Micro- and nanoplastics removal from water and solid matrices: Technologies, challenges, and future perspectives.

Area of Science:

• Environmental Science
• Water Treatment Technologies
• Polymer Science

Background:

• Plastic contamination, particularly microplastics (MPs) and nanoplastics (NPs), poses a significant environmental challenge.
• Research on MPs and NPs in wastewater and sludge has rapidly increased since 2015.
• Effective mitigation strategies are urgently needed to address this growing issue.

Purpose of the Study:

• To critically review current technologies for removing and degrading MPs and NPs in aqueous and solid matrices.
• To evaluate the effectiveness and limitations of various treatment methods.
• To identify research gaps and future directions for MP and NP remediation.

Main Methods:

• Bibliometric analysis of research from 2015-2025.
• Critical review of existing literature on MP and NP removal and degradation technologies.
• Evaluation of conventional and advanced treatment processes.

Main Results:

• Most water treatment processes transfer MPs and NPs to sewage sludge (>95%) rather than eliminating them.
• Conventional methods (filtration, coagulation, sedimentation, flotation) show >80% MP removal but are poorly validated for NPs.
• Advanced oxidation processes (AOPs) demonstrate high degradation potential (>80-99% mineralization) in controlled settings, but real-world applicability is limited.
• Remediation research in soils, sediments, and sludge is nascent, focusing on extraction over treatment.
• Emerging thermochemical and biological methods show potential but require further development.

Conclusions:

• Current water treatment technologies primarily redistribute MPs and NPs into sludge, necessitating integrated strategies.
• AOPs show promise for polymer degradation, but validation in complex matrices is crucial.
• Future research must focus on scalable, validated degradation technologies and preventing inter-matrix transfer of MPs and NPs.