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Co-precipitation with CaCO3 to remove heavy metals and significantly reduce the moisture content of filter residue

Author:
Li, Xuewei, Zhang, Qiwu, Yang, Bo
Source:
Chemosphere 2020 v.239
ISSN:
0045-6535
Subject:
cadmium, calcium carbonate, calcium hydroxide, copper, coprecipitation, heavy metals, iron, mechanochemistry, metal ions, neutralization, nickel, pH, sludge, wastewater treatment, water content, zinc
Abstract:
The co-precipitation of Fe2+, Cu2+, Zn2+, Cd2+ and Ni2+ were investigated by a mechanochemical processing with CaCO3. The results showed that the synergies of the metal ions led to efficient co-precipitation. The precipitation of Fe2+, Cu2+ and Cd2+ are over 99% and that of Zn2+ and Ni2+ about 98.4% and 93.8%. A significant advantage of the process is that the moisture content of filter residue is much lower (less than 50%) than that using the lime neutralization (more than 80%), offering a potential solution to the sludge problem in wastewater treatment. A further advantage is the neutral pH (about 7.5) obtained by using CaCO3 rather than the highly alkaline pH (about 11) obtained using lime (Ca(OH)2) neutralization method.
Agid:
6660547