[Extraction of heavy metals from sewage sludge using aspartic acid and citric acid].
Aspartic acid, as a biodegradable natural amino acid, was used to separate and remove the heavy metals from the sewage sludge based on chemical extraction technology. Under various conditions, the extraction processes were carried out for the sewage sludge from Shanghai Taopu Municipal Wastewater Plant. The comparison of extraction between aspartic acid and citric acid was also discussed for the separation of three heavy metals from sewage sludge. The results showed that pH and the dosage of aspartic acid or citric acid had a significant effect on the extraction efficiency. Zn, Ni and Cu can be apart extracted for more than 85% by aspartic acid at low pH. With the increment of pH value, the extraction ration decreased gradually for both two systems. Within the whole pH range, aspartic acid showed higher extraction efficiency for Ni, Cu than citric acid and the extraction efficiencies of aspartic acid for Ni, Cu were found to respectively be more than 50%, 40%. For the situation of Zn, citric acid had a higher extraction efficiency at pH > or = 3.0.
Zhang
Hua
H
State Key Laboratory of Pollution Control and Resource Reuse, College of Environment Science and Engineering, Tongji University, Shanghai 200092, China. ritinaway@gmail.com
Zhu
Zhi-Liang
ZL
Zhang
Li-Hua
LH
Qiu
Yan-Ling
YL
Zhao
Jian-Fu
JF
D001224:Aspartic Acid / Q000737:chemistry*; D005591:Chemical Fractionation / Q000379:methods; D019343:Citric Acid / Q000737:chemistry*; D019216:Metals, Heavy / Q000737:chemistry / Q000302:isolation & purification*; D012037:Refuse Disposal / Q000379:methods; D012722:Sewage / Q000737:chemistry*
D019216:Metals, Heavy; D012722:Sewage; D019343:Citric Acid; D001224:Aspartic Acid