The significance of recycling waste plastic
The consumption of plastics in China has been increasing year by year, with the apparent consumption of polyethylene and polypropylene reaching 15.8 million tons in 2003 and 26.85 million tons in 2010. As of 2003, China’s plastic processing volume had reached 17 million tons. Nearly half of plastic products become waste plastics after about two years of use, accounting for about 10% of solid waste. Waste plastics are stable under natural environmental conditions, not easily degradable, and have a serious impact on the environment.
Plastic has excellent chemical stability, corrosion resistance, electrical insulation, thermal insulation, excellent shock absorption and sound insulation effects, and has good elasticity. It can bond well with other materials such as metal, glass, wood, etc. and is easy to process and shape. Among the four major industrial materials, the quantity, function, status, and application range of plastics have rapidly expanded, leading the way and replacing metals, wood, paper, and other materials in large quantities. Plastic, a chemical raw material that can be molded arbitrarily and has excellent performance, is carrying modern technology trains and is increasingly widely used in every aspect of our lives. However, while plastics provide us with convenience, they also have certain negative impacts on the environment. Due to the corrosion resistance and non decomposition properties of plastics, especially disposable plastic packaging waste and plastic agricultural film, visual pollution caused by people’s indiscriminate disposal, known as “white pollution”, has become a source of soil pollution for some land use films buried in the soil. The potential harm caused by buried plastic waste to the environment is also known as potential pollution. Some animals eventually die due to ingestion of plastic film that cannot be digested by them, known as direct pollution.
Countermeasures for the treatment of waste plastics
Countermeasures for the treatment of waste plastics: reduction, recycling, and degradation of materials
The treatment of waste plastics needs to follow the principle of reduction, mainly through compression and volume reduction technology for waste plastics, film bag container technology, and thinning technology for products as much as possible while ensuring application performance; Improve product aging resistance, extend lifespan, multifunctionality, and appropriate product design, without excessive use of plastic parts; Without industrial waste, plastic waste is inevitably generated in all processing plants that produce plastic products. These wastes come from the operation and parking of processing machinery, unqualified products, etc. This type of material is defined as’ industrial waste ‘. Following the principle of resource reuse, the main methods include melt regeneration, thermal cracking, energy recovery, recycling of chemical raw materials, and other techniques. Following the principle of material degradation, fully biodegradable materials, water-soluble materials, and edible films. Although biodegradable materials can solve the pollution of waste plastics, they cannot recycle energy.
Disposal methods for waste plastics: Currently, three main methods are landfill, incineration, and recycling
Due to different national conditions, each country has its own differences. The United States mainly relies on landfilling, while Europe and Japan mainly rely on incineration. Landfilling treatment, due to the small weight, large volume, and non perishable nature of plastic products, can result in the landfill site becoming a soft foundation that is difficult to utilize in the future. Incineration treatment, as plastic is a high calorific value macromolecular material with high heat generation, is prone to damage the furnace. In addition, the gases produced after incineration can promote global warming. Some plastics also release harmful gases during incineration, polluting the atmosphere and being the culprits of harmful chemicals and chlorine gas. The method of recycling and reusing, due to its labor-intensive nature, high recycling costs, and lack of corresponding recycling channels, currently accounts for only about 15% of the world’s total plastic consumption.
The plastic waste generated annually in a medium-sized city can meet the raw material needs of 20 small and medium-sized plastic enterprises. Waste plastic resources are referred to by modern economists as the “second mineral deposit of humanity” and the “treasure in the city”. If the amount of plastic waste reaches 4 million tons, it is equivalent to the plastic production of four sets of one million ton polyethylene plants, and one million tons of polyethylene requires millions of tons of oil refining to provide raw materials. Oil and coal are scarce non renewable resources, and from the perspective of conserving Earth’s resources and protecting the environment, the recycling and reuse of plastics is of great significance. To this end, countries around the world are currently investing a large amount of manpower and material resources to develop key technologies for the recycling and utilization of waste plastics, and are committed to reducing the cost of plastic recycling and developing suitable application areas.