Green solutions for blue waters: Using biomaterials to purify water from microplastics and nanoplastics

Microplastics (MPs) are increasingly recognized as significant environmental contaminants due to their widespread presence in the atmosphere, soil, and, particularly, aquatic ecosystems. The amount of MPs is projected to increase globally from 41 kt in 2000 to 1397 kt in 2060. China, the world's top plastic producer, significantly contributes to this growing crisis. Despite the deployment of various methods and materials to cleanse water of MPs and nanoplastics (NPs) particles, a critical gap persists: the untapped potential of bio-based materials for extracting these tiny pollutants from aquatic environments. This review illuminates the urgent need for innovative and sustainable removal techniques to combat the microplastic menace, which is further intensified by the ever-increasing demand for plastic products. The novelty of this review lies in its focus on the groundbreaking application of biomaterials, such as modified biopolymers, bio-based aerogels, and bioflocculants, to capture and eliminate MPs and NPs. Uniquely, this review encapsulates the latest research from the past two years, ensuring a cutting-edge perspective on the subject. Biomaterials are presented as promising solutions due to their biodegradability, sustainability, and potential for functionalization, which are vital for developing eco-friendly water treatment technologies. The mechanisms, effectiveness, and practicality of these biomaterials in microplastic removal are discussed in detail. The review also highlights the need for a deeper understanding of biomaterial-micro/nano plastics interactions under various environmental conditions. Finally, the review proposes directions for future research to effectively address the microplastic crisis, underscoring the importance of optimizing the application of biomaterials within proven techniques like filtration, adsorption, and coagulation-flocculation-sedimentation methods to tackle micro- and nano-plastic pollution effectively.