Question

research proposal for the removal of micro plastics from water

discussion:

chemical analytic method for cost effective reduction

Answer 1

a) Micrplastics could be removed from water by using magnentite powder and oil.  Magnetite is freely avialable and environmetally benign. It is a natural chemical.

Oil is added to a suspension of microplastics. The volume of oil used is 5ml to 10ml per liter of water.Since plastic and oil, both are nonpolar, microplastic particles migrate to the oil phase. Then, magnetitie power is added. This leads to a ferro fluid containing magnetite powder, oil and microplastics. Since the ferro fluid has ferromagnetic properties i.e. getting attracted towards a magentic field, it can be easily separatied using strong magnets.

85% separation of microplastics can be achieved by using this method.

The microplastics that can be separated by this method include PVC, PP,, HDPE and PTFE.

Other methods to remove microplastics from water include :

• Granular Activated Carbon (GAC) faucet filters: Will remove some but not all microplastics.
• Carbon Blocks faucet filters:
• Reverse Osmosis filters: Can filter down to to 0.001 micron so will remove all known microplastics, but are more expensive and require maintenance.

Compared to these methods, the magnetite method is most efficient and the cost is lower since all the magnetite and oil is recovered when the ferro fluid is separated from water.

b) The method for analysis of micro plastics are:

1) Spectroscopy

2) Microscopy

In spectroscopy, the suspension of micro plastics in water is analysed using beer-lambert law. Light is passed through the suspenson and the absorbance of the suspension is measured. Beer Lambert Law states that the concentration of a sample is proportional to the absorption of light at a chosen wavelength. Thus, the absorption gives concentration of microplastics in water.

In microscopy, a digital microscope is used to photograph the suspension of microplastics in water. The photograph is divided into pixels. The amount of microplastic particles per pixel before and after the treatment is counted.