Abstract: To address the limitations of sulfonated biochar （SBC） in treating pharmaceutical wastewater （PW）, including its limited capacity for organic removal and the release of dissolved organic matter, SBC was prepared via in-situ sulfonation of rice husk with alkylation waste sulfuric acid, and a synergistic PW treatment method combining SBC with thermally regenerated biochar （RSBC） was proposed. Static adsorption experiments were conducted to evaluate SBC removal efficiency for inorganic and organic pollutants. Spent SBC was thermally regenerated to produce RSBC, and changes in physicochemical properties were characterized. The synergistic treatment effect and mechanism of combined SBC and RSBC application were also investigated. The results showed that at a dosage of 120 g·L⁻¹, SBC achieved removal rates of 77.3% for NH₄⁺-N, 100% for heavy metals （Cd²⁺, Cu²⁺）, and 98.3% for scale-forming cations （Ca²⁺, Mg²⁺） from PW. However, the removal rates for COD and DOC were less than 30%, and SBC itself released dissolved organic matter （SBC-DOM） into the aqueous phase. Thermal regeneration of the spent SBC revealed that high temperature gradually decomposed the oxygen- and sulfur-containing functional groups on the biochar surface. At 600 °C, the specific surface area of RSBC-600 increased from 11.80 m²·g⁻¹ to 362.07 m²·g⁻¹, a 30.68-fold increase. Combined application of SBC and RSBC-600 improved the DOC removal efficiency to 79.2%. SBC removed cationic pollutants mainly through its abundant functional groups, while RSBC-600 enhanced organic pollutant adsorption via its high specific surface area, hydrophobic interactions, and electrostatic adsorption. These complementary adsorption mechanisms provide mechanistic insights into the synergistic adsorptive removal of inorganic and organic pollutants from complex wastewater systems.