• • HAP was successfully loaded onto sandstone particles after 52 days of reaction with HAP-generating solution, confirming the feasibility of in-situ aquifer loading.
• • At pH 3, initial U(VI) 5 mg/L, and 24 h contact, a composite dosage of 3 g/L achieved 95.6% uranium removal; increasing dosage to 5 g/L raised removal to 99.9%.
• • Interfering ions suppressed uranium removal in the order Fe3+ > Mn2+ > Ca2+ > Mg2+ > SO4^2-, indicating that Fe3+ and Mn2+ are critical inhibitors in acidic mine waters.
• • The composite immobilizes uranium via electrostatic adsorption, ion exchange, and dissolution-reprecipitation, yielding stable uranium-bearing phases suitable for long-term containment.