MgFe2O4-loaded N-doped biochar derived from waste cooked rice for efficient low-temperature desulfurization of H2S

To improve their low-temperature desulfurization performance, the activated carbon-based materials have typically been modified by either metal oxide loading or nitrogen doping. However, most of the aforementioned materials are limited to only one of the above modification methods, resulting in relatively poor desulfurization performance. Herein, a novel MgFe2O4-loaded N-doped biochar (MgFe2O4@NBC) was fabricated by one-pot pyrolysis of a nitrogen containing precursor of g-C3N4, cooked rice waste, and metal salts for efficient low-temperature desulfurization of H2S. Different fabrication conditions such as pyrolysis temperature and the ni-trogen mixing ratio (i.e., the mass ratio of cooked rice waste to g-C3N4) have been extensively studied. The optimized MgFe2O4@NBC-500-2 sample delivered a superior breakthrough capacity of 1052.83 mg/g in an atmosphere of O2 content of 20% and relative humidity of 80% at 25 degrees C, and demonstrated high tolerance and stability of desulfurization performance to harsh environmental conditions with 80% relative humidity and no oxygen. The desulfurization mechanism of H2S on the surfaces of the MgFe2O4@NBC composites was attributed to the synergistic effects of reactive adsorption and catalytic oxidation process. The composite also demonstrated excellent reusability, retaining 85% of the initial breakthrough capacity after 5 recycled uses. Therefore, the as-prepared MgFe2O4@NBC composite offers a potentially promising carbon-based desulfurizers for practical ap-plications in the low-temperature desulfurization field.