Mercury removal agent as well as preparation method and application thereof

The invention provides a mercury removal agent as well as a preparation method and application thereof. The mercury removal agent comprises the following components in percentage by weight: 0.40 to 0.60 percent of iodine, 3.22 to 4.98 percent of potassium iodide, 1 to 2 percent of surfactant and the balance of water. The iodine is dissolved in the potassium iodide aqueous solution to form a potassium iodide aqueous solution, and the iodine in the potassium iodide aqueous solution reacts with the gaseous elemental mercury to generate mercury iodide, so that the elemental gaseous mercury is converted into mercury ions, thereby removing the gaseous elemental mercury. And the surfactant has a good washing effect, so that the oil sludge deposited in the equipment can be washed off. When the improved mercury removing agent disclosed by the invention is used for overhauling the interiors of containers such as a storage tank for carrying out three-phase separation by a low-temperature separation process, the improved