Characterization and treatment of liquid wastes from some analytical chemistry labs by using sodium sulfide

Abstract EN

Chemical laboratories discharge their liquid wastes to the general sewerage network without treatment.

This work aimed to remove heavy metals from inorganic liquid wastes generated from the laboratories of inorganic analytical chemistry.

Liquid waste samples were collected from some analytical laboratories (refractory, cement and masonry materials).

The method for treatment involve chemical precipitation of the heavy metals in the form of metal sulfides using sodium sulfide, which was added to the liquid wastes at different pH values, and then allowed to settle.

Based on the results obtained in the current study, single precipitation at pH value equal to 7 using sodium sulfide is considered the best method to be used for the removal of heavy metals from the liquid wastes of inorganic chemistry laboratories.

It can be seen that, for Pb, Zn, Fe and Al, the removal efficiency reached 99.89% , 99.96% , 99.91% , 99.99% , respectively.

In regards to Cr removal efficiency reached 45.03% at pH 5 while at pH11 it reached 81.05% .

It can be concluded that the resulted effluent after treatment comply with the regulations set by law.