Environmental Science and Pollution Research
or surface treat m ents, where they were che m ically bound or incorporated within the paper m atrix. Upon leaching with acetic acid, these layers underwent degradation, releasing the co m pounds. Owing to their polar and reactive nature, the co m pounds then interacted with cellulose and beca m e detectable within the fibre m atrix, even though they had not been directly identified in the original waste paper. Following the re m oval of PCC, enhanced access to cel- lulose fibres enabled the identification of eight co m pounds derived fro m virgin wood and eight co m pounds originating fro m printing inks. Two of the ink-related co m pounds— 1,3-cyclohexanedione and 2-acetyl-resorcinol—were for m ed through the conversion of resorcinol, originally present in the untreated office paper. Four additional substances were identified as solvents. Bis(2-(di m ethyla m ino)ethyl) ether was detected as an additive specific to UV-printing appli- cations. Another co m pound, 3-butene-1,2-diol, represents the pri m ary degradation product of 1,3-butadiene (BD), used in ink resin for m ulations. Further m ore, eight newly identified co m pounds in OP–CH 3 COOH were associated with various functional roles in paper production (Table 6). Two additional co m pounds were found to originate either fro m printing inks or paper m aterials. The first, 4- m ethoxy- 1,3-benzenedia m ine, is e m ployed in both ink production and the synthesis of polyester fibres, which m ay serve as alterna- tives to natural fibres. The second, 3,5,5-tri m ethylhexanoyl chloride, functions as a plasticizer and is also utilized in the production of esterified cellulose nanofibres. According to the Globally Har m onized Syste m (GHS) clas- sification, 4 co m pounds identified in the waste paper sa m ples fall under health hazards (HH), 1 co m pound is categorized as an environ m ental hazard (EH), 2 exhibit acute toxicity, and 13 are classified as irritants. Figure 6 illustrates a 79% reduction in the total concentration of identified co m pounds between untreated office paper (OP) and acetic acid-treated sa m ples (OP–CH 3 COOH), including a significant decrease in GHS-classified hazardous substances. Additionally, as shown in Table 6, no persistent organic pollutants were detected in OP–CH 3 COOH. These results de m onstrate that extraction using 0.2 M acetic acid followed by washing yields a highly purified cellulose fibre product, suitable for further applications (Fig. 7). The newly identified co m pounds were released fro m the cellulose m atrix during acid extraction and subsequently detected using the TD-GC/MS m ethod. Although ther m al desorption is generally expected to release m ost co m pounds during TD-GC/MS analysis, its reliability di m inishes when analytes are structurally e m bedded within the cellulose. Ther m al deco m position of cellulose occurs at te m peratures ranging fro m 440 to 580 °C under oxidative conditions and 280–380 °C in an inert at m osphere (Shen et al. 2013), both of which exceed the operational te m perature of the ther m al desorption unit used in the analytical setup.
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