title: Stability and Aggregation Kinetics of Titania Nanomaterials under Environmentally Realistic Conditions.
abstract: Nanoparticle morphology is expected to play a significant role in the stability, aggregation behavior, and ultimate fate of engineered nanomaterials in natural aquatic environments. The aggregation kinetics of ellipsoidal and spherical titanium dioxide (TiO2) nanoparticles (NPs) under different surfactant loadings, pH values, and ionic strengths were investigated in this study. The stability results revealed that alteration of surface charge was the stability determining factor. Among five different surfactants investigated, sodium citrate and Suwannee river fulvic acid (SRFA) were the most effective stabilizers. It was observed that both types of NPs were more stable in monovalent salts (NaCl and NaNO3) as compared with divalent salts (Ca(NO3)2 and CaCl2). The aggregation of spherical TiO2 NPs demonstrated a strong dependency on the ionic strength regardless of the presence of mono or divalent salts; while the ellipsoids exhibited a lower dependency on the ionic strength but was more stable. This work acts as a benchmark study toward understanding the ultimate fate of stabilized NPs in natural environments that are rich in Ca(CO3)2, NaNO3, NaCl, and CaCl2 along with natural organic matters.
authors.affiliation: School of Chemical and Process Engineering, University of Leeds , Leeds LS2 9JU, United Kingdom.
authors.forename: Ghulam
authors.initials: G
authors.lastname: Raza
authors.affiliation: School of Chemical and Process Engineering, University of Leeds , Leeds LS2 9JU, United Kingdom.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Amjad
authors.affiliation: School of Geography, Earth and Environmental Sciences, University of Birmingham , Birmingham B15 2TT, United Kingdom.
authors.forename: Inder
authors.initials: I
authors.lastname: Kaur
authors.affiliation: Center for Environmental Nanoscience and Risk, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina 29208, United States
authors.forename: Mohammed
authors.initials: M
authors.lastname: Baalousha
authors.affiliation: Center for Environmental Nanoscience and Risk, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina 29208, United States
authors.forename: Jamie
authors.initials: J
authors.lastname: Lead
authors.affiliation: School of Chemical and Process Engineering, University of Leeds , Leeds LS2 9JU, United Kingdom.|School of Aeronautic Science and Engineering, Beihang University , Beijing 100191, P. R. China.
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Wen
mesh_terms: D001578:Benzopyrans / Q000737:chemistry; D002951:Citrates / Q000737:chemistry; D007700:Kinetics; D053758:Nanoparticles / Q000737:chemistry*; D009994:Osmolar Concentration; D012492:Salts / Q000737:chemistry; D000077559:Sodium Citrate; D014025:Titanium / Q000737:chemistry*
chemical_list: D001578:Benzopyrans; D002951:Citrates; D012492:Salts; D000077559:Sodium Citrate; D014025:Titanium; C005023:fulvic acid