Reliability of biogas-fueled SOFC is tied directly to the purity of biogas used as fuel. Even miniscule amount of H2S can poison the anode material and drastically shorten the operation time of biogas-fueled SOFC. In order to prevent the performance degradation caused by H2S poisoning, the aim of this study is to develop an attractive process to obtain a nitrogen (N)-doped carbon derived from biomass feedstock using the digested liquid as a source of N, which can act as an excellent adsorbent material to reduce the H2S concentration in biogas below sub ppm level.Rice husk (RH) was pyrolyzed at 500oC for 2 h under O2-free atmosphere to produce biochar (BC). Rice husk biochar (RH-BC) was then treated with ammonia gas (25% NH3) at 500 or 900°C for 2 h (Intense N-doping) to have N-doped RH-BC (RH-BC(N500-120) and RH-BC(N900-120)). 10% NH3 solution was prepared to simulate the concentrated ammonia solution obtained from the digested liquid discharged from the methane fermentation reactor. The 10% NH3 solution was heated at 30oC through which 100 mL min-1 N2 was passed to obtain the vaporized NH3. RH-BC was treated with the NH3 vapor at 850°C for 90 or 270 min (Mild N-doping) to have N-doped RH-BC (RH-BC(EN850-90) and RH-BC(EN850-270)). Aiming at increasing the total H2S adsorption capacity (ACPH2S ), prior to the mild N-doping, pre-treatment of RH-BC with 15 vol% steam was performed at 850°C for 90 min (RH-BC(S850-90 + EN850-90)).Specific surface area (SSA) of the porous RH-BC was 146 m2 g-1. By the NH3 treatment of the RH-BC, pyridinic-like N can be doped on the surface contributing to the formation of the oxygen radicals to consume H2S, leading to the enhancement of the ACPH2S . RH-BC(N900-120) exhibited the highest breakthrough capacity (APCH2S(0) ) of 8.02 mg H2S g-BC-1 and ACPH2S of 9.58 mg H2S g-BC-1. However, the highest ACPH2S , 25.6 mg H2S g-BC-1, was obtained for RH-BC(S850-90 + EN850-90), while its APCH2S(0) was 3.64 mg H2S g-BC-1.XPS analysis revealed that, during the H2S adsorption, intense N-doping (RH-BC(N900-120)) resulted in the larger amount of sulfate formation on the surface compared to the mild N-doping (RH-BC(S850-90 + EN850-90)). Abundance of oxygen radicals on the surface is preferable for the sulfate formation. This explains the high ACPH2S(0) of the intensely N-doped sample, RH-BC(N900-120). On the other hand, for the mildly N-doped sample, RH-BC(S850-90 + EN850-90), interaction of the surface with H2S was moderately weakened to avoid the blocking of the micropore openings with sulfate, which enables the H2S molecules to adsorb into the micropores, resulting in the higher ACPH2S .