Micro-nano plastics (MNPs; size <5 mm), ubiquitous and emerging pollutants, accumulated in the natural environment through various sources, and are likely to interact with nutrients, thereby influencing their biogeochemical cycle. Increasing scientific evidences reveal that MNPs can affect nitrogen (N) cycle processes by affecting biotopes and organisms in the environmental matrix and MNPs biofilms, thus plays a crucial role in nitrous oxide (N2O) and ammonia (NH3) emission. Yet, the mechanism and key processes behind this have not been systematically reviewed in natural environments. In this review, we systematically summarize the effects of MNPs on N transformation in terrestrial, aquatic, and atmospheric ecosystems. The effects of MNPs properties on N content, composition, and function of the microbial community, enzyme activity, gene abundance and plant N uptake in different environmental conditions has been briefly discussed. The review highlights the significant potential of MNPs to alter the properties of the environmental matrix, microbes and plant or animal physiology, resulting in changes in N uptake and metabolic efficiency in plants, thereby inhibiting organic nitrogen (ON) formation and reducing N bioavailability, or altering NH3 emissions from animal sources. The faster the decomposition of plastics, the more intense the perturbation of MNPs to organisms in the natural ecosystem. Findings of this provide a more comprehensive analysis and research directions to the environmentalists, policy makers, water resources planners & managers, biologists, and biotechnologists to do integrate approaches to reach the practical engineering solutions which will further diminish the long-term ecological and climatic risks.

Micro-nano plastics (MNPs) are emerging contaminants that can easily enter the food chain, posing risks to both the aquatic ecosystem and human health. Various physical, biological, and chemical methods have been explored to remove MNPs from water, and recently, adsorption technology has gained attention as an effective approach. Among the potential candidates, carbon-based adsorbent has emerged as a promising choice due to their low cost, eco-friendly nature, and sustainability. This paper summarizes recent advancements in MNP removal using carbon-based adsorbents, with a focus on the modification methods and adsorption mechanisms. Additionally, the factors influencing the adsorption performance and the methods for characterizing the adsorption mechanism are analyzed. Finally, the advantages and disadvantages of carbon-based adsorbents over other adsorbents are discussed, along with the current state of sustainable recycling and future research prospects.

As a kind of novel pollutant, microplastics and nanoplastics have been commonly found in all regions of the world and have attracted widespread attention in recent years. Wastewater treatment plants are considered an important \"source\" and \"sink\" of micro-nano plastics pollution, so it is significant to study its transportation and fate in wastewater plants. This review summarizes the types and sources of micro-nano plastics in domestic wastewater and compares their removal efficiency and migration in different treatment processes in wastewater plants. The interlinkages and ecological risks among surface water, soil and atmospheric environments are also analyzed, providing a reference for future research on the impact of wastewater treatment plants on micro-nano plastics pollution.