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Coffee grounds can be turned into a semiconductor wastewater purification material
- Date : 22-12-05
- Views : 430
- KIST develops nano filter manufacturing technology for heavy metal removal using coffee grounds
- 150,000 tons annual domestic waste recycling path opened
Only 0.2 % of the coffee beans used to make a cup of coffee become the actual coffee we drink, whilst the remaining 99.8% of the coffee grounds are thrown away. The amount of coffee waste generated this way is equivalent to approximately 150,000 tons per year in Korea alone. When coffee grounds are landfilled, greenhouse gases are generated and furthermore, when they are incinerated large volumes of carbon are generated. This poses a significant environmental issue, and as a result, a new method of recycling this to make a semiconductor wastewater purification material has been developed.
The
Korea Institute of Science and Technology (KIST, President Seok-Jin Yoon)
announced that Dr. Min Wook Lee’s research team at the Functional Composite
Materials Research Center, in collaboration with Professor Young-Gwan Kim’s
research team at the Department of Chemistry at Dongguk University, have
succeeded in developing a nanocomposite filter for the removal of copper ions,
by combining coffee grounds discarded as household waste with biodegradable
polymers.
Heavy
metals in semiconductor wastewater can cause fatal damage to major human organs
such as the kidneys, liver, and brain, whilst emissions have also increased due
to the increase in recent semiconductor production. This explains why
purification technology that can allow the effective removal of heavy metals,
including copper, in semiconductor waste is needed.
Since the surface of coffee grounds not only has a porous structure, but also consists of various functional groups with negative charges, it can be used to adsorb positively charged heavy metals in wastewater. However, since existing research has used methods such as dissolving coffee grounds in water, one limitation was that the used coffee grounds had to be collected again. Utilizing the composite material technology possessed by the KIST Jeonbuk Branch, the research team was able to collect coffee grounds in the commonly used capsule coffee and uniformly compounded them in a solvent with PCL (Poly Capro Lactone), a biodegradable plastic, without a specific pretreatment process such as washing or removing impurities. Then, this composite solution was electrospun to construct a nanocomposite filter composed of coffee grounds and biodegradable polymers in a very dense and uniform conformation. Within 4 h, the resultant material could achieve a heavy metal removal efficiency of 90 % or more from wastewater with an initial concentration of 100 μM (micromolar), whilst satisfying the drinking water standards. With one coffee capsule (approximately 5g), a nanocomposite filter capable of purifying approximately 10 L of wastewater could be manufactured.
Dr. Min-Wook Lee of KIST stated, “This research is meaningful in that it developed an economical and environmentally friendly water treatment technology by simply making composite materials from waste, which is the cause of environmental pollution,” he continued, “In the future, we plan to surface-treat coffee grounds or explore other natural materials to develop various filters that are environmentally friendly and have high performance.” The results of this research are expected to not only lead the semiconductor process, which is a key national industry, but also to suggest solutions for problems that the coffee industry has been struggling with, and lead global environmental issues.
This study was conducted with the support of the Nano·Material Technology Development Program (Material Innovation Leading Project) of the Ministry of Science and ICT and the Carbon Reducing Petroleum Raw Material Alternative Chemical Process Development Project of the Ministry of Trade, Industry, and Energy. The research results were published online in the latest issue of Journal of Water Process Engineering (IF: 7.34, top 7.5 % in JCR field), an international academic journal in the field of water resource treatment.
[Figure 1] Conceptual diagram of the nanocomposite filter
Schematic diagram of the
process in which heavy metal ions contained in semiconductor wastewater are
removed through a nanocomposite filter and become drinking water. This
expresses the process of the rebirth of coffee grounds into a nanocomposite
filter
[Figure 2] Nanocomposite filter micrograph
A composite filter made of
Polycaprolactone (PCL) fibers and coffee particles