**Table 4.**

*The kinetic and thermodynamic parameter values of celluloses determined by FWO model.*


where *<sup>d</sup>*<sup>α</sup> *dt*

*R2 were above 0.98. <sup>a</sup> Acid-base b Organosolv.*

**Table 6.**

**α Log A (s**�**<sup>1</sup>**

**) ΔG (kJmol**�**<sup>1</sup>**

*DOI: http://dx.doi.org/10.5772/intechopen.93549*

specific value of <sup>d</sup><sup>α</sup>

(*g*ð Þ¼ � <sup>α</sup> ½ � ln 1ð Þ � <sup>α</sup> <sup>1</sup>

**589**

by the following equation [27].

Πð Þ¼ *x*

model-free methods at different heating rates, respectively.

multidimensional nuclei and random growth reaction mechanism

adsorption, dissolution, and defects on the crystallite within particle size of the

<sup>α</sup> is rate of reaction at a given conversion, α, and heating rate, β, Πð Þ *x*

dt, E<sup>α</sup> and Tα. The experimental z(α) master plots as a function of α

<sup>n</sup>Þ. This type of mechanism is often as a result of hydration,

*<sup>x</sup>*<sup>4</sup> <sup>þ</sup> <sup>20</sup>*x*<sup>3</sup> <sup>þ</sup> <sup>120</sup>*x*<sup>3</sup> <sup>þ</sup> <sup>240</sup>*<sup>x</sup>* <sup>þ</sup> <sup>120</sup> (10)

*<sup>x</sup>*<sup>3</sup> <sup>þ</sup> <sup>18</sup>*x*<sup>3</sup> <sup>þ</sup> <sup>88</sup>*<sup>x</sup>* <sup>þ</sup> <sup>96</sup>

The theoretical z(α) plots versus α depend on *f*(α) and g(α) functions. However, the experimental z(α) values can be obtained by using a specific heating rate for a

The experimental and the fitted z(α) master plots of acid-base cellulose showed a normal distribution behavioral curve trend for all model-free methods at investigated heating rates. However, Organosolv cellulose showed a sigmoid curve skewed more to the left hand side. The correlation coefficient of acid-base method ranged between 0.9789 and 0.9884, while that of Organosolv ranged between 0.9525 and 0.9795, signifying the accuracy in the reported data. It is worth to note that both methods had best fit at 15°C/min. The data were fit with polynomial curves of n = 3 and n = 4 for Organosolv and acid-base celluloses, respectively, implying third and fourth dimension growth as described by general Avrami-Erofeev model of

are compared with known theoretical model functions [28]. The best fit between the experimental z(α) master plots and theoretical model functions describes the probable biomass reaction mechanism. **Figures 6** and **7** show the experimental z(α) master plots and fitted model plots of acid-base and Organosolv, as determined by

approximates the temperature integral profile and x ¼ Eα*=*RTα. The x values used were in a range of 5–20 and the temperature approximation Πð Þ *x* function is defined

*The kinetic and thermodynamic parameter values of celluloses determined by STARINK model.*

**STARINK<sup>a</sup> STARINK<sup>b</sup>**

0.1 29.65 138.69 0.25 74.89 81.73 1.12 0.2 33.82 149.97 0.33 74.76 89.30 1.12 0.3 35.63 156.78 0.37 74.59 92.13 1.12 0.4 36.99 162.47 0.39 74.71 94.46 1.12 0.5 38.15 167.24 0.41 74.80 97.28 1.12 0.6 39.22 172.53 0.43 74.83 106.50 1.12 0.7 40.55 180.43 0.46 70.70 132.96 1.04 0.8 42.60 196.89 0.50 69.46 162.20 1.01 0.9 45.58 221.00 0.55 76.04 186.43 1.14 Av **38.02** � **4.75 171.78** � **25.05 0.41** � **0.09 73.86** � **2.21 115.89** � **36.65 1.10** � **0.04**

**) Log A (s**�**<sup>1</sup>**

**) ΔG (kJmol**�**<sup>1</sup>**

**) ΔS (Jmol**�**<sup>1</sup>**

**)**

**) ΔS (Jmol**�**<sup>1</sup>**

*Investigation of Nonisothermal Combustion Kinetics of Isolated Lignocellulosic Biomass…*

*R2 were above 0.98. <sup>a</sup>*

*Acid-base*

*b Organosolv.*

#### **Table 5.**

*The kinetic and thermodynamic parameter values of celluloses determined by KAS model.*

#### **2.6 Reaction model determination**

Malek method which is the commonly used approach to determine probable reaction mechanism involving heterogeneous reaction was used [26]. The Malek method is described by the following equation.

$$Z(\mathbf{a}) = \mathbf{f}(\mathbf{a})\mathbf{g}(\mathbf{a}) = \left(\frac{d\alpha}{dt}\right)\_a T\_a^2 \left[\frac{\Pi(\mathbf{x})}{\beta T\_a}\right] \tag{9}$$


*Investigation of Nonisothermal Combustion Kinetics of Isolated Lignocellulosic Biomass… DOI: http://dx.doi.org/10.5772/intechopen.93549*

**Table 6.**

*Organosolv.*

*The kinetic and thermodynamic parameter values of celluloses determined by STARINK model.*

where *<sup>d</sup>*<sup>α</sup> *dt* <sup>α</sup> is rate of reaction at a given conversion, α, and heating rate, β, Πð Þ *x* approximates the temperature integral profile and x ¼ Eα*=*RTα. The x values used were in a range of 5–20 and the temperature approximation Πð Þ *x* function is defined by the following equation [27].

$$\Pi(\mathbf{x}) = \frac{\mathbf{x}^3 + \mathbf{18x^3} + \mathbf{88x} + \mathbf{96}}{\mathbf{x}^4 + 2\mathbf{0x^3} + \mathbf{120x^3} + \mathbf{240x} + \mathbf{120}} \tag{10}$$

The theoretical z(α) plots versus α depend on *f*(α) and g(α) functions. However, the experimental z(α) values can be obtained by using a specific heating rate for a specific value of <sup>d</sup><sup>α</sup> dt, E<sup>α</sup> and Tα. The experimental z(α) master plots as a function of α are compared with known theoretical model functions [28]. The best fit between the experimental z(α) master plots and theoretical model functions describes the probable biomass reaction mechanism. **Figures 6** and **7** show the experimental z(α) master plots and fitted model plots of acid-base and Organosolv, as determined by model-free methods at different heating rates, respectively.

The experimental and the fitted z(α) master plots of acid-base cellulose showed a normal distribution behavioral curve trend for all model-free methods at investigated heating rates. However, Organosolv cellulose showed a sigmoid curve skewed more to the left hand side. The correlation coefficient of acid-base method ranged between 0.9789 and 0.9884, while that of Organosolv ranged between 0.9525 and 0.9795, signifying the accuracy in the reported data. It is worth to note that both methods had best fit at 15°C/min. The data were fit with polynomial curves of n = 3 and n = 4 for Organosolv and acid-base celluloses, respectively, implying third and fourth dimension growth as described by general Avrami-Erofeev model of multidimensional nuclei and random growth reaction mechanism

(*g*ð Þ¼ � <sup>α</sup> ½ � ln 1ð Þ � <sup>α</sup> <sup>1</sup> <sup>n</sup>Þ. This type of mechanism is often as a result of hydration, adsorption, dissolution, and defects on the crystallite within particle size of the

**2.6 Reaction model determination**

**α Log A (s**�**<sup>1</sup>**

Av **11.47** �**0.68**

**α Log A (s**�**<sup>1</sup>**

*R2 were above 0.98. <sup>a</sup> Acid-base b Organosolv.*

**Table 5.**

**588**

*<sup>R</sup><sup>2</sup> were above 0.98. <sup>a</sup> Acid-base. b Organosolv.*

**Table 4.**

**) ΔG (kJmol**�**<sup>1</sup>**

*Biotechnological Applications of Biomass*

**188.39** �**27.89**

**) ΔG (kJmol**�**<sup>1</sup>**

method is described by the following equation.

Malek method which is the commonly used approach to determine probable reaction mechanism involving heterogeneous reaction was used [26]. The Malek

**FWO<sup>a</sup> FWOb**

**) Log A (s**�**<sup>1</sup>**

**25.94** � **2.16** **) ΔG (kJmol**�**<sup>1</sup>**

**119.45** �**37.98**

**) ΔG (kJmol**�**<sup>1</sup>**

**) ΔS (Jmol**�**<sup>1</sup>**

**0.18** �**0.04**

**) ΔS (Jmol**�**<sup>1</sup>**

**)**

**)**

**) ΔS (Jmol**�**<sup>1</sup>**

0.1 10.17 151.46 �0.12 27.20 84.18 0.21 0.2 10.96 164.16 �0.11 27.24 91.96 0.21 0.3 11.34 171.76 �0.10 27.26 94.86 0.21 0.4 11.79 178.07 �0.09 27.15 97.26 0.21 0.5 12.13 183.36 �0.08 27.17 100.17 0.21 0.6 12.25 189.25 �0.08 27.53 109.59 0.21 0.7 12.17 198.03 �0.08 25.07 136.91 0.17 0.8 11.15 216.34 �0.10 21.64 167.53 0.10 0.9 11.28 243.04 �0.10 23.20 192.64 0.13

> �**0.10** �**20.01**

*The kinetic and thermodynamic parameter values of celluloses determined by FWO model.*

**) ΔS (Jmol**�**<sup>1</sup>**

0.1 31.09 138.51 0.28 76.86 81.66 1.16 0.2 34.78 149.86 0.35 76.54 89.24 1.15 0.3 36.56 156.67 0.38 76.62 92.06 1.16 0.4 38.05 162.34 0.41 76.69 94.38 1.16 0.5 39.18 167.12 0.43 76.76 97.21 1.16 0.6 40.29 172.40 0.46 76.72 106.42 1.16 0.7 41.65 180.30 0.48 72.62 132.86 1.08 0.8 43.89 196.73 0.52 71.44 162.07 1.05 0.9 46.97 220.82 0.58 78.19 186.28 1.18 Av **39.16** � **4.78 171.64** � **25.07 0.43** � **0.09 75.83** � **2.23 115.80** � **36.62 1.14** � **0.04**

**KAS<sup>a</sup> KAS<sup>b</sup>**

**) Log A (s**�**<sup>1</sup>**

*d*α *dt* 

α *T*2 α

*Π*ð Þ *x βT<sup>α</sup>* 

(9)

*Z*ð Þ¼ α fð Þ α gð Þ¼ α

*The kinetic and thermodynamic parameter values of celluloses determined by KAS model.*

**3. Conclusions**

*DOI: http://dx.doi.org/10.5772/intechopen.93549*

(99.77–173.76 kJmol�<sup>1</sup>

FWO model-free method.

(*g*ð Þ¼ � <sup>α</sup> ½ � ln 1ð Þ � <sup>α</sup> <sup>1</sup>

different heating rates.

Environment Research, UAEU (31R107).

The authors declare no conflict of interest.

**Acknowledgements**

**Conflict of interest**

**591**

model mechanism (*g*ð Þ¼ � <sup>α</sup> ½ � ln 1ð Þ � <sup>α</sup> <sup>1</sup>

method.

The low cost and high yield acid-base and Organosolv methods were assessed for isolation of cellulose from date palm lignocellulose waste biomass. The structural, chemical, and morphological characterizations of the isolated celluloses were studied. The nonisothermal combustion studies were investigated using three different model-free methods. The reaction mechanism was studied using Malek

*Investigation of Nonisothermal Combustion Kinetics of Isolated Lignocellulosic Biomass…*

• The SEM images revealed chiral nematic orderings structures distinctive of cellulose. The change in FTIR peak intensity and the difference in the

• The FWO model for the acid-base method gave the lowest activation energy

relationship between activation energy and enthalpy, and the positive enthalpy values confirmed that endothermic reaction took place during the pyrolysis of the cellulose samples. The Gibbs's free energy, ΔG, results revealed that Organosolv cellulose pyrolysis reaction would easily reach equilibrium, much easier in a trend of KAS > Starink> FWO models. The measure for disorder was less favorable for the acid-base method with negative entropy values in the

• The reaction mechanism by Malek method was described by Avrami-Erofeev

occurring in solid-state reactions due to variations in activation energy with the heating rates. The study provides important data information and a robust approach to understanding the cellulose pyrolysis structures and mechanisms by different isolation methods across a broad range of temperature and

<sup>3</sup>Þ for the Organoslv method.

• The results of this study confirm the existence of multistep mechanism

This work was financially supported by the Emirates Centre for Energy and

) and the Organosolv method by KAS model gave the

). There was a strong

<sup>4</sup>Þ for the acid-base method and

higher temperature where isoconversion was higher than 0.6.

highest activation energy (419.63–934.49 kJmol�<sup>1</sup>

vibrational bond stretching among the isolated celluloses and between original biomass signified component removal from the lignocellulose complex. The TGA results from both methods showed one major decomposition peak assigned to cellulose in contrast to original biomass with three peaks. The results further revealed a possible difference in the degradation chemistry at

**Figure 6.**

*Experimental and theoretical Z(α) master plots for pyrolysis of acid-base cellulose at (a) 10° Cmin<sup>1</sup> , (b) 15° Cmin<sup>1</sup> , (c) 20° Cmin<sup>1</sup> and (d) 25° Cmin<sup>1</sup> .*

**Figure 7.**

*Experimental and theoretical Z(α) master plots for pyrolysis of Organosolv cellulose at (a) 10° Cmin<sup>1</sup> , (b) 15° Cmin<sup>1</sup> , (c) 20° Cmin<sup>1</sup> and (d) 25° Cmin<sup>1</sup> .*

sample that can cause thermodynamic inhibition leading to varying activation energies [29]. Therefore, random nucleation and growth is the most probable reaction mechanism for the pyrolysis of celluloses isolated from DPW by acid-base and Organosolv methods.

*Investigation of Nonisothermal Combustion Kinetics of Isolated Lignocellulosic Biomass… DOI: http://dx.doi.org/10.5772/intechopen.93549*
