Recovery of heavy metals from industrial sludge using various acid extraction approaches.
Heavy metals were removed from industrial sludge by traditional and microwave-assisted acid extraction approaches. The effects of acid concentration, extraction time, sludge particle size and solid/liquid (S/L) ratio on copper-extraction efficiency were assessed. Leaching with increased acid concentrations increased the yield of heavy metals from the industrial sludge. In microwave-assisted acid extraction, reducing the S/L ratio and sludge particle size increased copper-extraction efficiency. These experimental findings indicate that S/L ratio most strongly influenced microwave-assisted acid extraction. Both traditional and microwave-assisted acid extraction demonstrate that sulfuric acid was an effective extractant, and the copper fraction in extracted sludge shifted from being primarily bound to Fe-Mn oxides and organic-matter partition, to being mostly bound to organic matter, remaining as a residue during acid extraction.
Wu
C H
CH
Department of Environmental Engineering, Da-Yeh University, 112, Shan-Jiau Road, Da-Tsuen, Chang-Hua, Chinese Taiwan. chunghsinwu@yahoo.com.tw
Kuo
C Y
CY
Lo
S L
SL
D000143:Acids / Q000737:chemistry*; D007220:Industrial Waste; D019216:Metals, Heavy / Q000737:chemistry / Q000302:isolation & purification*; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*
D000143:Acids; D007220:Industrial Waste; D019216:Metals, Heavy; D012722:Sewage