title: Role of combinatorial environmental factors in the behavior and fate of ZnO nanoparticles in aqueous systems: a multiparametric analysis.
abstract: To better understand the environmental behavior, fate, and exposure risks of engineered nanoparticles in aquatic systems, for the first time, combinatorial aqueous systems were established using three-level orthogonal array design (OAD), an OA27 (3(1)(3)) matrix, to assess the effects of six co-varying environmental factors (organic acid type, organic acid concentration, NP concentration, pH, salt content, and electrolyte type) on the aggregation of commercial zinc oxide nanoparticles (ZnO NPs, mean diameter ∼41nm). A separate set of OA27 (3(1)(3)) experiments including temperature was conducted for the dissolution of these NPs. The results showed that the organic acid concentration and the pH were the most significant factors (p<0.001) influencing aggregation and dissolution of ZnO NPs, respectively. The electrolyte type and the salt content were the next most important factors in both the aggregation and dissolution. Based on the kinetics study of the aggregation, a high rate of the NP aggregation resulted in decreased dissolution, such that observed in the presence of calcium chloride. Clear temperature-induced aggregation and reduced dissolution were further observed with increasing temperature. This approach demonstrates that the behavior of ZnO NP may vary substantially under combinatorial environmental conditions.
authors: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
authors: Seyed Mohammad
authors: SM
authors: Majedi
authors: Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Singapore.
authors: Barry C
authors: BC
authors: Kelly
authors: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore; National University of Singapore Environmental Research Institute, T-Lab Building #02-01, 5A Engineering Drive 1, Singapore 117411, Singapore. Electronic address: chmleehk@nus.edu.sg.
authors: Hian Kee
authors: HK
authors: Lee
mesh_terms: D000704:Analysis of Variance; D053758:Nanoparticles / Q000737:chemistry*; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D014874:Water Pollutants, Chemical; D015034:Zinc Oxide
keywords: Aggregation; Chemometrics; Dissolution; Water chemistry; Zinc oxide nanoparticle