# Integrated Process for Ballot Bin Waste Vaporization for High-Quality Cellulose Acetate Recovery
## 2 Materials and Methods
### Methods
#### 2.2.5 Characterizations  
Attenuated total reflectance (ATR) FT-IR measurements were performed using a NICOLET iS5 spectrometer (Thermo Scientific, Waltham, MA, USA) equipped with an iD7 ATR accessory and diamond crystal. All infrared spectra were recorded within the range of 4000-600 cm\({}^{-1}\) with a 4 cm\({}^{-1}\) resolution and 32 scans. The estimation of the degree of substitution (DS) was performed following the procedure reported by [PERSON] et al., 2017, specifically developed for highly acetylated samples [52]. For all the fractions, Cd, Co, Cu, Ni, Fe, Mn, Zn, Cr, Pb, and As were quantified using an inductively coupled plasma-optical emission mass spectrophotometer (ICP-OES Optima 7000 DV PerkinElmer, Waltham, MA, USA). All samples were prepared according to the following procedure: about 750 mg of oven-dried representative material was precisely weighted, placed in a PTFE vessel, and digested in a Milestone Ethos TC Microwave digestion system by adding 4 mL of aqua regia (HNO\({}_{3}\) 65% and HCl 37%) in a closed system to reduce the risk of contamination [53]. The system was programmed to use up to 1000 W of power to increase the detected temperature to 220 \({}^{\circ}\)C, at which time, the temperature was maintained for 15 min. After digestion, samples were made up to a total of 10 mL and analyzed by ICP-OES. The instrument's detection limit was 0.1 \(\upmu\)g/g. For every sample, three replicates were taken, and the average value and standard deviation were calculated. The data are expressed as the average of 2 purification experiments, analyzed 3 times each. For GPC characterization, the pulverized material (roughly 50 mg) was put in an 8 mL dried sample bottle equipped with a magnetic stirrer with 1 mL of pyridine and 250 mL of benzoyl chloride. The solution was vortexed until it became homogeneous and allowed to cool to room temperature. The sample was kept under magnetic stirring at room temperature for 2 h. To precipitate the benzoylated material, a deionized water-ethanol solution (1:3 \(v/v\), 20 mL) was added and the mixture was vigorously shaken and vortexed for 5 min. The solid was filtered off through a sintered funnel (grade 3), washed with further ethanol, and purified with methanol. The benzoylated samples were solubilized in THF and passed through a 0.45 m GHP Acrodisc syringe filter (Waters, Milford, CT, USA) for GPC analyses. Gel Permeation Chromatography analyses were performed on an Agilent HP1100 series (Agilent, Santa Clara, CA, USA) equipped with a UV-Vis detector set at 240 nm and RID (Refract Index Detection). The injection port was a Rheodyne loop valve equipped with a 20 m loop. The GP-column system was composed of a sequence of an Agilent PL gel of 5 m, 500 A, an Agilent PL gel of 5 m, 5000 A, and an Agilent PL gel of 5 m, 104 A. The solvent used was THF (Fluka 99.8%, Sigma-Aldrich). The PL Polymer Standards of Polystyrene from Polymer Laboratories (Church Stretton, UK) were used for calibration. An evaluation of the number-average molecular weight (M\({}_{\text{n}}\)) and the weight-average molecular weight (M\({}_{\text{w}}\)) of the samples was performed. The peak molecular weight M\({}_{\text{p}}\) is defined as the molecular weight of the species with maximum absorbance. Moreover, the ratio D = M\({}_{\text{w}}\)/M\({}_{\text{n}}\), defined as the dispersity index, was also calculated. The M\({}_{\text{n}}\), M\({}_{\text{w}}\), and M\({}_{\text{p}}\) values reported are the averages of three analyses (\(p\) = 0.05, \(n\) = 3). For \({}^{1}\)H-NMR characterization, 10 mg of cellulose acetate was dissolved in 750 m of d\({}_{6}\)-Acetone (Sigma-Aldrich, 99%) and placed in a 5 mm NMR tube.