NOVELTY - Demercuration of seaweed-based coke, comprises (i) preparing biomass char as flue gas demercuration adsorbent by pyrolysis of seaweed-based coke, and allowing the absorption of mercury to a beating-type column reactor, recovering mercury resources, and regenerated adsorbent by a separator, and cooling; and (ii) spraying mercury-containing flue gas to beating-type column reactor by a laval nozzle, and injecting seaweed-based coke adsorbent into the beating-type column reactor which is coaxially arranged on the laval nozzle, allowing two gas streams to pass through beating-type column reactor.    USE - The method is useful for demercuration of seaweed-based coke (claimed).    ADVANTAGE - The method does not produce secondary pollution, and produces adsorbent material utilized as renewable resource.    DETAILED DESCRIPTION - Demercuration of seaweed-based coke, comprises (i) preparing biomass char as flue gas demercuration adsorbent by pyrolysis of seaweed-based coke, and allowing the absorption of mercury into a beating-type column reactor, recovering mercury resources, and regenerated adsorbent using a separator, and cooling mercury-containing flue gas by adding into a combustor; and (ii) spraying mercury-containing flue gas into beating-type column reactor by a laval nozzle, and injecting seaweed-based coke adsorbent into the beating-type column reactor which is coaxially arranged on the laval nozzle, allowing two gas streams to pass through beating-type column reactor, so as to achieve the removal of adsorbed mercury, where the beating-type column reactor has symmetrical arrangement, and automatically switching the flue gas into the column reactor from the burner, when the column reactor is used during regeneration, where the two column reactor are used and regenerated. An INDEPENDENT CLAIM is also included for preparing seaweed-based coke adsorbent, comprising (a) naturally drying seaweed, crushing into 50-200 meshes under low ventilation state, to obtain seaweed powder, then placing inside a stirring kettle under controlled temperature, stirring for 2 hours by adding water at 60-80 degrees C, and repeating the step; (b) adding water and nitric acid mixed solvent, stirring at 40-80 degrees C for 6 hours, naturally drying seaweed for 240 hours under ventilation state, and naturally drying for 8 hours at 105 degrees C by placing in a drying tank under controlled temperature, to obtain dried seaweed; (c) grinding dried seaweed into a particle diameter of 50-200 meshes, and placing in a tubular-type furnace, and introducing mixed has of carbon-dioxide and nitrogen for 5-25 minutes at 400-800 degrees C, and cooling to normal temperature, to obtain seaweed biomass; and (d) grinding the obtained biomass char into 50-200 meshes particles, soaking for 12 hours in vanadium salt solution, naturally drying for 240 hours, filtering under ventilation conditions, controlling the drying tank temperature at 110-220 degrees C, and drying for 6 hours, to obtain the final product.