Pollen and spores could be used to remove pollutants from water

With a simple treatment pollens and spores can be converted into tiny sponge-like particles that can grab on to pollutants and remove them from water, suggests a study.

"Even very low levels of certain compounds, such as hormones, pharmaceuticals or those in household and personal care products, can cause toxic effects. However, they often can escape normal cleanup processes at wastewater treatment plants," said Andrew Boa, whose lab is working on the pollen project.

The study will be presented at the 'American Chemical Society Fall 2019 National Meeting.'

The spore grains used in the study are extracted from Lycopodium clavatum -- the common club moss. In their natural state, each of these microscopic grains carries genetic material inside a hard shell that's coated with an outer layer of wax and proteins, explains Aimilia Meichanetzoglou, a doctoral student in Boa's lab at the University of Hull.

Boa developed the original method to form non-allergenic, hollowed-out pollen and spore shells. Mackenzie's company uses the inert shells to encapsulate active ingredients for controlled release in pharmaceutical, food, cosmetic and medical applications.

Boa has taken the concept in an entirely different direction. When he and Meichanetzoglou were studying the empty shells' interactions with a variety of chemicals, they noticed that some of the compounds became adsorbed, or stuck to the surface of the shells. Boa realised this stickiness could potentially be used to grab low levels of pollutants, and so he pursued this type of application.

Meichanetzoglou used hydrolysis to rid the pollen of its genetic cargo and waxy coat, which makes the grains hypoallergenic. To target particular pollutants, she can vary the hydrolysis conditions and make modifications to the surface of the grains.

The researchers found that the grains could remove almost all of the phosphate from water samples and nearly 80 per cent of several other pollutants.

Treating wastewater will require consideration of various factors, such as scale and the degree of contamination. For example, homes that use a septic tank; particular buildings with a high level of pharmaceuticals in their wastewater, such as hospitals or care homes for the elderly; or municipal wastewater treatment plants that serve a whole city will all have different requirements. Boa is exploring options with local water authorities for the implementation of this technology.