• • The review establishes a unified transport-process framework that deconstructs ion separation into pore entry, solvation reorganization, interfacial partitioning, intrapore migration, and outlet release, enabling direct comparison of mechanisms across MOFs, COFs, zeolites, 2D materials, and biochars; this addresses the industrial bottleneck of non-comparable performance data that currently impedes material selection for salt-lake lithium extraction.
• • By explicitly incorporating biochar into the analysis (Introduction, Table 2, Sections 2.2 and 3.3), the review expands the material scope beyond conventional high-cost frameworks, offering a low-cost pathway for selective ion separation in water treatment and resource recovery where capital expenditure is a primary deployment barrier.
• • The review identifies three persistent gaps: (i) lack of data comparability across test conditions, (ii) insufficient direct evidence of ion solvation, site occupancy, and migration under operating conditions, and (iii) complexity of feed streams; these gaps directly hinder scale-up and techno-economic assessment for nuclear waste management and lithium recovery.
• • The manuscript is supported by the National Key R&D Program of China (2024YFB3612600) and NSFC grants (22375100, 22275098, 62288102), indicating national-level prioritization of selective ion separation technologies for strategic resources and environmental remediation.