every 10 min. Immerse the pH electrode meter in the degumming solutions to read the pH value every 10 min.</li>
		<li>Test the H2O2 content of the degumming solutions every 10 min by the KMnO4 titration method according to Chinese standard GB 22216-20087.</li>
	</ol>
	</li>
</ol>
3. Testing the Ramie Fiber Property
<ol>
	<li>Yield of degumming
	<ol>
		<li>Calculate the yield of degumming using the following equation: 
		<img alt="Equation 3" src="/files/ftp_upload/56461/56461eq3.jpg" /> 
		NOTE: Here w (g) is dry weight of fiber after degumming; W (g) is dry weight of ramie before degumming.</li>
	</ol>
	</li>
	<li>Residual gums of the fiber 
	NOTE: Residual gums of fiber were tested according to Chinese standard 5889 - 86.
	<ol>
		<li>Measure the dry weight of the fiber (about 5 g) in a weighing bottle and immerse it in a flask (with reflux condensing tube) containing 150 mL NaOH solution (20 g/L).</li>
		<li>Raise the temperature to 100 &#176;C and keep at this temperature for 1 h.</li>
		<li>Refresh the NaOH solution.</li>
		<li>Raise the temperature to 100 &#176;C and maintain for 2 h.</li>
		<li>Wash the fiber in a sample sieve.</li>
		<li>Measure the dry weight of the fiber in weighing bottle.</li>
		<li>Calculate the residual gums of fiber using the following equation: 
		<img alt="Equation 4" src="/files/ftp_upload/56461/56461eq4.jpg" /> 
		NOTE: Here m (g) is the dry weight of fiber; M (g) is the dry weight of ramie after NaOH scouring.</li>
	</ol>
	</li>
	<li>PD test 
	NOTE: Test the PD value of ramie fiber according to Chinese standard GB 5888-8615.
	<ol>
		<li>Degrease the ramie fiber by submerging in 2:1 (v/v) benzene and ethyl alcohol mixture.</li>
		<li>Evaporate the solvent in air at room temperature.</li>
		<li>Cut the samples into short pieces (1-2 mm, about ~20-23 mg for each sample) using scissors.</li>
		<li>Keep the samples in a controlled-humidity atmosphere (20 &#177; 2 &#176;C, relative humidity = 65 &#177; 2%) in a weighing container until it reaches equilibrium water content before removing the materials required for test purposes.</li>
		<li>Immerse a copper wire (0.5 mm diameter) in concentrated nitric acid, followed by 98% anhydrous ethylenediamine. Then, wash the copper granule thoroughly with distilled water.</li>
		<li>Put the fiber sample and copper granule in a plastic bottle (with top).</li>
		<li>Add 10 mL distilled water and 10 mL 1 mol/L cupriethylenediamine solution into the plastic bottle, and stir using a magnetic stir bar to prepare 0.2 g/100 mL (approximately) ramie fiber cupriethylenediamine solution.</li>
		<li>Transfer 6.5 mL ramie fiber cupriethylenediamine solution to a Ubbelohde viscometer to measure its intrinsic viscosity. Calculate the relative viscosity by the following equation: 
		<img alt="Equation 5" src="/files/ftp_upload/56461/56461eq5.jpg" /> 
		NOTE: Here &#951;r is the relative viscosity, t (s) is the average time of the ramie fiber cupriethylenediamine solution flowing through the Ubbelohde viscometer, and t0 (s) is the average time of the 0.5 mol/L cupriethylenediamine solution flowing through the Ubbelohde viscometer.</li>
		<li>Calculate the PD value of the ramie fiber by the following equation: 
		<img alt="Equation 6" src="/files/ftp_upload/56461/56461eq6.jpg" /> 
		NOTE: Here [&#951;]&#39; is the intrinsic viscosity, the [&#951;]&#215;C value can be obtained from a table in Chinese standard GB 5888-86, and C&#39; is the concentration of ramie fiber cupriethylenediamine solution.</li>
	</ol>
	</li>
	<li>Linear density of the fiber
	<ol>
		<li>Calculate linear density of fiber using the following equation: 
		<img alt="Equation 7" src="/files/ftp_upload/56461/56461eq7.jpg" /> 
		NOTE: Here Lc is the cutting length (40 mm), n is the numbers of fibers, and G (g) is weight of the fiber. Linear density of the fiber refers to the weight of a 1,000 m long fiber under official regain of ramie (12%).</li>
	</ol>
	</li>
	<li>Mechanical property test
	<ol>
		<li>Equilibrate the fiber samples in standard atmospheric condition (T = 20 &#177; 2 &#176;C, RH = 65% &#177; 2%) for 24 h.</li>
		<li>Test the tenacity, breaking elongation, and work of rupture of the fiber using the fiber strength instrument under the following setting of 20 &#176;C, RH 65%, and pre-tension of 0.3 cN/dtex. Set the clamping distance at 20 mm and the descending speed of the bottom clamp at 20 mm/min7,15.</li>
	</ol>
	</li>
	<li>COD value of degumming wastewater
	<ol>
		<li>Test the COD of degumming wastewater according to Chinese standard GB/T 15456-2008 &#39;Industrial circulating cooling water-Determination of the COD-Potassium permanganate method&#39;7,15.</li>
	</ol>
	</li>
	<li>XRD test
	<ol>
		<li>Obtain crystallinity of the fiber using X-ray diffraction. Record XRD patterns 2&#952; = 5-60 &#176; with a diffractometer equipped with a graphite monochromator and Cu K&#945; radiation at &#955; = 0.154 nm (40 kV, 200 mA).</li>
	</ol>
	</li>
	<li>FTIR analysis
	<ol>
		<li>Obtain the FTIR pattern of fiber using spectrometer. Set the scan times at 30, the range at 4,000-400 cm-1, and the resolution at 8 cm-1. Determine the chemical functional groups in treated fiber using FT-IR analysis.</li>
	</ol>
	</li>
</ol>

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The authors have nothing to disclose.

The setting of Mg(OH)2 substitution rate and reaction temperature was the key point of this protocol. Mg(OH)2 substitution rate can influence the pH value and thus oxidation ability of degumming solution. The best Mg(OH)2 substitution rate for ramie degumming was 20%, because cellulose cannot receive enough protection under a substitution rate below 20%, and an excessive amount of residual gums (low DP value and crystallinity) would be retained in fiber under a substitution rate above 20%...

Ramie, commonly known as &#39;China grass&#39; is a perennial herb whose fiber can be used as an excellent material for the textile industry1,2. It is one of the main economic crops native to China; the production of ramie in China has accounted for more than 90% of the total yield in the world1,2. Ramie fiber is one of the strongest and longest plant fibers, lustrous with an almost silky appearance3,4. The long length of ramie fiber make it suitable for single fiber spinning, which is seldom seen in bast fiber. The textile made from ramie fiber possesses many excellent properties, such as coolness, antibacterial, excellent thermal conductivity, ventilation, etc.3,4
Cellulose is the main component of ramie fibers, and the other components in ramie, such as pectin, lignin, water soluble materials, are defined as gums5,6. Ramie fiber can be extracted by dissolving the gums in solution containing chemical reagents, in a process defined as degumming5,6. Mainly two approaches of ramie fiber extraction exist: chemical degumming and bio-degumming. The energy consumption, time consumption, and COD value of degumming wastewater in traditional chemical degumming is rather high, as cellulose fiber is extracted by scouring raw ramie in concentrated NaOH under high pressure for 6 to 8 h7,8. Alternatively, bio-degumming is an eco-friendly option for ramie fiber extraction. Nevertheless, the harsh reaction condition and sophisticated equipment inhibit its further industrial application9,10. Therefore, oxidation degumming with alkali hydrogen peroxide presents a valuable and alternative application to focus on, for it requires shorter degumming time and lower degumming temperature11,12. However, due to the strong oxidation ability of the peroxides, substantial cellulose degradation may occur during the degumming process, which can cause great damage to fiber properties13,14. This is the biggest drawback of alkali peroxide oxidation degumming of ramie.
In previous studies, ramie fiber was extracted in an alkali hydrogen peroxide system supported only by sodium hydroxide15. However, due to the strong alkalinity of sodium hydroxide, the oxidation reaction speed of hydrogen peroxide was difficult to control and thus resulted in great damage to the treated fiber7. To improve the properties of ramie fiber, a controlled-release alkali source, which is composed of sodium hydroxide and magnesium hydroxide, is used in this study to offer an alkali condition and buffer the pH value of alkali hydrogen peroxide system16,17.
The rationale behind this technology can be described as follows. Magnesium hydroxide is slightly soluble in distilled water, and it can dissolve gradually into the degumming solution with the consumption of OH- and keep the pH value and thus oxidation ability of degumming solution in an appropriate range18. The substitution rate (SR) of magnesium hydroxide is defined as the mole proportion of NaOH replaced by magnesium hydroxide under the total alkali dosage of 10%, and the substitution rate can be calculated by the following equation. Moreover, Mg2+ can prevent cellulose degradation caused by over oxidation19,20.
<img alt="Equation 1" src="/files/ftp_upload/56461/56461eq1.jpg" />
Here, M2 (g) is the weight of Mg(OH)2, M1 (g) is the weight of NaOH, 40 is the molecular weight of NaOH, 58 is the molecular weight of Mg(OH)2, 2 is the number of OHs in Mg(OH)2, and SR is the substitution rate.
The technology of this protocol can be extended to the extracting, bleaching, and modifying of plant materials in an alkali hydrogen peroxide system. However, it must be noted that the selection of pH value and reaction temperature of the alkali hydrogen peroxide system is key for this technology21. The pH value of the alkali hydrogen peroxide system can be adjusted by changing the substitution rate17. The pH value and thus oxidation ability of the alkali hydrogen peroxide system decrease with the increasing of substitution rate. When the reaction temperature is set at 85 &#176;C, the free radical reaction plays the main role in the system and the strong oxidation of the system is suitable for dissolving materials; when the reaction temperature is set at 125 &#176;C, the free radical reaction is inhibited and a large amount of HOO exists in the system, which makes the system suitable for bleaching19.

<table><tbody><tr><td>Hydrogen peroxide, 30%</td><td>Fisher Scientific</td><td>H325-100</td><td>Chemical for degumming</td></tr><tr><td>Magnesium hydroxide, 99%</td><td>Fisher Scientific</td><td>AA1236722</td><td>Chemical for degumming</td></tr><tr><td>Sodium hydroxide</td><td>Fisher Scientific</td><td>S318-1</td><td>Chemical for degumming</td></tr><tr><td>Sodium bisulfite</td><td>Fisher Scientific</td><td>S654-500</td><td>Chemical for degumming</td></tr><tr><td>Sodium tripolyphosphate</td><td>Fisher Scientific</td><td>AC218675000</td><td>Chemical for degumming</td></tr><tr><td>Anthraquinone, &gt;98%</td><td>Fisher Scientific</td><td>AC104930500</td><td>Chemical for degumming</td></tr><tr><td>1-Hydroxy Ethylidene-1,1-Diphosphonic Acid</td><td>Fisher Scientific</td><td>50-901-10243</td><td>Chemical for degumming</td></tr><tr><td>Degumming oil</td><td>Minglong auxiliaries limited liability company, Yiyang, Hunan,China</td><td>&amp;mdash;&amp;mdash;</td><td>Chemical for degumming</td></tr><tr><td>Ethyl alcohol</td><td>Fisher Scientific</td><td>A962-4</td><td>Chemical for testing</td></tr><tr><td>Benzene</td><td>Fisher Scientific</td><td>AA43817AE</td><td>Chemical for testing</td></tr><tr><td>Copper wire,0.5mm (0.02in) dia</td><td>Fisher Scientific</td><td>AA10783H4</td><td>Chemical for testing</td></tr><tr><td>Cupriethylenediamine solution 1mol/L</td><td>Fisher Scientific</td><td>24991</td><td>Chemical for testing, caution toxic</td></tr><tr><td>Nitric acid (65% ~68% )</td><td>Fisher Scientific</td><td>A200-612GAL</td><td>Chemical for testing, caution</td></tr><tr><td>Ethylenediamine</td><td>Fisher Scientific</td><td>AC118420100</td><td>Chemical for testing</td></tr><tr><td>Potassium permanganate</td><td>Fisher Scientific</td><td>P279-500</td><td>Chemical for testing</td></tr><tr><td>Sulphuric acid</td><td>Fisher Scientific</td><td>A300C-212</td><td>Chemical for testing</td></tr><tr><td>Silver sulfate</td><td>Fisher Scientific</td><td>S190-25</td><td>Chemical for testing</td></tr><tr><td>Raw ramie</td><td>Guangyuan limited liability company, Changde, Hunan,China</td><td>&amp;mdash;&amp;mdash;</td><td>Raw materials</td></tr><tr><td>Electric-heated&amp;nbsp;thermostatic&amp;nbsp;water&amp;nbsp;bath</td><td>Senxin Experiment equipment limited liability company,Shanghai,China</td><td>DK-S28</td><td>Equipments for degumming</td></tr><tr><td>High temperature lbaorator dyeing machine</td><td>Shanghai Longda chemcials Crop.</td><td>RY-1261</td><td>Equipments for degumming</td></tr><tr><td>Thermometer</td><td>Sichuan Shubo (group)Co.,Ltd</td><td>100 &amp;deg;C</td><td>Equipments for degumming</td></tr><tr><td>Vacuum suction machine</td><td>Yukang KNET ,Shanghai,China</td><td>SHB-IIIA</td><td>Equipments for testing Mg(OH)2 solublity</td></tr><tr><td>Suction flask</td><td>Sichuan Shubo (group)Co.,Ltd</td><td>1000mL</td><td>Equipments for testing Mg(OH)2 solublity</td></tr><tr><td>Sand-core funnels</td><td>Sichuan Shubo (group)Co.,Ltd</td><td>35mL</td><td>Equipments for testing Mg(OH)2 solublity</td></tr><tr><td>Oxidation reduction potential meter</td><td>Dapu instrument, Shanghai, China</td><td>MODEL 421</td><td>Equipments for testing ORP value</td></tr><tr><td>pH meter</td><td>Hanna instruments,Beijing,China</td><td>HI 98129</td><td>Equipments for testing pH value</td></tr><tr><td>Acid burette</td><td>Sichuan Shubo (group)Co.,Ltd</td><td>50mL</td><td>Equipments for testing H2O2 content</td></tr><tr><td>Flask</td><td>Sichuan Shubo (group)Co.,Ltd</td><td>250 mL/500 mL</td><td>Equipments for testing H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; content;&amp;nbsp; residual gums content</td></tr><tr><td>Electric furnace</td><td>Jiangyi Experiment instruments limited liability company,Shanghai,China</td><td>800-2000W</td><td>Equipments for testing residual gums content</td></tr><tr><td>Reflux condensing tube</td><td>Sichuan Shubo (group)Co.,Ltd</td><td>250mL</td><td>Equipments for testing residual gums content; COD value</td></tr><tr><td>Fiber cutter (40mm)</td><td>Changzhou No.2 Textile Machine Co.,Ltd</td><td>Y171A</td><td>Equipments for testing fiber density</td></tr><tr><td>Ostwald viscometer</td><td>Taizhou, jiaojiang, glass instruments company</td><td>0.6mm</td><td>Equipments for testing fiber PD value</td></tr><tr><td>Spherical fat extractor</td><td>Sichuan Shubo (group)Co.,Ltd</td><td>250mL</td><td>Equipments for testing fiber PD value</td></tr><tr><td>Soxhlet extractor</td><td>Sichuan Shubo (group)Co.,Ltd</td><td>250mL</td><td>Equipments for testing fiber PD value</td></tr><tr><td>Torsion&amp;nbsp;balance</td><td>Liangping instrucments Co.,Ltd,Shanghai, China</td><td>JN-B</td><td>Equipments for testing fiber density</td></tr><tr><td>Fiber strength instrument</td><td>Xinxian instruments, shanghai,China</td><td>XQ-2</td><td>Equipments for testing fiber tensile property</td></tr><tr><td>Tension clamp</td><td>Depu textile technology Co.,Ltd, Changzhou, jiangsu, China</td><td>0.3cN/dtex</td><td>Equipments for testing fiber tensile property</td></tr><tr><td>COD&amp;nbsp;thermostatic&amp;nbsp;heater</td><td>Qiangdao Xuyu environment protection technology Lit company</td><td>DL-801A</td><td>Equipments for testing COD value</td></tr><tr><td>FTIR</td><td>Thermo Fisher, America</td><td>Nicolet</td><td>FTIR analysis</td></tr><tr><td>XRD</td><td>Rigaku, Japan</td><td>D/max-2550 PC</td><td>XRD analysis</td></tr><tr><td>Electronic balance</td><td>Shanghai jingtian Electronic instrument Co.,Ltd</td><td>FA2004A</td><td>Generral equipments</td></tr><tr><td>Drying oven</td><td>Tonglixinda&amp;nbsp; instruments, Tianjin,China</td><td>101-2AS</td><td>Generral equipments</td></tr><tr><td>Weighing bottle</td><td>Sichuan Shubo (group)Co.,Ltd</td><td>50x30</td><td>Generral equipments</td></tr><tr><td>Beaker</td><td>Sichuan Shubo (group)Co.,Ltd</td><td>500mL</td><td>Generral equipments</td></tr><tr><td>Sample sieve</td><td>Xiaojin hardware instruments Co.,Ltd, Shangyu, Zhejiang</td><td>120 mesh</td><td>Generral equipments</td></tr><tr><td>Glass rod</td><td>Sichuan Shubo (group)Co.,Ltd</td><td>&amp;mdash;&amp;mdash;</td><td>Generral equipments</td></tr><tr><td>Cylinder</td><td>Sichuan Shubo (group)Co.,Ltd</td><td>250mL, 50mL</td><td>Generral equipments</td></tr><tr><td>Pipette</td><td>Sichuan Shubo (group)Co.,Ltd</td><td>5mL, 10mL</td><td>Generral equipments</td></tr><tr><td>Rubber&amp;nbsp;suction&amp;nbsp;bulb</td><td>Sichuan Shubo (group)Co.,Ltd</td><td>&amp;mdash;&amp;mdash;</td><td>Generral equipments</td></tr><tr><td>Orign</td><td>OriginLab</td><td>8.0</td><td>Software for figure drawing</td></tr></tbody></table>

extraction of ramie fiber in alkali hydrogen peroxide system supported by controlled-release alkali source

This protocol demonstrates a method for ramie fiber extraction by scouring raw ramie in an alkali hydrogen peroxide system supported by a controlled-release alkali source. The fiber extracted from ramie is a type of textile material of great importance. In previous studies, ramie fiber was extracted in an alkali hydrogen peroxide system supported only by sodium hydroxide.However, due to the strong alkalinity of sodium hydroxide, the oxidation reaction speed of hydrogen peroxide was difficult to control and thus resulted in great damage to the treated fiber. In this protocol, a controlled-release alkali source, which is composed of sodium hydroxide and magnesium hydroxide, is used to provide an alkali condition and buffer the pH value of the alkali hydrogen peroxidesystem. The substitution rate of magnesium hydroxide can adjust the pH value of the hydrogen peroxide system and has great influence on the fiber properties. The pH value and oxidation-reduction potential (ORP) value, which represents the oxidation ability of alkali hydrogen peroxide system, were monitored using a pH meter and ORP meter, respectively. The residual hydrogen peroxide content in the alkali hydrogen peroxide system during the extraction process and the chemical oxygen demand (COD) value of wastewater after fiber extraction are tested by KMnO4 titration method. The yield of fiber is measured using a precision electronic balance, and residual gums of fiber are tested by a chemical analysis method. The polymerization degree (PD value) of fiber is tested by an intrinsic viscosity method using the Ubbelohde viscometer. The tensile property of fiber, including tenacity, elongation, and rupture, is measured using a fiber strength instrument. Fourier transform infrared spectroscopy and X-ray diffraction are used to characterize the functional groups and crystal property of fiber. This protocol proves that the controlled-release alkali source can improve the properties of the fiber extracted in an alkali hydrogen peroxide system.

The solubility of Mg(OH)2 in distilled water and degumming solution was studied (Figure 1). The effect of Mg(OH)2 substitution rate on pH value and ORP value (Figure 2) of the degumming solution was tested. The degumming yield and residual gums of fiber degummed under various Mg(OH)2 substitution rate were calculated (Figure 3). DP value, crystallinity, tensile proper...

Watch this Scientific Journal Video about Extraction of Ramie Fiber in Alkali Hydrogen Peroxide System Supported by Controlled-release Alkali Source at JoVE.com

Extraction of Ramie Fiber in Alkali Hydrogen Peroxide System Supported by Controlled-release Alkali Source

Presented here is a protocol for extraction of ramie fiber in alkali hydrogen peroxide system supported by controlled-release alkali source.

This protocol demonstrates a method for ramie fiber extraction by scouring raw ramie in an alkali hydrogen peroxide system supported by a ...

extraction-ramie-fiber-alkali-hydrogen-peroxide-system-supported

Universidad de Cartagena UDEC

Research

JoVE Journal

Chemistry

11.3K Views.  Donghua University. Presented here is a protocol for extraction of ramie fiber in alkali hydrogen peroxide system supported by controlled-release alkali source.

Video: Extraction of Ramie Fiber in Alkali Hydrogen Peroxide System Supported by Controlled-release Alkali Source

Extraction of Structural Extracellular Polymeric Substances from Aerobic Granular Sludge

To evaluate and develop methodologies for the extraction of gel-forming extracellular polymeric substances (EPS), EPS from aerobic granular sludge (AGS) was extracted using six different methods (centrifugation, sonication, ethylenediaminetetraacetic acid (EDTA), formamide with sodium hydroxide (NaOH), formaldehyde with NaOH and sodium carbonate (Na2CO3) with heat and constant mixing). AGS was collected from a pilot wastewater treatment reactor. The ionic gel-forming property of the extracted EPS of the six different extraction methods was tested with calcium ions (Ca2+). From the six extraction methods used, only the Na2CO3 extraction could solubilize the hydrogel matrix of AGS. The alginate-like extracellular polymers (ALE) recovered with this method formed ionic gel beads with Ca2+. The Ca2+-ALE beads were stable in EDTA, formamide with NaOH and formaldehyde with NaOH, indicating that ALE are one part of the structural polymers in EPS. It is recommended to use an extraction method that combines physical and chemical treatment to solubilize AGS and extract structural EPS.

The protocol provides a methodology to solubilize aerobic granular sludge in order to extract alginate-like extracellular polymers (ALE).

To evaluate and develop methodologies for the extraction of gel-forming extracellular polymeric substances (EPS), EPS from aerobic granular sludge (AGS) ...

Environment

Highly Stable, Functional Hairy Nanoparticles and Biopolymers from Wood Fibers: Towards Sustainable Nanotechnology

Nanoparticles, as one of the key materials in nanotechnology and nanomedicine, have gained significant importance during the past decade. While metal-based nanoparticles are associated with synthetic and environmental hassles, cellulose introduces a green, sustainable alternative for nanoparticle synthesis. Here, we present the chemical synthesis and separation procedures to produce new classes of hairy nanoparticles (bearing both amorphous and crystalline regions) and biopolymers based on wood fibers. Through periodate oxidation of soft wood pulp, the glucose ring of cellulose is opened at the C2-C3 bond to form 2,3-dialdehyde groups. Further heating of the partially oxidized fibers (e.g., T = 80 &#176;C) results in three products, namely fibrous oxidized cellulose, sterically stabilized nanocrystalline cellulose (SNCC), and dissolved dialdehyde modified cellulose (DAMC), which are well separated by intermittent centrifugation and co-solvent addition. The partially oxidized fibers (without heating) were used as a highly reactive intermediate to react with chlorite for converting almost all aldehyde to carboxyl groups. Co-solvent precipitation and centrifugation resulted in electrosterically stabilized nanocrystalline cellulose (ENCC) and dicarboxylated cellulose (DCC). The aldehyde content of SNCC and consequently surface charge of ENCC (carboxyl content) were precisely controlled by controlling the periodate oxidation reaction time, resulting in highly stable nanoparticles bearing more than 7 mmol functional groups per gram of nanoparticles (e.g., as compared to conventional NCC bearing &#60;&#60; 1 mmol functional group/g). Atomic force microscopy (AFM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) attested to the rod-like morphology. Conductometric titration, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), dynamic light scattering (DLS), electrokinetic-sonic-amplitude (ESA) and acoustic attenuation spectroscopy shed light on the superior properties of these nanomaterials.

Synthesis schemes to prepare highly stable wood fiber-based hairy nanoparticles and functional cellulose-based biopolymers have been detailed.

Nanoparticles, as one of the key materials in nanotechnology and nanomedicine, have gained significant importance during the past decade. While ...

A Novel Method for the Pentosan Analysis Present in Jute Biomass and Its Conversion into Sugar Monomers Using Acidic Ionic Liquid

Recently, ionic liquids (ILs) are used for biomass valorization into valuable chemicals because of their remarkable properties such as thermal stability, lower vapor pressure, non-flammability, higher heat capacity, and tunable solubility and acidity. Here, we demonstrate a method for the synthesis of C5 sugars (xylose and arabinose) from the pentosan present in jute biomass in a one-pot process by utilizing a catalytic amount of Br&#248;nsted acidic 1-methyl-3-(3-sulfopropyl)-imidazolium hydrogen sulfate IL. The acidic IL is synthesized in the lab and characterized using NMR spectroscopic techniques for understanding its purity. The various properties of BAIL are measured such as acid strength, thermal and hydrothermal stability, which showed that the catalyst is stable at a higher temperature (250 &#176;C) and possesses very high acid strength (Ho 1.57). The acidic IL converts over 90% of pentosan into sugars and furfural. Hence, the presenting method in this study can also be employed for the evaluation of pentosan concentration in other kinds of lignocellulosic biomass.

We present a protocol for the synthesis of C5 sugars (xylose and arabinose) from a renewable non-edible lignocellulosic biomass (i.e., jute) with the presence of Br&#248;nsted acidic ionic liquids (BAILs) as the catalyst in water. The BAILs catalyst exhibited better catalytic performance than conventional mineral acid catalysts (H2SO4 and HCl).

Recently, ionic liquids (ILs) are used for biomass valorization into valuable chemicals because of their remarkable properties such as thermal stability, ...

Microfluidic Dry-spinning and Characterization of Regenerated Silk Fibroin Fibers

The protocol demonstrates a method for mimicking the spinning process of silkworm. In the native spinning process, the contracting spinning duct enables the silk proteins to be compact and ordered by shearing and elongation forces. Here, a biomimetic microfluidic channel was designed to mimic the specific geometry of the spinning duct of the silkworm. Regenerated silk fibroin (RSF) spinning doped with high concentration, was extruded through the microchannel to dry-spin fibers at ambient temperature and pressure. In the post-treated process, the as-spun fibers were drawn and stored in ethanol aqueous solution. Synchrotron radiation wide-angle X-ray diffraction (SR-WAXD) technology was used to investigate the microstructure of single RSF fibers, which were fixed to a sample holder with the RSF fiber axis normal to the microbeam of the X-ray. The crystallinity, crystallite size, and crystalline orientation of the fiber were calculated from the WAXD data. The diffraction arcs near the equator of the two-dimensional WAXD pattern indicate that the post-treated RSF fiber has a high orientation degree.

A protocol for the microfluidic spinning and microstructure characterization of regenerated silk fibroin monofilament is presented.

The protocol demonstrates a method for mimicking the spinning process of silkworm. In the native spinning process, the contracting spinning duct enables ...

Manufacturing Of Robust Natural Fiber Preforms Utilizing Bacterial Cellulose as Binder

A novel method of manufacturing rigid and robust natural fiber preforms is presented here. This method is based on a papermaking process, whereby loose and short sisal fibers are dispersed into a water suspension containing bacterial cellulose. The fiber and nanocellulose suspension is then filtered (using vacuum or gravity) and the wet filter cake pressed to squeeze out any excess water, followed by a drying step. This will result in the hornification of the bacterial cellulose network, holding the loose natural fibers together.
Our method is specially suited for the manufacturing of rigid and robust preforms of hydrophilic fibers. The porous and hydrophilic nature of such fibers results in significant water uptake, drawing in the bacterial cellulose dispersed in the suspension. The bacterial cellulose will then be filtered against the surface of these fibers, forming a bacterial cellulose coating. When the loose fiber-bacterial cellulose suspension is filtered and dried, the adjacent bacterial cellulose forms a network and hornified to hold the otherwise loose fibers together.
The introduction of bacterial cellulose into the preform resulted in a significant increase of the mechanical properties of the fiber preforms. This can be attributed to the high stiffness and strength of the bacterial cellulose network. With this preform, renewable high performance hierarchical composites can also be manufactured by using conventional composite production methods, such as resin film infusion (RFI) or resin transfer molding (RTM). Here, we also describe the manufacturing of renewable hierarchical composites using double bag vacuum assisted resin infusion.

We present a novel method of manufacturing rigid and robust short natural fiber preforms using a papermaking process. Bacterial cellulose acts simultaneously as the binder for the loose fibers and provides rigidity to the fiber preforms. These preforms can be infused with a resin to produce truly green hierarchical composites.

A novel method of manufacturing rigid and robust natural fiber preforms is presented here. This method is based on a papermaking process, whereby loose ...

Bioengineering

Deposition of Porous Sorbents on Fabric Supports

A microwave deposition technique for silanes, previously described for production of oleophobic fabrics, is adapted to provide a fabric support material that can be subsequently treated by dip coating. Dip coating with a sol preparation provides a supported porous layer on the fabric. In this case, the porous layer is a porphyrin functionalized sorbent system based on a powdered material that has been demonstrated previously for the capture and conversion of phosgene. A representative coating is applied to cotton fabric at a loading level of 10 mg/g. This coating has minimal impact on water vapor transport through the fabric (93% of the support fabric rate) while significantly reducing transport of 2-chloroethyl ethyl sulfide (CEES) through the material (7% of support fabric rate). The described approaches are suitable for use with other fabrics providing amine and hydroxyl groups for modification and can be used in combination with other sol preparations to produce varying functionality.

This report details a microwave-initiated approach for deposition of porphyrin functionalized porous organosilicate sorbents on a cotton fabric and demonstrates reduction in 2-chloroethyl ethyl sulfide (CEES) transport through the fabric resulting from this treatment.

A microwave deposition technique for silanes, previously described for production of oleophobic fabrics, is adapted to provide a fabric support material ...

Extraction of Lignin with High &#946;-O-4 Content by Mild Ethanol Extraction and Its Effect on the Depolymerization Yield

Lignin valorization strategies are a key factor for achieving more economically competitive biorefineries based on lignocellulosic biomass. Most of the emerging elegant procedures to obtain specific aromatic products rely on the lignin substrate having a high content of the readily cleavable &#946;-O-4 linkage as present in the native lignin structure. This provides a miss-match with typical technical lignins that are highly degraded and therefore are low in &#946;-O-4 linkages. Therefore, the extraction yields, and the quality of the obtained lignin are of utmost importance to access new lignin valorization pathways. In this manuscript, a simple protocol is presented to obtain lignins with high &#946;-O-4 content by relatively mild ethanol extraction that can be applied to different lignocellulose sources. Furthermore, analysis procedures to determine the quality of the lignins are presented together with a depolymerization protocol that yields specific phenolic 2-arylmethyl-1,3-dioxolanes, which can be used to evaluate the obtained lignins. The presented results demonstrate the link between lignin quality and potential for the lignins to be depolymerized into specific monomeric aromatic chemicals. Overall, the extraction and depolymerization demonstrates a trade-off between the lignin extraction yield and the retention of the native aryl-ether structure and thus the potential of the lignin to be used as the substrate for the production of chemicals for higher-value applications.

Here, we present a protocol to perform ethanol extraction of lignin from several biomass sources. The effect of the extraction conditions on the lignin yield and &#946;-O-4 content are presented. Selective depolymerization is performed on the obtained lignins to obtain high aromatic monomer products.

Lignin valorization strategies are a key factor for achieving more economically competitive biorefineries based on lignocellulosic biomass. Most of the ...

Reactive Inkjet Printing and Propulsion Analysis of Silk-based Self-propelled Micro-stirrers

In this study, a protocol for using reactive inkjet printing to fabricate enzymatically propelled silk swimmers with well-defined shapes is reported. The resulting devices are an example of self-propelled objects capable of generating motion without external actuation and have potential applications in medicine and environmental sciences for a variety of purposes ranging from micro-stirring, targeted therapeutic delivery, to water remediation (e.g., cleaning oil spills). This method employs reactive inkjet printing to generate well-defined small-scale solid silk structures by converting water soluble regenerated silk fibroin (silk I) to insoluble silk fibroin (silk II). These structures are also selectively doped in specific regions with the enzyme catalase in order to produce motion via bubble generation and detachment. The number of layers printed determines the three-dimensional (3D) structure of the device, and so here the effect of this parameter on the propulsive trajectories is reported. The results demonstrate the ability to tune the motion by varying the dimensions of the printed structures.

This protocol demonstrates the ability to utilize reactive inkjet printing to print self-motile biocompatible and environmentally friendly micro-stirrers for use in biomedical and environmental applications.

In this study, a protocol for using reactive inkjet printing to fabricate enzymatically propelled silk swimmers with well-defined shapes is reported. The ...

Fabricating Degradable Thermoresponsive Hydrogels on Multiple Length Scales via Reactive Extrusion, Microfluidics, Self-assembly, and Electrospinning

While various smart materials have been explored for a variety of biomedical applications (e.g., drug delivery, tissue engineering, bioimaging, etc.), their ultimate clinical use has been hampered by the lack of biologically-relevant degradation observed for most smart materials. This is particularly true for temperature-responsive hydrogels, which are almost uniformly based on polymers that are functionally non-degradable (e.g., poly(N-isopropylacrylamide) (PNIPAM) or poly(oligoethylene glycol methacrylate) (POEGMA)). As such, to effectively translate the potential of thermoresponsive hydrogels to the challenges of remote-controlled or metabolism-regulated drug delivery, cell scaffolds with tunable cell-material interactions, theranostic materials with the potential for both imaging and drug delivery, and other such applications, a method is required to render the hydrogels (if not fully degradable) at least capable of renal clearance following the required lifetime of the material. To that end, this protocol describes the preparation of hydrolytically-degradable hydrazone-crosslinked hydrogels on multiple length scales based on the reaction between hydrazide and aldehyde-functionalized PNIPAM or POEGMA oligomers with molecular weights below the renal filtration limit. Specifically, methods to fabricate degradable thermoresponsive bulk hydrogels (using a double barrel syringe technique), hydrogel particles (on both the microscale through the use of a microfluidics platform facilitating simultaneous mixing and emulsification of the precursor polymers and the nanoscale through the use of a thermally-driven self-assembly and cross-linking method), and hydrogel nanofibers (using a reactive electrospinning strategy) are described. In each case, hydrogels with temperature-responsive properties similar to those achieved via conventional free radical cross-linking processes can be achieved, but the hydrazone cross-linked network can be degraded over time to re-form the oligomeric precursor polymers and enable clearance. As such, we anticipate these methods (which may be generically applied to any synthetic water-soluble polymer, not just smart materials) will enable easier translation of synthetic smart materials to clinical applications.

Protocols are described for the fabrication of degradable thermoresponsive hydrogels based on hydrazone cross-linking of polymeric oligomers on the bulk scale, microscale, and nanoscale, the latter for preparation of both gel nanoparticles and nanofibers.

While various smart materials have been explored for a variety of biomedical applications (e.g., drug delivery, tissue engineering, bioimaging, etc.), ...

Harnessing Gracilaria gracilis: Bioactive Potential for Sustainable Innovation

Valorization of the Red Seaweed Gracilaria gracilis Through a Biorefinery Approach

The interest in seaweeds as an abundant feedstock to obtain valuable and multitarget bioactive ingredients is continuously growing. In this work, we explore the potential of Gracilaria gracilis, an edible red seaweed cultivated worldwide for its commercial interest as a source of agar and other ingredients for cosmetic, pharmacological, food, and feed applications.
G. gracilis growth conditions were optimized through vegetative propagation and sporulation while manipulating the physicochemical conditions to achieve a large biomass stock. Green extraction methodologies with ethanol and water were performed over the seaweed biomass. The bioactive potential of extracts was assessed through a set of in vitro assays concerning their cytotoxicity, antioxidant, and antimicrobial properties. Additionally, dried seaweed biomass was incorporated into pasta formulations to increase food&#39;s nutritional value. Pigments extracted from G. gracilis have also been incorporated into yogurt as a natural colorant, and their stability was evaluated. Both products were submitted to the appreciation of a semi-trained sensorial panel aiming to achieve the best final formulation before reaching the market.
Results support the versatility of G. gracilis whether it is applied as a whole biomass, extracts and/or pigments. Through implementing several optimized protocols, this work allows the development of products with the potential to profit the food, cosmetic, and aquaculture markets, promoting environmental sustainability and a blue circular economy.
Moreover, and in line with a biorefinery approach, the residual seaweed biomass will be used as biostimulant for plant growth or converted to carbon materials to be used in water purification of the in-house aquaculture systems of MARE-Polytechnic of Leiria, Portugal.

Author Spotlight: Exploring Seaweed's Bioactive Compounds for Sustainable Innovations in Industries 

Here, we describe several protocols aiming at an integrated valorization of Gracilaria gracilis: wild species harvesting, in-house growth, and extraction of bioactive ingredients. The extracts&#39; antioxidant, antimicrobial, and cytotoxic effects are evaluated, along with the nutritional and stability assessment of food enriched with whole seaweed biomass and pigments.

The interest in seaweeds as an abundant feedstock to obtain valuable and multitarget bioactive ingredients is continuously growing. In this work, we ...