Direct decomposition of hydrogen sulfide through microwave-induced discharge of graphitized bio-char

Direct decomposition of hydrogen sulfide (H2S) can be used to obtain high-purity hydrogen, thereby avoiding the waste of hydrogen resources by traditional Claus process. Microwave-induced discharge with spherical bio-char for H2S decomposition is proposed. The bio-char was treated by graphitization modification in presence of microwave heating and iron additive. The influences of graphitization parameters including iron loading and microwave irradiation time on the bio-char graphitization degree were studied. Subsequently, the modified biochar was applied to induce microwave discharge, and the effects of graphitization parameters on discharge performance were discussed. Lastly, the attention was paid to investigate catalytic effect of microwave-induced discharge with the modified bio-char for H2S decomposition. The results showed the best graphitization degree of bio-char was achieved at iron loading of 6 mmol/g and microwave irradiation time of 60 min. The improvement of bio-char graphitization degree enhanced discharge intensity, thus promoting bed temperature. Microwave discharge exhibited a favorable catalytic effect on H2S decomposition, with initial and ending conversions at 97.4% and 83.2% in a two-hour test, respectively, because of synergistic effect of microwave discharge effect, microwave thermal effect and catalytic activity of the modified bio-char.