Recent innovations in microplastics and nanoplastics removal by coagulation technique: Implementations, knowledge gaps and prospects

Recently, microplastics (MPs) and nanoplastics (NPs) contamination is a worldwide problem owing to the immense usage of plastic commodities. Thus, the environmental risks by MPs and NPs demand the application of innovative, efficient, and sustainable technologies to control the pollution of plastic particles. Regarding this, numerous technologies, including adsorption, coagulation, filtration, bioremediation, chemical precipitation, and photocatalysis, have been engaged to eradicate MPs and NPs from contaminated waters. However, the coagulation technique is getting much attention owing to its simplicity, higher removal performance, low carbon footprint, and low operational and maintenance cost. Therefore, this paper has been designed to critically summarize the recent innovations on the application of coagulation process to eradicate MPs and NPs from both synthetic and real sewage. More importantly, the effect of pertinent factors, including characteristics of coagulants, MPs/NPs, and environmental medium on the elimination performances and mechanisms of MPs/NPs have been critically investigated. Further, the potential of coagulation technology in eliminating MPs and NPs from real sewage has been critically elucidated for the first time, for better execution of this technique at commercial levels. Finally, this critical review also presents current research gaps and future outlooks for the improvement of coagulation process for eradicating MPs and NPs from water and real sewage. Overall, the current review will offer valuable knowledge to scientists in selecting a suitable technique for controlling plastic pollution.