Extraction of copper from sewage sludge using biodegradable chelant EDDS.
[S,S]-Ethylenediaminedisuccinic acid (EDDS), a biodegradable chelant, was used to separate the heavy metals from the sewage sludge based on chemical extraction technology. Under various conditions, the extraction experiments were carried out for the sewage sludge from Shanghai Taopu Municipal Wastewater Plant, China. The influences of pH and the concentration of EDDS on the extraction efficiency for copper (Cu) were discussed. The results showed that EDDS had higher extraction efficiency for Cu from the sewage sludge than other heavy metals. The system pH and the concentration of EDDS had a significant effect on the extraction efficiency. The extraction efficiency of Cu increased gradually with the increase of system pH and reached a higher efficiency within pH range of 3-10. The extraction efficiency maintained at approximately 70% when the pH > or = 4.5 and the molar ratio of EDDS to total heavy metals was 10:1. From the fractional analysis of the heavy metals in sewage sludge before and after the extraction, it was found that the extracted Cu mainly came from the following four fractions, i.e. water soluble, acid-soluble, reducible, and oxidizable fractions.
Zhang
Lihua
L
State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China.
Zhu
Zhiliang
Z
Zhang
Ronghua
R
Zheng
Chengsong
C
Zhang
Hua
H
Qiu
Yanling
Y
Zhao
Jianfu
J
D001673:Biodegradation, Environmental; D002614:Chelating Agents / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D005029:Ethylenediamines / Q000737:chemistry*; D005590:Fractional Precipitation; D006863:Hydrogen-Ion Concentration; D019216:Metals, Heavy / Q000032:analysis; D010084:Oxidation-Reduction; D012722:Sewage / Q000737:chemistry*; D012995:Solubility; D013386:Succinates / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*
D002614:Chelating Agents; D005029:Ethylenediamines; D019216:Metals, Heavy; D012722:Sewage; D013386:Succinates; C041447:N,N'-ethylenediamine disuccinic acid; D003300:Copper