KR20240058639A - Sustainable management of plastic wastes in COVID-19 pandemic using biochar - Google Patents

Abstract

The present invention relates to a sustainable plastic waste management method for the COVID-19 pandemic using biochar. Specifically, the present invention relates to a method of producing biochar from plastic waste and a method of pyrolyzing plastic waste. It is about sustainable management of waste. The sustainable plastic waste management method for the COVID-19 pandemic using biochar provided by the present invention can effectively recover biochar from plastic waste, not only improving the environment polluted by plastic waste, but also improving the environment polluted by plastic waste. Biochar can be useful in various industrial fields.

Description

Sustainable management of plastic wastes in COVID-19 pandemic using biochar}

The present invention relates to a sustainable plastic waste management method for the COVID-19 pandemic using biochar.

Plastics had become one of the most common and persistent organic pollutants in marine and terrestrial environments before the pandemic, with an estimated 6.6 billion tons of plastic remaining in landfills or natural environments each year globally, which is more than 20% of annual plastic production. It accounts for 80%. Especially during the pandemic, as the use of plastic increases and lack of effort and interest in using recycled plastic, more plastic waste is being dumped on land and sea.

Marine creatures vulnerable to plastic include sea turtles, marine mammals, and seabirds. The ingestion of plastic by these marine animals increases PCBs accumulated in the fatty tissues and eggs of Great Shearwaters, and when plastic debris settles on the seafloor, it forms a gap between sediment and water. Plastic waste is causing serious problems of destruction of the ecosystem and environmental pollution, as it can disrupt the marine ecosystem by blocking gas exchange.

Accordingly, the seriousness of plastic waste is recognized worldwide, including in Korea, and the development of technology to manage waste is required. However, because waste management costs a lot of money, the economic burden is large.

Therefore, there is a need to develop technologies that can efficiently and economically manage plastic waste, which is continuously increasing in the era of the COVID-19 pandemic.

Republic of Korea Patent Publication No. 10-2016-0019914

Accordingly, the present inventors completed the present invention by developing a method for producing biochar from plastic waste that can be utilized in various industrial applications and a method for managing plastic waste using the same.

Therefore, the purpose of the present invention is to provide a method for producing biochar from plastic waste.

Another object of the present invention is to provide a method for sustainable management of plastic waste, comprising the step of thermally decomposing the plastic waste.

The present invention provides a method for producing biochar from plastic waste.

In one embodiment of the present invention, the method may be performed through thermal decomposition.

The present invention also provides a method for sustainable management of plastic waste, which includes the step of thermally decomposing the plastic waste.

Through the COVID-19 pandemic era, plastic waste is increasing in enormous amounts, and the resulting environmental problems pose a much greater threat to human health and ecological balance than before the COVID-19 pandemic. Meanwhile, the sustainable plastic waste management method for the COVID-19 pandemic using biochar provided by the present invention can effectively recover biochar from plastic waste, which not only improves the environment polluted by plastic waste, but also removes plastic waste from plastic waste. The produced biochar can be useful in various industrial fields.

The present invention relates to a sustainable plastic waste management method for the COVID-19 pandemic using biochar, and is characterized by providing a method of producing biochar from plastic waste.

Pyrolysis and co-pyrolysis of plastic waste is one of the environmentally friendly methods to convert plastic waste into value-added products. Research evidence shows that pyrolysis of biomass and plastic waste yields high bio-oil yields and low yields of biochar. For example, when pine cones and plastics (e.g. low-density polyethylene, polypropylene, polystyrene) are pyrolyzed at 500°C, a large amount of bio-oil is produced due to the synergistic effect of the pyrolysis mixture, and the obtained biochar exhibits higher calorific value. In general, due to negative synergies with the production of biochar, pyrolysis produces less biochar but more volatile products. As a related example, the thermal decomposition of rice husk and high-density polyethylene (HDPE) showed that free radicals derived from rice husk promoted the decomposition of HDPE and the formation of hydrocarbon radicals. Depolymerization, H transfer and initiation through reactions between radicals and secondary radical formation are the main steps involved. Similarly, a negative synergistic effect on biochar production was observed in the pyrolysis of HDPE. Biochar produced by pyrolyzing newspaper and HDPE at 500°C exhibits low oxygen-containing functional groups, high calorific value, high porosity, and high fuel ratio, so it is more likely to be used as a solid fuel and soil adsorbent. Additionally, by manufacturing recycled waste PET plastic bottles into engineered biochar for post-combustion CO2 capture, we have successfully alleviated two important environmental problems - plastic pollution and climate change - simultaneously, and this approach adds to the closed carbon loop from a life cycle perspective. It has been confirmed. This can help achieve carbon neutrality and sustainable plastics management by 2050. In addition, a study has been reported on the characteristics and environmental applications of biochar produced by pyrolyzing biomass and plastic. The cultivation medium and plastic cultivation bags used in the study were pyrolyzed at 550°C, while the feedstock mixture was pyrolyzed at 550°C. The plastic content was found to vary between 0, 0.25, 2.5, 5 and 10%. Increasing the plastic content of the mixture was shown to decrease the yield of biochar and reduce the formation of new surface functional groups such as carboxylate anions, amides, and aromatic groups. Additionally, all biochars produced from the used media and plastics did not show phytotoxicity. However, high phytotoxicity was observed for biochar produced from pyrolysis of mulch sheet feedstock mixtures and soybean crop residues. Phytotoxicity was shown to be significantly reduced after washing the resulting biochar derived from soybean crop residues with a mulch sheet feedstock mixture. Similarly, according to another research report, the results of biochar produced by pyrolysis of dehydrated pork solids and 10% used plastic covering film at 500℃ showed that the surface area and 1H NMR spectrum of dehydrated pork solids showed that biochar and There was no significant difference found only in pyrolyzed biochar of dehydrated pig solids and 10% waste plastic mulch film. It has been reported that pyrolysis of plastic waste with other biomass waste is an environmentally friendly method of processing pig solids and waste plastic covering films, and the pyrolyzed biochar can be used in agricultural applications.

Results of co-pyrolysis of cyanobacteria and plastics (e.g. polypropylene) as a solution to the water crisis showed that biomass and plastic mixtures were pyrolyzed with K2CO3 at different temperatures (e.g. 500-900 oC) and the polypropylene in the mixture was The results were observed to help increase the surface area and pore volume of biochar. Additionally, biochar showed increased methylene blue adsorption. It was found that when biomass (rice straw) and plastic (polypropylene (PP), polyethylene (PE), or polystyrene (PS)) are pyrolyzed at 550°C, carbon content, aromaticity, cation exchange capacity, surface area, and pH increase compared to rice straw biochar. appear. Additionally, co-pyrolyzed biochar showed significantly higher adsorption of 2,4-dinitrotoluene (DNT) (e.g., 10.3 mg/g) due to its high aromaticity and hydrophobicity, and lead adsorption due to its high cation exchange capacity, pH, and surface area. High adsorption (e.g. 62.1 mg/g) was observed. As a result, this study identified that pyrolysis of biomass and plastics is a suitable method to improve the properties of biochar for pollutant adsorption. In addition, another study found trace metals (e.g. Fe, Ni, Cu, Cr, Cd and Pb) in tea derived from waste plastics of polyethylene (PE), polyethylene terephthalate (PET) and polyvinyl chloride (PVC). ) was found to have better adsorption than biochar extracted from bamboo and sugarcane, which appears to be due to the high oxygen content on the surface.

Additionally, converting plastic waste into value-added products such as carbon nanotubes and other carbon nanomaterials (e.g. porous carbon nanosheets) that can be used for CO2 adsorption and other industrial applications could be very useful for the circular economy. For example, according to research results on the production of carbon nanotubes by catalyst-supported chemical vapor deposition by passing a gaseous intermediate of a polymer pyrolyzed at 800°C, the properties and yield of carbon nanotubes depend on the type of catalyst and catalyst pretreatment method ( e.g. pickling and heating to 800°C) and the type of polymer (e.g. polyethylene terephthalate, polyethylene, polystyrene, polypropylene). Catalytic (e.g. Ni-Fe bimetallic catalyst) pyrolysis of plastic waste, including polyethylene and polypropylene, effectively produces H2 and carbon nanotubes. These carbon nanotubes have shown advantageous properties such as thermal stability, high tensile and flexural strength in various industrial applications.

Although the environmental impact of plastic is not fully known, there are many noticeable long-term effects on life on Earth. Therefore, sustainable upcycling of plastic waste is an essential element in slowing the rate of plastic integration into the environment.

Investigation and application of modern approaches can provide tremendous benefits in overcoming environmental threats. The production of biochar can be developed as a highly sustainable solution to mitigate plastic waste generation globally. As discussed above, biochar can be produced by both pyrolysis and pyrolysis of plastic waste, and pyrolysis can serve as a viable route for plastic upcycling with the benefits of energy recovery along with simplicity for fuel and gas production. . More importantly, pyrolysis can minimize the enormous labor costs that must be involved in separating plastics from waste. The controlled operating conditions of pyrolysis can reduce secondary pollution, and the tea produced by pyrolysis can also be activated and used as an adsorbent for metal removal, odor and pollutant removal in wastewater treatment plants. Additionally, several gases such as H2, CO, and CF4 produced by the thermal decomposition of plastics can also be used for energy production.

So far, the present invention has been examined focusing on its preferred embodiments. A person skilled in the art to which the present invention pertains will understand that the present invention may be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered from an illustrative rather than a restrictive perspective. The scope of the present invention is indicated in the claims rather than the foregoing description, and all differences within the equivalent scope should be construed as being included in the present invention.

Claims (3)

How to produce biochar from plastic waste. According to paragraph 1,
A method of producing biochar from plastic waste, characterized in that the method is performed through thermal decomposition. A method for sustainable management of plastic waste, comprising the step of thermally decomposing plastic waste.