<p>The increasing demand for clean water, driven by population growth and industrial activities, has intensified the challenge of heavy metal contamination in aquatic environments. Conventional water treatment technologies often face limitations in selectivity, efficiency, and energy consumption, particularly when targeting trace level metal ions from complex aqueous matrices. In this context, nanotechnology has emerged as a powerful approach for developing advanced materials with enhanced interfacial and surface properties. Nanomaterials offer high surface to volume ratios, tunable physicochemical characteristics, and multifunctional behavior, making them highly suitable for environmental remediation applications. In particular, their integration into membrane systems has led to significant improvements in separation performance. Nanoparticle-enabled membranes can be engineered through several strategies, including blending, in situ polymerization, nano-embedding, and surface coating. Among these, layer-by-layer (LbL) assembly has gained increasing attention due to its ability to precisely control film architecture at the nanoscale, enabling the design of highly selective and functional interfaces. When combined with adsorption-based mechanisms, membrane systems evolve into adsorptive membranes, which integrate physical separation with chemical affinity for target contaminants. Despite substantial progress, a systematic understanding of how nanoscale architecture and fabrication methods influence adsorption-separation synergy remains limited. This review focuses on layer-by-layer-based adsorptive membrane technologies for heavy metal removal with emphasis on the relationship between nanoscale design, interfacial structure and separation performance.</p>