*2.4. Thermogravimetric Analysis (TGA)*

A thermogravimetric analyzer (STA 449 F1 Jupiter, Netzsch, Selb, Germany) was applied to record the mass loss as a function of temperature during the pyrolysis of AIW. The sample was placed in a crucible and heated from 40 to 1000 ◦C at three different heating rates (10, 15, 20 ◦C/min) with argon flowing at 75 mL/min. To ensure the repeatability of the experiment with an error of 1.5%, the experimental conditions were repeated at least three times. The results showed that the TG and DTG curves were almost identical, which consequently gave very low standard deviations for the calculated kinetic parameters obtained. The results presented here are a set of those experiments that satisfy the above conditions.

#### *2.5. Kinetic Analysis*

The mechanism of pyrolysis is characterized by a rather complex set of competitive and parallel reactions, which is also complicated by the variability of the lignocellulosic composition of the biomass [34]. The global pyrolysis reaction is expressed by the following equation [35]:

$$\text{Biomass (solid)} \stackrel{k(T)}{\rightarrow} \text{Volatility (condernable + noncondernable)} + \text{Char},\tag{1}$$

where *k*(*T*) is reaction rate constant, which is expressed by the Arrhenius equation:

$$k(T) = A e^{-E\_a/RT},\tag{2}$$

where *E<sup>α</sup>* is the activation energy (kJ/mol); *T* is temperature (K); *R* is the universal gas constant (8.314 J/mol·K); and *A* is the pre-exponential factor (1/s).

The biomass conversion rate *α* is defined as the mass fraction of the degraded sample. It can be calculated for each point of TGA according to the equation [36–38]:

$$\alpha = \frac{m\_0 - m}{m\_0 - m\_f}'\tag{3}$$

where *m0* is the initial sample weight of the sample (mg); *m* is actual weight to each point of analysis (mg); and *mf* is the final weight of the sample after pyrolysis (mg).

Generalized fundamental expression for non-isothermal TGA experiments at linear heating rate:

$$
\beta = \frac{dT}{dt} = \frac{dT}{d\alpha} \frac{d\alpha}{dt} \,\tag{4}
$$

Or

$$\frac{d\alpha}{dt} = \frac{A}{\beta} \cdot \exp\left(\frac{-E\_{\alpha}}{RT}\right) f(a),\tag{5}$$

where *f*(α) is function of conversion.

The analytical form of the function *f*(α) depends on the thermal decomposition mechanism. Integration of Equation (5) makes it possible to analyze the kinetic data obtained by the TGA method. Integration can be performed using model-free (isoconversion) methods [38,39], which estimate the activation energy (*Eα*) when changing the degree of conversion *α*. These methods are also called "multi-curve" since they require the use of several kinetic curves for analysis [40].
