Chemical Reaction Mechanism from Pyrolysis Degradation of Polystyrene Styrofoam Plastic Microparticles based on FTIR and GC-MS Completed with Bibliometric Literature Review to Support Sustainable Development Goals (SDGs)

The purpose of this study was to determine the chemical compound content of polystyrene-styrofoam microparticles after the pyrolysis process, and their pyrolysis chemical reaction mechanism, with a bibliometric literature review. The analysis was done using Fourier transform infrared (FTIR) and gas chromatography-mass spectroscopy (GC-MS). The pyrolysis method was carried out by decomposing 30 g of polystyrene particles (sizes of 3000 mu m) for 105 min at a temperature in the range of 120-190 degrees C in the absence of air. The process was done inside the batch reactor (length x width x height = 44.5 cm x 35.5 cm x 25 cm) equipped with an outlet connected to three condensers (24 degrees C). The condensers were set in series, in which condenser 1 was directly connected to the reactor and connector 2 connected condensers 1 and 3. The pyrolysis results in the first condenser was a two-phase liquid with a brownish-yellow liquid in the top layer and a colorless and pungent-smelling liquid in the bottom layer. In the second and third condensers, a colorless and pungent liquid was obtained. The results of the FTIR showed that different chemical compositions were detected in the samples. The first, second, and third condensers contained aromatic C=C bonds. The second and third condensers have the same functional groups, namely-CH3 and hydrogen bonds in H2O,, as well as aromatic functional groups with C-H bending alkenes, which are also possessed by the FTIR raw materials. Results analyzed by GC- MS showed that the second and third condensers contained styrene, toluene, methyl acetate, benzyl cyclopropane, and other styrene derivatives. The results analyzed by GC-MS showed a mixture of compounds with oxygen and nitrogen, as found in 2propanone and benzene methanamina compounds. This pyrolysis process showed that a degradation reaction occurs, in which polystyrene is degraded into small fragments such as styrene and other derivatives such as benzene, toluene, and ethyl benzene. However, the pyrolysis was incomplete as oxygen and nitrogen were present. This research had a helpful impact on providing ideas and information about the pyrolysis process. This study also gives ideas to be applied to the pyrolysis process in areas that are difficult to reach with traditional waste treatment infrastructure. This study also aims to support current issues in the Sustainable Development Goals (SDGs).