Phosphate contamination in aquatic systems contributes significantly to eutrophication and deteriorating water quality, yet conventional adsorbents often exhibit poor selectivity in complex water matrices. This study developed a surface anion-imprinted lanthanum–trimesate metal–organic framework composite (IIP MOF-LTA) for selective phosphate removal. XRD confirmed the formation of a crystalline LTA structure, while FTIR verified La3+–trimesate coordination and phosphate-binding functional groups. Adsorption kinetics followed the pseudo-second-order model (R2 > 0.99), indicating chemisorption-controlled interactions, while equilibrium data were best described by the Langmuir model (R2 ≈ 0.99), confirming monolayer adsorption with homogeneous binding sites. The IIP MOF-LTA exhibited maximum adsorption capacity of 60.24 mg g-1 and achieved >90% removal at 10ppm, while NIP showed <70%. The imprinting factor remained above unity (1.00–1.06) across competing ions (5–40 ppm), demonstrating stable selectivity. These findings provide a promising strategy for developing highly selective adsorbents for phosphate removal in complex aqueous systems. © 2026 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.