Plastic waste turned valuable chemicals with sunlight

A global team of experts dedicated to groundbreaking research has pioneered a method to repurpose polyethylene waste (PE), transforming it into valuable chemicals through light-driven photocatalysis.

Professor Shizhang Qiao, Chair of Nanotechnology and Director of the Center for Materials in Energy and Catalysis at the School of Chemical Engineering, University of Adelaide, led the team. Their findings, featured in the journal Science Advances, highlight the successful upcycling of polyethylene plastic waste into ethylene and propionic acid with remarkable selectivity, thanks to atomically dispersed metal catalysts.

The innovative approach utilized an oxidation-coupled room-temperature photocatalysis method, converting waste into high-value products, primarily propionic acid with an impressive 99% selectivity. Notably, this method avoids the complications associated with producing complex products requiring separation. Harnessing renewable solar energy, the team sidestepped traditional industrial processes reliant on fossil fuels and emitting greenhouse gases.

The waste-to-value strategy hinged on four key components: plastic waste, water, sunlight, and non-toxic photocatalysts leveraging solar energy for the reaction. A typical photocatalyst in this process featured titanium dioxide with isolated palladium atoms on its surface.

Given the prevalent disposal of plastics into landfills, especially polyethylene, one of the world’s most widely used plastics, the team’s work tackles a critical environmental issue. PE finds extensive use in daily items like food packaging, shopping bags, and reagent bottles, forming a significant portion of global plastic waste.

Professor Qiao emphasized the untapped potential of plastic waste as a recyclable resource. While catalytic recycling of PE waste faces challenges due to chemical inertness and side reactions from complex reactant molecules, the team’s approach provides a sustainable alternative. Unlike current chemical recycling methods operating at high temperatures exceeding 400°C, their process addresses contemporary environmental and energy challenges.

Ethylene, a crucial chemical feedstock, and propionic acid, sought after for its antiseptic and antibacterial properties, are valuable products derived from this process. The team’s work not only contributes to a circular economy but also holds promise for future scientific research, waste management, and chemical manufacturing.

Professor Qiao highlighted the broader impact of their research, presenting a green and sustainable solution to simultaneously combat plastic pollution and generate valuable chemicals from waste. The findings inspire the development of high-performance photocatalysts for solar energy utilization, advancing solar-driven waste upcycling technology.

Source: University of Adelaide

Leave a Comment