Metallic mercury removal from soil with organic chelating agent and oxidant - e.g. di:ethylene-tri:amine-penta:acetic acid and hydrogen peroxide for easy purificn. to legal limit

    公开(公告)号:DE4219420A1

    公开(公告)日:1993-12-16

    申请号:DE4219420

    申请日:1992-06-13

    Applicant: BASF AG

    Abstract: Removal of metallic Hg from soil is effected by treating the soil with organic chelating agent (I) in the presence of an oxidant (II). (I) has a Hg2+ complex formation constant of over 10 power 22 and pref. is diethylenetriaminepentaacetic acid (DTPA); and (II) is NaOCl, alkali peroxydisulphate or pref. H2O2. Treatment pref. is carried out with 3-8% (I) soln. and 0.1-1, pref. 0.3-0.8% H2O2 at pH under 9, pref. 5-8. ADVANTAGE - The Hg content of the soil can be reduced from values as high as e.g. 10000 ppm to 1-25 ppm, so that the legal limit can be attained easily. In an example, 100g samples of (A) loam contg. 105000 ppm Hg, (B-G) loam contg. 95 ppm Hg and (H) sandy soil contg. 80 ppm Hg (from a rstoration project), all homogenised by ball milling, placed in a column and covered with 1 kg aq. extn. soln. contg. (E) 1, rest 7% DTPA.Na5 and (F,G) 0.1, rest 0.6% H2O2, adjusted to pH (D) O, rest pH 6 with dil. HNO3. The flow rate was adjusted to 10-20 drops/min.. The Hg concn. was reduced to (A) 10, (B) 2.4, (C) 2.8, (D,E) 6, (F) 9, (G) 13, (H) 12 ppm.

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