Abstract: Sodium carbonate impregnated activated carbon (IACⅠ) and another highly effective desulphurization agent (IACⅡ)were made by impregnation. To compare the ability of AC, IACⅠand IACⅡfor removal of hydrogen sulfide, the breakthrough curves for removal of low concentration H2S on fixed bed were measured. The effects of relative humidity and inlet concentrations on the removal process were investigated. To simulate the breakthrough curves a one-dimension model for fixed beds was developed and numerically solved. The effective diffusion coefficients of H2S were evaluated by fitting the experiment breakthrough curves with the calculated ones. The results show that IACⅡhas the best performance, and its effective diffusion coefficient is higher than that of IAC I. Higher relative humidity is of benefit to improve the sulfur capacity, but the effective diffusion coefficients decrease slightly. With the increasing of inlet H2S concentrations, the effective diffusion coefficients increase, the breakthrough time gets shorter and the sulfur capacity decreases slightly.