<p>Selective removal of toxic lead ions (Pb²⁺) from complex wastewaters containing abundant competing cations (Ca²⁺, Mg²⁺, Na⁺) remains a critical challenge for water remediation. Herein, we report a ternary MXene/layered double hydroxide/activated carbon (MXene/LDH/AC) composite electrode for capacitive deionization (CDI) with high capacity, high energy efficiency, and selective Pb²⁺ removal. This hierarchical composite integrated the high electrical conductivity of Ti₃C₂T_x MXene, selective ion-exchange capability of ZnAl-LDH, and high surface area of activated carbon. Comprehensive characterization via SEM, XRD, FTIR, and BET analysis confirmed successful synthesis with hierarchical porosity (pore size of 1.21–2.34&#xa0;nm), enhanced hydrophilicity (contact angle of 45.2°), and intimate integration of all three components. Under optimized conditions (1.4&#xa0;V, 1 spacer, 10 mL min^-1), the composite electrode demonstrated high Pb²⁺ removal capacity of 29–106 mg g^-1, with good selectivity factors of 4-fold over Ca²⁺ and 6-to-7-fold over Mg²⁺ in multi-ion solution. The selective removal mechanism involves synergistic contributions from smaller hydrated radius, higher charge density, preferential intercalation in MXene interlayers, and chelation by surface functional groups. The composite electrode exhibited fast adsorption kinetics following pseudo-second-order behavior, with reasonable energy consumption 0.73–1.5 Wh g^-1). This work demonstrates a promising treatment pathway for heavy metal contaminated industrial effluents using the chemical-free and easily scalable CDI system with stackable modules.</p>