TMT 15® for heavy metal precipitation

Heavy metals are indispensable for many production processes, yet their use leaves behind wastewater that contains heavy metal. To minimize environmental pollution, national goverments and international organisations have established limits for heavy metals in waste waters and exhaust gases which may not be exceeded.

Usually, heavy metals in waste water are precipitated by adding sodium hydroxide or lime during neutralization. However, the results of this process are far from satisfying in many cases: The remaining heavy metal concentrations are too high. A complete hydroxide precipitation does not take place especially in the presence of complexing agents.

Adding small amounts of the organosulphide TMT 15® to the waste water solves this problem: The precipitation will be completed, and the remaining residues of e.g. cadmium, copper, lead, mercury, nickel, or silver are reduced to an extremely low level.

In order to achieve the best performance, the pH-value of the treated waste water should be adjusted to a neutral / slightly alkaline range. The precipitate of TMT 15® with heavy metals can be easily flocculated and separated, similar to the corresponding hydroxides.

Another application for TMT 15® is in the alkaline scrubber of a wet flue gas cleaning system to minimize the mercury (Hg) emissions. In this case, the chemical reduction of ionic mercury to elementary mercury by SO2 is suppressed by fixing the ionic mercury with TMT 15®. Thus, Hg is separated from the flue gas and the emission in the cleaned gas can be minimized.