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S. SUPRANTO*, A. TAWFIEQURRAHMAN, D. E. YUNANTO
Department of Chemical Engineering, Gadjah Mada University, Jalan Grafika No. 2, Yogyakarta 55282, Indonesia
*Corresponding Author: [email protected]
As a renewable material, Sugarcane5bagasse fiber waste, has a huge potential as raw material for production of the High Refined Cellulose (HRC) and the cellulose chemicals derivatives such as Carboxyl Methyl Cellulose 5emulsifier, cellulose5acetate addesive, nitrocellulose coating agent, and nitrocellulose membrane filter. The objective of the study is to find out the optimal process conditions of the chemical conversion of the Sugarcane5bagasse fibre waste to the HRC. The experiments were carried out in a 1000 mL reactor capacity, equipped with stirrer and temperature controller. Three5steps atmospheric processes were involved, firstly using nitric acid solution at 80oC for 2 hours, following by the second step using sodium hydroxide at 80oC for 2 hours and finishing using hydrogen peroxide at 80oC, 305300 min in the third step . The HRC quality was indicated by its cellulose content. The result shows that the HRC product with cellulose content of higher than 90% were succesfully performed using a three5steps of the sugarcane5bagasse fiber delignification process. The optimal process condition of the sugarcane5bagasse fiber conversion to the HRC were achieved at 80oC at atmospheric pressure with a combinations of the 355% HNO3 with ratio of HNO3 /bagasse of 15520 mL/g and 2N NaOH with ratio of NaOH/bagasse of 15520 mL/g and 10% H2O2 for 5 hours.
Keywords: High refined cellulose, Delignification process, Sugarcane5bagasse fiber.
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Ca(OH)2
FeCl3
HCl HNO3
H2O2
H2SO4
KOH L/D NaOH Na2CO3
Calcium Hydroxide Ferry Chloride Hydrochloric Acid Sulphuric Acid Hydrogen Peroxide Nitric Acid
Potassium Hydroxide Length to Diameter ratio Sodium Hydroxide Sodium Carbonate
BPS C HRC
Badan Pusat Statistik Indonesia Celsius
High Refined Cellulose SCB Sugar Cane Bagasse
The photosynthesis process which converts carbon dioxide to organic compound is the most important step in the growth of biomass. Cellulose, carbohydrate and fatty oil are the main three components in biomass produced by photosynthesis process, so the plantation cellulose is one of the renewable chemical performed in carbon dioxide photosynthesis conversion. The cellulose in plantation fibre generally is the most dominant organic components in most biomass. In sugar cane bagasse (solid waste in cane sugar production) the cellulose content were reported as high as 35,3% [1], 32544% [2], 35550% [3], 32544% [4], 45,5% [5], 47.5551.1% [6], 405 41.5% [7] [8]. BPS, 2013 [9] reported that in 2012, Indonesia with the production of sugar cane as much as 2.6 million ton, there would be produced solid waste bagasse as much as 13 million ton. The solid waste bagasse from sugar production may be counted as a potential raw material for HRC production, which can be converted further to some end product, Cellulose acetate, Carboxyl Methyl Cellulose, viscose cellulose and other cellulose derivatives.
The first step in converting the plantation fibre to cellulose derivatives is called delignification, in which lignin as component of plantation fibre was removed, leaving the relatively pure cellulose in solid phase as HRC product. Supranto, 2011 [10] reported that sago fibre can be converted to nitrocellulose through delignification and nitration processes. Delignification process of sugar cane bagasse (SCB) prior to further processes has been found in some publication. Some different method of SCB delignification process has been reported. Acid process and alkaline processes were the two most popular.
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Deschamps et al., 1995 [11], in cattle feed production processing from SCB, used Phosphoric acid as much as 3% (w/w) to remove lignin, followed by alkali washing.
Phosphoric acid process for lignin removal from SCB also reported by Gamez et al., 2006 [12]. Gomez et al. used Phosphoric acid concentration of 256%, time 05300 min and temperature of 122oC to remove lignin from SCB. Chong et al., 2004 [13], reported that releasing lignin from SCB was successfully done by using nitric acid at variable concentration of 256%, reaction time up to 300 min and temperature of 1005128oC. Diluted sulphuric acid used for pre5treatment of SCB hydrolysis was reported by Cassia et al., 2010 [14]. Combination of acid concentration, temperature and residence time was simulated. Zhang et al., 2012,[15] used 1.2% HCl, reaction time of 30 min and 130oC in delignification process of SCB. They found that HCl was more effective than H2SO4 of FeCl3. Zhao and Liu, 2013 [16] used 0.0550.4 % sulphuric acid and 60590 weight% acetic acid in delignification process of SCB.
The degree of delignification resulted were 53.7579.7%.
Sulphuric acid process in removing lignin from SCB with acid concentration of 0.455% at 975126oC was reported by Zhao et al., 2012 [17]. The model of kinetic behaviour of dilute acid hydrolysis of SCB has been introduced with determination coefficients (R) in the range of 0.9550.995. Disruption of lignocellulose structure of SCB using dilute sulphuric acid in microwave heating at temperature of 130, 160 and 190oC with two heating time of 5 and 10 min have been investigated by Chena et al., 2011 [18]. The result shows that an increase in reaction temperature destroyed the lignocellulose structure of SCB. Chena et al., 2012 [19] reported that around 40544% of bagasse was degraded in acid delignification process using dilute sulphuric acid solution at 180oC for 30 min in a microwave irradiation environment.
Leibbrandt et al., 2011 [20] reported that lignin was successfully removed from SCB using process of delignification as pre5treatment process for bioethanol production from SCB using three different pre5treatment methods, i.e. dilute acid, liquid hot water and steam explosion, at various concentration. Mandal and Chakrabarty, 2011 [21] successfully used the acid hydrolysis process in the delignification and isolation process of nanocellulose from SCB with fibre to liquor ratio of 1:20 for 5 h at 50oC. Cardona et al., 2010 [22] resumed that delignification of SCB with dilute acids (sulphuric, hydrochloric or acetic, typically 1510% weight) hydrolysed the hemicellulose fraction at moderate temperature (1005150oC). The usage of sulphuric acid, hydrochloric acid and acetic acid of 1510%, and temperature of 1005150oC in SCB hydrolysing process for ethanol production also reported by Cheng et al., 2008 [23]. Combination of sulphuric acid and phosphoric acid for delignification of SCB reported by Geddes et al., 2010 [24]. A low level of phosphoric acid (1% w/w on dry bagasse basis, 160 C and above, 10 min) was shown to effectively hydrolyse the hemicellulose in sugar cane bagasse into monomers with minimal side reactions and to serve as an effective pre5treatment for the enzymatic hydrolysis of cellulose. Sulphuric was more effective than phosphoric at low concentrations.
Playne, 1984 [7] used alkaline process ( using NaOH, Ca(OH)2 and Na2CO3) combining with steam explosion at 200oC, 6.9 MPA and 5 min cooking time to remove lignin from SCB prior to pulp digesting process. Mandal and Chakrabart,
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2011 [21] used 0.7% (w/v) sodium chloride solution, fibre to liquor ratio of 1:50, at pH4, adjusted by 5% acetic acid and maintained with buffer solution of pH4 while mixture was being boiled for 5 h to remove the lignin. After washing process, the residue was then boiled with 250 mL 5% (w/v) sodium sulphite solution for 5 h, followed by washing with distilled water to remove the lignin completely and hemicellulose partially. Sun et al., 2004 [25] investigated the delignification of SCB using various concentrations of alkali and alkaline peroxide yielded 44.7 and 45.9% as cellulose preparations process, which contained 6.0 and 7.2% associated hemicelluloses and 3.4 and 3.9% bound lignin, respectively.
Delignification with acidic sodium chlorite followed by extraction with alkali (10% KOH and 10% NaOH) gave cellulose yields of 44.7 and 44.2%, which contained 5.7 and 3.7% residual hemicelluloses and 1.6 and 1.5% remaining lignin, respectively. Sun et al., 2004 [26] used 0.5M NaOH and 0553.0% H2O2 at pH 11.5 for 2 h under 55oC in delignification process of SCB. The successive treatments released 89% of the origin lignin in SCB. One5step process using alkaline hydrogen peroxide for SCB delignification process was investigated by Brienzo et al., 2009 [27]. With the operating condition used were H2O2
concentration from 2 to 6% (w/v), reaction time from 4 to 16 h, temperature from 20 to 60◦C, and magnesium sulphate absence or presence (0.5%,w/v), 88% of lignin in SCB removed.
Rabelo et al., 2011 [28] reported delignification process involving lime in alkaline hydrogen peroxide process prior to enzymatic hydrolysis of SCB. The experimental result shows that lignin removal using the peroxide process was higher than lignin removal using the lime process. Velmurugan and Muthukumar, 2011 [29] using the sono5assisted alkaline pre5treatment prior to SCB hydrolysis. The cellulose and hemicellulose recovery observed in the solid content was 99% and 78.95%, respectively and lignin removal observed during the pretreatment was about 75.44%. Combination of alkaline process and acid process in SCB delignification was reported by Teixeira et al., 2011 [30]. Their work evaluates the use of SCB as a source of cellulose to obtain whiskers. These fibers were extracted after SCB underwent alkaline peroxide pre5treatment followed by acid hydrolysis at 45◦C. The influence of extraction time (30 and 75 min) on the properties of the nanofibre was investigated. The results showed that SCB could be used as source to obtain cellulose whiskers and they had needle5 like structures with an average length (L) of 255±55 nm and diameter (D) of 4±2 nm, giving an aspect ratio (L/D) around 64. More drastic hydrolysis conditions (75 min) resulted in some damage on the crystal structure of the cellulose.
Gunam et al., 2011 [31] used sodium hydroxide process to remove lignin in SCB.
Lignin removal of 32.11 % was reported as a result of alkaline delignification process using 6% sodium hydroxide at 50oC, with reaction time of 12 h.
Rezende et al., 2011 [32] reported that using sodium hydroxide process, 85%
of lignin in SCB was successfully removed using 1% (m/v) NaOH. Soares and Gouvenia, 2013 [33] used alkaline delignification process of SCB using 0.551%
NaOH. Lignin removal of 76% was achieved when SCB of 25% lignin content, was treated with alkaline delignification process using 1% NaOH. Asqher et al., 2013 [34] reported that lignin removal of 48.7% was achieved in alkali treatment process of SCB at 35oC, using 4% NaOH for 48 h. Two5step process for cellulose extraction from palm kernel cake involving H2O2 to separate hemicellulose, cellulose and lignin, was reported by Yan et al., 2009 [35]. Palm kernel cake was
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pretreated in hot water at 180oC and followed by liquid oxidation process with 30%
H2O2 at 60oC at atmospheric pressure. Through hot water treatment, hemicellulose in the palm kernel cake was successfully removed, leaving lignin and cellulose in solid phase. Lignin was removed to water soluble compounds in liquid oxidation step and almost pure cellulose was recovered.
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The objective of the study is to find out the optimal process conditions of the SCB conversion to HRC through a three5step delignification process.
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Locally available SCB from Yogyakarta Sugar Industry was collected, sorted and cleaned. SCB was dried in sunlight and cut into small pieces about 1 52 cm. The cut SCB was grinded and the fraction passing 60 meshes was selected for raw material of delignification process. The cellulose content in the SCB was around 29.4%. Other reagent used (nitric acid, sodium hydroxide and hydrogen peroxide) were technical grade.
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Three5step of SCB delignification was chosen, a combination of acid process, alkaline process and oxidation process. Variation of Nitric acid and NaOH concentration were chosen as referred to acid delignification process reported by Chong et al., 2004 [13]. They used nitric acid concentration of 256% and removed the lignin from SCB successfully, and alkaline delignification process reported by Soares and Gouvenia, 2013 [33] that used of 0.551% NaOH resulted in the lignin removal of 76% . The atmospheric pressure and temperature less than 100oC, were chosen, referred to Yan et al. work, 2009 [35], they extracted cellulose from palm kernel cake involving the use of 30% H2O2 at 60oC at atmospheric pressure.
The oxidation process was varied from 8512% H2O2, with reaction time of 155h, developed from the experimental oxidation process condition done by Brienzo et al., 2009 [27]. They used H2O2 concentration from 2 56%, reaction time from 45 16 h, temperature from 20 – 60oC and magnesium sulphate of 0.5% (w/v), resulted in more than 88% lignin in SCB was removed.
The experiments were carried out in a 1000 mL reactor capacity, equipped with stirrer and temperature controller. Three5steps atmospheric processes were used, firstly using nitric acid solution at 80oC for 2 hours, following by the second step using sodium hydroxide at 80oC for 2 hours and finishing using hydrogen peroxide at 80oC, 305300 min in the third step . The detail process diagram of the delignification process was shown in the following Fig. 1.
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The HRC quality was indicated by cellulose content in HRC product. Cellulose content in SCB and HRC were analyzed using method described by Kulić and Radojičić, 2011 [36]. This method is based on insolubility of cellulose in water and its resistance to action of dilute acids and bases. The sample was degraded with a mixture of nitric acid and acetic acid and boiled in apparatus that contained a Liebig's condenser. The solution was then filtered through a Büchner funnel.
Then the filter paper containing an insoluble residue was dried in oven and measured. Analysis was done at “Pusat Studi Pangan dan Gizi” Gadjah Mada University.
The effect of process condition to HRC product quality were interpreted using graphical method using interpolation and second order polynomial correlation. The optimal process condition was determined graphically, indicated by the region or area in which the variation of process condition would result in highest cellulose content in HRC was achieved.
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Figure 2 shows the effect of varying HNO3 concentration on HRC quality. The correlation formula between HNO3 concentration (x) with the HRC quality indicated by its cellulose content (z), was represented by second order polynomial with correlation constant (R2) of 0.9459 as shown in Fig. 2. Increasing the HNO3
concentration from 2 to 5 % will result on increasing the cellulose content in
HRC, but further increase in HNO3 concentration result on lowering the cellulose content in HRC product. HNO3 concentration of 5 % was taken as the optimal HNO3 concentration.
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Figure 3 show the effect of varying HNO3/SCB ratio on HRC quality. The correlation formula between HNO3 / SCB ratio (r) with the HRC quality indicated by its cellulose content (z) , was represented by second order polynomial with correlation constant (R2) of 0.9849 as shown in Fig. 3.
Increasing the HNO3/SCB ratio higher than 20 mL/g caused a reduction in the HRC cellulose content. The use of HNO/SCB ratio of 15 to 20 mL/g has no significance effect on HRC cellulose content. However solid5liquid mixing with HNO3/SCB ratio of 20 mL/g seem to be better. The optimal process condition of the 1st step delignification process was concluded as 355% HNO3 and 15520 mL/g ratio of HNO3/SCB.
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z = -0.4192x2+ 3.1824x + 81.73 R² = 0.9459
40 50 60 70 80 90 100
0 2 4 6 8 10 12
Cellulose content in HRC (z), %
HNO3 (x), %
z = -0.1079r2+ 3.2545r + 66.108 R² = 0.9849
40 50 60 70 80 90 100
10 15 20 25 30 35
Cellulose content in HRC (z), %
HNO3/bagasse (r), mL/g
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Figures 4 and 5 show the effect of varying NaOH concentration and NaOH/SCB ratio on HRC quality. The correlation formula between NaOH concentration (y) and NaOH/SCB ratio (r) with the HRC quality indicated by its cellulose content (z) , was represented by 1st and 2nd order polynomial with correlation constant R2 (R2) of 0.9957 and 0.9958 respectively, as shown in Figs. 4 and 5.# 4 - $ ) )*' . !/ 0 '( # % 1 /
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The optimal process condition of the 2st step delignification process was concluded as 2 N NaOH and 15520 mL/g ratio of NaOH/SCB.
z = 2.314y + 86.938 R² = 0.9957
40 50 60 70 80 90 100
0.5 1 1.5 2 2.5 3
Cellulose content in HRC (z), %
NaOH (y), N
z = -0.0573r2+ 1.9398r + 75.404 R² = 0.9992
60 65 70 75 80 85 90 95 100
10 15 20 25 30 35
Cellulose content in HRC (z), %
NaOH/bagasse(r), mL/g
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Figures 6 and 7 show the effect of simultaneous varying H2O2 concentration and 3rd step time process duration on HRC quality, presented as a graphical surface response. The correlation formula between H2O2 concentration and time process duration was presented on 3D picture in Fig. 6 and 2D plotting in Fig. 7.
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4 6
81012 4045
5550 60 7065 75 8580 90
60 120 180 240 300 360 420
Cellulose content in HRC (z),%
Time, min
85-90 80-85 75-80 70-75 65-70 60-65 55-60 50-55 45-50
4 6 8 10 12
60 90 120 150 180 210 240 270 300 330 360 390 420 450
Time, min
85-90 80-85 75-80 70-75 65-70 60-65 55-60 50-55 45-50
H 2 O 2 , %
The optimal process condition of the 3st step delignification process was concluded as 300 min and 10 % H2O2.
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An investigation has been made of the effects of HNO3, NaOH and H2O2 in three5 step delignification process of SCB on HRC product quality. The delignification process consisted of 3 steps, using HNO3, NaOH and H2O2 respectively. The result show that The optimal process condition of the sugarcane5bagasse fiber conversion to the HRC with cellulose content of 90% were achieved in three5step delignification processes in atmospheric processes, at 80oC with a combinations of 355% HNO3 with ratio HNO3 /bagasse of 15520 mL/g and 2N NaOH with ratio NaOH/bagasse of 15520 mL/g and 10% H2O2 in 5h process. HRC with 90%
cellulose or higher may be converted further to some end product, such as Cellulose acetate, Carboxyl Methyl Cellulose, Viscose cellulose and other cellulose chemical derivatives form of useful products.
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