Heavy metal adsorption device

The utility model discloses a heavy metal adsorption device which comprises a sewage tank, a blow-off pipeline, an annular filter screen, an annular adsorption plate, a plugging block and a driving mechanism, the blow-off pipeline, the annular filter screen and the annular adsorption plate are sequentially and coaxially arranged from inside to outside and are all installed in the sewage tank, and the blow-off pipeline penetrates through the bottom wall of the sewage tank. The blocking block can be adaptively inserted into the blow-off pipeline to block the blow-off pipeline and is connected with a driving mechanism for driving the blocking block to move up and down; when the heavy metal adsorption device provided by the utility model is used, impurities in sewage are accumulated at the bottom of the annular filter screen, and the impurities at the bottom of the annular filter screen fall onto the top wall of the second plugging part through the blanking channel between the first plugging part on the plugging