Chemical Engineering Department, University of Alicante, P.O. Box 99, 03080, Alicante, Spain.
Chemical Engineering Department, University of Alicante, P.O. Box 99, 03080, Alicante, Spain.
Chemosphere. 2020 Oct;256:127107. doi: 10.1016/j.chemosphere.2020.127107. Epub 2020 May 17.
The massive use of petroleum-based polymers and their improper waste treatment has brought on significant global environmental problems due to their non-biodegradable nature. Starch/poly(vinyl alcohol) (PVA) bioplastics are suitable substitutes for conventional polymers, such as polyethylene, due to their full biodegradability and excellent mechanical properties. Knowledge of the pollutant emissions during pyrolysis and combustion of starch/PVA films is important because they can arrive at landfills mixed with conventional polymers and be thermally degraded in uncontrolled fires. On the other hand, controlled thermal treatments could result in thermal valorization of the waste. Pyrolysis and combustion experiments were carried out at 650, 750, 850 and 950 °C in a laboratory furnace. The analysis of carbon oxides, light hydrocarbons, and semivolatile compounds, including polycyclic aromatic hydrocarbons (PAHs), is shown. Experiments showed lower pollutant emissions than those found with conventional polymers, such as polyethylene and polyester, in the same equipment. Nevertheless, the pyrolysis run at 950 °C showed the highest light hydrocarbon yield (123013 mg kg), but this is considerably lower than the values found for polyethylene. The main semivolatile compounds (not PAHs) emitted, with maximum yields ranging from 1351 to 4694 mg kg, were benzaldehyde, phenol, indene, and acetophenone. Specifically, the total semivolatile compounds emitted after pyrolysis and combustion of starch/PVA samples represent only 38 and 50%, respectively, of those emitted with polyethylene. Further, the main PAHs were naphthalene, acenaphthylene, and phenanthrene with maximum values of 4694, 2704 and 1496 mg kg, respectively. The PAH yield was considerably higher in experiments with low oxygen content.
由于石油基聚合物不可生物降解，大量使用和不当的废物处理给全球环境带来了重大问题。淀粉/聚乙烯醇（PVA）生物塑料由于其完全可生物降解性和优异的机械性能，是传统聚合物（如聚乙烯）的合适替代品。了解淀粉/PVA 薄膜在热解和燃烧过程中的污染物排放情况很重要，因为它们可能与传统聚合物混合并在不受控制的火灾中被热降解到垃圾填埋场中。另一方面，受控的热处理可能导致废物的热回收。在实验室炉中，在 650、750、850 和 950°C 下进行了热解和燃烧实验。分析了一氧化碳、轻烃和半挥发性化合物，包括多环芳烃（PAHs）。实验表明，与在相同设备中使用的传统聚合物（如聚乙烯和聚酯）相比，污染物排放量较低。然而，在 950°C 下进行的热解显示出最高的轻烃产率（123013 mg kg），但远低于聚乙烯的值。排放的主要半挥发性化合物（非 PAHs）最大产率范围为 1351 至 4694 mg kg，分别为苯甲醛、苯酚、茚和苯乙酮。具体而言，淀粉/PVA 样品热解和燃烧后排放的总半挥发性化合物分别仅占聚乙烯排放的 38%和 50%。此外，主要的 PAHs 是萘、苊烯和菲，最大值分别为 4694、2704 和 1496 mg kg。在低氧含量的实验中，PAH 的产率要高得多。
