[Mass transfer model of membrane extraction for recovery of cadmium ion and zinc ion].
By measuring the residence time distribution (RTD) curve of shell side and tube side of hollow fiber modules, it was found that the flow status in hollow fiber module with moderate or low packing density was complicated. For tube side, there were deviation between the experimental RTD curves and the theoretical laminar flow ones, which indicated that the flow status in tube side was between laminar flow and turbulent flow. For shell side, the experimental RTD curves agreed well with the laminar flow ones. The deviations as low as +/- 5% between the experimental average residence times and the theoretical ones suggested that there was no apparent non-ideal flow in the hollow fiber module with medium packing density. Based on the comparison between the experimental results and some typical correlations, a new velocity profile was purposed to describe the flow status in hollow fiber modules. According to the results of cadmium transport, the individual mass transfer coefficient correlations were developed. The zinc outlet concentrations predicted by the new correlations agreed relatively well with the experimental results, the relative deviation was among +/- 25%.
Wang
Yujun
Y
State Key Laborory of Solvent Extraction, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China. wangyj-d97@student.chemeng.tsinghua.edu.cn
Wang
Yan
Y
Luo
Guangsheng
G
Liu
Fei
F
Dai
Youyuan
Y
D002104:Cadmium / Q000302:isolation & purification*; D008567:Membranes, Artificial; D008962:Models, Theoretical; D014867:Water / Q000737:chemistry; D015032:Zinc / Q000302:isolation & purification*
D008567:Membranes, Artificial; D002104:Cadmium; D014867:Water; D015032:Zinc