Abstract: The issue of exceeded sulfate ion (\mathrmSO_4^2- ) in mine water in certain regions of Yellow River Basin, poses significant environmental challenges. High operational costs and variable effectiveness hinder traditional remediation methods, such as membrane filtration and dilution. This study focuses on the synthesis of ginkgo leaf biochar via pyrolysis combined with high-energy ball milling (designated as Zr-Fe@BC), followed by transition metal modifications using iron (Fe) and zirconium (Zr) to establish a more efficient and economical sulfate removal technology. The systematically examined the effects of various preparation conditions, adsorption parameters, and the presence of interfering ions on sulfate elimination efficiency were systematically examined. Optimal biochar synthesis parameters were identified: pyrolysis conducted in an inert atmosphere for 6 hours at 700 °C, a modifier-to-biochar mass ratio of 0.2, and a subsequent ball milling duration of 2 h. Post-modification, both Zr and Fe were successfully integrated onto the biochar surface using ZrOCl₂·8H₂O and FeCl₃·6H₂O. The high-energy ball milling notably improved the accessibility of these metals and significantly enhanced the surface area of the biochar. Quantitative analysis via X-ray photoelectron spectroscopy (XPS) revealed that the contents of Zr and Fe in the Zr-Fe@BC were 1.94% and 0.11%, respectively. Simulations conducted with MINTEQ software investigated sulfate ion morphology across a pH range of 1 to 12. Experimental results demonstrated that Zr-Fe@BC achieved a sulfate removal efficiency of 74.8% at an initial mass concentration of 500 mg/L and pH 2. Even with a pH increase to 8, where competing hydroxide ions (OH⁻) increase, the active sulfate binding sites on Zr-Fe@BC corresponded to a mass concentration of only 231 mg/L, complying with Class III Environmental Quality Standards for Surface Water (GB 3838—2002), which stipulate a limit of \mathrmSO_4^2- < 250 mg/L. Competitive adsorption studies indicated that carbonate ions (\mathrmCO_3^2- ) exert a significant inhibitory effect on sulfate adsorption, followed by phosphate ions (\mathrmPO_4^3- ). Conversely, the presence of chloride ions (Cl⁻) had minimal impact on sulfate uptake. Kinetic and thermodynamic analyses of the adsorption process demonstrated that sulfate absorption onto Zr-Fe@BC aligns closely with the Langmuir isotherm model and follows pseudo-second-order kinetics. The predominant sulfate sorption mechanisms were identified as physical adsorption (van der Waals forces), electrostatic interactions, and ion exchange processes involving \mathrmSO_4^2- with Zr—OH and Fe—OH groups. Crucially, Zr-Fe@BC could effectively reduce sulfate levels from an initial concentration of 436.4 mg/L in actual mine dewatering effluent to within regulatory limits in under 20 min. In summary, the Zr-Fe@BC synthesized in this study not only demonstrates robust and stable \mathrmSO_4^2- adsorption performance but also offers significant potential for practical applications, thereby contributing valuable insights and technical foundations for the advanced removal of sulfate in mine waters across Yellow River Basin.