Category Archives: Chemistry in the news

Image

CRUCIAL PLANT NUTRIENT RUNNING OUT : PHOSPHOROUS

Are we at the risk of global starvation? Scientists at the Global Phosphorus Research Initiative predict that in 30-40 years, there won’t be enough mined phosphorus to feed the planet.  

Nations around the world have committed to ensuring food security in alignment with UN Sustainable Development and Millennium Development goals. Exponential population growth, evolution of societal food habits, disproportionate fertilizer usage and absence of phosphorous recycling practices from organic waste has diminished our supply and put us at risk of a global food scarcity. 

Phosphorus Rock Remaining                                  Image Credits: Phosphorus Futures

From the composition of your DNA and bones to plant biomass, this overlooked element is a vital ingredient for survival of organisms. 

Phosphorous based fertilizers sparked the “Green Revolution”, which improved crop yields to feed the 4.2 billion population rise since 1950. The global demand for phosphorus is forecasted to rise by 50-100%. 

Alterations in food habits such as increased preference of dairy and meat-based diets over plant material, has put a strain on phosphorus demands. Studies show that livestock requires double the phosphorus for plant fecundation.

Historically, phosphorus enriched human detritus, decaying plant matter and manure was an  added stimulant for crop yields. Urbanization and innovation of household flush toilets meant human excreta was now disposed in water bodies and waste facilities.

Distribution of World Phosphorous Image credits : Phosphorous Futures

Currently,  the dominant reserves of phosphorous are exclusive to US, China, Morocco, Jordan and South Africa, leaving the mineral trade subject to international and geopolitical influences.

China has levied 135% duty on its phosphorus exports to secure its own domestic supply of the mineral. Morocco is subject to sanctions due to its transgressions of human rights. USA’s primary reserves in California are projected to dry up in approximately 30 years, whereas western European nations and India are utterly devoid of the element, forcing all three regions to heavily rely on imports.

An integrated global effort is imperative to resolve the phosphate scarcity.

Urbanization has birthed population dense cities brimming with phosphorus hotbeds since humans excrete nearly 100% of the phosphorus they consume, yet, only 10% of the waste is recirculated for fecundation. Government initiatives are in motion in European countries and China to extract the mineral from sewage treatment facilities. 

Furthermore, only 50% of phosphorous produced by animal waste and 40% of food residues is agriculturally recirculated. There is increasing movement to minimize phosphorus losses by recycling  plant and animal byproducts for soil nourishment.

Societal changes in food habits, such as ingesting more plant intensive diets and diminishing food wastage, are crucial in avoiding the impending calamity of food insecurity.

Video attributes: https://www.youtube.com/watch?v=Y17HqUsaoj8

References

Elser, J; White, S. Peak Phosphorus, and Why It Matters. Foreign Policy. 2010 

Cordell, D.; Drangert, J.-O.; White, S. Global Environmental Change 2009, 19 (2), 292–305.

Weavable Light-Emitting Fibers for Wearable Electronics

Integration of electronics into textiles (e-textiles) has emerged as a promising new technology because it can offer tremendous possibilities in many fields of science and fashion, leading to new applications and products.

Organic light-mitting fibers woven into knitted clothes. Source: The Korea Advanced Institute of Science and Technology (KAIST)

Numerous studies have been dedicated to developing the organic light-emitting fibers for wearable electronics. However, conventional fibre-based light emitting devices have limitations of their much lower emission performance compared to those fabricated on flat substances. So, a research team led by Professor Kyung Cheol Choi in the School of Electrical Engineering at Korea Advanced Institute of Science and Technology (KAIST) in South Korea has developed a simple and cost effective solution which is a fabrication technique, using a low-temperature process. Using their technique, the team successfully fabricated the thin and flexible fibre-based organic light-emitting diodes (fiber OLEDs) without any reduction in performance.

A video below briefly introduces OLED fibers. See source here.

https://www.youtube.com/watch?v=J9keKez6ryY

In the manufacturing process, eliminating the high temperature and vacuum processes is crucial since fibers such as cotton, polyester, nylon are thermally delicate. So, the research team used a thermal annealing and dip coating method in cylindrical fibers at as low temperature as possible. 

The team also designed the structure of fiber OLEDs to improve the electron injection efficiency on the fibers and to employ a low-temperature thermal annealing processable cathode, which significantly impacts on its performance. According to the researchers, their revised structure clearly exhibited high luminance and current efficiency compared to those of previously reported fiber-based OLEDs. In addition, the dip coating method at low temperature improved surface roughness and sufficiently ensured the device stability without any planarization layer.

Moreover, the technology demonstrates the scalability of the proposed fabrication scheme with diameter ranging from 300μm to 90μm, thinner than human hair. The research team ensured that the fiber OLEDs could be weavable into textiles and knitted clothes without any reduction in emission performance because their inherent empty spaces and the wavy structures enhance flexibility and stress distribution of the OLEDs.

Fiber OLEDs with different diameters. Source: The Korea Advanced Institute of Science and Technology (KAIST)

Professor Choi emphasized the versatility for application on delicate fibers by stating that the technology to incorporate display screens into our clothing is now a reality, and organic light-emitting clothes will have a significant influence not only on the e-textile industry, but also on the automobile and healthcare industries.

A video below briefly shows how wearable e-textiles may be used in future.      See source here.

Reference:

  1. Seonil Kwon, Hyuncheol Kim, Seungyeop Choi, Eun Gyo Jeong, Dohong Kim, Somin Lee, Ho Seung Lee, Young Cheol Seo, Kyung Cheol Choi. Weavable and Highly Efficient Organic Light-Emitting Fibers for Wearable Electronics: A Scalable, Low-Temperature ProcessNano Letters, 2017; 18 (1): 347 DOI: 10.1021/acs.nanolett.7b04204
  2. The Korea Advanced Institute of Science and Technology (KAIST). (2018, January 10). Fiber OLEDs, thinner than a hair. ScienceDaily. Retrieved January 15, 2018 from www.sciencedaily.com/releases/2018/01/180110101019.htm
  3. The Korea Advanced Institute of Science and Technology (KAIST). (2017, September 4). Light-emitting fibers for wearable displays. AsianScientistNewsroom. Retrieved January 15, 2018 from https://www.asianscientist.com/2017/09/tech/oled-flexible-wearable-display/

-Subi Kim