Fenton oxidation and chromium recovery from tannery wastewater by means of iron-based coated biomass as heterogeneous catalyst in fixed-bed columns

•A novel composite adsorbent was successfully used to treat tannery wastewater.•The achieved Crtot sorption capacity in preliminary batch tests was 12.66 mg/g.•Fenton reaction was developed in a two columns process by H2O2 addition.•The adsorbent was re-used up to 5 cycles in a continuous column process.