標題: Electrocoagulation for removal of silica nano-particles from chemical-mechanical-planarization wastewater
作者: Den, W
Huang, CP
環境工程研究所
Institute of Environmental Engineering
關鍵字: electrocoagulation;electrochemical;parallel plate;monopolar;silica colloids;chemical-mechanical-planarization;CMP wastewater treatment
公開日期: 10-三月-2005
摘要: Continuous-flow electrocoagulation process with vertical flow-channels was investigated as a method to treat synthetic chemical-mechanical-planarization (CMP) wastewater containing highly charged ultrafine silica particles (zeta = -55 mV, mean R-p = 45 nm at pH 9.5). The parallel-plate, monopolar electrochemical cells resembled a series of closed electrical circuits such that the electrical field strength was highly dependent of the current density and aqueous conductivity, but independent of the inter-electrode gap. The residual turbidity of the CMP wastewater decreased with the increases in either hydraulic retention time or applied current density, and removal efficiency as high as 95% was achieved for wastewater with both low (70NTU) and high (400 NTU) initial turbidities. The charge loading linearly correlated with turbidity removal efficiency up to a level of 8 F m(-3), presenting an appropriate design parameter. Further analysis indicated that turbidity removal was limited by the quantity of liberated ferrous ions at lower range of current density, but seemingly reached a critical level of current density beyond which the process performance gradually deteriorated. Comparisons between the effective particle retention time and the estimated electrophoretic migration time revealed that the electrocoagulation process was predominantly controlled by the rate of particle aggregation occurring near the anodic surfaces. Furthermore, this process generates lesser amount of dry sludge as compared to chemical coagulation with polyaluminum chloride, and does not require pH adjustment prior to treatment. (C) 2004 Elsevier B.V.. All rights reserved.
URI: http://dx.doi.org/10.1016/j.colsurfa.2004.11.026
http://hdl.handle.net/11536/13909
ISSN: 0927-7757
DOI: 10.1016/j.colsurfa.2004.11.026
期刊: COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
Volume: 254
Issue: 1-3
起始頁: 81
結束頁: 89
顯示於類別:期刊論文


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  1. 000227030400012.pdf