In this study, functionalized biocarbon (FBC) as a sorbent to capture mercury (Hg) from flue gas was developed and tested. The sorbent before and after Hg capture was characterized. The developed sorbent was tested for elemental Hg (Hg) capture efficiency in a (i) Hg pulse injection test, in an argon atmosphere, (ii) simulated flue gas of (a) 350 ppm of SO2, 5% O-2, and balanced with N-2 or (b) 300 ppm of NO2, 5% O-2, and balanced with N-2, and (iii) coupon test in a commercially operating coal-fired power plant. Hg capture by FBC in Hg pulse injection tests, simulated flue gas with NO2 and SO2, and flue gas from a coal-fired power plant were very promising and comparable to a commercial sorbent. An average Hg capture efficiency of >96% by FBC was noted in all of the experiments. The Hg concentration in the leachate solutions was negligible and below the regulated toxicity limits by a significant factor. Urea-activated biocarbon, used in this study, showed technical parameters comparable to commercial activated carbons (ACs) (high surface area of 500-800 m(2)/g and high nitrogen content of 4 wt %, on a dry basis) and captured the same amount of mercury with a lower cost, which proved the robustness of FBC. The developed FBCs can be employed to capture Hg, where ACs are currently in demand and would offer a cheap alternate replacement with similar capture efficiency.