J. Vite et al., LEACHING OF HEAVY-METALS FROM WASTE-WATER SLUDGE, USING A THERMOSTATTED COLUMN, International journal of environment and pollution, 8(1-2), 1997, pp. 201-207
We have previously patented a process for the extraction of toxic and
valuable metals from foundry sands using a thermostatted column. In th
is paper, we describe a similar device for the removal of toxic metals
from wastewater sludge. The wastes were finely ground and suspended i
n an aqueous pulp, and 10-40 g of mineral acid or sodium hydroxide wer
e added to reach a pH of 2, 5, 7 and 10, together with 4-10 g of a bis
ulphite and 0.3 - 1.5 g of sodium dodecyl sulfate. In some cases, this
method can remove 100% of heavy metals from samples of various wastew
ater sludges. To study the removal efficiency of heavy metals, we used
inductively coupled plasma atomic emission spectrometry (ICP-AES). Th
e metallic alloys in the samples were studied by X-ray diffraction.