when purifying mercury from sea water, a decrease in the volume to surface area ratio leads to a decline in the efficiency of the elimination.7 cost efficiency of the nanotrap process is indicated in the fact that the materials can be reused to recycle more water. tween 20-au nps are rapid, efficient and selective in capturing hg2+ in high salt water concentration when the gold nps catalyze the citrate ion induced reduction of hg2+ to hg0. icp-ms is used to quantify the hg2+ concentration to determine the level of elimination efficiency. figure 3 shows an illustration process of the nano trap filtration process.