Uv Light Causes Structural Changes in Microplastics Exposed in Biosolids

24 Pages Posted: 16 Feb 2022

See all articles by Somayye Sadat Alavian Petroody

Somayye Sadat Alavian Petroody

Shahid Beheshti University

Seyed Hossein Hashemi

Shahid Beheshti University

Luka Škrlep

Slovenian National Building and Civil Engineering Institute

Andrijana Sever Škapin

Slovenian National Building and Civil Engineering Institute

Cornelis A.M. van Gestel

VU University Amsterdam

Abstract

Biosolids (biological sludge) from wastewater treatment plants are an important source of microplastics (MPs) emission into the environment. Weakening the MP structure before their entering the environment may accelerate their degradation and reduce potential environmental exposure. We therefore studied the effect of UV-A and UV-C, applied at 70°C, on three types of MPs, polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), commonly found in sewage sludge, using three shapes (fibers, lines, granules). The MPs were exposed to UV radiation in biosolids suspensions, and in air and in water as control. Structural changes and degradation of the MPs were investigated using Attenuated Total Reflectance - Fourier Transform Infrared Spectrometry (ATR-FTIR). UV exposure led to the emergence of carbonyl and hydroxyl groups in all PP samples. In PE and PET these groups were formed only in the biosolids suspensions. The presence of carbonyl and hydroxyl groups increased with increasing exposure time. Overall, UV radiation had the greatest impact on the MPs in the biosolids suspension, probably due to the presence of organic matter and its water content. Fibers were more degraded than the other two plastic shapes, probably due to their higher surface-to-volume ratio. UV-A was slightly more effective in degrading the MPs than UV-C. These findings show that ultraviolet radiation in combination with an elevated temperature affects the structure of polymers in wastewater biosolids which can accelerate their degradation after entering the environment.

Keywords: Microplastics, Degradation, hydroxyl, carbonyl, ultraviolet light

Suggested Citation

Alavian Petroody, Somayye Sadat and Hashemi, Seyed Hossein and Škrlep, Luka and Sever Škapin, Andrijana and van Gestel, Cornelis A.M., Uv Light Causes Structural Changes in Microplastics Exposed in Biosolids. Available at SSRN: https://ssrn.com/abstract=3981579 or http://dx.doi.org/10.2139/ssrn.3981579

Somayye Sadat Alavian Petroody

Shahid Beheshti University ( email )

Velenjak
Bostan
Tehran, 19839
Iran

Seyed Hossein Hashemi

Shahid Beheshti University ( email )

Velenjak
Bostan
Tehran, 19839
Iran

Luka Škrlep

Slovenian National Building and Civil Engineering Institute ( email )

Andrijana Sever Škapin (Contact Author)

Slovenian National Building and Civil Engineering Institute ( email )

Cornelis A.M. Van Gestel

VU University Amsterdam ( email )

De Boelelaan 1105
Amsterdam, 1081HV
Netherlands

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