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| Performance of trapping mercury combined with organic coordination agent in water by novel macromolecule flocculant |
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Abstract A novel macromolecule flocculant polyethyleneimine-sodium xanthogenate (PEX) was synthesized by grafting a dithiocarboxylic group onto polyethyleneimine. The effect of pH values on the removal efficiency of mercury was investigated for the mercury-containing water sample. The performance of PEX trapping mercury was also studied for the water samples containing both mercury and some organic coordination agents, such as EDTA salt, ammonium citrate and aminoacetic acid. The experimental data show that the PEX had the strong binding capability with Hg2+ at all of pH values studied, and the removal rate nearly reaches 100% for some pH values. More dosage of PEX was needed at low pH values to reach the high removal efficiency obtained at high pH values. The coexistence of EDTA salt in water sample could affect the removal of Hg2+ to a certain extent, but this effect would be reduced or eliminated by the increased dosage of PEX. The coexistence of ammonium citrate in water sample could promote the removal of Hg2+. As far as the coexistence of aminoacetic acid was concerned, it could promote the removal of Hg2+ at low pH values, but depress the removal of Hg2+ with the increase in pH values. The lower Hg extraction rate obtained in the leaching experiment indicated that the flocs of PEX—Hg had the very good stability, and therefore it would not be easy to cause secondary pollution by the sludge produced in this treatment.
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Received: 01 September 2011
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