# Efficient Chemical Recycling of Polyester in Plastic Waste: A Heated High-Ethanol Alkaline Aqueous Process

## TL;DR

A new method efficiently breaks down plastic bottles into reusable components using a heated ethanol and alkaline solution, offering a sustainable recycling option.

## Contribution

The study introduces a catalyst-free, energy-efficient process for chemical recycling of PET under mild conditions.

## Key findings

- Complete PET hydrolysis was achieved in 20 minutes at 90°C using 0.624 g of NaOH/g of PET.
- The process was successfully scaled up with commercial PET bottles and reduced liquid-to-solid ratio significantly.

## Abstract

Plastic waste, especially
from packaging, poses major
recycling
challenges due to the presence of mixed polymers, which often result
in inconsistent blends that are unsuitable for reuse in food-grade
applications. Chemical recycling, particularly alkaline hydrolysis,
offers a promising solution in the case of chemically reactive polymers,
such as polyesters, with poly­(ethylene terephthalate) (PET) being
one of the dominant plastics suitable for both mechanical and chemical
recycling. Mechanical recycling is currently used for the largest
part of PET recycling, due to the fact that turning the polymer back
into its monomeric building blocks requires catalysts, elevated temperatures,
or prolonged reaction times. This study presents a recently developed
Heated High-Ethanol Alkaline Aqueous (HHeAA) process that enables
efficient, catalyst-free PET hydrolysis under milder conditions. Nearly
complete hydrolysis was achieved within just 20 min at 90 °C
using a loading of 0.624 g of NaOH/g of PET. The process was successfully
scaled up with commercial PET bottles, achieving full hydrolysis while
significantly reducing the liquid-to-solid ratio from 20 to just 5
L/kg. These results highlight the industrial potential of the HHeAA
method as a more sustainable and energy-efficient alternative for
PET recycling and chemical reuse and in turn reduced environmental
impact.