Microplastic materials in the environment: Problem and strategical solutions

Plastics are widely used in our daily life; however, poor management and disposal result in their ubiquity throughout the biosphere. Increased accumulation of microplastic (MP) or even nanoplastic materials in the aquatic, terrestrial and atmospheric environment has produced significant impacts on life in water and on land. Currently, an incisive overview of MP contamination in the different environments is lacking, which impedes the effective formulation of strategical solutions. In this review, distribution, sources, transport, fate, and potential risks of MPs in water, air, and soil are comprehensively identified and analyzed. Integrated strategies are proposed to stop or mitigate their input into the environment, including cleanup activities, source control, improved plastic waste management, adoption of biodegradable (bio)plastics, and the development of advanced techniques for the degradation and conversion of (micro)plastic materials. Technologies for degradation including biodegradation, advanced oxidation processes, and conversion including bio-recycling, photocatalysis, pyrolysis, hydrocracking, hydrogenolysis, alkane metathesis, microwave-initiated conversion, flash Joule heating, electrocatalysis, dehydrochlorination, and chemical depolymerization are critically reviewed. Emphases are placed on catalytic system design, technological innovation, and related mechanisms. Finally, an outlook is presented on the challenges of MP pollution. Perspectives within and beyond the research field of science and technology-based solutions are also discussed.