Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul 04763, Republic of Korea.
Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, New Territories 999077, Hong Kong.
Sci Total Environ. 2022 Aug 15;834:155384. doi: 10.1016/j.scitotenv.2022.155384. Epub 2022 Apr 20.
Plastic is a versatile material broadly used in a variety of industries. However, the current disposal practices for plastic wastes (incineration/landfilling) add the hazardous materials into the environment. To offer a sustainable valorization platform for plastic waste, this study adopted the catalytic pyrolysis process using CO as a co-feedstock. A model plastic waste collected from a seaport was waste buoy (WB), which has been widely used in fishing industry. Prior to the pyrolysis tests, the exact type of plastic in WB and the thermolytic characteristics of WB were examined. Since the WB was made of polystyrene, it was mainly converted into styrene monomer (styrene), dimer (diphenyl-1-butene), and trimer (2,4,6-triphenyl-1-hexene) from pyrolysis of WB. To further valorize/detoxify styrene derivatives into value-added syngas, catalytic pyrolysis of WB was practiced using the Ni-based catalysts (2/5/10 wt% Ni/SiO). The yield of H from the catalytic pyrolysis process of WB was more than one magnitude higher comparing to that from the non-catalytic one. H formation also increased as catalyst loading increased. When flow gas was switched from inert gas to CO, CO gas formation was enhanced due to the chemical reactions between CO and styrene derivatives over Ni catalysts. Syngas (H/CO) formation under the CO condition was 5 times higher in comparison to the N condition in catalytic pyrolyses of WB with 10 wt% Ni/SiO. CO also effectively suppressed coke deposition on a Ni catalyst. This study proposes a sustainable valorization and disposal platform for used plastic waste and greenhouse gas (CO), converting them into value-added fuel.
塑料是一种用途广泛的材料，广泛应用于各种行业。然而，目前塑料废物的处理方法（焚烧/填埋）将危险材料添加到环境中。为了为塑料废物提供可持续的增值平台，本研究采用了以 CO 为共进料的催化热解工艺。从一个海港收集的模型塑料废物是废浮标 (WB)，它已广泛用于渔业。在进行热解试验之前，检查了 WB 中塑料的确切类型和 WB 的热解特性。由于 WB 由聚苯乙烯制成，因此主要通过 WB 的热解转化为苯乙烯单体（苯乙烯）、二聚体（二苯-1-丁烯）和三聚体（2,4,6-三苯基-1-己烯）。为了进一步将苯乙烯衍生物增值/解毒为增值合成气，使用 Ni 基催化剂（2/5/10wt%Ni/SiO）对 WB 进行催化热解。与非催化热解相比，WB 催化热解过程中 H 的产率高出一个数量级。随着催化剂负载量的增加，H 的形成也增加。当气流从惰性气体切换到 CO 时，由于 CO 和 Ni 催化剂上的苯乙烯衍生物之间的化学反应，CO 气体的形成得到增强。与 10wt%Ni/SiO 的 WB 催化热解的 N 条件相比，CO 条件下合成气（H/CO）的形成高 5 倍。CO 还可以有效地抑制 Ni 催化剂上的积碳。本研究提出了一种可持续的废旧塑料和温室气体（CO）增值和处理平台，将它们转化为增值燃料。
