Electrocoagulation of silica nanoparticles in wafer polishing wastewater by a multichannel flow reactor: A kinetic study

Walter Den*, Ch-Hpin Huang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


A simplistic and systematic procedure has been developed for the design and upscaling of a multichannel, continuous-flow electrocoagulation reactor of monopolar configuration for the removal of submicron particles from wastewater. Using wastewater generated from the chemical-mechanical planarization process as the target wastewater, a series of laboratory-scale studies were conducted to determine the required operating conditions for the efficient removal of the ultrafine silica particles. These operating criteria included charge loading (≥8 F/m3), current density (ge;5.7 A/m2), hydraulic retention time (ge;60 min), as well as the initial pH (7-10). Furthermore, a steady-state transport equation with second-order reaction kinetics was employed to describe the rate of coagulation as the rate-limiting factor. The actual kinetic constant determined from the laboratory-scale experiments was approximately 1.2 × 10-21 m3/s, which was three orders of magnitude smaller than that calculated based on Brownian coagulation. The model was subsequently validated with a series of experiments using a pilot-scale electrocoagulation reactor geometrically similar to the laboratory-scale reactor with nearly 20 times volumetric scaleup.

Original languageEnglish
Pages (from-to)1651-1658
Number of pages8
JournalJournal of Environmental Engineering
Issue number12
StatePublished - Dec 2006


  • Channel flow
  • Coagulation
  • Colloids
  • Kinetics
  • Laminar flow
  • Silica
  • Wastewater management
  • Water treatment


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