Teen Soaks up and Reuses Phosphate as Fertilizer

A teen covered biochar with a thin layer of LDH which attracts and soaks up the excess phosphate and is even able to release it as a fertilizer again.

Stefan Wan, 17, invented a way to reduce the excess phosphate used as fertilizer and reapply it.

Nutrients are used to improve crop yield. However, if too much fertilizer is applied, it runs off in surrounding aquifers and pollutes them.

Stefan’s mother is an engineer and his father is a scientist studying soil. Since he was introduced to chemistry in school, he became passionate about environmental issues.

He presented his invention at the Regeneron Science Talent Search.

The overconsumption of nitrogen and phosphate used to boost plant growth causes a boom in algae growth in nearby waters. This subsequently encourages bacteria growth, as they break down the algae. As they use the oxygen, there is less of it for the fish which may cause them to die.

Stefan used layered double hydroxides (LDH) to stick on biochar, forming a thin layer.

Biochar is charcoal from plant material so it is safe for the environment.

LDHs are chemicals with pairs of positively charged atoms, which attract negatively charged chemicals (phosphate is one of them). LDH on their own are not too efficient as they form a sludge. However, spreading them on biochar, so they take a larger surface makes them better at attracting and removing phosphate.

The chemicals in LDHs that worked best were magnesium and aluminum, in 60% biochar and 40% LDH combination – 95% phosphate saturation is achieved in 1 hour.

To test if his product could release the phosphate back in the soil, he grew lettuce in sand with biochar and used the control test with only sand. He found that the lettuce did indeed contain phosphate.

The product is yet to be tested on farms.

Media

Taxonomy

• Fertilizers
• Soil
• Nutrients Recovery
• Eutrophication
• Fertilizer
• Soil Management
• Fertigation
• Chemicals
• Fertilizer
• Inorganic Chemicals
• Biochemicals
• Nutrient Recovery & Reuse
• Crops

2 Comments

1. Wow! That's really amazing.  I hope this works on a large scale, and that farmers are open to the idea.  Thanks for sharing

2. Thanks