According to media reports, marine scholar Charles Moore said that only us humans can create garbage that cannot be digested by nature. It is reported that in 1997, he discovered the marine garbage zone during the survey of the
Most people think that when marine garbage is usually a plastic product waste that enters the scope of sight. These materials are everywhere. We humans produce about 300 million tons of plastic each year, and about half of them are used at one time, which means that people have finished use. Plastic products will be discarded immediately. Usually most plastic waste is transported to the waste landfill for treatment, but some of these garbage are blown away, entering the river, and eventually flowing into the ocean. In fact, an average of about 8 million tons of plastic pollutants entered the ocean each year, wrapped around the marine life , Polluted coral reefs, eventually degraded by water, wind and sunlight, and decomposed into trillions of small plastic particles.
For many marine species, plastic particles look very attractive and look like food. They will eat marine pollutants. In the end, they starve to death due to lack of nutrition. Eventually, these pollutants were transported into the animal body, and scientists are still continuing to explore the influence of biological influence produced by marine waste. Micro -plastic may also cause harm to humans, because we take them by eating seafood or even drinking water. In 2019, the World Health Organization called for in -depth research to analyze the potential impact of micro -plastic pollution on human health.
The fact that supports all this is: According to the ingredients used by manufacturing plastic, plastic has incredible flexibility, and may never truly degrade biological degradation. In recent years, scientists hope to effectively restore it through microorganisms in the water and soil to effectively restore it as The compounds that can be reused in nature. Considering the plastic pollution in the natural environment, a clearer problem will be formed, such as the disposable plastic waste that enters the ocean may not be degraded for hundreds of years, which will pose a serious threat to the marine environment.
How do we create this persistent plastic crisis? The answer is in the process of making plastic, but first of all, the most important thing is that understanding "plastic" is not just a shopping bag that we imagine in seawater. At present, there are a large amount of plastic garbage fragments in the ocean, and even pollute the underwater environment.
What is plastic?
Karl Ryder, a chemist at
So, if plastic is so different, what do they have in common? They are composed of polymers, and polymers are molecules consisting of many duplicate units. The structure gives many plastic properties, such as: usually flexible, ductility and strength. In addition, plastic is usually divided into two major major major. Class: biological plastic and synthetic plastic, biological plastic polymers come from corn starch, vegetable oil, and bacteria sources. Synthetic plastic is a polymer synthesized with crude oil and natural gas.
Although the biological base polymer sounds very friendly, they do not have a good environmental record, because they may continue to exist in the environment and cannot be degraded. The polymer, not all biological degradable plastics are biological bases. However, the environmental harm caused by oil and natural gas derived materials is very serious, because this type of plastic has a longer time in the environment, and at the same time causes other others environmental impact.
In order to understand the reasons, let's observe an example of an oil -derived plastic: put the milk bottle in the refrigerator for refrigeration. This plastic bottle starts its life course. In fact Crude oil deep in the earth is gathered in high -pressure areas inside the crust. They are transmitted to the surface of the earth through drilling probes and pump devices, and then transported to the refinery through the pipeline. The dense substances of crude oil are composed of hydrocarbons. The hydrocarbons are combined by carbon and hydrogen atoms. They form a chain structure of different lengths and give them different characteristics. These hydrocarbons are the earliest plastic raw materials on the earth.
In the refinery, the production of plastic products has really begun. Crude oil like molasses is heated on the stove. According to the number of atoms contained in the hydrocarbons, and the molecular weight generated by this Nearby distilled pipes. In the distillation pipe, the long and heavier hydrocarbon compounds are deposited at the bottom, while the molecular structure that has a shorter and lighter carbon heavy compounds rises to the top, and the original is ultimately separated into several different chemicals, such as such as several different chemical substances, such as : Petroleum, gasoline, and paraffin, each of which contains a hydrocarbon compound with similar weight and molecular length, one of which is petroleum oil, which will become the main raw material for making plastics.
Petroleum is like gold powder in plastic production, because the hydrocarbon compounds contains ethylene and acrylic. These two compounds are critical to the most common and common plastic products on the plastic. For plastic manufacturing milk bottles, but in order to create substances that can be used to make plastic, ethylene and acrylic must first decompose their hydrocarbon raw materials into smaller units.
There are different methods to do this. One method is to use high temperature and high pressure in zero oxygen environment. This process is called "steam cracking". monomer.
Paial Bachti, a post -doctoral researcher of
In the next step, the study is carried out through a process called polymerization reaction. In the process, those separate monomer components are chemically combined in a new way to produce a long duplicate chain. Ethylene and acrylic form a polyethylene and polypropylene, which are the two most common and most widely produced polymers on the earth.
So why are these two polymers so popular? The structure of polyethylene can be used to make different density plastics, which means that it can be fragile and flexible, or a solid and tough substance, so its purpose is very wide. In addition, the structure of polypropylene also has unique flexibility and elasticity. Therefore, we can see many types of plastic products every day. Polypropylene is mainly used to create disposable plastic products, such as: milk bottle, plastic packaging used in daily life, plastic packaging used in daily life. , Straw, water bottle, shopping bag, shampoo bottle, bottle cap, etc.
However, these are only two of dozens of synthetic plastics. Other types of hydrocarbons are separated and decomposed from different sources. They not only come from crude oil, but also from natural gas. They are also used to make plastics. In some cases, the polymer may be composed of a single single, just like the polyethylene and polypropylene we see, or they may include several types of monomer combinations.
More importantly, each polymer chain will be processed in different ways and mixes with various additives, including: antioxidants, foaming agents, plasticizers, flame retardants, etc., so that they have all kinds of various types Ecological functions, so that plastic becomes so "universal".
Bachti said: "Different plastics have different characteristics. Take food packaging as an example. It should prevent excessive oxygen and sunlight from being degraded. Therefore, it contains additives After the polymer characteristics, the formation of plastic. "
In the end, these plastic industry chains created the diversity of plastic products we have today. They have made great contributions to food production and storage, cosmetics, technology research and development, and medical care.
"Foreign Materials"
Now let us "fast -forward" understand the production process of plastic products. The plastic synthesized from oil and natural gas is to separate the hydrocarbon compounds and decompose them into part of them, and then reorganize these parts in nature. New form. To put it simply, this creates a "external material", which is unfamiliar with microorganisms in the earth water and soil. Bachti explained that the carbon main chain in the synthetic plastic cannot be identified by soil bacteria, which means that this means They cannot be digested and converted them into water and carbon dioxide.
"Landiam said" Polyethylene such as polyethylene needed for a few centuries to decompose in garbage landfills, which means that many things we manufactured in our lives still remain close to the original form. Under the influence of the sun, water and wind, the plastic is gradually decomposed. Plastic products derived from oil and natural gas will release greenhouse gases and return the chemicals added during the production process to return to the environment. We need to pay special attention to the number of disposable plastic pollution. In addition to its persistent destruction of the environment for hundreds of years, the environmental disaster caused by plastic products in the future may be more serious. "
However, there are also ways to get rid of these plastic garbage that accumulated mountains. Ledexia believes that biodegradable plastic is one of the focus of future research. This may be a potential solution. In other words, making biodegradable plastic does not necessarily mean using it. Bio -raw materials such as corn starch are produced (although this may provide a solution), and more specifically, this process needs to be used to make plastic with polymers. These polymers can be reasonably and effectively decomposed by microorganisms in water and soil.
If you want to completely change the impact of plastic on the earth's environment, biological can reduce polymers to replace oily polyethylene and polypropylene, but at the same time, it is necessary to maintain the strength and flexibility of traditional polymers. This is why they are so popular. , But this is a difficult task, because traditional polymers are still competitive in the manufacturing cost, which makes the task more tricky.
However, in recent years, some biological degradable solutions are progressing. One is polystumin, which can be used to make disposable items such as cups, tableware and straws. Once it enters the human living environment, it can more effectively biodegradation. It is believed that as the demand for plastic products has continued to increase globally, such inventions may gradually increase.
There are also positive and optimistic signs in other areas. In 2016, researchers found a kind of bacteria that can eat plastic, and then other people found that worms that can eat polyethylene. In addition, they also found that enzymes that could break down plastic waste.
"Maybe in the next few years, we will obtain plastic decomposition and digestion from these bacteria and worms, and can even break down polyethylene plastic bags to cultivate larger worms, which can swallow our plastic garbage. "
In any case, in the process of making plastics, humans managed to obtain raw materials from nature and completely transformed them so that they could not digest them. This is the predicament caused by human wisdom and wisdom. Now we hope to change all this through research and development of new technologies!
All the above methods of solving plastic problems need to be further developed by science and technology, and there are problems with a certain technical obstacles and costs too high before the general use.
And the best way to solve plastic problems now is to recycling. Multiple utilization of plastic through the steps such as crushing and cleaning granules, which not only protects the environment, but also reduces the cost of plastic use. It is currently the most effective way to solve plastic problems.
RETECH is a creative company focusing on the technology R&D of Plastic recycling machinery solutions.
