Nanocellulose nano zero valent iron composite membranes for synergistic microplastic remediation and sustainable water purification a review

Abstract

Microplastic (MP) pollution in aquatic ecosystems has emerged as a critical environmental and public health crisis, necessitating advanced remediation technologies that surpass the limitations of conventional water treatment. This review provides a comprehensive analysis of MP sources, transport pathways, and ecological impacts, while critically evaluating the efficacy of conventional versus nanotechnology-based remediation strategies. Particular emphasis is placed on the synergistic potential of composite membranes combining nanocellulose (NC) with nano zero-valent iron (nZVI). Nanocellulose, distinguished by it’s high surface area, biodegradability, and hygroscopic nature, provides a porous matrix for the adsorption and physical retention of microplastic particles. Immobilized nZVI may provide additional reactive and adsorptive sites for the removal of co-occuring dissolved contaminants. However, the available evidence does not directly demonstrate polymer-chain degradation or mineralization of microplastics by NC- nZVI membranes. Therefore, microplastic remediation by these composites is interpreted primarily as particle capture rather than chemical degradation. Following the PRISMA 2020 guidelines, a systematic review of literature from 2010 to 2025 was conducted, screening 1,327 publications and synthesizing data from 142 selected studies. The analysis reveals that NC–nZVI composites leverage synergistic physicochemical effects to significantly enhance removal efficiency compared to standalone materials. Using the PICO framework, this review contrasts these advanced composites with conventional methods (e.g., coagulation, sand filtration), which often lack efficacy against nano-scale plastics. Unlike previous reviews that considered nanocellulose, nZVI or nano-enabled microplastic remediation technologies separately, the present review examines the intersection of these three research areas and distinguishes direct evidence from NC- nZVI systems tested against microplastics from indirect evidence from NC only materials, nZVI applications to other contaminants and related nanocomposites. Key contributions include a synthesis of recent experimental removal efficiencies and a discussion on the alignment of these technologies with Sustainable Development Goal 6 (Clean Water and Sanitation). Furthermore, the review identifies critical knowledge gaps, including the paucity of real-world field trials, potential ecotoxicological implications of nanomaterial release, and scalability challenges. By highlighting these deficiencies, this study outlines a strategic roadmap for developing engineered, bio-based water treatment solutions capable of mitigating the pervasive threat of microplastics.