Sediment washing by EDTA and its reclamation by sodium polyamidoamine-multi dithiocarbamate.
Sodium polyamidoamine-multi dithiocarbamate (PAMAM-DTC) is a kind of heavy metals capturing agent, containing functional groups of dithiocarbamate that could strongly chelate heavy metals. In this paper, it was applied to precipitate heavy metal ions from meal-EDTA and reclaim EDTA during sediment washing process. The extracting performance of fresh EDTA was studied as a function of EDTA concentration, liquid/sediment (L/S), pH, and extraction time. Then the EDTA effluents were treated with PAMAM-DTC, Na2S and sodium diethyldithiocarbamate (DDTC) to compare their effectiveness on capturing metals from metal-EDTA complexes. Four divalent heavy metals were investigated (Pb, Cd, Cu, Zn). PAMAM-DTC shows much better performance. Pb, Cd and Cu could almost be precipitated completely by PAMAM-DTC under the dosage of 350 mg L-1, while Zn could be only partly precipitated which may due to its failure in competition with the other three metal ions on chelation with PAMAM-DTC. The reclaimed EDTA was reused in three cycles of sediment washing, and the amount of heavy metals extracted just slightly decreased in each cycle.
State Key Lab of Pollution Control & Resource Reuse, UNEP-Tongji Institute of Environment for Sustainable Development, College of Environmental Science and Engineering, Tongji University, 1239 Siping Rd, Shanghai 200092, China.
Tianlin
T
Deng
State Key Lab of Pollution Control & Resource Reuse, UNEP-Tongji Institute of Environment for Sustainable Development, College of Environmental Science and Engineering, Tongji University, 1239 Siping Rd, Shanghai 200092, China; Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, 1239 Siping Rd, Shanghai 200092, China. Electronic address: zhangbingru2000@126.com.
Bingru
B
Zhang
State Key Lab of Pollution Control & Resource Reuse, UNEP-Tongji Institute of Environment for Sustainable Development, College of Environmental Science and Engineering, Tongji University, 1239 Siping Rd, Shanghai 200092, China.
Fengting
F
Li
State Key Lab of Pollution Control & Resource Reuse, UNEP-Tongji Institute of Environment for Sustainable Development, College of Environmental Science and Engineering, Tongji University, 1239 Siping Rd, Shanghai 200092, China.
Luyao
L
Jin
D002614:Chelating Agents / Q000737:chemistry*; D050091:Dendrimers; D004492:Edetic Acid / Q000737:chemistry*; D052918:Environmental Restoration and Remediation / Q000379:methods*; D019216:Metals, Heavy / Q000737:chemistry / Q000302:isolation & purification*; D011073:Polyamines; D012964:Sodium; D012989:Soil Pollutants / Q000737:chemistry / Q000302:isolation & purification*; D013859:Thiocarbamates
D002614:Chelating Agents; D050091:Dendrimers; D019216:Metals, Heavy; C104700:PAMAM Starburst; C531249:Poly(amidoamine); D011073:Polyamines; D012989:Soil Pollutants; D013859:Thiocarbamates; D004492:Edetic Acid; D012964:Sodium
Dithiocarbamate; EDTA reclamation; Heavy metals; Sediment washing; Soil and sediment contamination