Biochar, as an adsorbent, is widely used for the removal of organic pollutants in water body. Hence, after saturated adsorption, regeneration treatment is required to recover the adsorption performance of biochar. In this study, a biochar (P-GBC) prepared by phosphoric acid activation showed high adsorption capacity for methylene blue (MB) with the maximum adsorption capacity (Q m) of 599.66 mg/g. Then, regeneration treatments using 4 mM peroxymonosulfate (PMS), 0.2 M hydrogen peroxide (H 2 O 2) and their mixture were used to regenerate MB-saturated biochar with regeneration efficiencies of 58.24%, 66.01% and 94.88%, respectively. Combining with degradation and quenching experiments, it is found that synergistic effect of H 2 O 2 desorption and PMS degradation is responsible for the enhancement of regeneration efficiency of P-GBC in H 2 O 2 -PMS system and enables a high mineralization rate of 82.68% for the MB adsorbed on P-GBC. Furthermore, EPR tests indicate that singlet oxygen (1O 2) is assigned as the primary activate species for the degradation of MB and XPS analyses confirm that graphite nitrogen and carbonyl on P-GBC are the main active sites for the activation of PMS. Compared with conventional regenerants, H 2 O 2 -PMS system has the advantages of low dosage, high mineralization efficiency, and easy accessibility, and is also effective, sustainable and environmentally friendly for the regeneration of organic pollutants-saturated biochar. [Display omitted] • Biochar was prepared by phosphoric acid activation for the adsorption of methylene blue. • H 2 O 2 -PMS system was used for the regeneration of methylene blue-saturated biochar. • The regeneration performance of biochar is improved by synergistic effect of H 2 O 2 desorption and PMS degradation. • 1O 2 is the main activate species for the degradation of MB. [ABSTRACT FROM AUTHOR]