Waste repurposing services clothing, housing and transportation

The "Double Eleven" shopping festival has just passed, and the pleasure of "chopping hands" brought by "buying and buying" has not completely dissipated, and the mountains of express packages already need to "throw and throw".

In recent years, with the surge in online shopping orders, the waste generated by express packaging has also increased. In order to protect the environment and save resources, many enterprises have adopted recyclable packaging or set up waste packaging recycling points to reduce the generation of waste in a variety of ways.

In addition to people's common waste cardboard boxes, there are many things, such as waste plastic, old tires, waste glass, etc., can be recycled. Today, with the help of technology, many wastes are "transformed" and come back to us in another way, making daily life more green and sustainable.

Clothes can be made from plastic bottles

According to statistics, the average use time of a plastic bottle is only 15 minutes, but it takes hundreds of years to completely degrade it. But today, in addition to being buried as garbage and incinerated, plastic bottles have a new destination - becoming raw materials for clothing.

Plastic bottles are usually made from polyethylene terephthalate, which is mainly derived from petroleum. And people often wear polyester fabric in life, its raw material polyester fiber also comes from oil. The two are actually "relatives" with the same root and origin, which also determines that they can achieve mutual transformation with the help of scientific and technological means.

However, the process of turning waste plastic bottles into clothes that can be worn is not simple.

After the plastic bottles are recycled to the factory, they are first sorted and cleaned. After cleaning, the plastic bottle is dried and crushed into small plastic particles, which is the raw material for subsequent processing. These tiny plastic particles are fed into furnaces where they melt at high temperatures and turn into a viscous polyester solution. Then, in a crucial step, the solution turns into filaments five times thinner than a human hair. These filaments are called polyester fibers. The polyester fibers are then woven to turn them into polyester "noodles" that can then be used as raw material for clothing.

This kind of fiber made from waste plastic is called recycled polyester fiber. It has the same physical and chemical properties as the original polyester fiber, and the clothes made of it are also wrinkle-resistant, not easy to fade, not easy to deform, strong and durable, and dry quickly after washing. In terms of the feeling of clothing, this kind of clothing has no significant difference compared with clothes made of raw polyester fiber, and even has better elasticity than the latter.

In addition to waste plastics, waste clothing itself and a large number of scraps generated in the clothing production process can also be recycled.

Spandex and polyester, common in waste textiles, have similar chemical structures. In the traditional recycling method, the catalyst can only degrade the two at the same time, and can not be effectively separated, resulting in the recovery of related materials is difficult, and the recovery rate is reduced. The emergence of bio-enzyme targeting catalysis technology has solved this problem. The technology can depolymerize polyester materials into monomers under mild conditions and completely separate the spandex components. After further purification, the decomposed spandex can be polymerized into polyester fiber for textile.

 This recycling technology can replace some of the spandex production, thereby reducing the use of toxic chemicals. In addition, traditional spandex production consumes a lot of water, and this recycling technology uses a waterless process, which greatly saves water.

Old tires were mixed with asphalt to pave the road

As hard as plastic to break down are used tires. Due to its strong heat resistance, friction resistance and corrosion resistance, the traditional waste tire treatment methods are mostly buried and incinerated. No matter which method is adopted, it will have different degrees of negative impact on the environment. But thanks to technology, even a troublesome old tire can now be a usable resource.

The main components of waste tires are natural rubber and synthetic rubber, and the additives are carbon black, iron oxide, calcium oxide and other components.

For the harmless treatment of waste tires, the current international practice is to make them into rubber powder, and then further use it.

However, in recent years, there is a new method, that is, asphalt is mixed into the waste tires after processing, and it is used as a raw material to lay the road.

To pave the road with waste tires, we must first turn the waste tires into rubber powder. The rubber powder produced by the normal temperature crushing method (by pulling it to break) will form some "antennae" on the broken surface. These "antennae" then expand after absorbing the light components of the asphalt. When the amount of asphalt is incorporated to a certain extent, these expanded "tentacles" can be connected together. The connections between the "antennae" will form a stable three-dimensional spatial network structure, which can improve a number of properties of asphalt.

For example, after adding rubber powder, the viscosity of asphalt can be greatly improved, thus significantly improving its resistance to high temperature deformation. In addition, the addition of rubber powder can also reduce the low temperature brittleness of asphalt, so that its low temperature fracture deformation capacity is nearly 7 times higher than that of ordinary asphalt.

Therefore, adding the treated waste tires into asphalt can not only effectively solve the problem of waste tires treatment, but also significantly improve the performance of asphalt pavement materials, reduce the cost of modified asphalt, and have strong economic and social benefits.

According to Wang Jiaqing, associate professor of the College of Civil Engineering of Nanjing Forestry University, the team conducted a test in the simulated section of Lianxu high-speed (G30), which showed that the waste tire rubber powder was incorporated into the asphalt and 200 kilometers of pavement could reduce carbon emissions by nearly 3,000 tons.

Waste glass replaces sand in building

Glass is a common material in life, from small glass bottles to large glass curtain walls. The ubiquitous glass materials add convenience to life at the same time, but also create a large number of difficult to deal with glass waste. Rational use of these waste glass, not only can obtain economic benefits, but also can solve the environmental problems caused by waste glass.

In recent years, waste glass grinding powder has been used more and more in the field of concrete because of its low cost and good mechanical properties.

As a highly used building material, concrete is mixed with particulate matter of different sizes. Previously, this particulate matter was usually sand, but now it can also be waste glass dust.

The main component of glass is silicon dioxide, and sand is also composed of silicon dioxide, which makes glass have the possibility of replacing sand. The researchers crushed the glass waste into five different sized pieces: coarse, medium, fine, ultrafine and dusty, which were used in place of sand normally used as concrete aggregate.

The experimental results show that adding glass powder can improve the working performance of concrete and increase slump (plasticizing and pumpability of concrete). The compressive strength of concrete mixed with glass powder is higher than that of ordinary concrete without glass powder. The researchers also loaded concrete containing waste glass ground powder into a 3D printer and successfully printed a concrete object 40 centimeters high. During the entire printing process, the concrete can easily flow through the printer nozzle, there is no blockage and other phenomena, and the concrete does not deformation or collapse before curing.

Adding glass powder to concrete instead of sand has another advantage. Since glass is much less absorbent than sand, concrete mixed with glass powder also requires less water during production. Using glass powder instead of sand to make concrete not only makes a lot of waste glass that has nowhere to be placed useful, but also saves the increasingly scarce sand resources, bringing significant economic and social benefits.