Estimate the concentration of microplastic in sea water

Hello everyone

It is my fisrt time here, so be gentle =)

I'm building a system to estimate the concentration of microplastic in a tank full of sea water. The concentration of plastic will increase over time, as the water is filtered and return plastic free to the sea. When a concentration is reached, the plastic will be drained from the tank.

I am still in the comceptual phase, before making a new sensor for that, I'd like to know if there are products available to use or to at least help validate some hypothesis.

There are a few parameters I am considering to estimate the concentration of plastic in salt water: thrust, capacitancy and voltage drop. Please few free to sugegst any other as well as what I can use to do so.

Thanks

You need to read whatever scholarly articles there are about detection of microplastic.

Pete

I've tried that! Believe it or not, there aren't many useful stuff out there on the topic.

If other ideas come up, please do no hesitate

If scholarly articles don't help, you're very unlikely to get any better help here in the Arduino forums.

Pete

What concentrations are we talking? Capacitance won't work in a conducting fluid with a very
large unstable dielectric constant!

As for voltage drop and thrust can you explain what you are thinking? Conductivity of sea water is totally
dominated by ion concentration, chelating agents and temperature I suspect.

Thinking about it C13 NMR would be a good way to detect non-CO2, non-carbonate
organic molecules, but I've no idea how sensitive it would be with a dilute sample, nor how
expensive!

Let me ask a stupid question. How do you know there is ANY plastic in the sea water? How you answer that question will also tell you how to determine the concentration.

Paul

How are you filtering the plastic out of the water?

Humans are great at sorting out materials. A human with a microscope is probably your only option.

The following is nonsense:

There are a few parameters I am considering to estimate the concentration of plastic in salt water: thrust, capacitancy and voltage drop

How big are the particles. Could you use light scattering?

We got good results measuring the electric resistance of the solution. Some more investigations still has to be done, but an ohm-meter is all we need so far!

Thank you all for the help =)

zuanazzi:
We got good results measuring the electric resistance of the solution. Some more investigations still has to be done, but an ohm-meter is all we need so far!

Thank you all for the help =)

So a change in salinity tells you there is more plastic in the water?

Paul

Well for high concentrations you get steric hinderence effects, but you have to calibrate for baseline salinity
which means comparing to filtered water I think.

Wow - there is a team at my school that has used my FTIR instrument this semester to detect plastic content in pond water. I can pass your contact information to the PI if you'd like.