0 ITEM
Do you really know anything about biodegradable plastics?
Large-scale forest fires have broken out in the Arctic Circle for the second year in a row, the World Meteorological Organization (WMO) said.
No one could have imagined that the ice and snow of the North Pole would one day break out in flames.
Lightning and hot weather are one culprit and one accomplice in the Arctic's "Song of Ice and Fire" of extreme heat caused by global warming.
We are familiar with the specter of the greenhouse effect, but there is nothing we can do about it.
Compared with the rising sea levels and melting glaciers caused by the greenhouse effect, plastic pollution is also a major problem facing the oceans.
Fortunately, in recent years, the world's awareness of environmental protection has been increasing, the relevant policies and measures have been implemented, and the "plastic limit" has also been upgraded.
At the beginning of this year, the National Development and Reform Commission and the Ministry of Ecology and Environment released the Opinions on Further Strengthening the Control of Plastic Pollution, which further pushed degradable plastics into the spotlight.
However, the vast majority of people who speak of biodegradable plastics are in a state of half-comprehension.
Misunderstanding, green marketing and blind promotion have thrown the market for biodegradable plastics into chaos and hampered its development.
For example, if biodegradable plastics are not collected on a large scale and transported to professional disposal sites that can provide suitable degradation conditions and degradation time, the vast majority of so-called "degradable" materials and their packaging products will not completely degrade naturally in nature in a short period of time.
So, what exactly is biodegradable plastic?
Degradable plastics are degradable in the natural environment such as soil, sandy soil, fresh water environment, seawater environment, specific conditions such as composting conditions or anaerobic digestion conditions caused by the action of microorganisms existing in nature.
And eventually completely degrades into carbon dioxide (CO2) or/and methane (CH4), water (H2O) and their contained elements of mineralized inorganic salts and new biomass (such as microbial dead bodies, etc.) of plastics.
Commonly speaking, it is a plastic that can degrade into environmentally harmless substances under certain environmental conditions after use.
However, many people actually have a misunderstanding of degradable plastic. In their opinion, degradable plastic can not only replace the function of traditional plastic, but also will not have any negative effects. After using it, it can be degraded in a very short time when thrown at home.
But it's not.
Does biodegradable plastic break down quickly in any environment after use?
The degradable external factors are different, some are degraded by the role of sunlight;
Some due to fungi, bacteria and other natural microorganisms respiration or chemical energy synthesis and degradation, eventually decomposed into carbon dioxide and water;
Others are in light, heat, water, pollution compounds, microorganisms, insects, mechanical forces and other natural environmental conditions to reduce the solution.
This means that so-called biodegradable plastics need to break down under certain conditions, which cannot be achieved in any natural environment.
In addition, the rate of complete "natural degradation" is relatively slow, regardless of the degradation method.
If you want it to break down quickly, you have to rely on special facilities.
How do you determine if a material is biodegradable?
There are a series of standards for testing methods both in China and in the world.
Since degradation is related to environmental conditions, biodegradable materials should be clearly marked on the product in which environment they can be completely degraded, and the production standards, materials, ingredients and other information according to them should be clearly identified.
Biodegradable plastics are all made from plants?
There are two sources of biodegradable plastics. One is bio-based, such as directly derived from biomass, such as potato and cornstarch mixtures.
But some of it comes from fossil-based materials.
Does biodegradable plastic waste still need to be separated?
Nature is needed, and not all biodegradable plastics fit together.
Biodegradable plastics have different degradation behaviors under different conditions because of different varieties and different chemical structures.
Biodegradable plastics require a combination of temperature, humidity and microorganisms to fully degrade, producing environmentally friendly substances such as carbon dioxide and water.
If not sorted and recycled, biodegradable plastics can cause environmental hazards that are not too different from ordinary single-use plastics.
Therefore, the use of biodegradable material, does not mean that consumers are free to discard the class products, such products should be like traditional plastic products, unified garbage classification and recycling, carried out in accordance with the appropriate disposal way to recycle and reuse (including physical recycling, chemical recycling and recovery such as compost).
So where does biodegradable plastic fall in waste classification?
Ideally, biodegradable plastics would be recycled separately, followed by industrial composting to ensure that biodegradable plastics can be completely degraded and minimise their impact on the environment.
There is no clear rule on whether biodegradable plastics should be separated into separate recycling bins or thrown into kitchen waste bins to be disposed of with it.
Will the degradation products of biodegradable plastics cause secondary harm to the environment?
The degradability requirement of biodegradable plastics increases the index of heavy metal content;
The ecotoxicity test of composting of compostable plastics was carried out, including plant toxicity test, earthworm toxicity test, etc.
In addition to the degradation performance and heavy metal content of biodegradable soil mulching film, the new international standard also stipulates the ecological toxicity.
At present, biodegradable plastics that meet the standards do not cause secondary harm to the environment after degradation.
In addition, when biodegradable plastics are buried in landfills, most of the modern landfills will adopt some devices that can collect biogas during the landfill process for energy recovery. Even if there is no recycling, there are corresponding measures to release biogas after organic waste landfill.
In general, what you know as degradable plastics may not be truly "fully degradable."
Nor is "biodegradable" an excuse for excessive consumption and waste of resources.
Perhaps more important than material substitution is the substitution of means.
Reducing disposable items and avoiding unnecessary packaging has actually solved many problems.
