Degradation of ofloxacin by high-efficiency almond shell-based biochar via peroxymonosulfate activation: A study of the effect of pore structure

•Different pore structures were prepared by using almond shells as starting materials.•Catalysts with mesoporous pores can utilize the high mass transfer to activate PMS.•High TOC removal still can be achieved by the mesoporous catalysts.•Low TOC removal in 1O2 dominated systems can be solved via modulating pore sizes.