The treatment methods of polyethylene waste

The treatment methods of polyethylene waste mainly include the following:

‌ -chemical raw materials recovery method: waste plastics are decomposed into small molecules or oligomers by isolating air and heating cracking, catalytic cracking or enzymatic decomposition, etc., and are used as new chemical raw materials. This process is still being studied on an industrialscale, but is considered to be one of the most promising recycling methods for the future ‌1.

‌ -physical landfill: The waste plastic is buried directly in natural landfills below the surface. Due to the light texture and non-perishable plastic products,the landfill will become soft foundation, causing secondary pollution to the environment ‌1.

‌ -composite modification and utilization method: waste plastics are used for road laying or building materials ‌1 after composite modification with asphalt or building materials by physical method.

‌ -Combustion energy recovery: Waste plastic is burned to convert its heat into electricity or the heat is used in metal smelting. This method is currently

widely used, but it is also an environmentally friendly recycling method if the combustion exhaust gas is treated harmless ‌1.

‌ -mechanical and physical recovery method: the waste plastics are recycled and re-processed by crushing, cleaning, screening and classification, re-granulation and other technological processes, and can be used directly as raw materials or combined with new materials. This is currently the main harmless industrial treatment method and the most environmentally friendly recycling method ‌1.

‌ The latest research advances and technological innovations include:

‌ -University of Science and Technology of China's "hydrogen breathing" strategy: Researchers have devised a method to convert high-density polyethylene plastics into high-value-added cyclic hydrocarbons without the need for additional hydrogen or solvents, providing a new method for the "artificial carbon cycle" of waste plastics ‌2.

‌ -University of Adelaide's oxidation coupled chamber thermo-photocatalytic method: Highly selective conversion of polyethylene waste plastics to ethylene and propionic acid using atomically dispersed metal catalysts, using renewable solar energy, avoiding fossil fuel consumption and greenhousegas emissions ‌3.

These methods and technologies not only improve the recycling rate of waste plastics, but also reduce environmental pollution and promote the development of plastic circular economy.