Simultaneous Upcycling of Biodegradable Plastic and Sea Shell Wastes Through Thermocatalytic Monomer Recovery

Abstract

Development of effective upcycling methods for biodegradable plastic waste (for example, straws made of polylactic acid (PLA)) has emerged. In this study, a catalyst derived from sea shell waste (SSC) was used for a thermocatalytic conversion of biodegradable straw (BDS) for the recovery of monomer (for example, lactic acid). In effect, a strategy for simultaneously upcycling of biodegradable plastic waste (for example, straws made of polylactic acid (PLA)) and marine waste (for example, sea shell waste) was proposed. The SSC mainly consisted of calcium carbonate; thus, it had basicity with no acidity. Notably, a temperature of 500 °C and an SSC/BDS mass ratio of 0.5 led to the highest lactic acid recovery from BDS in this study. In particular, the use of SSC under the above-mentioned temperature and SSC/BDS mass ratio resulted in a 130 times higher lactic acid recovery than noncatalytic BDS conversion, most likely because the base sites present on SSC catalyzed the thermal cracking of PLA polymer bond. However, coke deposition was the major deactivation pathway of SSC during the thermocatalytic BDS conversion. In essence, SSC has the potential to be a catalyst used to thermocatalytically recover high-value chemicals from biodegradable plastic waste. In addition, this study can offer insight into developing waste conversion processes for the simultaneous upcycling of biodegradable plastic and marine wastes.

Approach for the Low Carbon Footprint of Biodegradable Plastic PBAT: Complete Recovery of Its Every Monomer via High-Efficiency Hydrolysis and Separation

“…Thermochemical conversion is recently used in the recovery of biodegradable plastics, especially biodegradable straws , and mulch film due to a simple process and wide tolerance to mixed wastes. However, the conversion process was usually conducted at a high reaction temperature (above 400 °C) and therefore consumed a large amount of energy.…”

“…8 However, in the easy-to-collect occasion, it is the recovery that should be considered as a preferable choice from the viewpoint of both resource utilization and carbon emission. Thermochemical conversion is recently used in the recovery of biodegradable plastics, especially biodegradable straws 9,10 and mulch film 11 due to a simple process and wide tolerance to mixed wastes. However, the conversion process was usually conducted at a high reaction temperature (above 400 °C) and therefore consumed a large amount of energy.…”

Upcycling of plastic and tire waste toward use as modifier for asphalt binder

“…14 The scale of a pyrolysis process can be varied flexibly, allowing the installation of the process at sites in which feedstock is abundantly available. 15 Pyrolysis process is versatile as it can make products in different phases (e.g., solid, gas, and liquid) [16][17][18] by simply varying operational parameters (e.g., temperature, heating rate, and feed and/or vapor residence time). 19 Furthermore, the environmental footprint of pyrolysis is smaller than that of landfilling, gasification, and incineration.…”

Plastic-Waste-Derived Char as an Additive for Epoxy Composite

“…This allows the system to be installed at sites with abundant feedstock [ 27 ]. Pyrolysis is a versatile process that anaerobically transforms waste feedstock (e.g., plastic waste) into products in various phases (e.g., gas, liquid, and solid) [ 28 , 29 , 30 ]. The product phase and yield can be readily controlled by varying the operational parameters (temperature, heating rate, residence time, reactor type, etc.)…”