In recent decades, the accumulation and fragmentation of plastics on the surface of the planet have caused several long-term climatic and health risks. Plastic materials, specifically microplastics (MPs; sizes < 5 mm), have gained significant interest in the global scientific fraternity due to their bioaccumulation, non-biodegradability, and ecotoxicological effects on living organisms. This study explains how microplastics are generated, transported, and disposed of in the environment based on their sources and physicochemical properties. Additionally, the study also examines the impact of COVID-19 on global plastic waste production. The physical and chemical techniques such as SEM-EDX, PLM, FTIR, Raman, TG-DSC, and GC-MS that are employed for the quantification and identification of MPs are discussed. This paper provides insight into conventional and advanced methods applied for microplastic removal from aquatic systems. The finding of this review helps to gain a deeper understanding of research on the toxicity of microplastics on humans, aquatic organisms, and soil ecosystems. Further, the efforts and measures that have been enforced globally to combat MP waste have been highlighted and need to be explored to reduce its potential risk in the future.

Mechanochemical engineering offers a green, solvent-free or solvent-minimized approach to producing advanced nanomaterials in the fields of water and wastewater treatment. Through the utilization of mechanical forces via ball milling, solid-state grinding, and twin-screw extrusion, many chemical transformations can be performed in light or ambient conditions without the need for toxic solvents, high temperatures, or complicated reactions. This review examines recent developments in mechanochemical synthesis of adsorbent materials with an eye toward their structure, surface design, and performance in the removal of dyes, heavy metals, pharmaceuticals, and emerging persistent contaminants. Mechanochemical activation produces defects, enhanced porosity, heteroatom incorporation, and accessibility of reactive surface sites, which improves adsorption and multi-functional contaminant removal. Aside from the material aspects, this review discusses process aspects such as scalability, integration into actual treatment systems (e.g. membranes and packed bed reactors), regeneration efficiency, and overall environmental sustainability. This review concludes that mechanochemically synthesized adsorbents can perform comparably to or better than conventionally prepared materials while requiring less solvent, energy, and waste generation. But mechanochemistry provides a powerful and sustainable route to develop new adsorbent materials in line with green and sustainable water treatment practices. Continuous reactive extrusion, in situ characterization, and artificial intelligence (AI) may enable consistent, scalable production of next-generation adsorbents. Graphical abstract