title: SEM analysis of particle size during conventional treatment of CMP process wastewater.
abstract: Engineered nanomaterials (ENMs) are currently employed by many industries and have different physical and chemical properties from their bulk counterparts that may confer different toxicity. Nanoparticles used or generated in semiconductor manufacturing have the potential to enter the municipal waste stream via wastewater and their ultimate fate in the ecosystem is currently unknown. This study investigates the fate of ENMs used in chemical mechanical planarization (CMP), a polishing process repeatedly utilized in semiconductor manufacturing. Wastewater sampling was conducted throughout the wastewater treatment (WWT) process at the fabrication plant's on-site wastewater treatment facility. The goal of this study was to assess whether the WWT processes resulted in size-dependent filtration of particles in the nanoscale regime by analyzing samples using scanning electron microscopy (SEM). Statistical analysis demonstrated no significant differences in particle size between sampling points, indicating low or no selectivity of WWT methods for nanoparticles based on size. All nanoparticles appeared to be of similar morphology (near-spherical), with a high variability in particle size. EDX verified nanoparticles composition of silicon- and/or aluminum-oxide. Nanoparticle sizing data compared between sampling points, including the final sampling point before discharge from the facility, suggested that nanoparticles could be released to the municipal waste stream from industrial sources.
authors.affiliation: State University of New York (SUNY) Polytechnic Institute, College of Nanoscale Science, Nanobioscience Constellation, 257 Fuller Road, Albany, NY 12203, United States.
authors.forename: Gary A
authors.initials: GA
authors.lastname: Roth
authors.affiliation: State University of New York (SUNY) Polytechnic Institute, College of Nanoscale Science, Nanobioscience Constellation, 257 Fuller Road, Albany, NY 12203, United States.
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Neu-Baker
authors.affiliation: State University of New York (SUNY) Polytechnic Institute, College of Nanoscale Science, Nanobioscience Constellation, 257 Fuller Road, Albany, NY 12203, United States. Electronic address: sbrenner@sunycnse.com.
authors.forename: Sara A
authors.initials: SA
authors.lastname: Brenner
mesh_terms: D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Chemical mechanical planarization; Nanoparticle; Scanning electron microscopy; Wastewater treatment