An eco-friendly pesticides sponge 

Pesticides are as controversial as they are ubiquitous in farming, illustrating the need for more sustainable practices. Now, KACST researchers have developed a compound that can reduce the impact of pesticides on groundwater poisoning.

Despite continuing criticism of their use, pesticides have important roles in protecting crops from soil-borne diseases and other unwanted flora and fauna that may damage plants and reduce their yield. Their application can entail large-scale waste and pollution, either through toxins dissipating into the atmosphere or leaking into groundwater.

A collaboration of US and Saudi researchers, led by KACST’s Omar Yaghi, developed a new metal-organic framework, or ‘MOF’, that can reduce the volume of pesticides needed and lessen their impact on the environment.

 MOFs act as molecular sponges that can be imbued with a chemical and release it over time. Spraying pesticide-loaded MOFs on farmers’ fields could replace the pumping of toxins directly into the ground, and reduce the environmental impacts.

Yaghi says that, aside from the environmental benefits, their discovery could reduce the financial burden of pesticide use. Using MOFs to carry and release the chemicals would also do away with the need for expensive specialist machinery to disperse pure-form fumigants into soil.

“A slow and controlled release of pesticides has been a long-time goal in agriculture,” says Yaghi.

Publishing their results in the Journal of the American Chemical Society, his team showed that their compound slowed the dispersal of a pesticide by 100 times its standalone rate as a liquid.

To date, more than 20,000 MOFs have been developed, with diverse industrial applications including the storage of gas and the catalysis of chemical reactions. According to Yaghi, his team’s compound is set apart by its environmentally-friendly composition, which, over time, degrades into calcium, lactate, and acetate, all non-toxic to the environment. This enables its use in settings that require non-poisonous materials, such as the food industry and agriculture. 

As well as use in pesticide dispersal, Yaghi says that the MOF can also be loaded with other functional agrochemicals such as fertilizers. As the team’s publication claims the discovery of the first environmentally safe carrier for fumigant pesticides, it’s likely that industry will be keen to see what other novel applications non-toxic MOFs can serve.

1. Yang, J., Trickett, C. A., Alahmadi, S. B., Alshammari, A. S., Yaghi, O. M. Calcium L-Lactate Frameworks as Naturally Degradable Carriers for Pesticides. Journal of the American Chemical Society 139, 8118 – 8121 (2017) | article