Team:TJUSLS China/Human Practices
Overview
As mentioned earlier, the problem of PET waste pollution is becoming more and more serious. It can be expected that if necessary measures are not taken, this problem will become more difficult and even threaten human survival in the next few years. Therefore, we hope to solve this problem through our design. In order to explore the feasibility of our idea, we specially conducted investigation and research to relevant government departments and enterprises.
We chose plastic as our focus, but the variety of plastics made it difficult to choose. For a better view with understanding of the plastic package market, we visited a couple of stores and agencies in a local industry market, where we did some interviews with the businessman. As market research, we have prepared a lot for this activity, including the study of business models and operating conditions.
One of the businessmen friendly shared his thoughts with us, “Recently the PET has been sold much better because of COVID-19. The PET is always a good material for disposable packages, and these kinds of stuff are used in a higher frequency in daily life for consideration of safety and health.” The epidemic promotes the market of disposable goods and also produces more waste, which is a heavy burden on our environment, leading that the recycling PET is a more heated topic on the green economy and scientific technology.
We visited several shopping malls as well as convenience stores to study the scale of PET applied in our daily life. It is a unique viewpoint for us to find the PET in markets, leaving us more thoughts and understandings of the commercial conditions. Milk-tea, an unprecedentedly popular beverage, is flooding the malls and streets. We found that parts of the one-time cups are made by PET, whose quality is really high, while their lifespan is much short. Besides, it is found that almost all plastic bottles in the supermarkets and stores are with a “1” label cycled by a triangle at the bottom, which is a universal sign of PET plastic. The facts in front of our eyes are more impressive than the data and words stated by news.
Based on the above, we chose degradation of PET as our goal.
The PET takes up a certain part of the market and the commercial goods are variant such as package bags, boxes, bottles, and so on. There are also diverse forms like the size and color, and the more important is its quality, which mainly decides the price and its fate.
It is an adventure to find out the process of industry PET recycling in the factory. We have watched the streamlined work steps and listened to the explanation from the officer in a plastic recycling factory. The most popular recycling method is using physical force to break plastic into pieces and particles, even fine, to recomposite them. There are advantages of the traditional method like the production could be reused. However, we cannot be optimistic about the current condition in many respects. The huge energy consumption and pollution of traditional models are critical problems of development. Furthermore, recycling production has limited quality and poor properties compared with the new plastic, which remains the potential of pollution and waste.
We also learned about chemical recycling of PET. Chemical processes produce toxins and contaminated byproducts which is not a good choice either. It is remarkable progress from mechanical power to chemical reactions. And there is still much space to improve.
Therefore, we chose enzyme degradation to ensure that the performance of PET is not damaged during degradation, so we found enzymes such as PETase、LCC、MHETase and etc.
Investigation to Tianjin Ribao Plastic Co., LTD inspired us that plastic commodities have special characteristics from which we had better consider more comprehensively. Inspired by this, we searched the literature for the special characteristics of PET and found that there were two kinds of crystallinity, among which the area with high crystallinity was difficult to be degraded. Therefore, we chose PETase specific PET to degrade high crystallinity. After finding its weak degradation ability, we decided to optimize this part.
Through the research on Tianjin Ribao Plastic Sales Co. LTD and Tianjin Maosheng Renewable Resources Recycling Co., LTD, we learnt that plastic recycling is a technology that can remodel our life by improving convenience and environmental protection. What we are doing is a meaningful step for PET recycling and reuse, from which we can dream of a greener and healthier world.
