Degradation of micro(nano)plastics in water via Fenton-based Advanced Oxidation Processes under intensified conditions

Project Information

PlasticOX

Grant agreement ID: 101062665

DOI

10.3030/101062665

Project closed

EC signature date 18 July 2022

Start date 15 September 2022

End date 14 October 2023

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 82 656,48

Coordinated by

UNIVERSIDAD AUTONOMA DE MADRID
Spain

Periodic Reporting for period 1 - PlasticOX (Degradation of micro(nano)plastics in water via Fenton-based Advanced Oxidation Processes under intensified conditions)

Reporting period: 2022-09-15 to 2023-10-14

Summary of the context and overall objectives of the project

Plastic debris, including micro and nano-sized particles, is considered a major environmental problem, and is recognized alongside climate change as an emerging concern that might affect human ability to preserve biodiversity and the availability of safe water supplies in the near to medium-term future. Hence, the removal of plastic litter and micro(nano)plastics (MNPs) released into the environment is and will remain as a top priority on the political agenda in Europe (The Green Deal and EU’s plastics strategy) and worldwide (UN Sustainable Development Goals) for the next few decades. Wastewater treatment plants (WWTPs) have been recently identified as an important pathway for MNPs releasing into the environment, needing the development of targeted processes to address this issue urgently. The challenge consists in degrading pollutants that do not dissolve in water, requiring the implementation of intensified and advanced treatment technologies.
PlasticOX is focused on the development and optimization of advanced treatment strategies, such as homogeneous Fenton and photo-Fenton processes, to age and degrade MNPs in water. Specifically, it is expect to: i) develop new degradation procedures for micro(nano)plastics and its derivatives; ii) develop kinetic models based on particles with decreasing diameters; iii) create new knowledge in the field of micro(nano)plastics analysis and determination; iv) raise the awareness of the risks of plastic pollution: v) disseminate and communicate the scientific results by using open science practices; vi) boost the scientific career of the researcher by acquiring new skills and training from a top research group and vii) develop a lasting scientific cooperation between the researcher and the European host group at the Autonomous University of Madrid, Madrid, Spain.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

PlasticOX has demonstrated for the first time the complete and fast photodegradation of polystyrene nanoplastics (PS NPs) in water in less than 40 min, upon photo-Fenton treatment at ambient conditions. This outstanding performance can be attributed to the specific wavelength range and light intensity employed, surpassing removal levels achieved by the photocatalytic processes reported in existing literature.
The project findings have facilitated the establishment and development of a set of characterization strategies to identify and quantify nanoplastics in water, allowing to follow their evolution upon oxidation tests. Moreover, the oxidation mechanism of PS NPs was addressed, as well as the influence of several relevant operating parameters such as particle size (from nano to micrometer range), morphology (spheres, fragments, and fibers), polymer nature (PS, PET and PES), and the impact of the water matrix (ultrapure water, tap water, and secondary wastewater).
Finally, a kinetic model based on the evolution of particle size along the oxidation time was developed to predict the performance of the photo-oxidative treatment.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The removal of micro(nano)plastics (MNPs) is currently a hot topic within the scientific community. So far, the investigation into the application of advanced oxidation processes for the degradation of MNPs has been limited, as denoted by the publication date (2019 – 2023) of the main literature in the field. Likewise, the characterization of nanoplastics (NPs) supposes a challenge among the research field. In PlasticOX, the progress of NPs degradation was effectively monitored in terms of Total Organic Carbon, turbidity, and particle size reduction (TEM analysis), as well as by other relevant characterization tools. Moreover, the viability of the photo-Fenton process (UV/H2O2/Fe) carried out at ambient conditions was demonstrated for the removal of polystyrene (PS) NPs from water. Under optimized conditions, complete mineralization of PS NPs was achieved in less than an hour at ambient conditions, exhibiting superior performance compared to the photocatalytic processes reported in the existing literature. To the best of our knowledge, these are the first studies reporting complete and rapid degradation of NPs in water, under ambient conditions. Furthermore, a kinetic model, based on the size change of the particles along the treatment time, was developed to predict the performance of the photo-oxidative treatment. Remarkably, no other studies elucidated the kinetic behavior of NPs degradation.
Therefore, the results of PlasticOX present a substantial contribution to: i) the scientific community, enhancing understanding in the fields of plastic pollution and wastewater treatment; ii) the wastewater treatment industry, especially companies focusing on commercializing photo-assisted treatment processes or the removal of micro(nano)plastics from water. Also, the companies operating municipal WWTPs seeking to incorporate advanced treatments as additional stages of their conventional installations, and iii) the general society, as one of the project’s main objectives was to raise awareness of environmental issues related to plastic pollution.