As one of the three major synthetic materials, synthetic resin (i.e. plastic) is a synthetic material with a large production and consumption. At the China Synthetic Resin Industry Development Conference and 2018 New Materials Development Trend Forum held in Xi'an in early November, the recycling of waste plastics became a hot topic among experts and scholars attending the conference.

Waste plastic has threatened the living environment

Du Huanzheng, President of the Plastic Recycling Branch of the China Synthetic Resin Supply and Marketing Association and Professor of Tongji University, introduced that in the past 50 years, the global plastic usage has increased by 20 times, and will double again in the next 20 years. It is expected that the global plastic production will reach 1.124 billion tons by 2050. At present, China's plastic production and consumption both rank first in the world, with production accounting for 28% of the total global production.

But plastic is also a double-edged sword. The contradiction between human economic activities and the ecological environment is becoming increasingly prominent due to the large production and consumption of waste plastic, which has seriously threatened the living environment of humanity. Du Huanzheng said with concern that more than 8 million tons of plastic waste enter the ocean every year, causing serious impacts on marine life, fisheries, tourism, and even humanity itself, with economic losses of up to 8 billion US dollars. Every year, millions of seabirds and hundreds of thousands of marine mammals die as a result.

For example, Du Huanzheng said that the sea area between California and Hawaii in the United States has formed a "Pacific Garbage Island", a giant "plastic vortex" garbage dump with an area equivalent to two Texas states and four France states. After being swallowed by marine animals such as fish and turtles, these plastic waste will produce a large amount of toxins, which eventually enter the human food chain through the bodies of marine organisms and birds.

Du Huanzheng also proposed the concept of "Marine PM2.5". 'Marine PM2.5' mainly comes from primary microplastics and secondary microplastics. Plastic particulate industrial products enter the ocean through rivers or sewage and decompose into smaller particles under natural action, or plastic waste is broken and decomposed under wind, waves, ultraviolet radiation, and biological effects, "Du Huanzheng told reporters.

The mainstream processing method is not scientific

In terms of waste plastic recycling recycling, the average recycling rates of waste plastics in Germany, the United States and Europe are 60%, 50% and 45% respectively; China accounts for only 25%, and approximately 14 million tons of waste plastic are not recycled annually, resulting in a direct resource waste of 28 billion yuan.

"Waste plastic is a resource misplaced and has great recycling value. Therefore, it should be dredged rather than blocked. It should be recycled rather than prohibited." Wang Qi, an academician of the CAE Member and professor of Sichuan University, said that if 15 million tons of waste plastic can be recycled every year, it would be equivalent to using 30 million to 40 million tons of crude oil less, reducing carbon dioxide and sulfur dioxide emissions, and saving 70% of energy consumption.

At present, the commonly used recycling methods include chemical and physical methods, which are collected, roughly classified and selected, simply cleaned and crushed, and then granulated for recycling. Wang Qi admitted, but some materials are difficult to recycle, such as blended composite polymer materials with complex components that are difficult to classify and separate; Crosslinked waste plastics are insoluble and non fusible, making it difficult to reprocess and reuse due to their inability to undergo thermoplastic processing. At present, the cumulative amount of waste plastic worldwide reaches 6.3 billion tons, with only 9% recycled, 12% incinerated, and 79% buried or accumulated in the natural environment. This not only seriously pollutes the environment but also wastes resources.

Du Huanzheng stated that the main methods currently used for landfill and incineration of waste plastics are unscientific, wasting resources and damaging the environment. The recycling of waste plastic recycling in China is facing serious problems such as the lagging behind of classified recycling and the confusion of recycling channels. The legislation on the recycling of plastic wastes needs to be strengthened and improved, and the systematic recycling system needs to be established.

It is reported that the new technology and equipment developed by the State Key Laboratory of Polymer Materials Engineering of Sichuan University can efficiently recycle waste plastic and rubber, turn waste into treasure, and make full use of resources. At present, they are being industrialized and popularized.

Both technology and business models require innovation

Wang Qi told reporters that measures such as policy guidance, enhancing citizens' environmental awareness, and establishing effective recycling mechanisms must be taken to comprehensively and comprehensively control waste plastic pollution in the synthesis, processing, application, and waste treatment processes.

Du Huanzheng also believes that the recycling of waste plastics requires innovative policies, technologies, and business models. Through reduced use, resource recycling, and biomass substitution, plastic zero waste can be achieved. He suggested the establishment of an Extended Producer Responsibility (EPR) system, which means that producers bear resource and environmental responsibility for their products, extending from the production process to the entire lifecycle of product design, circulation and consumption, recycling, waste disposal, and other aspects. Through EPR, relevant stakeholders such as enterprises, governments, and consumers can be connected, clarifying the rights and responsibilities between stakeholders, and playing a positive role in promoting the development of the waste classification and resource recycling industry.

It is reported that China has included the recycling and utilization of waste polymer materials as a strategic emerging industry, and has introduced the "Medium and Long Term Plan for the Construction of Renewable Resource Recycling System (2015-2020)" and "Solid Waste Pollution Prevention and Control Law (2018)". The "Industrial Norms and Conditions for Comprehensive Utilization of Waste Plastics" issued by the Ministry of Industry and Information Technology have determined the entry threshold for three major categories of enterprises, among which the annual waste plastic treatment capacity of newly built enterprises in the PET recycled bottle and sheet category is not less than 30000 tons; Newly established enterprises engaged in the crushing, cleaning, and sorting of waste plastics have an annual waste plastic processing capacity of no less than 30000 tons; The annual waste plastic treatment capacity of new enterprises engaged in plastic recycling and granulation shall not be less than 5000 tons. In terms of resource utilization, it is required that the comprehensive electricity consumption in the production process related to plastic recycling should be less than 500 kilowatt hours/ton of waste plastics, the comprehensive water consumption of PET recycling bottle sheet enterprises and waste plastic crushing, cleaning, and sorting enterprises should be less than 1.5 tons/ton of waste plastics, and the comprehensive water consumption of plastic recycling granulation enterprises should be less than 0.2 tons/ton of waste plastics.