<p>Toxic heavy metals (Pb²⁺/Cd²⁺) bioaccumulate in aquatic systems, posing severe health risks that necessitate efficient adsorbents for water purification. Hence, this study investigated the performance of the composite derived from rice straw-derived biochar (RSB) and MgAl-layered double hydroxide (LDH) for removing Pb²⁺ and Cd²⁺ from aqueous solutions. The morphological, elemental, crystalline, and surface properties of the co-precipitated RSB-LDH composite were comprehensively assessed through FE-SEM, EDS, XRD, FTIR, and BET techniques. The simultaneous effects of pH, initial heavy metal concentrations, adsorbent dosage, and contact time were optimized through response surface methodology, based on a central composite design. The analysis of variance confirmed the adequacy of the model, with <i>R</i>^<i>2</i> values of 0.9699 and 0.9573 for Pb²⁺ and Cd²⁺, respectively, demonstrating the maximum removal efficiencies of 100% for Pb²⁺ and 97.71% for Cd²⁺. The optimal conditions for maximum Pb²⁺ removal occurred in pH 5.40, with an initial concentration of 22.37&#xa0;mg/L, an RSB-LDH dosage of 0.94 g/L, and a contact time of 37.65&#xa0;min. In contrast, the optimal conditions for Cd²⁺ removal were pH 5.68, an initial concentration of 7.03&#xa0;mg/L, an RSB-LDH dosage of 1.31 g/L, and a contact time of 58.93&#xa0;min. The pseudo-second-order kinetic equation and Langmuir model well fit the adsorption kinetic data and isotherm data, respectively. The RSB-LDH adsorbent exhibited remarkable regeneration capability, preserving over 85% removal efficiency for both ions after five cycles. These results highlight RSB's crucial role in developing the RSB-LDH composite, which exhibits excellent adsorption performance with reusable capabilities for removing toxic Pb²⁺ and Cd²⁺ ions from contaminated water.</p> Graphical Abstract <p></p>