The adsorption dynamics of inorganic mercury, Hg(II) and organic methylmercury, MeHg(II) removal by low-cost reactive agrowaste adsorbents namely CP-Pure, CP-MPTES and CP-RR was investigated in a fixed-bed adsorber. The results show that the breakthrough and saturation times were delayed with decreasing flow rate (F) and initial concentration (Co), and increasing bed height (Z). The Hg(II) possessed better adsorption performance than MeHg(II). The isotherm and kinetic model analyses of adsorption data followed the Temkin isotherm and the pseudosecond order kinetic models, respectively. The breakthrough curve was simulated well by the Thomas and Yoon-Nelson models, and then was further used for scale-up studies. The empty bed contact time (EBCT) concept was successfully demonstrated for the adsorber design and scale-up studies. The regeneration studies showed that the regenerated CP-Pure and CP-MPTES have a high regeneration efficiency up to third adsorption cycle. © 2019, The Korean Institute of Chemical Engineers.